CONSTRUCTION AND FIRE PROTECTION OF COTTON WAREHOUSES. 65 
if -tracks conflict with the preferred hydrant location, the hydrants 
should be staggered, that is, alternate hydrants should 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 
hydrants 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-J-inch nozzle will discharge 
250 gallons per minute each. Good working 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 system under such conditions. Standpipes should be lo- 
cated in such manner as to be accessible during fire and provide 
available streams for any 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. 1 
1 If the wet-pipe system ( with pipes filled with water to the hose valve is 
1 used, the hose valve should contain a drip outlet and be turned in such posi- 
128983°— 19— Bull. 801 5 
