16 BULLETIN 801, U. S. DEPARTMENT OF AGRICULTURE. 
type which may be called semi slow-burning (or " wood-end") con- 
struction. In addition to these, there is the less desirable frame and 
^ iron clad " construction. 1 
FIRE-RESISTIVE CONSTRUCTION. 
Fire-resistive — sometimes called " fireproof " — construction for 
the warehouse ranks first both in protection against fire and in low 
cost of maintenance and depreciation charges. However, the first 
cost is more than that for the other types of construction. For this 
reason it is not to be preferred usually to the best design of slow- 
burning construction, for single story warehouses. On the other 
hand, fire-resistive construction should be used for warehouses sev- 
1 The adaptation of the compartment to withstand fire and admit of effective 
use of fire protective equipment is of great importance. The features of con- 
struction will be discussed under that heading, but it may be stated here that 
effective use of hose streams demands that the length of the compartment, or 
the distance between exterior walls, usually should not exceed 100 feet. Ex- 
ceptions to this rule are the cases of fire-resistive construction where there is 
but one story with large skylights through which streams of water may be 
thrown to the center of the building, and where the construction is fire-resistive, 
of several stories and fully protected by sprinkler equipment. In the latter 
case the increased length of the compartment would be desirable in order to 
reduce the cost of the platforms. In this case the compartment length (be- 
tween exterior walls) should not exceed 150 feet. 
Compartments may be combined horizontally in considerable numbers, the 
only limitation being that single combinations constituting one building should 
not be so long that in case of fire it would require an unreasonably long time 
for a fireman or other person to pass around the building from one side to the 
other. Usually the building should not exceed 700 feet in length, and there 
should be an open space between the ends of these buildings of at least 50 feet, 
unless the exterior walls are of substantial masonry, in which case a 25-foot 
space is sufficient. 
The whole consideration of size of compartments is, of course, an effort to re- 
strict fire damage. Any definite limit is necessarily arbitrary. The limit of 13 
feet in story height is well adapted to the storage of fiat cotton two bales high 
on end or one tier on end and two tiers flat, and is a suitable proportion where 
bales are stored entirely on the side as is frequently the case for compressed 
cotton, bales in this position are piled five high. In this latter case additional 
story height results in less effective use of automatic sprinkler (see section on 
fire protection), and other fire-extinguishing equipment to such an extent that 
the maximum should not exceed 18 feet. There should also be taken into ac- 
count the fact that usually with the increased height, additional cotton is sub- 
jected to fire. As previously stated, the best distance between exterior walls is 
100 feet and this should not be exceeded except under conditions similar to 
those explained, and in no usual case should the distance exceed 200 feet. The 
remaining dimension for the compartment — the distance between division walls — 
may be adjusted entirely in reference to the value of cotton thus subjected to 
a single possible fire. Preferably this dimension should be such as to limit the 
volume of the compartment to 72,000 cubic feet. 
