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IC 9134 
 
 Bureau of Mines Information Circular/1987 
 
 Mining Applications of Life Support 
 Technology 
 
 Proceedings: Bureau of Mines Technology Transfer 
 Seminar, Pittsburgh, PA, November 20, 1986 
 
 Compiled by Staff, Mining Research 
 
 UNITED STATES DEPARTMENT OF THE INTERIOR 
 
Information Circular 9134 
 
 Mining Applications of Life Support 
 Technology 
 
 Proceedings: Bureau of Mines Technology Transfer 
 Seminar, Pittsburgh, PA, November 20, 1986 
 
 Compiled by Staff, Mining Research 
 
 UNITED STATES DEPARTMENT OF THE INTERIOR 
 Donald Paul Hodel, Secretary 
 
 BUREAU OF MINES 
 Robert C. Horton, Director 
 
WV 
 
 
 >0 
 
 ) 
 
 Library of Congress Cataloging in Publication Data: 
 
 Bureau of Mines Technology Transfer Seminar (1986: Pittsburgh, Pa.) 
 Mining applications of life support technology. 
 
 (Information circular/United States Department of the Interior, Bureau of Mines; 9134) 
 
 Includes bibliographies. 
 
 Supt. of Docs, no.: I 28.27: 9134. 
 
 1. Mine rescue work - Congresses. I. United States. Bureau of Mines. II. Title. III. Series: 
 Information circular (United States. Bureau of Mines); 9134. 
 
 --TN95.-U4 
 
 [TN297] 
 
 622 s 
 
 [622'.8] 
 
 86-607916 
 
PREFACE 
 
 The papers contained in this Information Circular reflect the results 
 of a Bureau of Mines research effort to improve life support technology 
 used by the mining industry. The papers provide practical, up-to-date 
 information concerning the use of mine rescue breathing apparatus and 
 improved equipment for mine rescue teams. Such information can posi- 
 tively impact the mining community by enhancing mine workers' chances of 
 surviving an underground mine disaster. 
 
 The seven papers were presented at a technology transfer seminar on 
 mining applications of life support technology in November 1986. Tech- 
 nology transfer seminars represent a major portion of the Bureau's tech- 
 nology transfer program, which is designed to bring useful research re- 
 sults to industry's attention so that they can be adopted without delay. 
 Those desiring further information about developments resulting from 
 other Bureau research programs should contact the Bureau of Mines, 
 Branch of Technology Transfer, 2401 E St., NW, Washington, DC 20241. 
 
CONTENTS 
 
 Page 
 
 Preface i 
 
 Abstract 1 
 
 Introduction 2 
 
 Overview of life support escape breathing apparatus technology, by John G. 
 
 Kovac and Nicholas Kyriazi 3 
 
 Problems in donning self-contained self -rescuers , by Charles Vaught and 
 
 Henry P. Cole 26 
 
 Physiology of mine escape: Performance decrements due to resistance breathing 
 
 during three exercise protocols, by Kurt Saupe and Eliezer Kamon 35 
 
 Second-generation self-contained self -rescuers, by John G. Kovac 39 
 
 Development of a low-profile rescue breathing apparatus and a mine rescue team 
 
 helmet , by Nicholas Kyriazi 47 
 
 Training in the use of the self-contained self-rescuer, by Henry P. Cole and 
 
 Charles Vaught 51 
 
 Abstract of "Development of an automated breathing and metabolic simulator," 
 
 by Nicholas Kyriazi (Information Circular 9110) 57 
 

 
 UNIT OF MEASURE 
 
 ABBREVIATIONS 
 
 USED IN THIS 
 
 REPORT 
 
 °c 
 
 
 degree Celsius 
 
 lb 
 
 pound 
 
 cm 
 
 
 centimeter 
 
 
 m 
 
 meter 
 
 cu 
 
 in 
 
 cubic inch 
 
 
 mi/h 
 
 mile per hour 
 
 h 
 
 
 hour 
 
 
 min 
 
 minute 
 
 in 
 
 
 inch 
 
 
 mm 
 
 millimeter 
 
 kg 
 
 
 kilogram 
 
 
 ms 
 
 millisecond 
 
 L 
 
 
 liter 
 
 
 s 
 
 second 
 
 L/min 
 
 liter per minute 
 
 yr 
 
 year 
 
MINING APPLICATIONS OF LIFE SUPPORT TECHNOLOGY 
 
 Proceedings: Bureau of Mines Technology Transfer 
 Seminar, Pittsburgh, PA, November 20, 1986 
 
 Compiled by Staff, Mining Research 
 
 ABSTRACT 
 
 The Bureau of Mines has conducted considerable research to improve 
 life support technology for underground mining applications. This pro- 
 ceedings volume presents several new developments that may help increase 
 the chances of mine workers in surviving underground disasters. Several 
 papers address the performance of present self-contained self-rescuers 
 (SCSR's) and provide proposed guidelines for the design and testing of a 
 second-generation SCSR. Improvements in the safety and effectiveness of 
 mine rescue and recovery operations are described, including the design 
 of a low-profile rescue breathing apparatus and a rescue team helmet. 
 
INTRODUCTION 
 
 The Bureau of Mines life support re- 
 search program is directed toward re- 
 search into and development of breathing 
 apparatus technology that increases the 
 chances of miners surviving or being res- 
 cued after an underground mine disaster. 
 When a mine disaster occurs, the basic 
 survival technique for a miner is to es- 
 cape from the mine. Following a mine 
 fire or explosion, the atmosphere inside 
 the mine sometimes becomes oxygen defi- 
 cient or filled with toxic gases. Under 
 these circumstances, escape is nearly im- 
 possible unless a miner is equipped with 
 a self-rescue device that supplies oxygen 
 without the need for breathing mine air. 
 Federal regulations (30 CFR 75.1714) re- 
 quire that every person who goes into 
 an underground coal mine in the United 
 States must be supplied with a self-con- 
 tained self -rescuer (SCSR), a device 
 capable of providing at least 1 h of oxy- 
 gen regardless of ambient atmosphere. 
 Only SCSR's approved by the National In- 
 stitute for Occupational Safety and 
 Health (NIOSH) and the Mine Safety and 
 Health Administration (MSHA) can meet the 
 provisions of the regulations. All of 
 the 1-h-duration SCSR's are much larger 
 and heavier than the conventional filter 
 self -rescuer (FSR) which a miner wears on 
 his or her belt as personal protective 
 equipment. Unlike oxygen self -rescuers , 
 FSR's protect only against low levels of 
 carbon monoxide. Because of the size and 
 weight of the 1-h SCSR's, in most cases 
 the mining industry has elected to comply 
 with the SCSR regulations by deploying 
 the apparatus in a carry and store mode, 
 which involves transporting the SCSR's 
 into and out of the mine on a shift ba- 
 sis. The carry and store mode allows the 
 miner to store the SCSR within 5 min of 
 the work site, provided that he or she 
 
 continues to wear an FSR. The Bureau is 
 conducting research to develop a second- 
 generation, person-wearable SCSR (PWSCSR) 
 that is approximately twice the size and 
 weight of an FSR. A PWSCSR meeting these 
 requirements could be worn on a miner's 
 body, making it immediately available in 
 the event of an emergency. 
 
 A mine disaster may also result in the 
 entrapment of miners whose normal egress 
 from the mine is cut off. This often ne- 
 cessitates a rescue operation by a spe- 
 cially trained and equipped mine rescue 
 team sent into the mine from the surface. 
 Other Federal regulations (30 CFR 49) 
 specify that mine rescue teams must be 
 provided with rescue breathing apparatus 
 (RBA's) that have at least 2-h service 
 time and are approved for in-mine use. 
 The Bureau of Mines is pursuing the de- 
 velopment of smaller, lighter weight 
 RBA's appropriately designed for use in 
 the postdisaster environment, especially 
 for low-coal rescue and recovery mis- 
 sions. Another related technology in- 
 volves the development of a rescue team 
 helmet designed to integrate full head 
 and eye protection with communication, 
 illumination, and life support functions. 
 
 The papers presented in these proceed- 
 ings address some of the recent research 
 conducted by the Bureau of Mines that has 
 been directed toward the life support 
 problems outlined above. The topics cov- 
 ered range from basic research on the 
 respiratory physiology of mine escape to 
 new SCSR training programs. Any ques- 
 tions or comments pertaining to this re- 
 search are encouraged and appreciated. 
 
 Throughout the proceedings, mention of 
 trade names is made to facilitate under- 
 standing; this mention does not imply 
 endorsement by the Bureau of Mines. 
 
OVERVIEW OF LIFE SUPPORT ESCAPE BREATHING APPARATUS TECHNOLOGY 
 By John G. Kovac 1 and Nicholas Kyriazi 2 
 
 ABSTRACT 
 
 This paper provides an overview of life 
 support technology available today that 
 is designed to meet the requirements 
 of emergency escape following a mine 
 
 disaster. The basic kinds of escape 
 breathing apparatus are described, and 
 U.S. and foreign experience with this 
 technology is examined. 
 
 INTRODUCTION 
 
 When a mine disaster occurs, the basic 
 survival technique for a miner is to es- 
 cape from the mine. Following a mine 
 fire or explosion, the atmosphere inside 
 a mine may become oxygen deficient or 
 filled with toxic gases. Under these 
 circumstances, escape is impossible un- 
 less a miner is equipped with a self-con- 
 tained breathing apparatus. 
 
 The purpose of this paper is to review 
 the respirator technology available today 
 to meet the requirements of emergency es- 
 cape following a mine disaster. 
 
 This paper is organized into three sec- 
 tions. The first section defines the 
 self-contained self-rescuer (SCSR). The 
 next section describes the basic kinds of 
 SCSR technology. Both U.S. and foreign 
 experience with SCSR technology are exam- 
 ined in the third section. 
 
 DEFINITION OF SCSR 
 
 Federal regulations (30 CFR 75.1714) 
 require that every person who goes into 
 an underground coal mine in the United 
 States be supplied with an SCSR. An SCSR 
 is an emergency breathing apparatus de- 
 signed for the purpose of mine escape. 
 It must be capable of providing at least 
 a 60-min supply of oxygen (O2). Only 
 SCSR's approved by the Mine Safety and 
 Health Administration (MSHA) and the Na- 
 tional Institute for Occupational Safety 
 and Health (NIOSH) meet the provisions of 
 these regulations. 
 
 ^Supervisory mechanical engineer. 
 ^Biomedical engineer. 
 Pittsburgh Research Center, Bureau of 
 Mines, Pittsburgh, PA. 
 
 Other nations, including the Federal 
 Republic of Germany and the U.S.S.R., 
 have developed self-contained breathing 
 apparatus designed for mine escape. Al- 
 though some of these apparatus are not 
 approved for use in the United States be- 
 cause they do not satisfy performance or 
 duration requirements contained in Fed- 
 eral regulations for testing and certi- 
 fication of respirators (30 CFR 11), all 
 of these devices will be referred to as 
 SCSR's. 
 
 DESCRIPTION OF BASIC TECHNOLOGY 
 
 All of the apparatus described in this 
 report are one of two types: chemical- 
 oxygen or compressed-oxygen. Most of the 
 chemical-oxygen apparatus use potassium 
 superoxide (KO2), a solid chemical, for 
 both the oxygen source and the carbon 
 dioxide (CO2) absorbent. One of the 
 chemical-oxygen apparatus uses a sodium 
 chlorate (NaC103) candle for an oxygen 
 source and a separate chemical bed for 
 CO2 absorption. An engineering drawing 
 of a generic chemical-oxygen SCSR is 
 shown in figure 1. 
 
 Mouthpiece 
 
 -Breathing hose 
 
 Check valves 
 
 Relief valve' 
 FIGURE 1.— Chemical oxygen SCSR schematic. 
 
The compressed-oxygen apparatus use 
 bottled oxygen under high pressure for 
 the oxygen source with a separate chemi- 
 cal bed, either lithium hydroxide (LiOH) 
 or soda lime, both solid chemicals, for 
 C0 2 absorption. An engineering drawing 
 of a generic compressed-oxygen SCSR is 
 shown in figure 2. 
 
 U.S. AND FOREIGN EXPERIENCE 
 
 Worldwide experience in SCSR technology 
 can be broken down into three categories: 
 SCSR's approved by MSHA and NIOSH, Bureau 
 of Mines-developed prototypes, and for- 
 eign apparatus. All of the apparatus are 
 listed in table 1, with their rated ser- 
 vice lives, country of origin, oxygen 
 source, and size and weight. The sizes 
 and weights of the different appara- 
 tus are also shown in bar chart form in 
 figures 3 and 4. The PASS and the MSA 
 10/60 are not shown, the PASS because, it 
 is unusual and unrepresentative and the 
 10/60 because it has two parts. 
 
 Mouthpiece 
 
 'Breathing hose 
 
 Check valves 
 
 Cing bag ) 
 Aij ) 
 
 Relief valve"^ 
 
 Demand 
 Pressure ^ valve 
 reducer and 
 regulator 
 
 Pressure gauge 
 FIGURE 2.— Compressed oxygen SCSR schematic 
 
 MSHA-NIOSH-Approved SCSR's 
 
 CSE AU-9A1 
 
 The AU-9A1 (figs. 5-6) is a compressed- 
 oxygen self-rescuer with a throwaway 
 steel bottle but otherwise reusable 
 parts. It is field serviceable by 
 trained personnel only. It has a 
 
 TABLE 1. - Oxygen self -rescuers tested 
 
 Apparatus 
 
 Rated 
 
 duration. 
 
 min 
 
 Country 
 
 O2 source 
 
 Weight, lb 
 
 In use 
 
 In case 
 
 Volume, 
 in 3 ' 
 
 NIOSH-APPROVED 
 
 CSE AU-9A1 
 
 Draeger OXY-SR 60B 
 MSA 60-min SCSR... 
 Ocenco EBA 6.5.... 
 
 PASS 700 
 
 U.S.D. SCEBA-60... 
 
 60 
 60 
 60 
 60 
 60 
 60 
 
 United States 
 Germany (FRG) 
 United States 
 
 • • •uO» • ••••• • 
 
 ...do 
 
 .do. 
 
 Cylinder. 
 
 K0 2 
 
 K0 2 . 
 
 Cylinder. 
 ...do 
 
 ,do. 
 
 9.48 
 7.49 
 6.61 
 6.83 
 14.55 
 7.14 
 
 10.91 
 8.38 
 8.91 
 7.74 
 
 18.96 
 7.56 
 
 384 
 459 
 506 
 528 
 2,439 
 453 
 
 
 
 BUREAU PROTOTYPES 
 
 
 
 
 
 60 
 10 
 70 
 60 
 
 United States 
 
 ...QO. ....... 
 
 K0 2 
 
 4.41 
 
 1.81 
 
 10.43 
 
 3.85 
 
 4.65 
 
 2.73 
 
 NA 
 
 7.58 
 
 210 
 
 MSA 10-min PBA 1 . . . 
 
 K0 2 
 
 144 
 
 Westinghouse PBA.. 
 
 K0 2 
 
 NA 
 
 NaC10 3 candle 
 
 459 
 
 FOREIGN— NOT NIOSH-APPROVED 
 
 Auer SSR-90 
 
 AZG-40 
 
 Draeger OXY-SR 30. 
 Draeger OXY-SR 45. 
 Fenzy Spiral II... 
 WC-7 
 
 90 
 40 
 
 30 
 45 
 45 
 45 
 
 Germany (FRG) 
 
 China 
 
 Germany (FRG) 
 ...do 
 
 France 
 
 U*o*o»£\.« • • •• • 
 
 K0 2 
 
 K0 2 , 
 
 Cylinder. 
 ...do 
 
 K0 2 , 
 K0 2< 
 
 6.79 
 3.70 
 5.27 
 5.27 
 6.72 
 5.62 
 
 10.34 
 4.48 
 5.27 
 5.27 
 7.69 
 6.48 
 
 310 
 253 
 369 
 369 
 400 
 196 
 
 NA Not available. 
 
 NIOSH-approved prototype. 
 
Westinghouse PBA 
 
 MSA 10-min PBA 
 
 Lockheed PBA 
 
 WC-7 
 
 Fenzy Spiral II 
 
 Draeger OXY-SR 45 
 
 Draeger OXY-SR 30 
 
 AZG40 
 
 Auer SSR 90 
 
 U.S.D. SCEBA-60 
 
 Ocenco EBA 6.5 
 
 MSA 60-min SCSR 
 
 Draeger OXY-SR 60B 
 
 CSE AU-9A1 
 
 KEY 
 ^ NIOSH-MSHA-approved 
 CSS Foreign; not NIOSH-approved 
 ■I Bureau prototypes 
 
 100 
 
 200 300 400 
 
 VOLUME OF SCSR'S, cu in 
 
 500 
 
 600 
 
 FIGURE 3.— Size comparison bar chart. 
 
 4 5 6 7 
 
 WEIGHT OF SCSR'S, lb 
 FIGURE 4.— Weight comparison bar chart. 
 
bidirectional flow path, a constant O2 
 flow of at least 1.5 L/min, and a pres- 
 sure-activated demand valve and relief 
 valve. The cylinder contains 130 L 2 , 
 and the CO2 absorbent is LiOH. 
 
 Draeger OXY-SR 60B 
 
 The OXY-SR 60B (figs. 7-8) is a chem- 
 ical-oxygen self-rescuer which can be 
 returned to the distributor, National 
 Mine Service, for refurbishing. It has 
 a unidirectional flow path through the 
 KO2 bed and a pressure-activated relief 
 valve. A chlorate candle is provided for 
 an initial spurt of oxygen until the K0 2 
 bed is sufficiently activated by the 
 user's breath. The K0 2 is pelletized. 
 
 MSA 60-Min SCSR 
 
 The MSA SCSR (figs. 9-10) is a chem- 
 ical-oxygen self-rescuer that is entirely 
 throwaway. It has a unidirectional flow 
 path through the KO2 bed and a volume- 
 activated relief valve. A chlorate can- 
 dle is utilized for initial oxygen flow. 
 The KO2 is in granular form. 
 
 Ocenco EBA 6.5 
 
 The EBA 6.5 (figs. 11-12) is a com- 
 pressed-oxygen self-rescuer with a fiber- 
 glass-wrapped, reusable aluminum bottle. 
 The apparatus is ref urbishable only by 
 the manufacturer. It has a unidirec- 
 tional flow path with directional check 
 valves in the mouth bit assembly, a con- 
 stant flow of at least 1.5 L/min, and 
 pressure-activated demand and relief 
 valves. The cylinder contains 157 L O2, 
 and the CO2 absorbent is LiOH. 
 
 PASS 700 
 
 pressure-activated relief valve. The 
 cylinder contains 240 L O2, and the CO 2 
 absorbent is soda lime. This apparatus 
 is no longer being produced. 
 
 U.S.D. SCEBA-60 
 
 The SCEBA-60 (figs. 15-16) is a com- 
 pressed-oxygen system that has some re- 
 usable parts; it is not presently being 
 commercially produced because it became 
 available only after mine operators were 
 required to have placed orders for their 
 oxygen self -rescuers. It has a bidirec- 
 tional flow path, a constant flow rate of 
 oxygen of at least 1.5 L/min, and volume- 
 activated demand and relief valves. The 
 relief valve is triggered by bag volume 
 but dumps from the breathing hose air 
 that has not yet been scrubbed of CO 2 or 
 enriched with oxygen. The device is 
 available with a standard steel, throw- 
 away bottle or a lightweight, fiberglass- 
 wrapped aluminum, reusable bottle con- 
 taining 130 L O2. The CO2 absorbent is 
 LiOH. 
 
 Bureau of Mines-Developed Prototypes 
 
 Lockheed PBA (Personal 
 Breathing Apparatus) 
 
 The Lockheed PBA (figs. 17-18) is a 
 NIOSH-approved prototype. The apparatus 
 were manufactured in 1974 and stored in 
 warehouses until tested for this study. 
 These chemical-oxygen self-rescuers were 
 intended to be throwaway devices. The 
 flow path is unidirectional with check 
 valves in the mouth bit. It has a pres- 
 sure-activated relief valve and a chlo- 
 rate candle for initial oxygen flow. 
 
 MSA 10-Min PBA 
 
 The PASS (Portable Air Supply Systems) 
 self-rescuer (figs. 13-14) is a com- 
 pressed-oxygen system with an aluminum 
 bottle which is reusable after refur- 
 bishing by the manufacturer. It has a 
 unidirectional flow path through the 
 CO2 scrubber, an enclosed breathing bag, 
 no demand valve, a constant flow of 
 oxygen of at least 3 L/min, and a 
 
 These NIOSH-approved prototypes (figs. 
 19-20) were also manufactured in 1974 and 
 were similarly stored in warehouses until 
 being tested. The 10-min PBA is a one- 
 use, chemical-oxygen self -rescuer with 
 bidirectional flow, a chlorate candle, 
 and two breathing bags, one of which con- 
 tains a volume-activated relief valve. 
 
MSA 10/60 Oxygen Self -Rescuer 
 
 These NIOSH-approved prototypes (figs. 
 21-22) were built in 1979 and were stored 
 until being tested. The chemical-oxygen 
 10/60 was designed so that the 10-min ap- 
 paratus could be belt-worn with the 60- 
 min canister being stored. In an emer- 
 gency, the 10-min device is donned and 
 the user proceeds to the storage place of 
 the 60-min canisters, which are then at- 
 tached without the need to remove the 
 mouth bit. The oxygen source in both 
 portions is KO2 . Chlorate candles are 
 provided on both portions of the device; 
 the candle on the 60-min portion is auto- 
 matically activated when the device is 
 attached to the 10-min portion. The en- 
 tire apparatus is one-use only. The 10- 
 min apparatus has a bidirectional flow 
 path, but when the 60-min canister is at- 
 tached, the flow path is changed to uni- 
 directional flow. Figure 21 shows the 
 10-min apparatus in the case and de- 
 ployed, and the 60-min canister. The 60- 
 min canister does not have its own case 
 but is stored in a plastic bag. Figure 
 22 is a schematic of the combined appara- 
 tus, showing the flow scheme. 
 
 Westinghouse PBA 
 
 The Westinghouse PBA (figs. 23-24) is 
 the first Bureau prototype ever devel- 
 oped. The apparatus tested were manufac- 
 tured in 1971 and were not certified by 
 NIOSH. The flow path is bidirectional 
 with a two-chambered breathing bag, one 
 chamber for exhalation and one for inha- 
 lation, with a pressure-activated relief 
 valve on the inhalation side of the bag. 
 The oxygen source is a large, L-shaped, 
 NaC103 candle which provides at least 3 
 L/min of O2 flow continuously, regardless 
 of usage rate. The CO2 scrubber uses 
 LiOH. The original directive for this 
 contract included face protection, and 
 the design included a combination hood- 
 lens -noseclip-mouth-bit. Only three of 
 these prototypes remained for testing in 
 this study. 
 
 Foreign Apparatus 
 
 Auer SSR-90 
 
 The SSR-90 (figs. 25-26), manufactured 
 in the Federal Republic of Germany (FRG) 
 by Auer, a subsidiary of MSA, is a chem- 
 ical-oxygen self -rescuer which can be 
 user-reburbished. It has a unidirec- 
 tional flow path through the KO2 bed, a 
 volume-activated relief valve, and a 
 "quick starter" for initial oxygen flow. 
 
 AZG-40 
 
 The Chinese AZG-40 self -rescuer (figs. 
 27-28) uses KO2 and is not reusable. It 
 has a bidirectional flow path, a volume- 
 activated relief valve which vents from 
 the breathing hose, a heat exchanger, and 
 a quick-starting mechanism for initial 
 oxygen flow. 
 
 Draeger OXY-SR 30 
 
 The West German OXY-SR 30 (figs. 29-30) 
 is a compressed-oxygen self -rescuer which 
 is user reburbishable. It has a uni- 
 directional flow path through the soda 
 lime scrubber, a pressure-activated re- 
 lief valve, a volume-activated demand 
 valve, and a constant flow of oxygen of 
 at least 1.5 L/min. The steel cylinder 
 contains 64.5 L 02* 
 
 Draeger OXY-SR 45 
 
 The OXY-SR 45 (fig. 31) is nearly iden- 
 tical to the OXY-SR 30 with two differ- 
 ences: The constant flow rate is only 
 1.2 L/min, and the oxygen flow cannot be 
 turned off once it is activated. 
 
 Fenzy Spiral II 
 
 The French Spiral II (figs. 32-33) is 
 a chemical-oxygen self -rescuer which is 
 user serviceable. It has a unidirec- 
 tional flow path through the KO2 bed and 
 a pressure-activated relief valve. A 
 very small compressed-oxygen bottle is 
 
utilized for initial startup. The bottle 
 is yanked upward by pulling on a plastic 
 ball connected to the bottle; this breaks 
 a metal seal, rapidly releasing the con- 
 tents into the system. 
 
 WC-7 
 
 The Soviet WC-7 self-rescuer (figs. 34- 
 35) uses K0 2 as the oxygen source and is 
 throwaway. It has a bidirectional flow 
 path device with a volume-activated re- 
 lief valve. The starting device utilized 
 delivers 6 L 2 within 30 s. 
 
 PERFORMANCE COMPARISON 
 
 A performance study of oxygen self- 
 rescuers from the United States and other 
 countries was undertaken as an assessment 
 
 of present worldwide technology. The ap- 
 paratus were tested on a breathing and 
 metabolic simulator in the life support 
 laboratories of the Bureau of Mines. 
 Parameters monitored during the testing 
 were inhaled levels of C0 2 and 2 , in- 
 haled gas temperature, and breathing re- 
 sistance. The metabolic demand placed on 
 the apparatus represented the average 
 demand of the 50th-percentile miner per- 
 forming a 60-min Man-Test 4, as described 
 in 30 CFR 11H. 
 
 Results presented in tables 2 and 3 in- 
 clude apparatus duration, reasons for 
 terminating a test, and averages and 
 peaks of monitored parameters. Figures 
 36 and 37 are the comparison curves of 
 weight versus capacity and volume versus 
 capacity, respectively, for SCSR's that 
 are, or could have been, deployed in 
 
 TABLE 2. - Means of average values of monitored parameters 
 (Standard deviations in parentheses) 
 
 Apparatus 
 
 Dura- 
 tion, 
 min 
 
 Cause of 
 termination 
 
 2 , pet 
 
 C0 2 , pet 
 
 Resistance, 
 mm H2O 
 
 Exha- 
 lation 
 
 Inha- 
 lation 
 
 Temper- 
 ature, 
 °C 
 
 CSE AU-9A1 
 
 Draeger OXY-SR 
 
 60B. 
 MSA 60-min SCSR. . 
 
 Ocenco EBA 6.5. . . 
 PASS 700 
 
 U.S.D. SCEBA-60. . 
 
 Lockheed PBA 
 
 MSA 10-min PBA... 
 MSA 10/60: 
 
 10-min 
 
 60-min 
 
 Westinghpouse PBA 
 
 Auer SSR-90 
 
 AZG-40 
 
 Draeger OXY-SR 30 
 Draeger OXY-SR 45 
 
 Fenzy Spiral II. . 
 WC-7 
 
 73 (6) 
 
 72 (4) 
 
 83 (6) 
 
 110 (8) 
 
 86 (7) 
 
 79 (10) 
 
 34 (9) 
 
 14 (1) 
 
 9 (1) 
 
 73 (21) 
 60 (1) 
 82 (2) 
 38 (3) 
 47 (4) 
 55 (7) 
 
 34 (3) 
 
 67 (4) 
 
 High C0 2 
 
 Low bag volume 
 
 Low bag volume 
 
 or high C0 2 . 
 Low bag volume 
 
 • • • & O • • •• ••• •• 
 
 Low bag volume 
 or high C0 2 . 
 
 High CO 2 , low 
 bag volume, 
 or low 2 . 
 
 High C0 2 
 
 High C0 2 
 
 Low bag volume 
 
 • • • CO • •••••••• 
 
 Low bag volume 
 
 High C0 2 
 
 Low bag volume 
 Low bag volume 
 
 or high C0 2 . 
 Low bag volume 
 High C0 2 or 
 
 low bag 
 
 volume. 
 
 70 
 78 
 
 (13) 
 (3) 
 
 2.5 
 1.0 
 
 (0.1) 
 (.1) 
 
 82 (1) 
 
 74 (7) 
 81 (3) 
 71 (10) 
 
 60 (16) 
 
 44 (4) 
 
 1.0 (.2) 
 
 .7 
 1.1 
 2.2 
 
 (.2) 
 (.1) 
 (.4) 
 
 1.6 (.5) 
 
 1.8 (.2) 
 
 50 (8) 
 46 (6) 
 
 58 (6) 
 
 51 (5) 
 51 (4) 
 54 (7) 
 
 113 (30) 
 
 63 (8) 
 
 50 (4) 
 
 26 (6) 
 
 26 (3) 
 
 38 (3) 
 
 24 (3) 
 
 56 (2) 
 
 120 (46) 
 
 119 (5) 
 
 42 
 37 
 
 (1) 
 (2) 
 
 44 (2) 
 
 41 
 39 
 40 
 
 (1) 
 (1) 
 (1) 
 
 49 (10) 
 
 47 (3) 
 
 37 
 67 
 84 
 81 
 66 
 80 
 76 
 
 (10) 
 (ID 
 (1) 
 (5) 
 (5) 
 (3) 
 (7) 
 
 64 (4) 
 77 (4) 
 
 1.6 
 2.2 
 .6 
 .7 
 2.5 
 1.5 
 1.6 
 
 1.7 
 1.8 
 
 (.1) 
 (.6) 
 (.1) 
 (.1) 
 (.1) 
 (.2) 
 (.1) 
 
 (.7) 
 (.1) 
 
 74 
 83 
 
 121 
 57 
 
 116 
 45 
 42 
 
 (10) 
 (13) 
 (35) 
 (5) 
 (9) 
 (3) 
 (9) 
 
 56 (12) 
 63 (5) 
 
 79 
 60 
 31 
 35 
 101 
 19 
 18 
 
 22 
 59 
 
 (12) 
 (15) 
 (6) 
 (3) 
 (9) 
 (2) 
 (1) 
 
 (7) 
 (5) 
 
 38 
 42 
 40 
 40 
 50 
 41 
 41 
 
 (2) 
 (2) 
 (2) 
 (2) 
 (4) 
 (0) 
 (1) 
 
 36 (2) 
 56 (4) 
 
TABLE 3. - Means of peak values of monitored parameters 
 (Standard deviations in parentheses) 
 
 Apparatus 
 
 °2> pet 
 
 C0 2 , pet 
 
 Resistance, mm H2O 
 
 Exhalation 
 
 Inhalation 
 
 Tempera- 
 ture, °C 
 
 CSE AU-9A1 
 
 Draeger OXY-SR 60B 
 MSA 60-min SCSR. .. 
 Ocenco EBA 6.5. .. . 
 
 PASS 700 
 
 U.S.D. SCEBA-60. .. 
 
 Lockheed PBA 
 
 MSA 10-min PBA 
 
 MSA 10/60: 
 
 10-min 
 
 60-min 
 
 Westinghouse PBA.. 
 
 Auer SSR-90 
 
 AZG-40 
 
 Draeger OXY-SR 30. 
 Draeger OXY-SR 45. 
 Fenzy Spiral II... 
 WC-7 
 
 76 
 93 
 91 
 81 
 89 
 79 
 75 
 57 
 
 44 
 76 
 91 
 88 
 79 
 82 
 81 
 89 
 85 
 
 (10) 
 (2) 
 (2) 
 
 (12) 
 (4) 
 (6) 
 
 (13) 
 (5) 
 
 (10) 
 (12) 
 (1) 
 (4) 
 (2) 
 (3) 
 (8) 
 (1) 
 (5) 
 
 4.0 (0) 
 1.3 (0.1) 
 
 3.1 (1.2) 
 (.5) 
 (.4) 
 (.8) 
 
 (1.0) 
 (0) 
 
 1.8 
 1.5 
 2.9 
 3.4 
 4.0 
 
 4.0 
 3.0 
 .9 
 1.7 
 4.0 
 2.0 
 2.8 
 2.0 
 3.8 
 
 (0) 
 (.8) 
 (.2) 
 (.3) 
 
 (0) 
 (.4) 
 (.9) 
 (.7) 
 (.4) 
 
 56 
 83 
 69 
 54 
 53 
 59 
 148 
 82 
 
 114 
 
 117 
 
 136 
 
 66 
 
 160 
 
 52 
 
 48 
 
 80 
 
 75 
 
 (9) 
 
 (18) 
 
 (13) 
 
 (5) 
 
 (3) 
 
 (7) 
 
 (34) 
 
 (15) 
 
 (15) 
 (40) 
 (35) 
 
 (7) 
 (10) 
 
 (4) 
 
 (7) 
 (29) 
 
 (9) 
 
 55 
 
 45 
 40 
 41 
 27 
 65 
 157 
 221 
 
 137 
 80 
 61 
 48 
 
 153 
 21 
 21 
 42 
 78 
 
 (6) 
 
 (19) 
 
 (14) 
 
 (1) 
 
 (3) 
 
 (7) 
 
 (48) 
 
 (13) 
 
 (31) 
 
 (47) 
 
 (13) 
 
 (4) 
 
 (9) 
 
 (2) 
 
 (3) 
 
 (19) 
 
 (12) 
 
 44 
 44 
 53 
 43 
 42 
 42 
 64 
 53 
 
 (2) 
 (3) 
 (1) 
 (1) 
 (1) 
 (1) 
 (16) 
 (3) 
 
 45 (2) 
 
 47 (3) 
 44 (2) 
 
 48 (2) 
 60 (6) 
 44 (1) 
 44 (1) 
 43 (2) 
 69 (5) 
 
 large numbers in underground mines. Both 
 curves were generated by using standard 
 linear regression analysis on SCSR per- 
 formance comparison data. Because the 
 SCSR's were tested at a constant oxygen 
 
 consumption rate, capacity is defined as 
 the product of oxygen consumption rate 
 and duration. Capacity measures the 
 amount of oxygen an SCSR can provide for 
 escape purposes. 
 
 CONCLUSIONS 
 
 The comparison curves illustrate three 
 important points: (1) Size and weight 
 of SCSR's can be reduced by decreasing 
 the oxygen capacity; (2) more efficient 
 designs in terms of size and weight uti- 
 lization are possible using current tech- 
 nology; (3) at an average oxygen con- 
 sumption rate of 1.35 L/min, an 81-L 
 
 apparatus would have a duration of 60 
 min. Reducing the oxygen capacity to 81 
 L would result in an SCSR at least 20% 
 smaller than current apparatus, thus 
 opening up the possibility of developing 
 second-generation SCSR's, which could be 
 worn by a miner as personal equipment. 
 
10 
 
 FIGURE 5.— CSE AU-9A1 in case and deployed. 
 
 Demand valve 
 
 2 
 
 pressure gauge 
 
 2 
 cylinder 
 
 Breathing 
 bag 
 
 Nose 
 clip 
 
 Pressure-reducing 
 valve 
 
 Relief valve 
 
 Relief valve 
 chamber 
 
 Bypass 
 hose 
 
 KEY 
 i=zz> Inhale 
 ■■► Exhale 
 i=r>0 Oxygen 
 
 FIGURE 6.— CSE AU-9A1 schematic. 
 
11 
 
 FIGURE 7.— Draeger OXY-SR 60B in case and deployed. 
 
 Mouthpiece 
 Corrugated hose 
 
 Inhalation valve disks 
 Exhalation valve 
 
 Plug , mouthpiece 
 
 Upper valve chamber 
 Heat exchanger 
 
 Breathing bag 
 Hose clamp 
 
 K0 2 bed 
 
 KEY 
 C=£> Inhale 
 ^■^ Exhale 
 
 FIGURE 8.— Draeger OXY-SR 60B schematic. 
 
12 
 
 FIGURE 9.— MSA 60-Min SCSR in case and deployed. 
 
 Breathing hose 
 
 Mouthpiece 
 
 Breathing bag 
 
 Breathing bag 
 
 KEY 
 C=£> Inhale 
 ^■^ Exhale 
 
 Detail "A" 
 
 FIGURE 10.— MSA 60-MIN SCSR schematic. 
 
13 
 
 FIGURE 11.— Ocenco EBA 6.5 in case and deployed. 
 
 Goggles 
 
 Nose clip 
 
 Breathing 
 bag 
 
 Relief 
 valve 
 
 KEY 
 i > Inhale 
 — "^ Exhale 
 c=£C> Oxygen 
 
 Neck 
 harness 
 
 Mouthpiece 
 assembly with 
 check valves 
 
 Demand 
 valve 
 
 C0 2 -absorbent 
 canister 
 
 Waist 
 harness 
 
 FIGURE 12.— Ocenco EBA 6.5 schematic. 
 
14 
 
 FIGURE 13.— PASS 700 in case and deployed. 
 
 Mouthpiece 
 
 Breathing 
 hose 
 
 Start valve 
 
 KEY 
 i > Inhale 
 ■■^ Exhale 
 <=$£> Oxygen 
 
 FIGURE 14.— PASS 700 schematic. 
 
15 
 
 FIGURE 15.— USD SCEBA-60 in case and deployed. 
 
 Mouthpiece and 
 breathing hose 
 
 Constant- flow regulator 
 and demand — -^^,- 
 valve inside bag .^f 
 
 Outer case 
 
 KEY 
 
 > Inhale 
 
 Exhale 
 
 c=J>t> Oxygen 
 
 FIGURE 16.— USD SCEBA-60 schematic. 
 
16 
 
 FIGURE 17.— Lockheed PBA in case and deployed. 
 
 Mouthpiece with 
 check valves 
 
 N aC 1 3 candle 
 
 KO2 catcher 
 
 Baffles 
 
 Nose clip 
 
 Hoses 
 
 m ^— Return duct 
 
 Filters 
 
 KEY 
 :> Inhale 
 
 + Exhale 
 
 Relief valve 
 
 Breathing bag 
 
 FIGURE 18.— Lockheed PBA schematic. 
 
17 
 
 FIGURE 19.— MSA 10-Min PBA in case and deployed. 
 
 Breathing bag 
 
 Relief valve 
 
 Filtered K0 2 bed 
 
 Mouthpiece 
 
 Heat exchanger 
 
 KEY 
 <=> Inhale 
 
 ■"■+- Exhale 
 
 NaCI0 3 candle 
 
 Breathing bag 
 
 FIGURE 20.— MSA 10-Min PBA schematic. 
 
18 
 
 FIGURE 21.— MSA 10/60 oxygen self-rescuer in case and deployed, and 60-min canister. 
 
 »» Inhalation 
 
 Exhalation 
 
 FIGURE 22.— MSA 10/60 oxygen self-rescuer schematic. 
 
19 
 
 0^ 
 
 „#' 
 
 ** 
 
 »*•'■■ 
 
 FIGURE 23.— Westinghouse PBA in case and deployed. 
 
 Inhalation 
 check valve 
 
 Inhalation hose 
 
 Exhalation 
 check valve 
 
 Exhalation hose 
 
 KEY 
 
 i > Inhale 
 
 ^^^ Exhale 
 <=» Oxygen 
 
 FIGURE 24.— Westinghouse PBA schematic. 
 
20 
 
 FIGURE 25.— Auer SSR-90 in case and deployed. 
 
 Cover 
 
 Breathing hose 
 with mouthpiece 
 
 Heat exchanger 
 Breathing bag 
 
 Check-valve housing 
 Particle filter 
 
 Heat protection 
 K0 2 bed 
 
 Bottom part 
 of container 
 
 Locking device 
 
 Safety goggles 
 
 Nose clip 
 
 Relief valve 
 Neck strap 
 
 Corrugated hose 
 
 Breathing bag 
 connector 
 
 Waist strap 
 
 NaCIO, candle pull pin 
 
 Carrying strap 
 
 FIGURE 26.— Auer SSR-90 schematic. 
 
21 
 
 FIGURE 27.— AZG-40 in case and deployed. 
 
 Mouthpiece 
 
 Relief valve Valve _/_ 
 
 (see detail) 
 
 Rubber casing 
 
 Heat exchanger 
 
 Nose clip 
 
 Breathing 
 bag 
 
 K0 2 canister 
 
 FIGURE 28.— AZG-40 schematic. 
 
22 
 
 
 FIGURE 29.— Draeger OXY-SR 30 in case and deployed. 
 
 Nose clip 
 
 Breathing hose 
 with mouthpiece 
 
 Breathing bag 
 
 Constant-flow regulator 
 Demand valve 
 
 Nose clip 
 
 Pressure gauge 
 
 Relief valve 
 Check valve 
 
 Valve chamber 
 
 C0 2 absorbent 
 Central pipe 
 
 -Collecting chamber 
 FIGURE 30.— Draeger OXY-SR 30 schematic. 
 
 Breathing hose 
 with mouthpiece 
 
 Breathing bag 
 
 Constant- flow regulator 
 Demand valve 
 
 Relief valve 
 Check valve 
 
 Valve chamber 
 
 C0 2 absorbent 
 Central pipe 
 
 -Collecting chamber 
 FIGURE 31.— Draeger OXY-SR 45 schematic. 
 
23 
 
 FIGURE 32.— Fenzy Spiral II in case and deployed. 
 
 Mouthpiece 
 
 Relief valve 
 
 Full-depth plenum 
 
 FIGURE 33.— Fenzy Spiral II schematic. 
 
24 
 
 '-> 
 
 FIGURE 34.— WC-7 in case and deployed. 
 
 Mouthpiece 
 
 Breathing hose 
 
 NaCI0 3 candle 
 
 KEY 
 Inhale 
 Exhale 
 
 Nose clip 
 
 Relief valve 
 
 Breathing bag 
 
 Outer case 
 
 FIGURE 35.— WC-7 schematic. 
 
o 
 
 10 
 
 =9 6 
 
 4 - 
 
 25 
 
 .-* ■ 
 
 50 
 
 100 
 
 150 
 
 2 CAPACITY, L 
 
 FIGURE 36.— Weight versus capacity comparison curve of self-contained self-rescuers 
 generated from data compiled by the Bureau of Mines. 
 
 600 r 
 
 500 
 
 400 
 
 3 
 O 
 
 O 300 
 
 > 
 
 200 
 
 100 
 
 /■ 
 
 50 
 
 100 
 
 150 
 
 2 CAPACITY, L 
 
 FIGURE 37.— Volume versus capacity comparison curve of self-contained self-rescuers 
 generated from data compiled by the Bureau of Mines. 
 
26 
 
 PROBLEMS IN DONNING SELF-CONTAINED SELF-RESCUERS 
 By Charles Vaught 1 and Henry P. Cole 2 
 
 ABSTRACT 
 
 In 1986 University of Kentucky and Bu- 
 reau of Mines researchers participated in 
 a series of related SCSR donning studies. 
 To establish a baseline for their inves- 
 tigations, they interviewed more than 50 
 mine safety instructors, rescue team mem- 
 bers, and inspectors. The interviews 
 support a widely held notion that very 
 few underground coal miners ever actually 
 don an SCSR in training. Rather, the 
 typical training session will include a 
 film, a slide-tape presentation, or a 
 talk by an instructor who stands before 
 the class and demonstrates the steps 
 involved. 
 
 Given the industry's heavy reliance on 
 abstract training methods, the research 
 staff reviewed all generally available 
 literature for the four models in common 
 use (CSE, Draeger, MSA, and Ocenco). 
 
 They targeted three main concerns with 
 current training materials: (1) The rec- 
 ommended donning position appears diffi- 
 cult and inefficient and is impossible 
 for miners working in low coal, (2) the 
 donning sequence tends to place nones- 
 sential and time-consuming tasks such 
 as strap adjustment ahead of some of the 
 steps necessary to isolate one's lungs 
 from the surrounding atmosphere, and 
 (3) the materials present no simplified, 
 easy-to-remember procedural rules to help 
 miners order the complex array of tasks 
 needed to use the device in an emergency. 
 An innovative training package was 
 developed and field-tested. The data in- 
 dicate that the new approach has great 
 promise for improved SCSR donning 
 efficiency. 
 
 INTRODUCTION 
 
 During 1986 researchers and technical 
 staff from the University of Kentucky, 
 the Bureau of Mines, the Mine Safety and 
 Health Administration, the Kentucky De- 
 partment of Mines and Minerals, and two 
 coal companies conducted a series of re- 
 lated SCSR donning studies. Prior to 
 this research there had been little sys- 
 tematic investigation of miners' ability 
 to put the devices into use, although 
 there had been many evaluations of SCSR 
 durability, reliability, and duration of 
 oxygen supply under various levels of 
 physical exertion. 
 
 One exception found in the literature 
 is the report of a field evaluation of 
 the Draeger OXY-SR 60B and the MSA Model 
 464213. 3 Donning times for 46 miners 
 were recorded and shown to range from 30 
 
 'Research sociologist, Pittsburgh Re- 
 search Center, Bureau of Mines, Pitts- 
 burgh, PA. 
 
 ^Educational pychologist, University of 
 Kentucky, Lexington, KY. 
 
 to 192 s. The average time for all sub- 
 jects was 90 s. This report, although 
 informative, does not indicate the fre- 
 quency and types of donning errors, times 
 for completion of part tasks, or whether 
 the individuals were given assistance 
 during their performance trials. 
 
 INITIAL AREAS OF CONCERN 
 
 To establish a baseline for the pres- 
 ent studies, project researchers reviewed 
 all available training materials dealing 
 with the care and donning of the four 
 SCSR models in common use (CSE, Draeger, 
 
 ^Peluso, R. G. Results from the Field 
 Evaluation of Self-Contained Self-Res- 
 cuers. Paper in Proceedings of the 12th 
 Annual Institute on Coal Mining Safety 
 and Research, ed. by M. Karmis, M. H. 
 Suthrland, J. L. Patrick, and J. R. Lu- 
 cas. VA Polytech. Inst, and State Univ., 
 Dep. Min. and Miner. Eng. , Blacksburg, 
 VA, 1981, pp. 125-131. 
 
27 
 
 Ocenco, and MSA). They also interviewed 
 more than 50 mine safety instructors, 
 rescue team members, and inspectors. 
 These individuals were asked to describe 
 the performance capabilities of under- 
 ground coal miners in using the devices. 
 The preliminary inquiries suggested sev- 
 eral actual or potential problem areas 
 both in approaches to training and in ac- 
 tual performance. The most significant 
 of these are discussed in the following 
 sections. 
 
 Logical Problems With Existing 
 Training Materials 
 
 The research staff targeted three main 
 concerns with current training materials 
 for donning SCSR's. First, the recom- 
 mended donning position appears difficult 
 and inefficient. It is impossible for 
 miners working in low coal. Second, the 
 donning sequence tends to place nonessen- 
 tial and time-consuming tasks such as 
 strap adjustment ahead of some of the 
 steps necessary to isolate one's lungs 
 from the ambient atmosphere. Third, the 
 materials present no simplified, easy-to- 
 remember procedural rules that will help 
 miners order the complex array of tasks 
 needed to use the device in an emergency. 
 
 Generally, the available materials show 
 an individual donning the SCSR while 
 standing in a well-lighted room. The 
 demonstrator first inspects the seals and 
 pressure gauge and then performs those 
 tasks necessary to allow him to work with 
 the device while standing. Only then 
 does he or she complete the steps needed 
 to isolate the lungs from the surrounding 
 atmosphere; the final critical task (put- 
 ting on the nose clips, for instance) may 
 be slotted as late as 10th in a sequence 
 of 14 or more steps. Furthermore, in the 
 materials it is not clear what is to be 
 done with the cap and cap lamp. Some 
 illustrations depict the cap without a 
 lamp. Some show the demonstrator hanging 
 the lamp cord around the neck, letting 
 the cap and lamp dangle down the side. 
 Still others seem to indicate that the 
 individual removes and replaces the cap 
 as he or she does steps that require the 
 cap to be off. 
 
 In sum, these materials seem to advocate 
 a training approach that is decidedly 
 less than optimum for real-life condi- 
 tions. An actual emergency might well 
 entail a miner kneeling in a smoky entry 
 in low coal where the only illumination 
 would be that provided by his or her cap 
 lamp. In such a predicament the SCSR 
 would have to be donned quickly; it would 
 have to be put on while working in an 
 awkward position; and the lamp would 
 need to be placed so that its beam could 
 shine directly on the device. If one can 
 imagine this situation, the value of a 
 straightforward, easily remembered don- 
 ning procedure and thorough hands-on 
 training becomes readily apparent. 
 
 Lack of Hands-on Training 
 
 The interviews support a widely held 
 notion that a majority of underground 
 coal miners never actually don an SCSR. 
 The typical training session will include 
 a film, slide-tape presentation, or a 
 talk by an instructor who stands before 
 the training class and demonstrates the 
 steps involved. Summary statistics for a 
 series of mine trainer workshops con- 
 ducted by Cole 4 revealed that the modal 
 prior donning experience for individuals 
 in most workshops was zero. This indi- 
 cates there are a number of instructors 
 teaching miners how to don the SCSR who 
 have never themselves had one on. 
 
 The widespread lack of hands-on exper- 
 ience is a serious matter. There is a 
 myriad of research to support the common- 
 sense notion that lecture and demonstra- 
 tion do not constitute an effective means 
 of teaching motor tasks. In the inter- 
 views, dollar costs were most frequently 
 cited as the reason there is not more 
 practice with the devices. The cost of 
 using real SCSR's for the training of 
 miners is approximately $400 to $600 per 
 unit. Training models cost about the 
 same. Thus, training facilities that 
 
 4 See "Training in the Use of the Self- 
 Contained Self-Rescuer," by H. P. Cole 
 and C. Vaught, later in these 
 proceedings. 
 
28 
 
 have an SCSR for demonstration purposes 
 rarely provide more than one. 
 
 A second factor often mentioned by the 
 interviewees is the time required to 
 train each individual on the apparatus. 
 The session itself, with corrective in- 
 structions and practice, requires from 5 
 to 10 min per person. Sanitizing the 
 mouthpiece and repacking the SCSR for the 
 next trainee is reported to take an addi- 
 tional 5 to 10 min. With large groups of 
 miners and limited time for training, 
 these time requirements are seen as 
 prohibitive. 
 
 Observed Motor Performance Errors 
 
 Six of the individuals interviewed had 
 observed miners putting on one or more of 
 four SCSR models and were able to provide 
 impressionistic data about types of per- 
 formance errors most commonly committed. 
 In all cases reported, the units were 
 being donned to carry out equipment re- 
 liability and duration studies, or for 
 training purposes. The informants were 
 asked to list the kinds of errors they 
 witnessed and to comment on the ability 
 of miners to put the devices into 
 operation. 
 
 One mine safety instructor had recently 
 carried out a hands-on exercise with the 
 Ocenco EBA 6.5. The training was done 
 with a total of 96 workers. These indi- 
 viduals were divided into groups of ap- 
 proximately 18 subjects. Each group was 
 taken underground and given a 10-min dem- 
 monstration of the function, care, and 
 use of the unit. Immediately following 
 the demonstration the miners were se- 
 lected nine at a time and placed near an 
 overcast. Each person was given an SCSR. 
 At a signal from the trainer all nine be- 
 gan to don the devices. The instructor 
 observed and prompted the trainees during 
 the process. 
 
 This informant agreed to rank observed 
 errors according to frequency, but cau- 
 tioned that mistakes he noticed with the 
 first subjects were pointed out to miners 
 in later groups before they could make 
 the error. The trainer summarized his 
 impressions as follows: (1) Most of the 
 miners had the SCSR's on in approximately 
 
 1 min, but some required prompting for 
 specific steps, (2) the most common error 
 was failure to put on the nose clips — 
 made by about one-fourth of the subjects, 
 (3) approximately one person in each 
 group of nine failed to put on the gog- 
 gles, (4) slightly less than one person 
 in each trial group had difficulty with 
 the oxygen valve, (5) a few individuals 
 put the neck strap over the lamp cord — 
 this necessitated removing the SCSR and 
 then the cap in order to put on the head 
 strap, and (6) 2 out of the 96 had the 
 bite lugs gripped in their incisors and 
 the mouthpiece seal on the outside of the 
 lips. 
 
 The other informants who had witnessed 
 miners putting on SCSR's were less sys- 
 tematic in their recollections. However, 
 they tended to agree that the most common 
 problems were kinked air hoses, failure 
 to put on nose clips, and omission of the 
 goggles. It was also noted that trainees 
 often did not follow the recommended se- 
 quence when donning the equipment. 
 
 None of these observations were based 
 upon planned studies of performance. 
 Therefore, little can be inferred about 
 the optimal sequence of steps, the par- 
 ticular parts of the task most prone to 
 error, or the effect of training. Yet 
 this type of information is useful in de- 
 veloping a more systematic approach to 
 donning the SCSR. It can reveal some- 
 thing about the parts of the task that 
 are retained well and those that are not 
 so well retained. It can be useful in 
 designing controlled human performance 
 studies such as the one conducted during 
 the present research. 
 
 THE FIRST CONTROLLED DONNING ASSESSMENT 
 
 A coal company in eastern Kentucky par- 
 ticipated in the initial study and fur- 
 nished working models of the SCSR (the 
 CSE AU-9A1) in use at its mines. The 
 company trainers assisted in the design 
 of the experiment, which is shown in ta- 
 ble 1. Performance was observed under 
 three trial conditions: (1) The baseline 
 group (N=14) had no previous hands-on 
 training with an SCSR, had never parti- 
 cipated in a demonstration of an SCSR, 
 
29 
 
 and had not received written or oral 
 instructions about the device; (2) the 
 control group (N=20) had hands-on train- 
 ing with the CSE 4 yr previously and 
 at least one demonstration of the same 
 model annually, the most recent having 
 taken place 7 months prior to the study; 
 (3) the treatment group (N=16) was iden- 
 tical to the control group in terms of 
 previous experience except that they col- 
 lectively received a donning demonstra- 
 tion immediately preceding their perfor- 
 mance trial. 
 
 The tasks were administered individ- 
 ually in a specially arranged training 
 room. Each person, wearing a miner's 
 cap, belt, lamp, and filter self-rescuer 
 (FSR), was brought into the room and 
 asked to stand behind a line near the 
 front wall. The SCSR was placed one 
 case-length in front of the line with its 
 bottom latch pointed toward the subject 
 and the neck strap adjusted all the way 
 out. The individual was given a standard 
 set of instructions which stated the pur- 
 pose of the study and requested him or 
 her to put the SCSR on as if there were a 
 fire. At a signal from the researchers 
 the person began to don the unit. A 
 video camera mounted on a tripod at the 
 back of the room recorded the entire se- 
 quence. When the individual was fin- 
 ished, he or she took one step forward 
 and raised the right arm. After the 
 trial the person was shown the videotape, 
 and all donning errors were corrected. 
 
 The purpose of the study was to compare 
 the SCSR donning performance of the three 
 groups. Differences in donning speed, 
 proficiency, and errors could be related 
 to no training (baseline group) ; initial 
 hands-on training and annual demon- 
 strations (control group); and initial 
 
 TABLE 1. - Treatment groups and 
 conditions 
 
 Group 
 
 Base- 
 
 Control 
 
 Treat- 
 
 
 line 
 
 
 ment 
 
 
 14 
 
 20 
 
 16 
 
 Underground miner. . 
 
 No 
 
 Yes 
 
 Yes 
 
 Hands-on training. . 
 
 No 
 
 Yes 
 
 Yes 
 
 Demonstration: 
 
 
 
 
 7 months prior... 
 
 No 
 
 Yes 
 
 Yes 
 
 Immediately prior 
 
 No 
 
 No 
 
 Yes 
 
 hands-on training, annual demonstrations, 
 and a recent demonstration (treatment 
 group). 
 
 It was assumed that the treatment re- 
 fresher given by the company trainer 
 would be based on the manufacturer's rec- 
 ommended sequence, as had all his earlier 
 training. During the week in which the 
 experiment was conducted, however, the 
 trainer started to doubt the efficacy of 
 the donning procedure he had been teach- 
 ing. After consulting with a fellow in- 
 structor, he began to develop a simpli- 
 fied method designed to allow the miner 
 to kneel and to isolate her or his lungs 
 before completing secondary tasks. When 
 It was time to give his demonstration to 
 the treatment group, the trainer kneeled 
 and performed the task using the new se- 
 quence. The procedure was not presented 
 to the miners either visually or orally, 
 because at that time it had not been for- 
 malized. This change in the training of 
 the treatment group confounded the exper- 
 iment. Observed differences in donning 
 sequence, proficiency, and times could be 
 caused both by recency of training and by 
 change in approach. Nevertheless, much 
 was learned from the study. Selected 
 findings are discussed below. 
 
 Completion of Critical Tasks 
 
 There are three tasks that a miner must 
 perform correctly in order to survive 
 in a toxic atmosphere: (1) activate the 
 oxygen, (2) insert the mouthpiece, and 
 (3) put on the nose clips. This does 
 not, of course, ensure that the SCSR is 
 secured in a manner that will allow 
 enough maneuverability for him or her to 
 get out of a mine. Completion of the 
 critical tasks should be regarded as an 
 absolute minimum, therefore, not as a 
 criterion for self-rescue and escape. 
 
 The individuals in the experiments were 
 allowed all the time they wanted to com- 
 plete the donning trial. The performance 
 was stopped only when a person signaled 
 that he or she was finished. Generally, 
 the subjects believed that they had been 
 able to isolate their lungs from the sur- 
 rounding atmosphere and were prepared to 
 travel through heavy smoke. As table 2 
 
30 
 
 indicates, however, a majority of people 
 in all three groups would probably have 
 perished in an actual mine fire or explo- 
 sion. This might be expected with naive 
 individuals such as those in the base- 
 line group, but those in the control and 
 treatment groups were atypical in that 
 they, unlike most miners, had had hands- 
 on SCSR training and systematic annual 
 demonstrations. 
 
 Inspection of table 2 shows that only 1 
 of the 14 subjects in the untrained group 
 would have had a chance of surviving and 
 he required approximately 95 s to com- 
 plete the three critical steps. An im- 
 portant conclusion to be drawn from the 
 performance of the baseline group is that 
 the sequencing of steps necessary to don 
 the apparatus proficiently is not well- 
 cued by the equipment or by previously 
 completed steps. Tasks that are not ade- 
 quately cued are those most likely to be 
 forgotten. -* 
 
 Only 9 (56.25%) of the 16 miners in the 
 treatment group were successful in doing 
 the critical tasks. As can be seen in 
 table 2, they tended to finish this part 
 of the donning sequence more quickly than 
 
 -Mlagman, J. D., and A. M. Rose. Reten- 
 tion of Military Tasks: A Review. Human 
 Factors, v. 25, No. 2, 1983, pp. 199- 
 21 3. 
 
 TABLE 2. - Number of persons completing 
 the critical steps within specific 
 time frames 
 
 Time frame, s 
 
 Base- 
 line, 
 14 
 
 0-19 
 
 20-39 
 
 40-59 
 
 60-79 
 
 80-99 
 
 100-119 
 
 120-139 
 
 140-159 
 
 160-179 
 
 180-199 
 
 Total completing 
 
 Group and number 
 attempting 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 Control, 
 20 
 
 13 
 
 Treat- 
 ment, 
 16 
 
 those in the control group. The shorter 
 times required by these individuals are 
 related to two factors which cannot 
 be unconfounded. First, miners in the 
 treatment group received a refresher 
 demonstration only 2 to 4 h prior to 
 their trial. Some of the increased speed 
 with which they performed is probably due 
 to this experience. Second, however, the 
 procedure was changed by the instructor. 
 Treatment group members were shown a new 
 position (kneeling) and a new donning 
 method that had them attempt the critical 
 steps early in the sequence. The more 
 rapid completion of these tasks by this 
 group is due primarily to the second 
 factor. 
 
 There is another element that has a 
 bearing on the percentage of subjects in 
 the treatment group who were able to com- 
 plete the critical tasks. In the demon- 
 stration they were instructed to open the 
 case on the floor, do the critical steps, 
 slip the neck strap under and around the 
 unit, and then don it. As was mentioned 
 previously, in the experiment the SCSR 
 was placed with the bottom latch toward 
 the subject. Eight (50%) of the miners 
 in the treatment group opened the case 
 from the wrong end and proceeded to per- 
 form the critical tasks. When it was 
 time to slip the neck strap under and put 
 it on, they found they had the device 
 turned backward. Several of them became 
 confused and in trying to correct the er- 
 ror omitted one or another of the criti- 
 cal steps. 
 
 Given all the time they needed, 13 
 (65%) of the 20 individuals in the con- 
 trol group were successful in isolating 
 their lungs. If they had had to do so 
 within 1 rain, however, only five (25%) 
 would have survived. Members of this 
 group were trained in the approved man- 
 ner. In this procedure, adjusting the 
 neck strap precedes and delays completion 
 of the three critical tasks. Likewise, 
 working in a standing position also makes 
 it more difficult to open the case and 
 complete the donning sequence. Many of 
 the miners in the control group quickly 
 gave up or did not attempt to don the 
 head strap, adjust the neck strap, or tie 
 the waist straps. Rather, a typical 
 
31 
 
 response was to lift the SCSR up in one 
 arm (usually crushing the breathing bag) 
 and carry the unit with straps unadjusted 
 and untied. Indeed, review of the video- 
 tapes reveals that the individuals in the 
 control group were even less prepared for 
 escape than were those in the treatment 
 group. 
 
 Completion of Secondary Tasks 
 
 Some idea of the effect of the recent 
 demonstration on performance can be got- 
 ten by inspecting table 3, which gives 
 the percentage of each group completing 
 each task. The miners in the treatment 
 group were conscientious about attempting 
 secondary tasks such as donning the head 
 strap, putting on their goggles, adjust- 
 ing the neck strap, and tying the waist 
 straps. On average, the members of this 
 group finished significantly more steps 
 than those in the control group but spent 
 no less time on the total trial (table 
 4). All in all, however, it must be con- 
 cluded that both groups of trained miners 
 generally lacked proficiency. They often 
 made errors and interrupted tasks. Both 
 groups required relatively long times to 
 complete the secondary donning steps, as 
 
 TABLE 3. - Percent of each group 
 completing each task 
 
 TABLE 4. - Mean times and standard 
 deviations for persons completing 
 critical and secondary donning 
 steps, seconds 
 
 
 Group and number 
 attempting 
 
 
 Base- 
 line, 
 14 
 
 Control, 
 20 
 
 Treat- 
 ment, 
 16 
 
 
 100 
 50 
 86 
 
 100 
 36 
 93 
 21 
 57 
 64 
 71 
 71 
 50 
 7 
 
 
 100 
 95 
 75 
 
 100 
 85 
 95 
 75 
 80 
 60 
 65 
 
 100 
 65 
 25 
 20 
 
 100 
 88 
 
 Air hose extended.. 
 Mouth plug pulled. . 
 Mouthpiece inserted 
 
 88 
 100 
 
 88 
 100 
 
 69 
 
 81 
 100 
 
 Breathing bag open. 
 
 100 
 
 100 
 
 94 
 
 Neck strap adjusted 
 Waist strap tied... 
 
 100 
 100 
 
 
 Control 
 group 
 
 Treat- 
 ment 
 group 
 
 Critical steps: 
 
 84.5 
 44.8 
 
 130.4 
 73.4 
 
 13 
 
 44.9 
 
 Standard deviation.... 
 Secondary steps: 
 
 14.6 
 127.4 
 
 Standard deviation.... 
 Total persons completing 
 
 45.9 
 9 
 
 table 4 indicates. Most importantly, a 
 sizable number probably could not have 
 escaped a fire or explosion. 
 
 SUBSEQUENT DONNING ASSESSMENTS 
 
 Insights gained from the first con- 
 trolled assessment led the researchers to 
 formalize a more logical donning position 
 and a simplified procedure. Using this 
 method, the miner in an emergency would 
 take the SCSR from its storage box, 
 kneel, and place the unit on the mine 
 floor directly in front of his or her 
 knees. He or she would then lay the hat 
 on the mine floor so that the lamp could 
 shine directly on the SCSR. After loop- 
 ing the neck strap loosely over the head, 
 the miner would bring his or her face 
 close to the unit and work with both 
 hands to complete the following "chunked" 
 sequence of steps: (1) activate the oxy- 
 gen, (2) insert the mouthpiece, and 
 (3) put on the nose clip. Doing these 
 three things on the front end would rap- 
 idly isolate her or his lungs from a 
 toxic mine atmosphere. The next tasks 
 would be to (4) put on her or his gog- 
 gles, (5) adjust both the neck and waist 
 straps to place the SCSR close to chin 
 and chest, and (6) replace the cap and 
 move out. 
 
 This new approach is a generalized se- 
 quence which assumes the individual steps 
 for implementing a particular model of 
 SCSR have been demonstrated to and (ide- 
 ally) practiced by miners in hands-on 
 
32 
 
 training. What people forget is not how 
 to do the discrete tasks. Rather, they 
 tend to omit steps, or attempt them out 
 of sequence. If miners were to be given 
 a performance trial shortly after being 
 trained in a 12- or 14-step donning pro- 
 cedure, they could be expected to jump 
 around from task to task, to begin but 
 not complete a step before starting on 
 another, and to forget some steps entire- 
 ly. In fact, the experimental data from 
 the first donning assessment showed this 
 to occur frequently. 
 
 It is much easier to remember to do 
 tasks in their proper sequence if the en- 
 tire process is placed in a simple, logi- 
 cal framework that organizes them all. 
 The approach developed in this research 
 serves that purpose. If a miner can re- 
 member the general steps given above, 
 each one cues the recall of the tasks 
 that are part of that step. addition, 
 the simplified procedure helps the indi- 
 vidual to order the overall sequence of 
 donning tasks so that critical steps are 
 done early and secondary ones later. 
 
 This donning method has been field- 
 tested with approximately 16 groups of 
 coal industry people in 3 States. Each 
 group was given an explanation of the new 
 donning position and the simplified se- 
 quence. The advantages of the procedure 
 were explained, and then demonstrated by 
 showing a 2-min videotape. The individ- 
 uals next began actual donning trials. 
 While one miner was putting an SCSR on, 
 instructors and other group members were 
 working in pairs to record the perfor- 
 mance on a simple evaluation form." The 
 finished form provided a record of each 
 person's donning sequence, time to com- 
 pletion of critical tasks, total time, 
 and any errors made. 
 
 Table 5 provides summary data from 12 
 of these groups — 5 for the Draeger, 4 for 
 the Ocenco, 2 for the CSE, and 1 for the 
 MSA. It is important to note that the 
 
 6 See "Training in the Use of the Self- 
 Contained Self-Rescuer," by H. P. Cole 
 and C. Vaught, later in these 
 proceedings. 
 
 TABLE 5. - Summary of data collected from SCSR donning workshops 
 
 
 
 
 
 
 
 
 
 Prior 
 
 Perfect 
 
 SCSR type 
 
 Test 
 date 
 
 Critical time, s 
 
 Secondary time, s 
 
 donni 
 
 ng 
 
 donning 
 
 and site 
 
 N 
 
 Mean 
 
 SD 
 
 N 
 
 Mean 
 
 SD 
 
 Mode 2 
 
 No. 3 
 
 sequence, 
 
 
 
 
 
 
 
 
 
 
 
 % of total 
 
 Draeger: 
 
 
 
 
 
 
 
 
 
 
 
 E. Kentucky. . . . 
 
 1/22 
 
 7 
 
 17.00 
 
 5.77 
 
 7 
 
 55.00 
 
 20.78 
 
 NAp 
 
 NAp 
 
 28.57 
 
 
 1/28 
 
 27 
 
 23.89 
 
 10.61 
 
 27 
 
 64.70 
 
 29.08 
 
 3 
 
 12 
 
 62.96 
 
 
 1/29 
 
 15 
 
 20.47 
 
 4.93 
 
 15 
 
 52.20 
 
 19.18 
 
 
 
 11 
 
 53.33 
 
 W. Kentucky.... 
 
 3/18 
 
 16 
 
 16.25 
 
 4.97 
 
 17 
 
 41.12 
 
 17.09 
 
 
 
 6 
 
 22.22 
 
 
 3/19 
 
 17 
 
 17.53 
 
 6.71 
 
 18 
 
 59.17 
 
 19.45 
 
 
 
 11 
 
 38.89 
 
 Ocenco: 
 
 
 
 
 
 
 
 
 
 
 
 E. Kentucky.... 
 
 1/22 
 
 11 
 
 26.27 
 
 5.87 
 
 11 
 
 79.45 
 
 26.16 
 
 NAp 
 
 NAp 
 
 63.64 
 
 
 1/29 
 
 11 
 
 33.73 
 
 10.00 
 
 11 
 
 82.45 
 
 24.11 
 
 
 
 9 
 
 45.45 
 
 W. Kentucky. . . . 
 
 3/18 
 
 16 
 
 26.44 
 
 5.66 
 
 15 
 
 69.06 
 
 25.42 
 
 0,1 
 
 3,3 
 
 4 11.76 
 
 
 3/19 
 
 17 
 
 38.64 
 
 11.10 
 
 19 
 
 84.32 
 
 19.08 
 
 
 
 16 
 
 47.37 
 
 CSE: E. Kentucky 
 
 1/22 
 
 9 
 
 21.67 
 
 4.77 
 
 9 
 
 68.88 
 
 17.95 
 
 NAp 
 
 NAp 
 
 66.67 
 
 
 1/29 
 
 16 
 
 24.94 
 
 11.39 
 
 16 
 
 62.44 
 
 20.91 
 
 
 
 9 
 
 64.71 
 
 MSA: E. Kentucky 
 
 1/29 
 
 10 
 
 17.90 
 
 5.15 
 
 10 
 
 51.50 
 
 14.35 
 
 
 
 8 
 
 50.00 
 
 NAp Not applicable. 
 Mode = most frequent 
 more than once. 
 
 3 No. = number of peopl 
 
 Of the 17 trainees, 
 
 this deviates from the p 
 
 Experience with this model, 
 occurring value in a set where different 
 
 values may occur 
 
 e who gave the modal response for their group. 
 
 9 adjusted the straps before donning their goggles. 
 
 erfect sequence, it is not a critical error. 
 
 Although 
 
33 
 
 TABLE 6. - Mean times and standard deviations for 
 critical and secondary donning tasks by type 
 of SCSR 1 , seconds 
 
 
 Draeger 
 
 Ocenco 
 
 CSE 
 
 MSA 
 
 Critical tasks: 
 
 20.47 
 4.93 
 
 52.20 
 19.18 
 
 33.73 
 10.00 
 
 82.45 
 24.11 
 
 24.94 
 11.39 
 
 62.44 
 20.91 
 
 17.90 
 
 Standard deviation 
 Secondary steps: 
 
 5.15 
 51.50 
 
 Standard deviation 
 
 14.35 
 
 ' TT/-V.- /-. 1 .-. ,7. ^ /-> «-. s*nnAii~t-n. 
 
 A 1 /OQ/RA 
 
 
 
 
 data represent the first hands-on SCSR 
 experience for most of these people. 
 Therefore, the performance results must 
 be related to instructional procedures 
 rather than to practice with the units. 
 Some of the more intriguing findings are 
 discussed in the following sections. 
 
 Completion of Critical Tasks 
 
 Inspection of the mean donning times 
 for critical tasks suggest that the sim- 
 plified procedure results in more rapid 
 completion. In addition, an examination 
 of the evaluation forms revealed that the 
 performance also tended to be smoother 
 than the trials of the subjects in the 
 initial study. There were fewer task 
 interruptions, and most steps were done 
 in the proper sequence. Very few errors 
 were made in completing the three criti- 
 cal steps. 
 
 Table 6 shows the means and standard 
 deviations of the critical task comple- 
 tion (part) times recorded for the CSE 
 group whose trial occurred on January 29, 
 1986. Comparison of these values with 
 those in table 4 reveals that the new 
 
 approach has great promise in improving 
 SCSR donning efficiency. Even the mean 
 time (44.9 s) for completion of critical 
 steps required by miners in the initial 
 treatment group far exceeded the average 
 of those in the CSE group of January 29, 
 1986. Since both of these groups had had 
 the new position and simplified sequence 
 demonstrated to them, these large differ- 
 ences are undoubtedly due to the improved 
 and more explicit instruction developed 
 after the first experiment. 
 
 Completion of Secondary Tasks 
 
 Using the same two groups to compare 
 overall proficiency is also encouraging. 
 Their difference in mean total donning 
 time (127.4 versus 62.4 s) is even great- 
 er than their difference in average time 
 needed to do the three critical tasks. 
 In addition, as can be seen in table 5, 
 the percentage of those who turned in a 
 perfect trial with the CSE's on January 
 29, 1986 (64.71%) is higher than the per- 
 centage of initial treatment group mem- 
 bers who were able to meet the absolute 
 minimum for survival (56.25%). 
 
 DISCUSSION 
 
 The complexity of existing instruc- 
 tional approaches, combined with the 
 infrequency of hands-on training, con- 
 tributes significantly to miners' diffi- 
 culties in getting the SCSR on flawlessly 
 and rapidly. The research reported in 
 this paper suggests a more efficient don- 
 ning procedure. The data contained in 
 table 5, especially the percentages of 
 each group having a perfect sequence on 
 
 the first trial, are encouraging. Much 
 remains to be done, however. 
 
 Two important issues have not been 
 addressed in these or earlier studies. 
 First, it is not known how well or how 
 long miners retain their skills in don- 
 ning SCSR's. The optimum training neces- 
 sary to achieve and maintain high levels 
 of proficiency needs to be empirically 
 determined. Then, recommendations to the 
 
34 
 
 industry can be made based on an under- 
 standing of what constitutes an effec- 
 tive and valid approach. Second, the 
 present research has identified donning 
 tasks that are time-consuming, are diffi- 
 cult to perform, and/or result in fre- 
 quent errors. This information can as- 
 sist in the improvement of SCSR designs. 
 
 Well-controlled human performance studies 
 of equipment design changes can reveal 
 which modifications optimize miners' don- 
 ning capabilities. Continued investi- 
 gation of problems in implementing the 
 self-contained self-rescuer may well help 
 to prevent future tragedies. 
 
35 
 
 PHYSIOLOGY OF MINE ESCAPE: PERFORMANCE DECREMENTS 
 DUE TO RESISTANCE BREATHING DURING THREE EXERCISE PROTOCOLS 
 
 By Kurt Saupe 1 and Eliezer Kamon 2 
 
 ABSTRACT 
 
 In the event of a mine fire or ex- 
 plosion, an irrespirable atmosphere is 
 formed and self-contained breathing 
 apparatus are necessary to support life. 
 An ideal breathing apparatus would simu- 
 late ambient air in every way; however, 
 this has not been achieved in any type of 
 portable apparatus. Apparatus that are 
 used for escape are best when light in 
 weight and small in size. Small size and 
 light weight, however, usually result 
 in apparatus that are physiologically 
 stressful in other ways. The most common 
 stressors of concern are levels of CO2 
 and O2 , temperature, and breathing resis- 
 tance. From research being conducted at 
 
 the Noll Laboratory for Human Performance 
 Research, it has been found that breath- 
 ing resistance can significantly affect 
 performance in a number of areas. One 
 significant finding is that a given level 
 of breathing resistance may negatively 
 affect escape speed if the speed is high 
 and yet not affect escape at a lower es- 
 cape speed. Three exercise protocols 
 were performed to study effects on maxi- 
 mum attainable oxygen consumption rate 
 and, thus, escape speed. It was found 
 that the higher the exercise intensity, 
 the greater the negative effect of a 
 given breathing resistance. 
 
 INTRODUCTION 
 
 To fulfill all the potential needs of a 
 worker, a respirator should not limit the 
 worker's performance under a wide range 
 of conditions. Some of these conditions 
 include low-intensity steady-state exer- 
 cise, short-duration high-intensity exer- 
 cise, and gradually increasing work to 
 ventilatory exhaustion. These three con- 
 ditions place different demands on respi- 
 rators. Resistance is the stressor that 
 seems to have the greatest effect on the 
 standard measures of performance, such as 
 maximum attainable speed of travel. This 
 is probably due to the lower attainable 
 ventilation rate, and consequently, lower 
 attainable oxygen consumption rate, so 
 that the worker is forced to slow down. 
 Conclusions about the amount of resis- 
 tance that can be tolerated before a per- 
 formance limitation is seen may well be 
 
 ' Graduate student. 
 
 2 Prof essor . 
 Penn State University, Noll Laboratory 
 for Human Performance Research, Univer- 
 sity Park, PA. 
 
 different depending upon the intensity of 
 exercise used to evaluate the resistance. 
 The purpose of this investigation was 
 to quantify the performance decrements 
 caused by resistance breathing during a 
 simulated coal mine escape. Since there 
 is no one protocol that adequately simu- 
 lates all the possible scenarios that 
 might be encountered during an emergency 
 mine escape, three different escape pro- 
 tocols were examined. These three proto- 
 cols were chosen both to represent a wide 
 range of demands on the respirator and to 
 give insight into the physiological mech- 
 anisms responsible for the performance 
 decrements. The three protocols used 
 were — 
 
 1. A 2-mile run for time at a maximum 
 (variable) self-paced speed. 
 
 2. A progressive exercise test to 
 exhaustion. 
 
 3. An hour-long walk at the maximal 
 speed-grade combination (fixed) that 
 could be maintained for the hour. 
 
36 
 
 EXPERIMENTAL DESIGN AND TEST METHODS 
 
 SUBJECTS 
 
 Male subjects were recruited from the 
 Perm State University area. Subjects 
 were either undergraduates, graduate stu- 
 dents, or staff of Penn State. Different 
 subjects were used for each of the three 
 protocols with some subjects taking part 
 in both the hour walk and progressive 
 exercise tests. Subject characteristics 
 are listed in table 1. 
 
 METHODS 
 
 The physiological variables of heart 
 rate, ventilation rate (VE), fraction of 
 expired O2 (FEO2), fraction of expired 
 CO2 (FEC0 2 ), and pressure at the mouth 
 were continuously measured and recorded 
 on-line via a PDP-11 (or PDP-8) computer 
 and in-house software. From these vari- 
 ables, rate of O2 consumption (VO2), rate 
 of CO2 production (VCO2), respiratory 
 quotient (R), and VE/VO2 were continuous- 
 ly calculated. 
 
 The inspired and expired resistances 
 were caused by inserting a small-diam- 
 eter, 5-cm-long tubing segment in both 
 the inspired and expired sides of the 
 data collection system. The resistance 
 of the system without these restrictive 
 segments was 1.5 cm H2O at 120 L/min. 
 
 PROCEDURES 
 
 Maximal aerobic capacity was measured 
 using a separate progressively graded 
 
 test to exhaustion, 
 preliminary medical 
 
 treadmill exercise 
 as part of a 
 examination. 
 
 The short-term exercise called for 2.5% 
 increases in the grade of the treadmill 
 every 4 min. The data over the last 
 minute of exercise at each grade were 
 used to represent the steady state value 
 for that exercise intensity. 
 
 The prolonged exercise was performed 
 at the maximum speed and grade that could 
 be maintained for 1 h by the subject. 
 One hour of exercise was first performed 
 without resistance to breathing; the ex- 
 ercise was repeated next with a randomly 
 selected resistance to breathing. If 1 h 
 of exercise could not be accomplished, 
 the subject returned on another occasion 
 to attempt the same resistance at an ex- 
 ercise intensity obtained by a reduction 
 in the grade of the treadmill. This was 
 repeated until the hour of exercise was 
 completed, and that exercise intensity 
 was considered the highest sustainable 
 for the given resistance. 
 
 The 2-mile runs for time were performed 
 so that subjects had a visual display 
 of how far they had run. Subjects were 
 able to control their speed by giving a 
 thumbs-up or thumbs-down to an investiga- 
 tor who was sitting at the treadmill con- 
 trol panel. Four, all-out 2-mile runs 
 were initially done by each subject with 
 no resistance to establish a reliable 
 baseline. When these runs were com- 
 pleted, subjects ran a low-resistance 
 (10 cm H 2 at 120 L/min) and a high- 
 resistance (34 cm H2O at 120 L/min) all- 
 out 2-mile run in a randomly assigned or- 
 der. These self-paced, all-out runs were 
 performed a week apart to minimize any 
 training effect. 
 
 TABLE 1. - Mean subject characteristics 
 (Standard deviation in parentheses) 
 
 Exercise protocol 
 
 N 
 
 Age, 
 yr 
 
 Height, 
 cm 
 
 Weight, 
 kg 
 
 VO2 max, 
 L/min 
 
 Short-term progressive 
 
 5 
 7 
 5 
 
 26 (2) 
 26 (4) 
 24 (3) 
 
 177 (8) 
 
 178 (7) 
 178 (4) 
 
 72 (9) 
 75 (10) 
 
 73 (9) 
 
 3.95 (0.77) 
 3.77 (.56) 
 
 
 4.20 (.60) 
 
37 
 
 RESULTS 
 
 The problem of how to best quantify the 
 resistance-induced performance decrements 
 so that they could be compared across all 
 three protocols was addressed by express- 
 ing the V0 2 that could be maintained dur- 
 ing a resistance trial as a percentage of 
 the V0 2 that could be maintained during a 
 no-resistance control trial. If, for ex- 
 ample, a subject could maintain a V0 2 of 
 4 L/min during a no-resistance 2-mile run 
 and a V0 2 of 3 L/min during a 2-mile run 
 
 with a resistance of 34 cm H 2 at 120 
 L/min, the performance decrement would be 
 expressed by stating that he or she could 
 maintain a V0 2 of 75% of the control val- 
 ue with the 34-cm H 2 at 120-L/min resis- 
 tance. These data suggest that as the 
 task performed by the subject becomes 
 increasingly difficult (higher percentage 
 of V0 2 max), the performance decrement 
 that one sees with a given resistance 
 becomes greater. Figure 1 shows the 
 
 100 
 
 
 m 
 o 
 
 o 
 ■> 
 
 _J 
 
 o 
 
 on 
 
 O 
 
 o 
 o 
 
 KEY 
 
 H 2-mile run 
 
 |~l 1-hour walk 
 
 Progressive exercise 
 
 20 30 40 50 
 
 RESISTANCE, cm water at 120 L/min 
 
 FIGURE 1.— Percent of control V0 2 obtained versus breathing resistance for three exercise intensities. 
 
 60 
 
38 
 
 percentage of a control trial VO2 that 
 could be maintained over a range of re- 
 sistances for the three protocols. The 
 somewhat nebulous term "maximal maintain- 
 able VO2" was defined differently for 
 each of the three protocols. For the 
 progressive exercise test, this terra was 
 
 defined as the VO2 at the highest obtain- 
 able exercise intensity. For the hour- 
 long walks it was defined as the mean 
 V0 2 between minutes 15 and 45. For the 
 2-mile runs it was defined as the mean 
 V0 2 from minute 5 to the end of the 2 
 miles. 
 
 DISCUSSION 
 
 These data illustrate a principle that 
 is often overlooked when one looks at 
 the level of breathing resistance allow- 
 able in a specific breathing apparatus. 
 This principle can best be illustrated 
 by imagining what would happen to an in- 
 dividual whose only source of air was 
 through a soda straw. The individual 
 would be able to perform tasks such as 
 reading and writing with no noticeable 
 performance decrement. If the individual 
 
 were asked to perform tasks of increased 
 physical demand, he or she would find 
 that the more strenuous the task (in 
 terras of VO2 required), the more he or 
 she was encumbered or restricted. 
 
 Any standard or specification defin- 
 ing the maximum allowable resistance to 
 breathing of a respirator should be spe- 
 cific to the intensity of physical activ- 
 ity that the users of this respirator are 
 expected to maintain. 
 
 CONCLUSIONS 
 
 Breathing resistance levels that sig- 
 nificantly impair performance at a maxi- 
 mal work intensity may not impair per- 
 formance at a lesser work intensity. 
 Breathing apparatus that are designed to 
 be used at low or medium work intensi- 
 ties, therefore, might be permitted to 
 have higher breathing resistance levels 
 than apparatus that are expected to be 
 used at high work intensities. 
 
 The present limit on exhalation breath- 
 ing resistance is 5.1 cm H2O at 120 L/min 
 flow; the limit for inhalation resistance 
 is 10 cm minus this value, or 4.9 cm. If 
 one is willing to accept a 5% decrease in 
 maximal maintainable VO2 during a 1-h, 
 maximal-effort escape, from the evidence 
 presented in the figure, there is no rea- 
 son why it should not be permitted to al- 
 low three times the presently permitted 
 exhalation resistance. The 2-mile run, 
 taking substantially less time, suffers a 
 greater decrease in maximum attainable 
 VO2 of approximately 13%. 
 
 Because human subjects can tolerate 
 high stressors for a short period of 
 time, it is currently a popular belief 
 that short-duration apparatus, such as 
 those for escape, can be permitted to 
 stress the subject more than longer dura- 
 tion apparatus, such as those used for 
 rescue. This philosophy may not apply 
 well to breathing resistance, however. 
 If performance is not to be limited, 
 breathing resistance limits may actually 
 need to be lower for escape than for res- 
 cue apparatus. In other words, an escape 
 apparatus, if expected to be used at 
 a high work intensity, should have low 
 breathing resistance so as not to nega- 
 tively impact performance. A breathing 
 resistance of 8 cm H2O has been proposed 
 for both inhalation and exhalation resis- 
 tances for the belt-wearable oxygen self- 
 rescuer being pursued by the Bureau of 
 Mines and MSHA. 
 
39 
 
 SECOND-GENERATION SELF-CONTAINED SELF-RESCUERS 
 By John G. Kovac 1 
 
 ABSTRACT 
 
 It appears to be technologically fea- 
 sible to develop a second-generation 
 SCSR that is approximately twice the size 
 and weight of an FSR and that has a 
 rated duration of 1 h. This paper summa- 
 rizes proposed performance criteria, test 
 
 methods, and approval and certification 
 procedures for second-generation SCSR's. 
 If designed and developed to meet the 
 proposed standards, the resulting SCSR 
 would be safe and reliable, and could be 
 worn by a miner as personal equipment. 
 
 INTRODUCTION 
 
 Federal mining regulations (30 CFR 
 75.1714) require that every person who 
 goes into an underground coal mine in the 
 United States must be supplied with a 
 self-contained self-rescuer (SCSR). An 
 SCSR is an emergency breathing apparatus 
 designed for use during mine escape. It 
 must be capable of providing a breathable 
 atmosphere, regardless of the ambient en- 
 vironment, and it must have a rated dura- 
 tion of 1 h. Only SCSR's approved by the 
 Mine Safety and Health Administration 
 (MSHA) and the National Institute for Oc- 
 cupational Safety and Health (NIOSH) can 
 meet the provisions of the regulations. 
 
 Four models of MSHA- and NIOSH-ap- 
 proved, 1-h-duration SCSR's are commer- 
 cially available: CSE AU-9A1, Draeger 
 OXY-SR 60B, MSA 60-min SCSR, and Ocenco 
 EBA 6.5. In order to meet the 1-h-dura- 
 tion requirement, all of the SCSR's are 
 closed-circuit breathing apparatus. Both 
 the Draeger OXY-SR 60B and the MSA 60-min 
 SCSR use potassium superoxide (KO2), a 
 solid chemical, to generate O2 and remove 
 C0 2 . The CSE AU-9A1 and the Ocenco EBA 
 6.5 store O2 as a compressed gas and use 
 lithium hydroxide (LiOH) to absorb CO2. 
 All of the 1-h-duration SCSR's are much 
 larger and heavier than the conventional 
 filter self-rescuer (FSR), which a miner 
 wears on his belt as personal protective 
 equipment. Unlike SCSR's, FSR's protect 
 only against low levels of CO. 
 
 'Supervisory mechanical engineer, 
 Pittsburgh Research Center, Bureau of 
 Mines, Pittsburgh, PA. 
 
 Because of the large size and weight of 
 the current 1-h SCSR's, miners and mine 
 operators have elected to either store or 
 carry and store SCSR's in daily oper- 
 ational use rather than wear SCSR's as 
 personal protective equipment. 
 
 It appears to be technologically feasi- 
 ble to develop a second-generation SCSR 
 that is approximately twice the size and 
 weight as an FSR, and that has a rated 
 duration of 1 h, if testing and certi- 
 fication criteria are changed. Such an 
 apparatus has been designated as a per- 
 son-wearable self-contained self-rescuer 
 (PWSCSR). A PWSCSR meeting these re- 
 quirements could be worn on a miner's 
 belt and replace the FSR. The mining in- 
 dustry, mine workers, breathing apparatus 
 manufacturers, and MSHA are interested in 
 an emergency breathing apparatus of this 
 kind. 
 
 However, much work remains to be accom- 
 plished before prototype technology can 
 be expected to function in a reliable 
 manner. Additional research and develop- 
 ment must be done to guarantee that the 
 devices will provide safe and appropriate 
 levels of life support capability and 
 will be sufficiently rugged and mine- 
 worthy to serve as a replacement for 
 FSR's. Practical deployment options, as 
 well as miner training in the use of 
 PWSCSR's must also be investigated. 
 
 The purpose of this paper is to summa- 
 rize proposed criteria and test proce- 
 dures for PWSCSR's that would provide 
 safe performance, be rugged for under- 
 ground use, and be within desirable 
 
40 
 
 physical limitations. The proposed test- 
 ing and certification criteria for 
 PWSCSR's are presented in the appendix. 
 
 The information presented in this paper 
 is based on the technical recommendations 
 of the Person-Wearable SCSR Task Force, 
 which was an interagency task force com- 
 posed of representatives from MSHA, the 
 Bureau, and NIOSH. The task force used a 
 variety of sources in formulating its 
 recommendations, including current re- 
 search findings, conversations with res- 
 pirator manufacturers and other technical 
 specialists, and discussions with repre- 
 sentatives of miners and mine operators. 
 
 DEFINITION OF ESCAPE-ONLY DEVICE 
 
 There are emergencies in which the need 
 for an escape breathing apparatus is im- 
 mediate. In these situations, an indi- 
 vidual who has an apparatus on his or her 
 person is more likely to survive than an 
 individual who has an apparatus located 
 a distance away. Whether an individual 
 wears an escape breathing apparatus or 
 not depends to a large degree upon the 
 physical requirements of the job and the 
 size of the escape apparatus. 
 
 An escape-only device is designed to 
 supply, in an emergency, an atmosphere 
 that will permit the user to escape to a 
 safe environment. The ideal escape-only 
 device is one that is worn by the indi- 
 vidual at the job, is rugged so that it 
 will survive its environemnt and perform 
 its function, and is safe for its in- 
 tended use. 
 
 PWSCSR's are escape-only devices in- 
 tended for use in underground coal mine 
 emergencies. 
 
 NEW PERFORMANCE CRITERIA 
 
 The proposed performance criteria focus 
 mainly on defining safe, physiologically 
 defensible stressor levels for PWSCSR's. 
 Four physiologically important variables 
 are considered: carbon dioxide (CO2) 
 concentration, oxygen (O2) concentration, 
 breathing resistance, and inhaled gas 
 temperature. 
 
 CO 2 Level 
 
 The present requirement for a 1-h es- 
 cape apparatus is no more than 1.5% CO2 
 in inspired air, during the course of 
 person-testing when sampling breathing 
 gases. Breathing gases are sampled dur- 
 ing rest intervals, so gas concentrations 
 are monitored intermittently. 
 
 The proposed requirement for CO 2 
 stressor levels is to raise the 1.5% CO2 
 maximum inhaled concentration to 3.0% for 
 a 1-h escape apparatus, while monitoring 
 continuously. The new stressor level is 
 to be determined by time-averaging the 
 inhaled CO2 levels over the entire dura- 
 tion of the apparatus. When testing 
 presently approved 1-h-duration SCSR's, 
 it was observed that some apparatus ex- 
 hibited inhaled CO2 levels exceeding 4% 
 during certain exercise levels and near 
 the end of life. This testing utilized 
 continuous monitoring, unlike that pres- 
 ently conducted at NIOSH. Therefore, in 
 addition to a 3% inhaled CO2 average lev- 
 el for a 1-h apparatus, a termination 
 peak concentration of 8% CO2 for a single 
 breath and a 1-min average concentration 
 of 6% CO2 are added for safety. 
 
 Oxygen Level 
 
 The oxygen concentration has been in- 
 creased from 19.5% to 20.9% after the 
 first 3 min. In addition, a 17% minimum 
 O2 concentration is required for the 
 first 3 min. The reason for these two 
 requirements is to eliminate the need for 
 a self-starter. All presently approved 
 1-h apparatus exceed 21% O2. 
 
 Breathing Resistance 
 
 The present standard measures breath- 
 ing resistance utilizing a breathing 
 machine as specified in 30 CFR 11.85-3. 
 The maximum resistance for exhalation is 
 51 mm H2O or less, and the maximum for 
 inhalation is 100 mm H2O minus the exha- 
 lation resistance. 
 
41 
 
 The new proposal allows for a maximum 
 of 80 mm H2O for both inhalation and ex- 
 halation resistance when measured during 
 the time-duration test. During the high- 
 demand test, the allowable resistance 
 levels are 300 mm H2O for inhalation and 
 200 mm H2O for exhalation. 
 
 Inhaled Gas Temperature 
 
 The present inhaled gas temperature re- 
 quirement divides the inspired air into 
 two categories, from 0% to 50% RH (rela- 
 tive humidity), and the other from 50 to 
 100% RH. 
 
 The new criteria allow for alternate 
 wet bulb temperature measurements that 
 automatically take into account tempera- 
 ture and relative humidity. Owing to the 
 complexity of measuring wet bulb tempera- 
 ture, it may be more practical to monitor 
 both relative humidity and dry bulb tem- 
 perature of inspired air and use conver- 
 sion charts. Both options are provided 
 for in the criteria. 
 
 Time-Duration Test 
 
 The Escape Duration Analysis Task Force 
 has determined that 80 L of usable O2 
 will allow 95% of the miners to escape 
 from working sections to fresh air. This 
 quantity of O2 will last 60 min when con- 
 sumed at a rate of approximately 1.35 
 L/min. The 50th percentile miner, when 
 performing the 1-h Man Test 4 (30 CFR 
 11), will use approximately 80 L O2. 
 
 The proposed time-duration test uses a 
 human subject who works at a fixed rate 
 of 1.35 L/min O2. This is a simple and 
 repeatable test. According to the pro- 
 posed procedure, a human subject would be 
 placed on a treadmill, and the treadmill 
 speed would be adjusted to require a met- 
 abolic demand of 1.35 L/min O2. After 
 the treadmill speed for a human subject 
 had been determined, the human subject 
 would remount the treadmill with the ap- 
 paratus to be tested. This approach sim- 
 plifies the time-duration test and pro- 
 vides repeatability. The apparatus being 
 
 tested would have to supply the wearer 
 with a breathable atmosphere for 1 h. 
 
 High-Demand Test 
 
 Man tests contained in 30 CFR 11 pro- 
 vide information on the function of 
 breathing apparatus at various work 
 rates. The new time duration test is 
 performed at a fixed work rate. To de- 
 termine how well a breathing apparatus 
 functions at various work loads, a high- 
 demand test has been proposed. 
 
 During the high-demand test, a human 
 subject walks or runs in place on a 
 treadmill, varying the rate of O2 con- 
 sumption, according to a predetermined 
 schedule of exercises. The high-demand 
 test ensures that the apparatus will 
 function across a set of work rates. 
 Stressor levels are monitored continu- 
 ously to ensure a breathable atmosphere 
 at the different work rates. 
 
 The rated duration of the units is es- 
 tablished by the time-duration test and 
 need not be achieved in the high-demand 
 test. Time is monitored to ensure that 
 the units can be worn for a minimum time 
 period at the elevated work rates of the 
 high-demand test. The minimum time for 
 a 1-h unit during the high-demand test 
 is 40 min. The time-duration and high- 
 demand tests provide a simple means to 
 objectively determine performance charac- 
 teristics of the units. 
 
 Ruggedness Tests 
 
 Ruggedness tests are intended to deter- 
 mine raineworthiness of PWSCSR's that 
 would be worn as personal equipment on a 
 daily basis. 
 
 There are four ruggedness tests to sim- 
 ulate a range of environmental conditions 
 likely to be found in underground coal 
 mines. The first test exposes a PWSCSR 
 to high and low temperatures. The second 
 and third tests expose an apparatus to 
 shock and vibration. The fourth test is 
 a submersion test designed to evaluate 
 the integrity of the protective case. 
 
42 
 
 All four tests are applied to an appa- 
 ratus. Afterwards, the respirator is 
 inspected for safe operation, and then 
 performance-tested. 
 
 Human Factors Test 
 
 The human factors test addresses ergo- 
 nomic considerations for comfort and 
 wearability of such apparatus. The human 
 factors test is designed to evaluate the 
 unit while human subjects are performing 
 simple tasks that may be encountered dur- 
 ing an escape. As in the time-duration 
 and high-demand tests, physiological var- 
 aibles are monitored continuously during 
 the human factors test. 
 
 The time required to perform these 
 tests is not related to the rated dura- 
 tion of the units. A 1-h unit is re- 
 quired to be worn and perform the func- 
 tions listed for 33 min. This time 
 requirement is to assure that the per- 
 formance of these activities does not re- 
 duce the wearing of time of the units. 
 
 ADMINISTRATIVE ISSUES 
 
 Administrative changes to current ap- 
 proval and certification procedures are 
 recommended. 
 
 Third-Party Testing 
 
 The most significant administrative 
 change is to allow third-party testing of 
 respirators. A manufacturer can test his 
 own apparatus, or use an independent lab- 
 oratory. The Government reserves the 
 right to witness all tests at the loca- 
 tion specified by the manufacturer. The 
 Government will review the test results, 
 and, if necessary, require retesting. 
 
 Special Use Escape-Only Devices 
 
 The technical specifications developed 
 by the Task Force apply to PWSCSR's, 
 which are escape-only devices intended 
 for use in underground coal mine emer- 
 gencies. The proposed approval and cer- 
 tification criteria encourage other in- 
 dustries or organizations to recommend 
 alternate performance criteria, test 
 methods, and procedures for specialized 
 escape-only devices. 
 
 Training 
 
 Hands-on training is critical for the 
 successful deployment of PWSCSR's. Manu- 
 facturers are required to have realistic 
 training units available for purchase. 
 
 CONCLUSIONS 
 
 The PWSCSR Task Force has developed 
 proposed standards for second-generation 
 SCSR's. These recommendations include 
 new performance criteria, test meth- 
 ods, and procedures for approval and 
 
 certification. If designed and developed 
 to meet the proposed standards, the re- 
 sulting PWSCSR would be safe and reliable 
 and could be worn by a miner as personal 
 equipment. 
 
APPENDIX. —PROPOSED TESTING AND CERTIFICATION CRITERIA FOR PWSCSR'S 
 
 43 
 
 A. TEST PROCEDURES 
 
 C-l. 2 Levels 
 
 MSHA and the Institute reserve their 
 right to witness all tests at the loca- 
 tion specified by the equipment manufac- 
 turer. The equipment manufacturer will 
 reimburse MSHA and the Institute for 
 travel, subsistence and incidental ex- 
 penses of its representatives in accord- 
 ance with Standardized Government Travel 
 Regulations. MSHA and the Institute will 
 be notified at least two months prior to 
 testing in order to determine if instru- 
 mentation is adequate to perform tests. 
 The notification will include one unit 
 that represents the escape respirator to 
 be tested. The equipment manufacturer 
 will be responsible for all clearances 
 necessary at the test facility for MSHA 
 and Institute personnel. The equipment 
 manufacturer is responsible for supply 
 test reports, test procedures, instrumen- 
 tation specifications, calibration trace- 
 ability, instruction manual and other 
 documentation as requested by MSHA or the 
 Institute. MSHA or the Institute may re- 
 quire instrumentation capability to be 
 verified prior to or during testing, by 
 calibration standards, calibration gases, 
 or by the testing of a respirator whose 
 characteristics are known. 
 
 B. UNITS REQUIRED FOR TEST 
 
 MSHA and the Institue may require sub- 
 mittal of up to 12 units for testing. 
 The applicant will not be charged for 
 testing. 
 
 Units must meet the criteria and the 
 tests outlined in "E" through "H-2". If 
 the units are prototypes, six production 
 units will be tested when available. The 
 production units must meet all approval 
 and certification criteria. 
 
 C. CRITERIA 
 
 Units must meet all the criteria speci- 
 fied in "C-l through -4." 
 
 Inhaled oxygen will not fall below 17% 
 (dry atmosphere) during the first 3 min 
 of operation. After 3 min, the minimum 
 2 level will not be less than 20.9% 2 
 (dry atmosphere). During respirator 
 testing, the 2 will be monitored contin- 
 uously at the mouthpiece by a sensing 
 unit with at least a 90% response within 
 100 ms and an accuracy of ±0.1% 2 . 
 
 C-2. C0 2 Levels 
 
 C0 2 will be monitored continuously at 
 the mouthpiece and the average inhaled 
 C0 2 concentration will not exceed 3% over 
 the time rating of the unit. This value 
 will be an arithmetical average of C0 2 
 concentration over the inhalation cycle. 
 The arithmetical average of the C0 2 level 
 for any 1-min-time period will not ex- 
 ceed 6.0% for the inhalation cycle; and 
 for a single breath, the average will not 
 exceed 8%. 
 
 C-3. Temperature Levels 
 
 Inhalation temperatures will not exceed 
 45° C wet bulb temperature. If wet bulb 
 temperature cannot be measured at the 
 test location by instrumentation having 
 a 90% response within 500 ms with an 
 accuracy of ±1° C, the temperature will 
 meet the requirements in 30 CFR, Section 
 11.85-18(c). 
 
 C-4. Pressure Limitations 
 
 The exhalation pressure will not exceed 
 80 mm H2O, and the inhalation pressure 
 will not exceed 80 mm H 2 measured at the 
 mouthpiece with a breathing machine as 
 described in 30 CFR 11.85-3. Pressure 
 will be continuously monitored during the 
 time duration and high— demand tests and 
 will not exceed 300 mm H 2 for inhalation 
 and 200 mm H 2 for exhalation when mea- 
 sured by a sensing unit with at least a 
 
44 
 
 90% response within 5 ms and an accuracy 
 of ±1 mm. 
 
 D. GENERAL CRITERIA 
 
 the manufacturer displayed on the labels, 
 and will meet or exceed all criteria 
 listed for the specified duration as 
 evaluated in "F. Time Duration Test." 
 
 Devices are intended for escape only 
 and will be made as small and lightweight 
 as possible to improve the user-wearing 
 capability. 
 
 D-l. Special-Use Escape Devices 
 
 Escape devices for use in specialized 
 areas or industries will be designed for 
 use during escape from those environ- 
 ments expected to be encountered. The 
 following four examples of specialized 
 areas/industries are in no way intended 
 to limit the number of users or types of 
 testing involved. Users with special re- 
 quirements should meet with the Institute 
 and MSHA to develop performance criteria, 
 test methods and procedures to meet their 
 needs, which will then be distributed to 
 all "interested parties." Limitations 
 will be identified on the manufacturers' 
 labels. 
 
 1. Fire Service - Fire service escape 
 devices will have fire-resistant exposed 
 parts, and be self-contained devices. 
 
 2. Chemical Industry - Chemical indus- 
 try escape devices may have exposed parts 
 that must be resistant to chemical vapors 
 expected to be encountered in the spe- 
 cific environment. 
 
 3. Mining Industry - Mine escape de- 
 vices will be self-contained, and must be 
 worn by miners as part of their personal 
 protective equipment. 
 
 4. U.S. Naval Shipyards - Confined 
 space escape devices will be self-con- 
 tained, have fire resistant parts and 
 hood, provide means for carrying by 
 shipyard personnel, and be streamlined, 
 small, and lightweight to allow rapid es- 
 cape through 20-in accesses. 
 
 D-2. Time Duration Test 
 
 E. TEST METHOD 
 
 The 12 units will be randomly divided 
 into four groups of three units each. 
 These groups will be tested as specified 
 in "F" through "H-2." 
 
 E-l. Human Subject Testing Procedure 
 
 The equipment manufacturer is responsi- 
 ble for all testing and test equipment, 
 as well as obtaining the human subjects, 
 appropriate medical releases, pretesting 
 physicals, and all other necessary physi- 
 cal and documentary evidence for conduct- 
 ing a safe human subject testing proce- 
 dure on these apparatus. Appropriate 
 medical attendance at the human subject 
 testing is the responsibility of the 
 equipment manufacturer. 
 
 E-2. Human Subject Profile 
 
 a. Test subject Type A will be an in- 
 dividual of at least 100 kg body weight. 
 
 b. Test subject Type B will be an 
 individual between 65 and 100 kg body 
 weight. 
 
 c. Test subject Type C will be an 
 individual with a maximum body weight of 
 65 kg. 
 
 F. TIME DURATION TEST 
 
 Three units will be 
 subjects as follows: 
 
 evaluated on human 
 
 a. Human subjects (one of each subject 
 type) will be mounted on a treadmill. 
 The speed of the treadmill, for each hu- 
 man subject, will be adjusted to obtain 
 the following minimum oxygen consumption 
 rates, based on the apparatus time rat- 
 ing, according to the following table: 
 
 Escape-only devices will have the time 
 duration of the apparatus as specified by 
 
45 
 
 TABLE A-l. - Apparatus time rating 
 
 G-3. Shock Tests 
 
 10. . . 
 
 Time, 
 
 min 
 
 O2 consumption 
 rate, L/min 
 
 2.1 
 
 15. . . 
 
 
 
 2.0 
 
 30. . . 
 
 
 
 1.7 
 
 45. .. 
 
 
 
 1.5 
 
 
 
 
 
 For example, if a 60-min device is to be 
 tested, each human subject type would 
 mount the treadmill and the treadmill 
 speed would be adjusted until the oxygen 
 consumption rate is 1.35 L/min. The 
 treadmill speed for each human subject 
 type would then be documented. 
 
 b. A human subject, wearing the appa- 
 ratus to be tested, will mount a tread- 
 mill with the speed preset to at least 
 the value determined in "a" above for 
 that subject. Treadmill speed must meet 
 or exceed the value determined in "a" for 
 rated duration of the apparatus. 
 
 c. All units will meet or exceed the 
 criteria listed under "C" for the time 
 duration specified. 
 
 G. RUGGEDNESS TESTS 
 
 Three units with protective cases will 
 be tested as specified in "G-l through 
 6," and in the sequence listed. 
 
 G-l. Temperature Test 
 
 Temperature tests will be conducted by 
 exposure of all three units to a temper- 
 ature of at least -30° C for 8 h. All 
 three units will thereafter be stabilized 
 at room temperature before exposure to a 
 temperature of 71° C for 4 h. After ex- 
 posure to a temperature of 71° C, all 
 three units will then be stabilized at 
 room temperature. 
 
 G-2. Vibration Test 
 
 The three units will be vibrated as per 
 MIL-STD-810B. 
 
 The three units will be dropped from 
 a height of 1 m onto a concrete floor. 
 Each unit will be dropped a minimum of 
 six times, at least once on each axis. 
 
 G-4. Water Submersion Test 
 
 The three units will be stabilized at a 
 room temperature of 22° C±2°, and then 
 will be submerged in a water bath until 
 they are completely covered with water, 
 for a period of 1 min. The water bath 
 must be at a temperature of 15° to 18° C. 
 Upon completion of this test, all units 
 must be intact without water penetration 
 to the unit interior. 
 
 G-5. Inspection 
 
 The three units will be 
 to ensure they are in safe 
 condition. 
 
 inspected 
 operating 
 
 G-6. Time Duration Test for 
 Environmentally Treated Units 
 
 All units will meet or exceed the cri- 
 teria listed under "C" for the time dura- 
 tion specified. 
 
 H. OTHER TESTS 
 
 H-l. High-Demand Test 
 
 One human subject of each profile type 
 (total of 3), wearing an apparatus, will 
 mount a treadmill which will be run at 
 the conditions specified in the High- 
 Demand Test table. 
 
 a. Temperature will be monitored dur- 
 ing this test and will meet the require- 
 ments in "C-3." 
 
 b. Oxygen, CO2, and pressure will be 
 continuously monitored and will meet 
 the criteria in "C-l, C-2, and C-4" 
 respectively. 
 
 c. All subjects must complete the de- 
 mand test. 
 
46 
 
 TABLE A-2. - High-demand test 
 
 Activity 
 
 Walk 
 
 Run, uphill. 
 
 Walk 
 
 Run 
 
 Walk 
 
 Run , 
 
 Walk , 
 
 Run, uphill. 
 
 Walk , 
 
 Run , 
 
 Walk 
 
 Service time, min 
 
 10 
 
 2 
 1 
 
 2 
 3 
 2 
 
 NAp 
 NAp 
 NAp 
 NAp 
 NAp 
 NAp 
 
 15 
 
 2 
 1 
 2 
 3 
 
 2 
 2 
 3 
 
 1 
 NAp 
 NAp 
 NAp 
 
 30 45 60 
 
 2 
 1 
 2 
 3 
 2 
 2 
 3 
 1 
 11 
 2 
 6 
 
 2 
 1 
 2 
 3 
 2 
 2 
 3 
 1 
 
 11 
 3 
 
 10 
 
 Walk - 0% grade, 3.0 mi/h; 
 
 Run - 0% grade, 5 mi/h; 
 
 Run uphill - 15% grade, 5 mi/h. 
 
 H-2. Human-Factors Test 
 
 One human subject of each profile type 
 (a total of 3) will perform the tests as 
 specified in the Human Factors Test table 
 after donning a unit. 
 
 a. Carbon dioxide and oxygen will be 
 continuously monitored and will meet 
 the requirements in "C-l and C-2" 
 respectively. 
 
 b. Due to the short service times of 
 the 10- and 15-min units, the sequence 
 of activities for human factors testing 
 will be divided into two equal groups. 
 At least one test subject will perform 
 
 the activities of each group. All three 
 test subjects will perform all the activ- 
 ities listed for the 30-, 45-, and 60-min 
 units. 
 
 TABLE 3. - Human factors test 
 
 Activity 
 
 Bending motion 
 
 Stand 
 
 Stretching 
 
 Stooped walking 
 
 (127 cm, 2.5 mi/h) 
 Crawl (0% grade, 
 
 1.5 mi/h) 
 
 Carry 20 kg (0% 
 
 grade, 3 mi/h). . . . 
 
 Twisting 
 
 Lie on back side, 
 
 front 
 
 Duck walk 
 
 Walk (0% grade, 
 
 3 mi /h ). 
 
 Run (0% grade, 
 
 5 mi/h) 
 
 Service time, min 
 
 11 
 
 2 
 
 2 
 2 
 
 2 
 
 2 
 
 2 
 
 2 
 
 2 
 2 
 
 
 
 2 
 
 15 
 
 30 
 
 45 
 
 60 
 
 I. TRAINING MATERIAL 
 
 Manufacturers who obtain an approval 
 are required to have available to users 
 training units that closely duplicate the 
 stressor levels that the approved unit 
 exhibits, and training manuals. 
 
DEVELOPMENT OF A LOW-PROFILE RESCUE BREATHING APPARATUS 
 AND A MINE RESCUE TEAM HELMET 
 
 By Nicholas Kyriazi 1 
 
 ABSTRACT 
 
 The Bureau of Mines has funded the de- 
 velopment of two items of mine rescue 
 team equipment in order to make mine res- 
 cue missions safer and more efficient. A 
 2-h breathing apparatus was developed 
 with the goals of low profile, light 
 weight, positive pressure, cooler breath- 
 ing air, and low breathing resistance. 
 These goals were achieved through the use 
 of efficient design, proper choice of 
 
 materials, dual spring-loaded breathing 
 bags, and an internal heat exchanger. 
 The apparatus, the LP-120, has a profile 
 of 10 cm, weights 10 kg, and contains 240 
 L 2 . A rescue team helmet was also de- 
 veloped that combines the functions of 
 full head protection, breathing apparatus 
 facepiece, communications, and lighting. 
 This helmet was designed to be used with 
 the LP-120. 
 
 INTRODUCTION 
 
 Since mine rescue teams constitute a 
 small market in the view of equipment 
 manufacturers, their needs remain unful- 
 filled when they are unique. At present, 
 mine rescue teams utilize equipment that 
 largely has been designed for other pur- 
 poses and are hampered in their duties by 
 being forced to use safety equipment that 
 only marginally serves their needs. Sim- 
 ply stated, the problem is that the more 
 general the need, the more likely it is 
 
 to be satisfied; whereas the more unique 
 the need, the more likely it is to be 
 unsatisfied. 
 
 The Bureau is attempting to solve the 
 problem of how to advance technology in 
 mine rescue team equipment through sub- 
 sidizing its development costs. At 
 present, the Bureau is involved with two 
 such developments: a low-profile rescue 
 breathing apparatus and a mine rescue 
 team helmet. 
 
 DESCRIPTION OF APPARATUS 
 
 The low-profile rescue breathing appa- 
 ratus is being developed by U.S.D. Corp. 
 through contract H0123008. The mine res- 
 cue team helmet is being developed by 
 Gentex Corp. through contract H0252050. 
 Both pieces of equipment are being devel- 
 oped to improve the efficiency, safety, 
 and comfort of mine rescue team mem- 
 bers involved in mine rescue and recovery 
 missions. 
 
 LOW-PROFILE RESCUE BREATHING APPARATUS 
 
 Four agencies are cofunding the low- 
 profile rescue breathing apparatus 
 (LPRBA) contract - the U.S. Bureau of 
 
 'Biomedical engineer, Pittsburgh Re- 
 search Center, Bureau of Mines, Pitts- 
 burgh, PA. 
 
 Mines, for use by mine rescue teams on 
 rescue and recovery missions in under- 
 ground coal mines; the U.S. Air Force, 
 for use by Air Force firefighters in 
 chemical warfare f iref ighting; the U.S. 
 Federal Emergency Management Agency (sub- 
 group - U.S. Fire Administration), for 
 use by firefighters in situations when 
 long-duration apparatus are needed, such 
 as in high-rise buildings, tunnels, and 
 subways; and the U.S. Coast Guard, for 
 use in cleaning up chemical spills or 
 toxic waste dumps. 
 
 The LPRBA is a closed-circuit apparatus 
 and has a rated duration of 120 min, 
 hence its name, the LP-120. Figure 1 
 shows the LP-120 in its present configu- 
 ration; figure 2 is a schematic of the 
 apparatus. Since duration is dependent 
 upon O2 use rate, the apparatus is better 
 
48 
 
 Positive - pressure-biased 
 demand valve \ 
 
 Pneumatic alarm 
 
 Spring 
 
 KEY 
 -\ — Inhaled air 
 — Exhaled air 
 
 FIGURE 1.-The LP-120. 
 
 FIGURE 2.— LP-120 schematic. 
 
 described as containing 240 L 02* The 
 apparatus has a number of features that 
 make it unique among closed-circuit 
 RBA's: 
 
 1. The most significant feature is the 
 low profile of the apparatus, which is 
 effectively 10 cm from the farthest pro- 
 jection of the back. The actual thick- 
 ness will be greater than 10 cm, but use 
 of the contour of the human back keeps 
 the 10-cm profile. The most widely used 
 RBA, the Draeger BG-174A, has a thickness 
 of 16 cm and contains 400 L O2. This is 
 considered a 4-h device but is not usu- 
 ally used for more than 2 h. 
 
 2. The weight of the LP-120 is also 
 a significant improvement over that of 
 present apparatus. It is projected to 
 weigh approximately 10 kg compared to 
 16 kg for the Draeger BG-174A. 
 
 3. The apparatus is a positive-pres- 
 sure system, which means that, in most 
 circumstances, the pressure in the face- 
 piece remains positive compared to ambi- 
 ent. This ensures that any inadvertent 
 
 leaks will be outward and will not result 
 in any inward leakage that could contami- 
 nate the breathing air and endanger the 
 wearer. The positive pressure is main- 
 tained through the use of a biased demand 
 valve and two spring-loaded bags. 
 
 4. Dual breathing bags enable the 
 breathing resistance to be split between 
 inhalation and exhalation, unlike other 
 closed-circuit RBA's in which most of the 
 effort is placed on exhalation. This is 
 because other apparatus place their sin- 
 gle breathing bag in the breathing loop 
 after the C02 _ absorbent canister, or CO2- 
 scrubber, so that the user must force the 
 air through the chemical bed on exhala- 
 tion. The use of two breathing bags 
 splits the work of breathing, and, be- 
 cause of the pressure gradient between 
 the bags on either side of the CO2- 
 scrubber, some of the air flows through 
 the scrubbers by itself. 
 
 5. A lithium nitrate, phase-change, 
 heat exchanger is utilized to cool the 
 air after it is heated by the LiOH in the 
 scrubber. 
 
49 
 
 MINE RESCUE TEAM HELMET 
 
 The major improvement offered by the 
 mine rescue team helmet (MRTH) (figs. 
 3-6) is that it consolidates a number of 
 separate pieces of equipment produced by 
 different manufacturers: the hardhat, 
 the facepiece of the breathing apparatus, 
 the cap lamp, and the communications sys- 
 tem. All of the separate items have been 
 designed to be compatible with each oth- 
 er, and the MRTH has been designed to be 
 compatible with the LP-120. Following 
 are listed the benefits of the MRTH: 
 
 1. The new helmet increases head pro- 
 tection through the use of impact- and 
 penetration-resistant materials and in- 
 creased coverage at the back and sides of 
 the head. 
 
 2. Unlike a hardhat, it will not fall 
 off if you lower your head. 
 
 3. It offers a lower profile than hard 
 hats. This will result in hitting the 
 roof less often. 
 
 4. The MRTH utilizes a new, smaller 
 light source designed and sold by MSA. 
 
 5. The faceplate is removable and 
 attaches to the chest straps of the 
 
 breathing apparatus when breathing pro- 
 tection is not needed. See figure 6 for 
 a concept drawing. 
 
 6. A three-position switch in the com- 
 munications system enables the wearer to 
 speak to ambient, or the fresh air base, 
 if connected to the lifeline, or to turn 
 off the communications system. 
 
 FIGURE 4.— MRTH, side view. 
 
 FIGURE 3.-MRTH, front view. 
 
 FIGURE 5.— MRTH, back view. 
 
50 
 
 FACEPIECE HARD SHELL 
 IN DONNED POSITION 
 
 FACEPIECE HARD SHELL 
 IN DOFFED POSITION 
 
 FIGURE 6.— MRTH concept drawing. 
 
51 
 
 TRAINING IN THE USE OF THE SELF-CONTAINED SELF-RESCUER 
 By Henry P. Cole 1 and Charles Vaught 2 
 
 ABSTRACT 
 
 Researchers from the University of Ken- 
 tucky and the Bureau of Mines have devel- 
 oped a set of training materials designed 
 to increase SCSR donning proficiency. 
 The package presents a generic procedure 
 for the four SCSR's in common use (CSE, 
 Draeger, MSA, and Ocenco). It offers 
 (1) a donning position that is easy and 
 efficient, (2) a donning sequence that 
 moves critical steps (those necessary to 
 isolate one's lungs from the ambient 
 atmosphere) up front, and (3) a set of 
 simplified, easy-to-remember procedural 
 rules that can help miners order the 
 
 complex array of tasks needed to put a 
 self-contained self-rescuer into use. 
 
 This training package has been field- 
 tested with 16 groups of coal industry 
 people in 3 States. The preliminary data 
 suggest that the generic procedure is 
 more efficient than training approaches 
 currently in use. Additionally, the sum- 
 mary statistics indicate a need for con- 
 sistent and thorough training that in- 
 cludes hands-on performance trials. The 
 optimum interval for such activities has 
 yet to be determined. 
 
 The air in the immediate area of an un- 
 derground coal mine explosion or fire may 
 contain so little O2 and such high levels 
 of CO that filter self -rescuers would be 
 ineffective. Under such conditions, sur- 
 vivors would have to don the self-con- 
 tained self-rescuers (SCSR's) rapidly and 
 flawlessly. Miners located at some dis- 
 tance from an explosion or fire might 
 have more time to put their SCSR's into 
 use, but a mine's ventilation system can 
 quickly sweep deadly levels of smoke and 
 CO into relatively distant places. In 
 either case, proficient donning of the 
 device is critical. 
 
 Researchers from the University of 
 Kentucky and the Bureau of Mines, in co- 
 operation with MSHA, the Kentucky Depart- 
 ment of Mines and Minerals, and several 
 private coal companies, have developed a 
 set of training materials designed to 
 increase donning proficiency. To pro- 
 vide an empirical base for the construc- 
 tion of these materials, the investi- 
 gators videotaped, under experimental 
 conditions, 50 miners putting on the CSE 
 
 . . . 
 
 'Educational psychologist, University 
 of Kentucky, Lexington, KY. 
 
 2 Research sociologist, Pittsburgh Re- 
 search Center, Bureau of Mines, Pitts- 
 burgh, PA. 
 
 INTRODUCTION 
 
 AU-9A1.3 This was the model in use at 
 their mine. Each person's performance 
 trial was first timed. The entire don- 
 ning sequence was then broken into sub- 
 tasks and evaluated (fig. 1). Finally, 
 errors, interruptions, and omissions that 
 occurred at each step of the procedure 
 were logged. This analysis of the tapes 
 allowed the researchers to target actual 
 or potential problems that might be dealt 
 with by modifying existing approaches to 
 training. 
 
 A NEW SCSR DONNING PROCEDURE 
 
 Based on the initial findings, an 
 instructor's manual and short videotape 
 demonstration were then prepared for 
 field testing under Bureau contract 
 H0348040. This package presents a ge- 
 neric procedure for the four SCSR's in 
 common use (CSE, Draeger, MSA, and Ocen- 
 co). It offers (1) a donning position 
 that is easy and efficient, (2) a don- 
 ning sequence that moves critical steps 
 (those tasks necessary to isolate one's 
 lungs from the surrounding atmosphere) 
 up front, and (3) a set of simplified, 
 
 -*See "Problems in Donning Self-Con- 
 tained Self-Rescuers," by C. Vaught and 
 H. P. Cole, earlier in these proceedings. 
 
52 
 
 Completed First 
 
 Task Sequence Time Attempts Time Errors 
 
 Neck strap on 
 
 Case opened 
 
 Oxygen on 
 
 Goggles saved 
 
 Breathing hose out 
 
 Mouthpiece plug pulled 
 
 Mouthpiece inserted 
 
 Nose clip on 
 
 Head strap on 
 
 Goggles on 
 
 Breathing bag open 
 
 Neck strap adjusted 
 
 Waist strap tied 
 
 Mining cap on 
 
 Time to signaled completion 
 
 FIGURE 1.— Example performance scoring sheet for the CSE. 
 
53 
 
 easy-to-remember procedural rules that 
 can help miners order the complex array 
 of tasks needed to don an SCSR. 
 
 An Efficient Donning Position 
 
 The instructor's manual provides the 
 following directions to the trainee get- 
 ting ready to put on an SCSR: (1) Kneel 
 and place the unit directly on the mine 
 floor in front of your knees, (2) crouch 
 so that your face is just above the SCSR, 
 
 (3) lay your cap on the mine floor so 
 that the lamp shines on the unit, and 
 
 (4) after quickly looping the neck strap 
 over your head, use both hands to don the 
 unit. 
 
 This position has a number of advan- 
 tages. First, in many mines it is not 
 possible to stand erect. The crouching 
 position works well in any seam height. 
 Therefore, all miners can be trained 
 alike. Second, in high coal, crouching 
 keeps the individual's face nearer to the 
 mine floor, where the air and visibility 
 are generally better. Third, with the 
 unit on the mine floor it is easier to 
 work with both hands. Fourth, with one's 
 face directly over the SCSR, it is easier 
 to see the unit. Fifth, the cap and lamp 
 lie still on the same surface as the 
 SCSR. The unit is constantly illuminated 
 and the miner can see what he or she is 
 doing. Sixth, if something is dropped 
 (such as the goggles) the individual has 
 a much better chance of finding it. 
 
 A Logical Sequence of Steps 
 
 There are three tasks that a miner must 
 complete successfully if he or she is 
 to survive in a rapidly developing toxic 
 atmosphere: (1) activate the oxygen, 
 (2) insert the mouthpiece, and (3) put on 
 the nose clips. When this is done, the 
 individual can take as long as necessary 
 to complete the rest of the donning pro- 
 cedure. For this reason, these "criti- 
 cal" steps were placed ahead of such non- 
 essential tasks as adjusting straps. The 
 crouching position, which allows a person 
 to let the unit rest on the mine floor, 
 makes this possible. 
 
 Simply completing the absolute minimum 
 for survival does not mean that a miner 
 
 has the SCSR secured in a manner that 
 will allow enough maneuverability for him 
 or her to get out of a mine, however. 
 Once an individual's lungs are protected, 
 he or she must then proceed to (4) put on 
 the goggles, (5) adjust the straps, and 
 (6) replace the cap and move out. 
 
 An Advance Organizer 
 
 Figure 2 shows a practice performance 
 evaluation that includes a simple con- 
 nect-the-dot method that helps miners to 
 remember the logical ordering discussed 
 above. The scheme is arranged clockwise. 
 The part time, which is recorded immedi- 
 ately upon completion of the critical 
 steps, helps to break the procedure into 
 two groups of activity: (1) isolate the 
 lungs and (2) prepare to escape. 
 
 Research has shown that when presented 
 with a lengthy ordering of tasks to be 
 done, what people forget is not how to 
 perform individual steps but the overall 
 sequence. Each of the six points in this 
 advance organizer helps to cue the per- 
 son's recall of the appropriate discrete 
 tasks it includes. The "3 + 3" organiza- 
 tion is much more mnemonic than the list 
 of a dozen or so steps typical of exist- 
 ing training materials. For example, it 
 is much easier for a miner to remember to 
 "activate oxygen" and to do this first 
 than it is for him or her to recall and 
 do in proper order all the separate parts 
 of that task. 
 
 A Caveat 
 
 Of course, the "chunked" sequence given 
 above assumes that the trainee has been 
 filled in on the details of how to acti- 
 vate the oxygen and to do all the other 
 tasks for the particular model of SCSR he 
 or she is being trained on. Likewise, it 
 is assumed that the trainer has gone over 
 details of how to care for and inspect 
 the units and has discussed the storage 
 plan for his or her mine. The general- 
 ized sequence outlined here deals solely 
 with how to get a unit on efficiently; it 
 does not replace other parts of a total 
 SCSR training session. When used for its 
 intended purpose, however, the procedure 
 has potential to reduce significantly 
 
54 
 
 Performance Evaluation for 
 
 Date 
 
 1 . Did the miner answer the following? 
 
 
 A. Name the exact place where you started working 
 
 last shift. 
 
 Yes No 
 
 
 B. Tell me how to get to the nearest SCSRs from that place. 
 
 Yes No 
 
 
 2. Connect the dots in the diagram below to show the ! 
 
 steps the miner took in 
 
 donning the SCSR. DO NOT TOUCH THE DOT IF HE OR SHE DID THE 
 
 STEP INCORRECTLY. 
 
 
 Total Time (seconds) 
 
 
 n. Oxygen 
 
 Nv O 
 
 , , ~ 1 Start 
 Hat On ^ 
 
 & Mouthpiece 
 
 © 
 
 Loop 
 
 
 Straps 
 
 ^ Noseclips 
 
 © 
 
 Goggles ^ 
 
 
 Total Time (seconds) 
 
 3. After the task is completed please list any errors that need to be corrected 
 
 and then correct them. 
 
 
 Trainer's Signature 
 
 
 
 FIGURE 2.— Example SCSR evaluation form. 
 
 the errors miners make when donning the 
 devices. 
 
 time efficient way to put the unit into 
 use. 
 
 FIELD TESTING THE PROCEDURE 
 
 Conduct of the Workshops 
 
 The training package has been field- 
 tested with 16 groups of coal industry 
 people in workshops held in 3 States. 
 The workshops were attended primarily by 
 trainers and by State and Federal inspec- 
 tors. The purpose of the field tests was 
 to add to the knowledge of how long it 
 takes individuals to put on an SCSR, to 
 document the types of errors they make, 
 and to improve the materials aimed at 
 teaching and assessing a simpler and more 
 
 All workshops followed the same format. 
 An instructor who had helped design the 
 procedure first talked about the training 
 activity and discussed the factors that 
 had led to its development. He then ex- 
 plained that the people present would be 
 introduced to five innovations: (1) a 
 donning sequence that rapidly gets the 
 miner on oxygen, (2) fewer steps to re- 
 member to don the SCSR fast and correct- 
 ly, (3) a donning position that makes the 
 
55 
 
 new sequence possible, (4) a performance 
 evaluation that records skill, errors, 
 and completion times for critical and 
 secondary tasks while helping observers 
 learn the procedure, and (5) the use of a 
 simple, adjustable mine simulator. With 
 the aid of overhead visuals, the instruc- 
 tor next outlined in detail what the par- 
 ticipants would be doing. 
 
 After this introduction, the entire 
 group was shown short videotapes of two 
 trainers putting on each of the four SCSR 
 models while in the simulator. The in- 
 structor pointed out the critical donning 
 steps, reviewed the advantages of the 
 demonstrated position and sequence, noted 
 the times these two trainers required to 
 complete the critical steps, and opened 
 the floor for discussion. Following a 
 brief question and answer period, the 
 participants were sent to their choice of 
 small workshop sessions devoted to the 
 CSE, Draeger, MSA, or Ocenco. 
 
 In each small group a trainer presented 
 tips on the care, inspection, and place- 
 ment of the SCSR in question. He then 
 gave instruction on the proper way to do 
 the various subtasks, such as opening 
 
 the case. After this preliminary, the 
 trainees reviewed the videotape dealing 
 with their particular model. One at a 
 time, individuals next put on a miner's 
 belt, filter self -rescuer, cap, and cap 
 lamp and entered the simulator, which was 
 adjusted to approximately 40 in. At a 
 signal from the trainer, the person in 
 the simulator began to don the unit. 
 During each donning trial, which was done 
 with no prompting from anyone, other 
 members of the group worked in pairs to 
 evaluate the performance. While one per- 
 son in each pair observed the trainee's 
 sequence and recorded it on the form 
 shown in figure 2, the other noted the 
 part time (for critical tasks) and the 
 total time. At the end of each trial the 
 trainer, who had also been evaluating 
 the performance, noted and corrected any 
 error that had been made. 
 
 Findings From the Workshops 
 
 Table 1 presents summary statistics for 
 individuals donning the four SCSR's in 
 workshops in eastern and western Ken- 
 tucky. No data are reported for West 
 
 TABLE 1. - Summary of data collected from SCSR donning workshops 
 
 
 
 
 
 
 
 
 Prior 
 
 Perfect 
 
 SCSR type 
 
 Test 
 date 
 
 Critical time, s 
 
 Secondary time, s 
 
 donning 
 
 donning 
 
 and site 
 
 N 
 
 Mean 
 
 SD 
 
 N 
 
 Mean 
 
 SD 
 
 Mode 2 
 
 No. 3 
 
 sequence, 
 
 
 
 
 
 
 
 
 
 
 
 % of total 
 
 Draeger: 
 
 
 
 
 
 
 
 
 
 
 
 E Kentucky. . . . 
 
 1/22 
 
 7 
 
 17.00 
 
 5.77 
 
 7 
 
 55.00 
 
 20.78 
 
 NAp 
 
 NAp 
 
 28.57 
 
 
 1/28 
 
 27 
 
 23.89 
 
 10.61 
 
 27 
 
 64.70 
 
 29.08 
 
 3 
 
 12 
 
 62.96 
 
 
 1/29 
 
 15 
 
 20.47 
 
 4.93 
 
 15 
 
 52.20 
 
 19.18 
 
 
 
 11 
 
 53.33 
 
 W. Kentucky. . . . 
 
 3/18 
 
 16 
 
 16.25 
 
 4.97 
 
 17 
 
 41.12 
 
 17.09 
 
 
 
 6 
 
 22.22 
 
 
 3/19 
 
 17 
 
 17.53 
 
 6.71 
 
 18 
 
 59.17 
 
 19.45 
 
 
 
 11 
 
 38.89 
 
 Ocenco: 
 
 
 
 
 
 
 
 
 
 
 
 E. Kentucky.... 
 
 1/22 
 
 11 
 
 26.27 
 
 5.87 
 
 11 
 
 79.45 
 
 26.16 
 
 NAp 
 
 NAp 
 
 63.64 
 
 
 1/29 
 
 11 
 
 33.73 
 
 10.00 
 
 11 
 
 82.45 
 
 24.11 
 
 
 
 9 
 
 45.45 
 
 W. Kentucky.... 
 
 3/18 
 
 16 
 
 26.44 
 
 5.66 
 
 15 
 
 69.06 
 
 25.42 
 
 0,1 
 
 3,3 
 
 4 11.76 
 
 
 3/19 
 
 17 
 
 38.64 
 
 11.10 
 
 19 
 
 84.32 
 
 19.08 
 
 
 
 16 
 
 47.37 
 
 CSE: E. Kentucky 
 
 1/22 
 
 9 
 
 21.67 
 
 4.77 
 
 9 
 
 68.88 
 
 17.95 
 
 NAp 
 
 NAp 
 
 66.67 
 
 
 1/29 
 
 16 
 
 24.94 
 
 11.39 
 
 16 
 
 62.44 
 
 20.91 
 
 
 
 9 
 
 64.71 
 
 MSA: E. Kentucky 
 
 1/29 
 
 10 
 
 17.90 
 
 5.15 
 
 10 
 
 51.50 
 
 14.35 
 
 
 
 8 
 
 50.00 
 
 NAp Not applicable. Experience with 
 Mode = most frequently occurring value 
 
 more than once. 
 
 3 No. = number of people who gave the mo 
 4 0f the 17 trainees, 9 adjusted the st 
 
 this deviates from the perfect sequence, 
 
 this model, 
 in a set where different values may occur 
 
 dal response for their group, 
 raps before donning their goggles. 
 it is not a critical error. 
 
 Although 
 
56 
 
 Virginia owing to the small number of 
 persons in trainig sessions for each 
 unit. The table presents (1) the means 
 and standard deviations for critical 
 tasks and secondary tasks, (2) the modal 
 response and frequency for the number of 
 times trainees had donned the model be- 
 fore, and (3) the percent of individuals 
 who recorded a perfect sequence on the 
 first trial. Since all participants at a 
 workshop were encouraged to try every 
 SCSR being used, there is a confounding 
 factor: no attempt was made to control 
 for whether an individual had just gotten 
 hands-on training with the Ocenco before 
 donning the CSE, etc. There might be 
 some negative or positive transfer of 
 training in such situations, but that was 
 ignored for purposes of the present 
 research. 
 
 Table 1 reveals some interesting find- 
 ings. First, it will be noted that the 
 critical tasks necessary to isolate one's 
 lungs from the ambient atmosphere take up 
 significantly less than half the total 
 time needed to get most units on. When 
 it is considered that some existing 
 
 training materials recommend doing one or 
 more of the critical tasks near the end 
 of the donning sequence, it can be seen 
 that the procedures suggested in this pa- 
 per are an improvement from the stand- 
 point of efficiency. Second, even the 
 simplified sequence offered in the work- 
 shops is difficult to get correct on the 
 first trial. The highest percentage 
 (66.67%) of people having a perfect don- 
 ning performance was recorded for the 
 trainees putting on the CSE at the work- 
 shop in eastern Kentucky. Although many 
 of the errors recorded could be consid- 
 ered minor, the figures nevertheless un- 
 derscore the need for hands-on training. 
 That brings up the third point: the 
 modal prior donning experience for most 
 persons in most workshops was zero. Un- 
 less most participants skipped the work- 
 shops devoted to the models in use at 
 their operation, which is unlikely, the 
 implication is that there are a number of 
 trainers teaching miners how to don the 
 SCSR who have never themselves had one 
 on. 
 
 CONCLUSION 
 
 The preliminary data tabulated here 
 suggest there are ways to make a more 
 efficient donning sequence for each mod- 
 el of SCSR. Additionally, the summary 
 
 statistics indicate a need for consistent 
 and thorough hands-on training as well as 
 further study to determine the optimum 
 interval for such activities. 
 
57 
 
 DEVELOPMENT OF AN AUTOMATED BREATHING AND METABOLIC SIMULATOR (ABSTRACT) 1 
 
 By Nicholas Kyriazi 2 
 
 The U.S. Bureau of Mines has been de- 
 veloping breathing and metabolic simu- 
 lator technology since 1970. Breathing 
 simulation has been widely achieved 
 throughout the world and used in the 
 testing of open-circuit breathing appa- 
 ratus, but satisfactory metabolism simu- 
 lation has not been achieved. This situ- 
 ation required that the testing of 
 closed-circuit breathing apparatus, which 
 are the only type used in mines, be done 
 using human test subjects. The goal was 
 a machine that could accurately simulate 
 both the breathing and the metabolic 
 functions of a human being for testing of 
 closed-circuit breathing apparatus. The 
 
 1 Reprinted from Bureau of Mines Infor- 
 mation Circular 9110. 
 
 ^Biomedical engineer, Pittsburgh Re- 
 search Center, Bureau of Mines, Pitts- 
 burgh, PA. 
 
 advantages of using such a machine in- 
 stead of a human being for testing respi- 
 ratory protective devices lie in its 
 ability to quantify metabolic input, its 
 repeatability, and the lack of a need to 
 deal with the vagaries of human subjects. 
 The foregoing paragraph abstracts the 
 contents of a report describing the 
 breathing and metabolic simulators that 
 have been developed and used by the Bu- 
 reau over the past 15 years; this report 
 is available as Bureau of Mines Informa- 
 tion Circular (IC) 9110. A free single 
 copy of this report may be obtained by 
 writing: 
 
 Bureau of Mines 
 
 Publications Distribution Section 
 
 Cochrans Mill Road 
 
 P.O. Box 18070 
 
 Pittsburgh, PA 15236 
 
 1068 470 
 
 U.S. GOVERNMENT PRINTING OFFICE: 1 987 - 60501 7/60033 
 
 INT.-BU.0F MINES, PGH., PA. 28469 
 
U.S. Department of the Interior 
 Bureau of Mines- Prod, and Diatr. 
 Cochrane Mill Road 
 P.O. Box 18070 
 Pittsburgh, Pa. 15236 
 
 OFFICIAL BUSINESS 
 PENALTY FOR PRIVATE USE, S300 
 
 I I Do not wish to receive this 
 material, please remove 
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 "2 Address change. Please 
 correct as indicated* 
 
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