CONSTRUCTION AND FIRE PROTECTION OF COTTON WAREHOUSES. 47 



The variety of luateriiil untl construotion is usually liuiiled to those 

 adapted to roofs of very slight pitch since this slight incline is pre- 

 eminent for warehouse designs. That the roofing material should be 

 non-inflanunable is of even greater importance for this construction 

 than for the fire-resistive. In the case of a concrete slab the dan- 

 ger would be limited to access of sparks through ventilators and sky- 

 lights and all fire damage would be confined to the possible loss of 

 the roofing material. On the contrary, for slow-burning construc- 

 tion, the roofing material itself must serve as a protection to the 

 roof planking against exterior fire. Furthermore, the roofing is 

 called upon to resist the lifting, or " sucking," action of wind and, 

 therefore, must have either considerable strength or weight or both. 

 There are ceiiain elements peculiar to a fire in a cotton warehouse 

 which render unsuitable for roofing some materials, such as tin and 

 sheet iron, which are well suited to other purposes. It is true that 

 these materials are proof against spark hazard from external sources, 

 but they present a serious handicap to the extinguishment of fire 

 which has originated in or gained access to an individual compart- 

 ment. Some critics hold that the chief objection to tin or sheet iron 

 is that when the supporting framing is burned away the metal falls 

 upon the cotton and prevents effective application of water with a 

 consequent heavy loss of the cotton. Others hold that it is better in 

 case of fire that a hole be burned through the roof so as to permit the 

 direct escape of heat and smoke in order that all openings may be used 

 more readily for application of water. Such action is retarded when 

 the burning framing with metal clinging to it falls bodily on the cot- 

 ton. The composition roofings, on the other hand, break up under 

 such conditions and do not present any material hazard. Certainly 

 the feature of salvage from a cotton fire is sufficient to make the use 

 of metal roofings inadvisable unless applied over 2-inch planking, 



that the corners of timbers be beveled or chamfered, but in any event splinters 

 on corners should be removed as these afford ready facility to ignition. 



The wearing or surface floor should be laid diagonally or at right angles to 

 the heavy floor plank. The surface floor may be pine, though a hardwood such 

 as maple should be used where much trucking is contemplated. 



The waterproof paper should be turned up at wall and columns 6 inches. 

 This construction is very desirable for warehouses used by cotton mills where 

 fire or water damage may result in a loss greater than the connnercial value of 

 the cotton because of expense and delay in making replacement with cotton of 

 like character. 



The " Regulations of the National Board of Fire Underwriters Govex'uing 

 Standard Mill or Slow-Burning Construction " is a concise specification of the 

 very best practice. Every engineer and builder should endeavor to follow these 

 recommendation which were prepared by the foremost engineers engaged in 

 commercial, scientific, and fire-prevention work. 



