CONSTRUCTION AND PIRE PROTECTION OF COTTON WAREHOUSES. 65 



if tracks conflict with the preferred hydrant location, the hydrants 

 should be staggered, that is, alternate hydrants shoidd be placed 

 50 feet or more from the building or storage area considered, the 

 remaining hydrants being similarly located with reference to the 

 other building. The hydrants should be spaced at intervals of from 

 150 to 250 feet, depending on the risk. The arrangement desirable 

 for some conditions is shown in Plate II. It may be seen that 

 liydrants are placed in the center of the clear space of 100 feet, 

 except that where tracks interfere the hydrants are placed alter- 

 nately on either side. The entire proposed system of hydrant pro- 

 tection should be approved by the insurance rating bureau and in- 

 surance concessions should be arranged before the work is begun. 

 The effectiveness of hydrant equipment depends largely on the 

 volume and pressure (under flow) of the water supply. This is 

 discussed in some detail under the head of "Water supply," but 

 it may be stated here that the minimum requirements for pres- 

 sure should be such that two streams — from any hydrant — ^flow- 

 ing through 100 feet of hose and a 1^-inch nozzle will discharge 

 250 gallons per minute each. Good w^orking pressure is from 60 

 to 80 pounds. 



STANDPIPE SYSTEM. 



Warehouses of more than three stories in height or having the 

 third floor more than 30 feet above the ground should be equipped 

 with a system of standpipes. This is a valuable adjunct to the 

 hydrant sj^stem under such conditions. Standpipes should be lo- 

 cated in such manner as to be accessible during fire and provide 

 available streams for anj^ compartment. The distance between the 

 risers should be governed by the proportions of the compartment 

 and the amount of hose provided. In nearly all cases standpipes 

 should extend through platforms and provide an outlet for each 

 platform. 



Water connections may be such as to keep the pipes filled with 

 water or the connection may be such that water is admitted only 

 when needed. The first, or wet system, should be used whenever 

 possible, as it provides an instant supply of water. If the pipes 

 must be kept emptied in winter it is desirable to provide mechan- 

 ical control on each floor for operating a control valve protected 

 from freezing. If this can not be accomplished there is likely 

 to be delay in geting water to the hose in case of fire. Dry-pipe 

 risers should be galvanized.^ 



^ If the wet-pipe system fwitli pipes filled with Avater to the hose valve is 

 used, the hose valve should contain a drip outlet and be turned in such posi- 



128983°— 19— Bull. 801 5 



