FRANKLIN INSTITUTE LIBRARY PHILADELPHIA CIass..<$. Book.(2ai.3..^. Accession.. S^.^Z..-^.. 6 REFERENCE Given by ... Copyright 1901, by The American Fireproofing and Construction Co. new YORK. ISAAC H. BLANCHARD CO. Printers and Binders 268-270 Canal St. New York • MARK ' The American Fireproofing AND Cement Construction Co. St. James Building, 1 1 35 Broadway, New York. TH 'oS'i LIST OF U, S. PATENTS of ALPHONSE DeMAN, Inventor No. 603,130, dated April 26th, 1898, Fire resisting wooden stairs. No. 693,442, dated May 3d, 1898, Fire resisting frames and doors. No. 606,988, dated July Sth, 1898, Fire-proof Constructions. No. 607,223, dated July 12th, 1898, Artificial slabs. No. 607,224, dated July 12th, 1898, Fire-proof floor constructions. No. 609,795, dated A ugust 30t^-, 189.% Fire-proof structures. No. 6x0,435, dated wSeptonber 6th, 1893, Fire-proofing and deafening for frame structures. No. 625,544, dated May 23d, 1899, Fire-proof floor and ceiling con- structions. No. 639,961, dated December 26th, 1899, Joints for structural building members. OTHER PATENTS PENDING. '^J^HE American Fireproofing and Cement Construction Company, incorporated under the laws of the State of New York, was organized to develop in the East the several branches of the De Man System of fire proofing and concrete con- struction, which has been used for the past few years in some important structures in the West. This system is the result of a life study of the prob- lem of fireproofing, and also of the re-enforcing of concrete. All of its improvements are not only based upon sound theoretical data, but were submitted to practical tests as to fireproof quaUties, strains under loads, resistance to weather, frost, etc. These tests have been going on for years. The system has subse- quently been adopted in some large structures in the West, with complete success. Fireproof constructions can be divided into two classes: THE FIRST, which we will call the complete fire- proof construction, in which non-combustible ma- terials are used exclusively. THE SECOND, called semi-fireproof construction because some combustible materials entering the structure are rendered slow burning by certain meth- ods of construction and by the use of some pro- tective substances. Class 1 — Complete Fireproof Construction. It can be stated that absolute fireproof buildings do not exist, but their resistance to fire depends on the intensity and duration of the action of the heat and on the materials of which the building is made up; on the layout and insulation of certain parts, such as elevator shafts, stairs, etc., and on the protection of metal columns and beams and adoption of fire-walls with protected openings in them, which are features of great importance. The best method of protecting metal is to embed it entirely in concrete, which not only protects it against heat and water in case of fire, but also pro- tects the metal from rusting. It is a known fact that 8-— The DeMan System of concrete has preserved iron anchors from rusting in structures exposed to outdoor cHmatic influences for centuries. Concrete is the name given to artificial stone made up of an aggregate of broken stone or coarse gravel or broken brick or pottery, and sometimes furnace- slag, gravel or cinders, united by a mortar composed of sand and cement, forming a binding material suffi- cient to fill up the voids between the aggregate. The proper proportions for wall or pier work are i part cement, 2 parts sand, and 6 parts aggregate — either stone or brick. For suspended floor work, I part cement, 2 parts sand, and 4 parts aggregate — either stone or brick. For absolute fireproof work, Port- land cement should be used in connection with any fireproof aggregate, such as brick, furnace slag, or, preferably, cinders, on account of its light weight. Concrete has been used from time immemo- rial; numerous Roman constructions standing to- day testify as to its lasting qualities. In all of these constructions, however, the material was used so that it only had to resit compression stresses, as in walls, piers and arches. Of late years concrete has been used in constructions where it had to sustain both compression and tensile stresses, as in a beam or a supported floor slab. In such cases the material of the beam or the floor slab is subjected to compression Fireproof Construction.— 9 on the upper part and to tension at the bottom part. The resistance of concrete to compression is very great and amply sufficient to withstand the most se- vere stresses to which it is ever subjected in ordinary Fig. I. (Diagram showing by arrows the direction of the upper compression stresses and the lower tensile stresses. The intermediate plane between the two is called the neutral plane where the materials are not subjected either to compression or tensile stresses.) constructions, but its resistance to tension is very small. One of the greatest improvements in modern construction has had for object to increase the tensile strength of concrete by introducing steel tension members in the lower portion of its mass. This forms what is known as reinforced concrete, which is practically a new building material. Tension members should be made of steel on ac- count of its great strength. The essential condition is that there be complete unity of action between every part of the steel tension members and the enveloping concrete mass. Al- though concrete adheres well to a steel surface, the adhesion is insufficient to resist the great stresses 10 — The DeMan System of which are developed at the surface of the tension members. The tendency of tensile stress upon a metal bar is to elongate it, which of necessity causes a slight motion of its surface, destroying the former absolute contact of its molecules with the surround- ing concrete. It then no longer transmits the stresses to the concrete and becomes merely a suspen- sion member, elongating throughout the span, and causing a corresponding sag. It entirely fails in its function and ceases to reinforce the concrete. This is found to be the invariable result whenever wire, or rods, or bars of any uniform section are used for this purpose. Their ductility permits elongation; ulti- mately the adhesion is overcome and from that very moment they become useless as tension members. It has been found, therefore, that to effectively and per- manently reinforce concrete by metal tension mem- bers those members must be of such special shape as- to form locking shoulders suited to engage firmly with the concrete and to diffuse the stresses throughout the mass, without relying on adhesion as the means of transmission. Some inventors have attempted to remedy the de- fects set forth above as resulting from uniform sec- tion, by drilling holes in flat bars and putting cross rods or dowels through them, but this method adds greatly to the cost and reduces the strength of the Fireproof Construction. — ii tension member by the amount of metal taken out for the perforation. Moreover, the metal of the cross rods or dowels does not increase the tensile strength of the slab, as the line of tensile stress is at right angles to their axis and those of the beams. It is obvious that members parallel with the beams are not in the line of stress and cannot give additional tensile strength to the floor slab. This applies also to those wires in wire netting occupying a parallel posi- tion with the supporting beams. Generally speaking, it can be stated that in each case where metal ties or ribs are used to reinforce concrete, as soon as their direction is deviating from the Hne of stress, their use- fulness decreases in proportion to this deviation. The tension member in the De Man system is a flat bar (shown at A in Figs. 2, 3 and 4) with twists (B) at short intervals, from 2" to 4" apart, according to the size of the bars, which varies from ^i^" to in thickness and from to V in wddth, according to the stresses which they have to resist. These twists present bold anchoring shoulders and for a given quantity of metal have a larger sphere of action than any other device; the reaction of the concrete should extend as near as possible to the lower surface of a floor slab, as that is the part where the tensile strains are the highest. A cross section of a floor slab, with the tension 12 — The DeMan System of Fig. 2. Strengthening member (A) with anchor twist (B) at 90°. Section through a floor slab at right angle to the supporting beams and parallel with tension member. Fig. 4. bection through a floor slab parallel with the supporting beams and across the tension member. Fireproof Construction. — 13 member in place, shows that the axis of the member, owing to its flat shape and vertical position, is further removed from the lower surface of the slab than pos- sible in any other form; consequently a flat tension member is better protected in case of fire than any other. Fig. 5. Section through a floor slab parallel with the tension members (A), showing how they are connected to the top flange of the floor beam and hooked over them at h. B shows the twists in the tension member, which generally are at 4" center to center. The natural cohesion of concrete is great and is of itself abundantly sufficient to support the stresses on lines parallel to the floor beam, for this reason there is no need of reinforcing concrete by tension members running in that direction, as is erroneously done in some systems. The diagram shows the position of the tension members. They can be spaced closely or widely, ac- 14 — The DeMan System of cording to the loads to be carried, and as they are parallel with the line of stress, they use to advantage the full tensile strength of the metal. Fig. 6. Showing two floor beams in the ordinary position which they • usually occupy. The DeMan system can be applied to any ordinary spacing of beams. No tie rods are necessary, as the tension members take their place. For ordinary floor construction the usual size of steel for tension members is or ^xf inches; the spacing of the tension members varies from 2" to 12" center, according to the loads per square foot v^hich the floor has to carry. The following table gives the necessary thickness of slab and number of tension members per foot for given spans and loads. As previously stated, the tension members in an or- dinary floor slab should run in the same direction as the lines of stresses, i. (?.,at right angles with the beams Fireproof Construction.— 17 Table of Loads and Spans for Solid Concrete Floor Slab. grrr-^-r TOO cou 3 //or-js--^// roT-^/. £>^ OA" *^/-£>? Z f z / / 3 3 / J 1 z 3 / s / Z 3 a 4 J 1 3 / 3 / 3 £ 3 4 E »^ 1 5 1 3 Z 3 3 3 4 3 7 3 J 4 2. 3 3 3 3 3 3 3 ^ 3 3 3 3 4- S S 3 3 3 4 d S 4 4 3 4> 1 8— The DeMan System of Formula used in Computing Tables: -» d w d (a-f c-f 2 )+3o (area bar sections) c w d +30 (area bar sections) -f^ (Ii) + 30 I.) I,==(^H-wdh^) =3^05.(1^-^^1^ +30 I,) I3=:!?L^+Wdh« ^ 3P K,=3oK, All dimensions in inches except span length. X =co-ordinate of center of gravity of composite section, a =distance from bottom of composite section to centre of steel section, w =width of beam concrete used m computations=i2 inches, d =depth of concrete considered in computations, c =distance of bar centers above bottom face of beam. Ei=co-efficient of elasticity for concrete: Ea_ E,=co-efflcient of elasticity for steel: Ei M =bending moment in inch lbs. which section of beam 12 inches wide can resist. K, =maximum intensity of stress in concrete (comp. 500 lbs. per sq. in.) K2 =maximum intensity of stress in steel ( 20,000 lbs. per sq. in.) di =distancc from c. g. to most remote concrete fibre. d =distance fromc. to most remote steel fibre. 1 =moment of inertia of concrete section, about horizontal axis through c. g. Ia=moment of inertia of steel section, about horizontal axis through c. g. p =uniform load per sq. ft. which beam may carry. 1 =span length in feet. Tension concrete not considered in computations. N =Numberof Bars. E 3=30,000,000. E 1=1,000,000. or supports, and the use of steel members in a floor slab along lines parallel with the beams is only a waste of material. There are, however, exceptional condi- tions in which it may be well to use tension mem- bers in tw^o directions at right angles: — for instance: A floor slab for a square room with supports on the four sides; or, in cases where the floor beams are more than 8' — o" apart it is also advisable to put cross tension members at every four feet of space to act as ties; again, whenever hydrostatic pressures are in- volved, such as in water reservoirs, grain bins, etc., it will be advisable to run tension members at right an- gles to each other. See diagram, Fig. 7, showing the Fireproof Construction.— 19 arrangement of tension members at right angles to each other, forming the skeleton for the concrete body of a water reservoir. Fig. 7. The De Man system is applied in two forms: the monolith and the sectional. Monolith Floor Construction. The floors of a building are the most important part to be considered in connection with fireproof con- struction. The common brick arch and the flat arch in porous terra-cotta were first used, but their ex- cessive weight is objectionable, and they are now re- placed by cinder concrete arches or by the still more modern flat floor slab of reinforced cinder concrete. As stated before, the light weight and the good fire-and-water resisting qualities of the Portland Ce- 20— The DeMan System of Showing a floor slab 3' x 6' x 3" thick carrying a load of 14,000 lbs. of pig iron. Cinder concrete with tension members at 6" centres. DeMan floor construction in Bicycle Shelter, Belle Isle Park, Detroit, Mich. Tivoli Brewery at Detroit, Mich., showing DeMan's floor construction carrying fermenting tanks 8' x 14'. ment Cinder Concrete make it a most desirable building material. Although it is of comparatively recent adoption, its excellence as a fireproof material is now generally recognized. Monolithic Arch Foors* This construction can only be used when the spans between the floor beams are comparatively small, moreover, the same as all arches do, it causes a great lateral thrust on the beams and it requires also some tension members put crosswise of the floor beams, which, in this case, act as tie rods. The cov- FiG. 8. ering of the lower flange of beams can be left off where fireproofing is not essential, thereby reduc- ing the cost. The top can be surfaced with cement or asphalt. The heavy weight and the necessary nar- row spacing of floor beams make this method rather obsolete. (Fig. 8 shows this construction in section.) Fireproof Con struction . —2 3 Monolithic Flat Floor Slab in Reinforced Concrete, Supported by Steel Beams. This construction is suitable for wide spans be- tween the floor beams. It is composed of a concrete Fig. 9. Reinforced concrete slab, with cement or asphalt top surfacing and unprotected beams, suitable for breweries or for buildings where fireproofing is unnecessary. slab, reinforced with the De Man patent steel tension member, twists 4" centers. Figs. 9, 10, 11, and 12 give four applications of this construction. 24— The DeMan System of Fig 10. Reinforced concrete slab, with protected beams and wood floors on sleepers, suitable for storage warehouses and for buildings where fireproofing is desirable. Fig. II. Reinforced concrete floor slab, protected floor beams, plaster ceiling on metal furring and lath ; suitable for dwelling and other private buildings. Fireproof Construction.— 2$ Fig. 12. Reinforced cencrete floor slab, protected beams with sectional blocks for lower flange and reinforced ceiling slab ; suitable for public buildings. The tension members of ceiling slab lay on lower flanges of I-beams; spacing of tension members in ceiHng slab, 12" ; thickness of ceHing slab, . Monolithic Floor Construction, with Reinforced Concrete Beams in Substitution of the Steel Floor Beams. A comparatively large space without steel beams can be floored with a monolith reinforced concrete floor. It will, however, be necessary to increase the depth (which is the distance from the upper surface of the floor to the tension member in the lower part) until a proper proportion is obtained between the span and the depth. A good proportion between depth and span is obtained by adopting the ratio of five- 26— The DeMan System of eighths of an inch depth to every foot of span. In order to avoid an unnecessary waste of material in the lov^er part of such a floor construction, the tension members can be placed into the bottom part of ribs which are added to the under side of the compression part of the floor forming cross reinforced concrete beams, which gives a paneled ceiling. However, steel furring can be fastened to the under side of the con- crete beams, which can be covered with metallic lath to receive a coat of plaster, which gives a flat ceiling. Fig. 13. Fig. 13 is a portion of a floor construction with monolithic beams, showing a panneled ceiling of hollow squares. Beamless Monolithic Floor Construction. Triplex Slab. In this floor the ordinary steel floor beam can be omitted and at the same time large spaces can be covered with this kind of construction. This floor is composed of three parts: First, a lower one of concrete just thick enough to embed a course of tension members, spaced closely or widely Fireproof Construction. — 27 according to the loads the floor is to carry, which tension members are to resist all the tension stresses developed in the floor; a few tension members should be run crosswise of the main ones, spaced from 4 to 6 feet apart, running the full length between the end supports, where they should be anchored, forming ties between these supports. Second, an upper part of concrete of sufficient thickness to resist the com- pression stresses developed in the floor. Third, a middle part of hollow tile with sufflcient upright webs to resist the shearing stress in the central neutral plane of the floor; the height of these webs, which estabHshes the thickness of the hollow tile, must be sufficient to make up the depth of the floor after taking out the thickness of the lower and upper con- crete parts. The depth being the distance from the upper surface of the floor to the center of the ten- sion members in the lower part of the floor. The three parts of this floor should act in unison as if they were all one. This unity of action can be secured by doing the work methodically, as follows : On tem- porary forms commence to lay a section of floor taking in the whole span of such a width as to permit the laying up and finishing of the three parts of the floor before the cement is set, so that the whole of this working section will knit together and make a monolith mass. Similar sections will be built, until 28— The DeMan System of the whole floor is completed, forming practically a succession of box girders, the blocks of hollow tile being laid so as the joints of one course break with those of the adjoining course, so as to form bound. The webs of the tiles must run parallel with the ten- sion members, which lay across the short side of the floor space. The tiles are placed, the webs vertically and butting end to end in such a manner as to have all the webs line up throughout the span, so they Fig. 14. will transmit the stresses from the lower concrete containing the tension members to the upper con- crete, where the compression takes place. The tiles, previously wetted, are laid end to end, surrounded and bedded in soft cement mortar. These floors are directly supported by the main walls, and the tension members can run in the walls to form anchors, which can easily be done in case the. floors are built when the walls are at their height. Fireproof Construction, — 29 Table of Loads and Spans for Triplf-x Floor Slab. ^^^^^^^ j^rjr^ A* S 4 jS /8 4 S 6 /o /s 8 /o /z /3 /o /Z JS 6 ^ ^ i 'i /8 4 /O /2 /8 yf 4 3 /o /2 /s i J 4 /2 AS /8 ^ ^ 4 /8 6 18 S /S 4, 4 /Z /S /8 i ^ ^ /S f8 6 S JO /o /8 6 S f /S /S 6 S /8 6 30— The DeMan System of In case a floor is to be put in after the walls are above the level of the floor, special anchors are to be pro- vided to hold the walls. Great spans can be covered with this construction, and because of the air spaces in its central section, it gives a sound proof floor; it has also the advantage of giving a flat ceiHng. See Fig. 14. The preceding table gives the depth of tile and num- ber of tension members per foot in width for given spans and loads. Verify by same formula as given under preceding table. Concrete Protection for Columns and Beams. All the preceding floor constructions are supported by columns and beams. They should be protected Fig. 15. against fire. This can be done by forming around them a solid concrete mass, in rectangular shape, with rounded angles, using removable false-work for that Fireproof Con struction . — 3 1 purpose; the concrete of itself adheres strongly to the metal, but the very shape of the column will retain the covering. See Fig. 15. Monolithic Concrete Fireproof ing. When the beams of structures are subjected to great vibrations, as those of bridges or factories, it may be well to reinforce the concrete protections to prevent cracking, using two longitudinal tension members and some U shape hangers embedded at in- tervals in the concrete; around the columns can also be strengthened by tie strips put in the concrete pro- tection, as shown in Fig. 15. Reinforced Concrete for Supported SidewalKs and Areas. Area coverings with sidewalk top finish can be con- structed with reinforced concrete, even the supporting beams can be made with this material, taking two Fig. 16. Reinforced concrete sidewalk slabs. Reinforced concrete; beams running from retaining wall to the front of building. heavy tension members for the bottom of the beams and using the regular tension members for the spans between the beams. See Fig. 16. 32 — The DeMan System of This form of construction was used for a large sub- way in front of the Edison Hght plant in Detroit, Mich. See ilkistration page 41. Fig. 17. Area covering. Supporting deck beams can be run from the retaining wall to the building, spaced from 4' o" to 6' o" centers, then ordinary tension members spaced 6" centers ; the slab should be about 5" thick with i" cement top finish. Monolith Construction for Reservoirs, Aquaria, Greenhouse Benches, Etc. Water reservoirs and tanks can conveniently be made of reinforced concrete. The best body material for this class of work is crushed granite, the binding material being of Portland cement and sharp sand, in the proportions of i part cement, 2 parts sand and 4 parts granite. This forms a good grouting, which should be made from 2" to 4" thick, according to the Fireproof Construction.— 33 size of the reservoir, and reinforced by two courses of tension members, running at right angles, spaced about 6" to lo" centers, according to size of reservoir. The inside of the reservoir is finished v^ith a coat of cement and sand, in the proportion of i to 2, troweled to a smooth facing. If the tank is to be used for alkali solutions or salt water, it is necessary to protect the Fig. 18. Showing a water reservoir with cross tension members. tension members against the corrosive action of these liquids, and prior to being used the tension members should be dipped in R. I. W. paint. Whenever it is desirable to prevent the absorption of water or other liquids into the mass of concrete forming the walls of a reservoir, a coating of some adhesive waterproof material should be put on the inside walls of the reser- 34 — The DeMan System of voir, and to protect this coating from injury a facing of cement may be spread over it. Aquarium Tanks. For the construction of aquarium tanks, every hori- zontal tension member should be bolted to a metal frame, so as to form a rigid skeleton. Concrete body Open Top Reinforced Concrete Sides Plate Glass Front hetdl Frame Fig. 19. made in the general way and coated and faced as described in the preceding paragraphs, is also suitable for this class of v^ork. See Fig. 19. Greenhouse Benches. Reinforced concrete is a suitable material for the construction of greenhouse benches, especially those used in the method of raising plants known as ''culti- vation by sub-irrigation," in which a constant amount of water is kept in the bottom of the bench. Fireproof Construction. — 35 Fig. 20. This bench is made of reinforced concrete about ij" thick, having two courses of the De Man tension members embedded in the concrete at right angles to Fig. 21. each other. The bench is supported by columns of vitrified sewer pipe put on a concrete foundation, and filled with the same material. If the trough is fifty 36— The DeMan System of feet long it is necessary to provide for the expansion and contraction in the trough itself; this is accom- plished by placing one or two flexible water-tight cross joints capable of accommodating the variations in the length of the trough. The De Man flexible water-tight joint (Fig. 22) accompHshes this result. Fig. 22. The fold of this joint is made of sheet metal, pref- erably lead, the two flat single wings being embedded in two adjoining sections of the concrete trough. Roofs of Reinforced Concrete. The following diagram shows the De Man rein- forced concrete roof construction and waterproof sur- facing, with concrete protection covering and flexible water-tight joint. In this construction the tension members are hooked over the top of the roof beams, the top flange of them are bedded in the bottom of the slabs; the whole beam can be cased in with concrete, as shown in preceding illustrations of floor construction. The advantages of this construction are that it gives a fireproof roof, when the slab is made of cinder con- FiREPROOF Construction. — 37 Crete and the roof beams protected by a casing of concrete. The roof slab is made non-absorbent by an adhesive waterproof coating. A thin layer of pro- FiG. 23. tective cement surfacing above it makes the roof sur- face as durable as an artificial stone sidewalk. When monolith concrete is used in a roof exposed to great variations of temperature it is necessary to Cement Surhcina Waterproof Coating tiSteel tension f1emhen$ Reinforced concrete Skb Fig. 23A, provide for expansion and contraction; besides, a fire- proof roof is generally supported by steel structural framing, which is also subjected to more or less ex- pansion and contraction, which cause some movement in the surface of the roof. 38— The DeMan System of Section A B Detroit Free Press.— DeMan system of floor construction used in Pressroom. The DeMan flexible water-tight joint, before de- scribed, serves that purpose. It is only necessary to locate the joints at proper positions, which, generally spcaxing, correspond with the steel supports of the roof, this will divide the roof surface into a number of monolithic sections connected by the flexible water- proof joints, which permit free expansion and relieve the end slab of all stresses incident to expansion and contraction. Heavy walls and piers have been built of concrete for centuries. In modern construction a skeleton of steel bears all structural strains. Reinforced concrete walls can be adopted to advantage; they serve admi- rably to fill in the panels between the perpendicular and horizontal structural members of a high building, and when properly combined with the structural steel will make a lighter and stronger structure than can be obtained by any other building material. The gain of floor space which results from the use of concrete walls is alone an advantage which is suffl- cient reason for its adoption in crowded cities. When used for such thin walls concrete construction must Fireproof Construction.— 43 Fig. 24. Concrete Walls and Partitions. 44-— The DeMan System of be reinforced with a double course of tension mem- bers placed at right angles to each other. The large open squares made by the crossed tension members permit the concrete to be thoroughly tamped between sectional moulds used in building the walls. Metal lath can be fastened to the tension members and concrete applied without the use of sectional moulds. The horizontal tension members should pass just outside the principals and the outside of the wall will be a plane surface and the prin- cipals protected against dampness from without. On the inner surface the concrete may be moulded around the angles of the principals, which will thus be wholly covered and form buttresses on the inside. The vertical tension members should be connected to the horizontal structural pieces between the uprights. These concrete walls form a strong enclosure and should be protected with an adhesive waterproof coat- ing, but as they are thin, it is necessary to face them on the inside with some kind of insulating material to resist the variations of the outside temperature. If thorough insulation is desired, a course of hollow tile can be added inside to receive the finishing coat of plaster. Such walls will resist all ordinary lateral pressures, and they can, for special uses, be made to sustain any degree of stress, as they are practically floor slabs set in a vertical position, with tension mem- FiREPROOF Construction. — 45 bers at both surfaces, so as to equally resist pressures either from the inside or the outside. These outside walls may be veneered with brick if desirable for architectural effect. Brick veneer can be easily anchored to the concrete backing, and if the brick and concrete courses are built at the same time they will knit firroly and form a very strong facing. Light inside partition walls can also be built in con- crete by using vertical and horizontal tension mem- bers, secured at the ends and fastened together at their intersections. The concrete is rammed in be- tween sectional boards put on opposite sides of the partition, forming a movable mould to build up the work. Reinforced Concrete Sectional Construction. In this class of construction all the floor slabs and protecting pieces for columns and beams are ready made and put up in sections, which admits of very rapid erection, and the floors can be used as fast as the slabs are laid, which can be done as soon as the floor beams are in place; this gives a working floor for subsequent erection. In some special cases there may be another advan- tage in this class of construction — the pieces being seasoned it will bring less dampness in the building; the only fresh material used being cement mortar to 46 — The DeMan System of put up the casings around the beams and make the joints for laying the floor slabs. Fig. 27 is a reinforced concrete floor slab of sec- tional construction, showing the DeMan tension mem- FiG. 27. ber at the bottom of the slab (a, k) and some aux- iliary twisted wire (L) on top, the latter preventing the slabs from breaking in transportation when acci- dentally they are inverted. Fig. 28. A, floor slab; B, floor beams; P, protecting pieces; K, iron straps ; J, protecting piece for lower flange of beam ; e, rab- bet forming ledge for floor slab ; h, hook af strap, holding floor slab. Fig. 28 is a concrete beam protection of sectional construction, showing when in position how the floor slabs rest on it. These beam protectors are pieces of Fireproof Construction. — 47 convenient length moulded to the proper form; when hardened they are secured to the floor beams by iron straps which hold them in position till the floor slabs are in place. These straps also carry the floor slabs. The slab can also be rabbeted on the edgte so that one lays on the other, forming lap joints. The protection of the lower flange of the beam is a dovetailed piece, held by the side pieces; their butt joints should not correspond with those of the side pieces so as to have a break in the joint. In this construction the top of the floor slab corre- sponds with the top of the floor beam, but this could be modified by changing the depth of the straps and the rabbet at the upper part of the side pieces. Fig. 29. Fig. 29 shows a modification of the preceding method — the floor slabs lie on top of the beam and are rabbeted out at the bottom so that they drop low enough to hold the side protection pieces, which have a small rabbet on the top, enough to be locked in place when the floor slab is in position. A strap (S), which holds the side pieces in place until the floor 48— The DeMan System of slabs are laid, is put at the bottom, which at the same time can be used to lace the furring channels (F), which are to receive metal lath, to form a fiat ceiling. The sides of the floor slabs and the ends of the pro- tecting pieces of the beams are concaved and con- vexed, as shown in Fig. 29, so as to make a lock joint when the pieces are brought together. J, protecting block for column ; K, protecting block for beam ; D, metal expansion joint. Fireproof Construction. — 49 Fig. 30 represents a concrete column and beam protection of sectional construction. The pieces for columns are made so that four of them encase the column. The voids between it and the column can be filled with fresh concrete when each tier is in place. When it is desirable to have waterproof joints or a joint that admits expansion for beams, this can be obtained by the DeMan expansion joint. In order to apply the joint between two pieces ready made, they should have the edges grooved so as to admit the two flanges of the metal part of the joint, which are to be introduced in the edge grooves previously filled with fresh cement, as shown in Fig 31. Fig. 31- This joint will prevent the water used in fighting a fire to reach the beam or column; it will also accom- modate any expansion that may take place without loosening the protection casing. All of these protecting casings are made of Port- land cinder concrete, which is a good non-conductor and resists the action of fire and water. De Man's Fireproof Frame and Door« In a fireproof building where floors, walls and par- 50 — The DeMan System of titiori^ are all made of fireproof materials, the doors should also be fireproof, so that if the contents of one room take fire it would not spread to adjacent rooms. The DeMan door will accomplish this and Figs. 32 and 33. Showing portion of a fireproof frame and door. at the same time will match in appearance any wood finish which may be used in the rooms. This door is composed of a core, which is a mono- lith slab made of a fireproof composition and veneered with thin wooden facings which match the wood trim Fireproof Con struction. — 5 1 in the respective rooms. The door frames are treated in a similar manner. In case the contents of a room take fire, the facing of the door and frame may be destroyed on the side of the room where the fire originated, but the mono- lith fireproof core will arrest the progress and will absolutely prevent the spreading of the fire. Semi Fireproofing, The DeMan system of semi-fireproof construction is based upon the general principle that live combus- tion cannot take place when combustible material is deprived of air. Wood is the principal building ma- terial which is to be protected in this class of work. In order to obtain the desired result, the DeMan system uses, first, insulated wood; and, second, an outside protection. A construction of insulated wood is one in which every piece or group of pieces of structural timber is insulated, excluding air by a coating of some incom- bustible material surrounding the timber on all sides, preventing the blast of air necessary to live combus- tion. It is, however, essential that this coating ma- terial, besides being fireproof, should be sufficiently porous so as to admit of a slow circulation of air and prevent thereby the possibility of dry rot in the tim- ber. Experiments extending over a period of several years have demonstrated that asbestos paper is a suit- able material for the purpose. The DeMan System of— 52 An actual application of the use of insulated wood was made in large buildings erected several years ago, and recent alteration in one of these buildings has shown that the timber is as sound as the day it was used. In this case a coating of asbestos paper was pasted all over the surface edges and ends of the tim- ber. This confirms the results of the original experi- ments and proves that the porosity of asbestos paper is sufficient to admit of a slow change of air, and that the seasoning of timber insulated with asbestos paper can take place as if it were not so covered. This system provides also for an outside protection of the insulated wood. It consists of a coat of hard plaster or cement put on wire laths, which is secured to the wood, leaving a small space between it and the asbestos insulating coating; the plaster filling up this space prevents the paper from being damaged, and is of itself a very good protection against fire. Semi-fireproofing, to be effective, should only be applied to constructions which are of themselves slow burning. Generally speaking, a slow burning con- struction is obtained by suppressing all the hollows left between the close spaced joists of the ordinary construction, widening the spacing and replacing the joists by heavy beams supporting thick floors. This is the method used in the well-known mill construc- FiREPROOF Construction.— 53 tion. When a mill construction is improved, accord- ing to the r3eMan Semi-fireproof System, it be- comes very resistant to fire. More recently, slow burning floors have been made of built-up timber, making one solid mass, using 2x4 or 2x6 edgewise, spiked together side by side, giving solid floors 4" and 6" thick respectively. They are very rigid and can span bays from lo-o to 20-0 feet. When a building has a structural steel framing sup- porting a mill construction floor, or a built-up timber floor, the steel members can be well protected by insu- lated wood, according to the DeMan system. The insulated wood being rigidly secured to the steel struc- ture, it does not depend upon the floor support to be held in place, as in the case when porous tile is used for protection; besides, in case of fire, the insulated v/ood gives absolute protection against the streams of water thrown on the heated structure. The de- structive eflfect of water thrown on heated structural steel is well known. Insulated wood is very effective in protecting structural steel; it is not only rigidly secured in each steel member so that in case of fire it cannot crumble down by heat and water, as tile casing does; it cannot blaze up and be rapidly destroyed by fire, as the wood is deprived from air; intense heat can only carbonize it, and in that condi- tion it is still a good protection, as charcoal is one 54 — The DeMan System of of the best non-conductors known; it will protect the steel structure until the carbonization is pushed to dis- integration, but this cannot occur unless the heat is intense and of a very long duration. When heavy timber is exposed to a fire and carbonization has penetrated to a small depth, it takes a long time after that for the fire to make further inroads of destruc- tion. A heavy log lasts a good while before it is en- tirely consumed. All people familiar with fires know that heavy wooden columns resist fire very well, and it is only when they are broken up by the falling debris that they consume more rapidly. These facts were utilized some years ago to protect iron columns in warehouses. The iron had a cross-shape section, having four quarter-circle spaces between the ribs of the cross shown in the diagram, Fig. 35. Fig. 35. These spaces were filled with four pieces of quarter cylindrical wood pieces, protecting the iron. This made a good fire resisting column, but it would make a far better one if each of those four pieces were insu- lated by the DeMan System. Fireproof Construction. — 55 Semi-Fireproof " Built-Up Timber Con» struction." This is composed of solid, built-up timber floors, insulated by completely inclosing the timber in asbes- tos paper and protecting the structural steel skeleton Fig. 36. Key to Fig. 36. — A, beams ; B, columns ; H, built-up floor, 2x6 timber ; D^ asbestos paper, used for insulation ; E, insu- lated plank for protection of columns and beams ; F, metal furring and lath ; G, plastering ; N, finished floor. 56 — The DeMan System of by using wood covered with asbestos paper, and plas- tering on metal lath. The preceding diagram gives an illustration of the above mentioned methods, appHed to a modern build- ing having a structural steel skeleton with outside brick walls. The columns are spaced twenty feet apart and connected with I beams; the outside col- umns are built in brick walls, the beams supporting solid built-up timber floors, made of 2x6, spiked to- gether edgewise, which spans the 20' — o" bays. The wooden floor, being a mass of solid timber, is of itself slow burning, and to apply the DeMan Sys- tem for still further retarding the cobustion by insu- lation, the following method is used: To start making the floor put a strip of asbestos paper on the outside of the first piece wide enough to project one inch above and below the floor; do the same at the end; spike in succession about six pieces, only taking care of the ends of the pieces at the wall so the asbestos keeps the same position; then between the sixth and seventh piece insert a separa- tor of asbestos paper, cut about 2" wider than the thickness of the floor, taking care while inserting it that one inch of the paper projects above and below the floor. Keep on doing the same till the floor is completed, then cover the whole top surface with as- bestos, folding down all the projecting edges of the Fireproof Construction. — 57 separators and the ends at the wall; hold the sheeting of asbestos down with wooden strips, ^"x2", spaced about i6" centers, and running crosswise of the joints between the 2"x6" forming the floor. The space be- tween the strips is to be filled with common concrete on top of the asbestos paper before laying the finished floor surfacing. The under side of the floor is also to receive a coat of asbestos paper, which can be pasted on with common paper hanging paste. Metal finidhed Floor Fig. 37. furring strips of V shape are nailed under the floor, pressing the paper to the ceiling. Metal lath, secured with long staples, is put over the furring and is to receive a coat of hard plaster, the clinches of which fill up the space between the lath and the asbestos paper. This arrangement divides the mass of wooden pieces, forming the floor into groups, each one of which is independently insulated by the asbes- tos paper, excluding the air necessary for active com- bustion. The upper and lower coat of mortar prevent any damage to the asbestos paper and assists also in 58— The DeMan System of Jefferson Apartment, Detroit, Mich.- l)t. Man sl mi-rireproof rioor connection, partitions and doors. limiting the action of heat upon the wood. All as shown in Fig. 37. The steel beams are protected against fire by a box- ing of insulated plank. These planks are fitted in place so as to form a tight box with close-fitting joints at the ends, then taken down and each piece independently insulated by hav- ing asbestos paper pasted on all faces, edges and ends. The side pieces are secured by bolts going through the beam; at the boltholes separators in insulated wood are put between the web of the beam and the insulated boxing so that the pressure of the bolt would not split the side pieces. The bottom piece of the beam protection previously insulated is spiked to the bottom edge of the side pieces. Then the metal fur- ring is put on the beam, as shown in end section, and metal lath is stapled over them, which is to receive the hard plaster. Fireproof Construction. — 61 Fig. 38. The columns are also boxed in with insulated plank- ing. Each plank previously fitted into place is inde- pendently insulated by having asbestos paper pasted all over the faces and ends, then they are spiked to- gether to form a base around the column; the latter, however, has insulated blocks driven in between the flanges of the Z bars, which acts as flue stopper and to which the planks are also spiked. The column cov- erings are ribbed up with V-shaped metal furring strips and covered with metal lath and plaster, the same as the beams. All as in Fig. 39. This protection for columns and beams is well adapted in connection with the wooden floor construe- 7. bar Cohmo — .. hetal Lath h^u/dCed Wood phnk fosaldted Wood 'Sepdrdtor Cola mo Fig. 39. 6z—Tm DeMan System op tion, as described, and the whole is as near fireproof as any wooden construction can be made. DeMan's Semi»Fireproof Frames and Doors, In semi-fireproof buildings, when it is advisable to prevent incipient fire originating in one room to spread rapidly to another, the DeMan frame and door described below will accomplish the desired result. This frame and door have fire-resisting cores of in- sulated wood; they are either covered by a metal sheeting or they are insulated by a coat of asbestos paper pasted all over these cores, so as to exclude the necessary air for combustion. Practical tests have demonstrated that the asbestos covering is entirely sufficient to resist the fire long enough for all prac- tical purposes, especially in a building which is only semi-fireproof. These insulated cores are faced up with wooden veneers, which match the finish of the rooms where the doors are intended to be used; these facings would burn down to the insulated core at the side of the room where the fire originated, but active combustion would stop right there, and if the fire in the room is kept on long enough, the cores might carbonize; but it would require an intense heat and of such a duration that other parts of the building would be destroyed before the fire could spread through the door. Fireproof Construction. — 63 The following diagrams illustrate the several parts of the frame and door: Figs. 40 and 41. A Fireproof Wall. B' B" Insulated Cores of Frame. D Facing of Frame forming Rabbet. r Threshold. G Extension Jamb. H Trim. J Wood Facings of Door. K Edge Strips of Door. M Floor. N Fire-Proof Filling between 1 nsulated Core and Fire-Proof Wall. 64 — The DeMan System of Ferguson Building, Detroit, Mich.— DeMan semi-fireproof floor construc- tion and fireproof metallic partitions throughout, also column and beam protection as shown in Fig. 36. Metal and Mortar Partitions, De Man*s System, Single Partitions. These partitions are built with sheet metal studs, gauge 24 steel, folded in V form; the connections at door lintels and at ends are as shown on diagram No. I, also the ends for fastening at top and bottom, which are nailed through the flaps; metal lath is faced on the flange side of the stud and plastered with hard mortar on two sides, making a solid mortar partition of If" to 2" thick. Hollow partition can also be obtained with single studs by putting metal lath on the two opposite sides of the studding", as shown on diagram No. I. The door jambs, which can be insulated with asbestos paper, and the way to put on grounds is also shown. Double Metallic Mortar Partition. These partitions are built with the same sheet metal studs as described for the single partitions, using two studs connected with sheet or metal clips, shown in Fig. 43, which engages the flanges of the studs, using these clips in pairs, and about 16" from one to the other a double stud is formed, and the width of this double stud is regulated by the length of the clip, of which there are several sizes, according to the thick- ness of the partition. Fireproof Construction.— 67 A. De Mann's rmc-fncMif MtTALuic p/SRTmoHO: OWOLtTv^TrVD HVPTTTJOA* No.1. Studs at openings are to be doubled, which takes four single at each jamb, and grouped together so as to form a regular truss, as shown in diagram No. 2. Fig. 42. There are also stiffening trusses running horizontally and braced on top of a row of clips; they are shown at B, which also shows the way to fasten the grounds by driving a nail through the ground into the fold of the horizontal rib, which is the same shape as the single stud. Metal lath and plaster on two sides form a double partition. Fireproof Construction. — 69 riWC-PnOQF METAULIC PARTITIONS ^ I>RA,WLNCr roT*. Dcudixv3tud Partiticw. ^No.2. 70— The DeMan System of Triple Metal and Mortar Partition. This partition is more sound proof than the ones described before. It has one center web, forming two air spaces; they are built with the same studs as de- scribed for the preceding partitions, only the clips are of different shape, as shown in diagram No. 3; this diagram gives a combined elevation of a triplet partition under a beam of a solid build of wooden floor construction. There are two rows of studs alter- nating, as shown in the plan. One row is put up first with the loop clips turned towards the center of the partition and metal lath is fastened to the back of the loop clips, then the second row of studs is put in position, with the loop clips touching the center curves of metal loops, and are secured thereto. Then a coat of plaster is put on the two sides of the center web of metal lath, and when this is sufficiently set then the two outside courses of metal lath are put in place and plastered, which forms a partition with two air spaces, and is very sound proof, the loop clips taking all the vibrations and the studs being alter- nated, each row can only be affected by the vibrations of its own side. Fireproof Con struction.— 7 1 to 72 — The DeMan System of SOME TESTIMONIALS Detroit, Mich., April 15, 1901. I have used your system of floor construction in the Detroit Opera House and Wonderland Theaters of this city, and con- sider it a first-class system in every respect, and I can cheer- fully recommend it as especially adapted to this class of work. It is very simple in construction, and it is my opinion that it is one of the best of the cinder concrete systems, and should recommend itself to any one desiring a first-class fireproof floor. I greatly prefer these systems to the old hollow tile system for many important reasons. I consider them vastly better in their fireproof qualities to the old systems. I trust that you may be successful in the introduction of your system, as I have no doubt you will be if its advantage is carefully considered by those contemplating the erection of a fireproof building. Sincerely yours, J. M. Wood. Detroit, Mich., April 13, 1901. We are pleased to state that the fireproof partition erected in our Central High School Building by your method, some years ago, also the doors of your construction used there and elsewhere by us, have proven satisfactory as regards wear and tear, and from information and testimony as to their effi- ciency in regard to fire protection we have no doubt that, should occasion arise, they will perform the service for which they were calculated. Very respectfully yours, MaLCOMSON & HiGGINBOTHAM. Queens, May 24, 1901. To whom it may concern: — This is to certify that the cement benches constructed by A. DeMan have stood all tests for two years, and have proved satisfactory. C. W. Ward. ^ Fireproof Construction.— 73 Detroit, Mich., April 12, 1901. To whom it may concern : — This is to certify that the DeMan system of reinforced con- crete construction has been used with satisfactory results in the Davis Bridge and Belvidere erected from our designs and under our superintendence in Water Works Park, Detroit, Mich. Respectfully, Donaldson & Meier. Detroit, Mich., April 12, 1901. The fireproof floors built by you in Berry Brothers', Lim- ited, factory have proven very satisfactory. The pressroom floor in the Detroit Free Press Building, also of the same construction, was loaded with rolls of paper, two, and in some places three, rolls high, each roll weighing 750 pounds, five days after the floor was completed. They are comparatively light, and of almost unlimited strength. In fact, I have found that there is no use to which floors may be put that these would not have sufficient strength, both for the usual and unusual span. I consider the system one which can be practically and expeditiously put into any building. Very respectfully, Geo. D. Mason. Detroit, Mich., April 11, 1901. Your twisted steel and cement construction forming the roof of our feeder pit, and simultaneously forming the side- walk in front of our building, has been in service now for two years and a half. It has proved amply strong under extra- ordinary stresses, including the moving over it of heavy en- gine and dynamo frames. There is not a crack nor flaw of any kind, and it remains absolutely waterproof. Yours truly. The Edison Illuminating Company. Alex. Dow, Gen'l Mgr. 74 — The DeMan System of Detroit, April i6, 1901. We have used your semi-fireproof system for protection of columns and entire steel frame of six-story building erected by us in this city for the E. Ferguson estate, and believe it to be well adapted to buildings of this class, with floors of mill construction, as it is rigidly secured to steelwork and does not require any other support, and at the same time is an excellent protection against fire and water. We also installed in this building a considerable amount of your 4" and 6" mortar and metallic partitions, from 12' o" to 18' o" in height. This work was done about five years ago, and recent altera- tions in the building have disclosed the fact that the insulated wood protection is sound and in perfect condition. Yours, etc., M. L. Smith & Son. Detroit, Mich, April 6, 1901. Your methods of fireproofing, especially the fire-doors, have been used in several buildings erected under my supervision, and I must say that they have been effective and gave very good satisfaction. Very truly yours, R. E. Raseman. Detroit, Mich., June 13, 1896. A. D eMail, Esq., Detroit, Mich.: Dear Sir — I have witnessed a test of your fireproof door made on a core insulated with tin, covered with wood facings to match the wood of any room. The door stood the fire of a furnace for over two hours. I can fully recommend the fire- resisting qualities of your doors as being equal to the regulation fireproof doors. Yours truly, James R. Elliott, Chief of the Department. Fireproof Construction. — 77 Detroit, Mich., April 13, 1901. To zvhom it may concern: — This is to certify that we have used the semi-fireproofing system of Mr. A. DeMan in a six-story flat building erected under our charge in 1895, and that we felt (and still feel) satisfied, after elaborate tests made at the time, that the sys- tem will retard the progress of a fire very materially at least, if it will not prohibit the burning of the protected parts of the building altogether. Recently we had occasion to make use of Mr. A. DeMan's fireproof floor or roof construction, which was executed under his personal supervision. We can conscientiously recommend the same, and we are glad to state that the work done by him, both in the roof and in the cement flooring, has been entirely satisfactory to the owners, as well as to us. Respectfully, Spier & Rohns. Detroit, Mich., June 13, 1896. A, DeMan, Esq., Detroit, Mich.: Dear Sir — The writer has witnessed several tests of the fire- resisting doors, having inner section protected with asbestos paper, made under your patent, and while the endurance of these is not as great as that of the standard metal-clad doors recommended by this bureau, for use in warehouses and mer- cantile or manufacturing buildings, yet their merits were so satisfactory that we would be willing to accept these doors for use in covering openings in walls dividing dwellings and apartment houses of ordinary construction as a substitute for the metal-clad doors now required. Where metal is used for covering for the inner sections, as is proposed for your ware- house doors, we would regard them as equal with the standard fire door we now recommend. Yours truly, E. F. Chapman, Inspector. 78— The DeMan System of Di: MAN'S Block Floor Construction is lighter than any other; gives a flat floor and ceiling surface ; protects the floor beams on all sides ; does not exert any side thrust on the floor beams; and makes a completely sound=proof floor because of the dead air spaces formed between the blocks. It does not require any false work, as the blocks reach from floor beam to floor beam, and are ready to carry the full load as soon as they are in place. They require no special expert labor to place them, as they are "set" and ready for immediate use. They can be made to suit any size of beam, and by regulating the strength of tension member and the thickness of the top flange can be made to carry any given load. This floor construction is illustrated on the other side : Fig. I representing a sectional side view; Fig. II a plan; Fig. Ill a horizontal section ; Fig. IV a perspective view ; Fig. V a cross section; and Fig. VI a part of the end of the block, showing in perspective the filling-in piece which protects the lower flange of the floor beam. These blocks can be made of any suitable material, preferably of re-enforced cinder concrete, on account of its durability, lightness and fireproof qualities. The floor is formed by blocks placed side by side, each block reaching from one steel floor beam to the adjoining one, covering the whole bays between succeeding floor beams. The blocks have end lugs engaging the floor beams resting on the lower flanges which carry the blocks and the load. The cross section of each block has the general form of an I beam, giving the greater strength with a minimum of material. The end lugs are in line with the web, but are thicker. The lugs project out from cross webs which, when the blocks are in place, correspond vertically with the edges of the flanges of the I beam. These cross webs form dead air spaces at the sides of the steel floor beams; the upper flanges of the blocks form the floor and the lower flanges form the ceiling. The latter drop below the bottom flange of the beam and are beveled at the end, forming a dovetailed space under the bottom flange which is to receive a filling piece protecting the bottom flange of the floor beam. To put the blocks in place a small movable platform can be used suspended from the floor beams with iron hooks. This platform facilitates the work, and as it slides along the beams the work can be done very rapidly. When the spans are wide and consequently the blocks longer than usual it may be advantageous to use a metal tripod or light derrick to handle the blocks by lifting them by the wire hooks in the countersunk holes on the top flange. Cftv\tvw\.^ "i^twwui, ^Vae^ Detroit, Mich., June 15, 1896. A. DeMan, Esq.: On June 6 I witnessed an experiment with your wood-faced fireproof door, made up of an asbestos insulated core with panel facings on each side. This door stood the fire under a fifty- horse power boiler for over an hour. I consider doors of this character fully capable of resisting fire of almost any degree of heat, and have no hesitation in commending their general use in buildings. Respectfully, Wm. H. Baxter, Fire Marshal. Detroit, Mich., April 10, 1901. We take pleasure in stating, for whom it may concern, that we have adopted your system of reinforced concrete for the floors of our brewery. The building was erected in 1897, and your patent construction has given us entire satisfaction up to date. They carry very heavy loads and resist the strain very well, in spite of the disintegrating action of the constant streams of water running on it. Since the time we have used your floor we never experi- enced any trouble with that part of the building. We can cheerfully recommend your construction to any one who wants a clear, strong and durable floor. Yours truly, F. Brogniez, Vice-Pres. and Mgr. April 15, 1901. To whom it may concern: — I have t^s.e.d the DeMan System Floor Construction in sev- eral buildings jail d;Viite^5/^^^ giveli 2eKfirl*sGfi6*Yacfi6h*. •••£.V.**SCHiLBINV • Architect. Fireproof CoNSTRU(rric^^C-4-i9. • • • *> • t • • • •• • • •••••« •••••o • ••• Detroit, Mich., April 13, 1901. The sidewalk which you laid for us last summer, using your patent bars, has proved, after a winter's hard usage, exceed- ingly satisfactory, and we take pleasure in saying that when we have another piece of similar work we will be very glad to use your bars again. We can recommend it most highly. Yours very truly, Rogers & MacFarlane. Detroit, Mich., April 13, 1901. Your patent floor construction, which I have specified for brewery work, has given satisfaction and has not shown any weakness or defects. Respectfully yours, Louis Kamper. Detroit, Mich., April 18, 1901. It gives us great pleasure to recommend your wire-lath partition. We have used it in making some alterations in the Chamber of Commerce Building, this city, of which we have charge, and found it satisfactory in every respect. Very truly yours, Homer Warren & Co. GETTY CENTER LIBRARY 3 3125 00009 1088