CONSTRUCTION AND FIRE PROTECTION OF COTTON WAREHOUSES. 55 
knots and cross grain less objectionable than for most purposes. 
Square edge plank free from wanes (bark or splintered corners) 
should be insisted upon. 
Wall siding and other planking which will be exposed to the 
weather or will be in contact with the earth preferably should be 
heart material, but, if it is to be kept well painted or is to be treated 
thoroughly with a preservative preparation, sap lumber may be used. 
Wood for fire-door cores — the door designed to be covered with 
tin — should be nonresinous or nearly so ; white pine or cypress is the 
best material. 
Paving blocks of wood are excellent for the compress compartment 
floor. It is desirable that these blocks be set with a pitch cement and 
be laid over a 3-inch rough slab of concrete. 
The tendency of wood to decay should be checked by either pre- 
ventive methods or preservative treatment or both. Decay of wood 
is caused by a fungus which, under moist conditions or through lack 
of ventilation or infection, affects the wood with alarming rapidity. 
This growth not only causes rapid deterioration in timbers infected, 
but spreads to other timbers in the building or in the lumber yard. 
From the present knowledge of the subject it appears that the 
occasional buyer of lumber may find his best protection in a thorough 
air drying of lumber as it is received. Timbers showing any indi- 
cation of white mold, which indicates the presence of the fungi, 
should be isolated. If the presence of " dry rot " is suspected, as soon 
as the building is sufficiently complete it should be heated to a temper- 
ature of 115° F. and held at this temperature for at least one hour. 1 
The firedoor core, or the wooden door proper which is covered with 
tin, is subject to dry rot, as the absence of adequate ventilation con- 
tributes largely to growth of the fungi. The heat treatment de- 
scribed is essential to the life of wood so to be used. The heating 
'After heating:, the building should be thoroughly ventilated and the process 
preferably should be repeated for four consecutive days. If sprinkler equip- 
ment is provided it should be operative while the heating is in progress, care 
being exercised not to raise the temperature within 50° of the sprinkler 
head fusing temperature. In the usual case of warehouses not designed to 
be heated, the heat may be supplied by small stoves located on the ground 
floor with flues carried out through ventilator collars or openings. If the 
building is several stories in height, the plank for the upper floors should 
be laid loosely with 2-inch strips interposed between them and the support- 
ing floor timbers while the heating is in process. (Of course, this requires 
the cooperation of the sprinkler contractor.) Thermometers should be dis- 
tributed properly and carefully read, for under such conditions there will 
be considerable leakage of air and a wide range of difference in temperature 
at and far above the first floor. It is apparent that extreme care must 
be exercised to prevent setting fire to the building. The unfinished building and 
materials should be insured and a representative of the insurance interest 
should be present while the heating is in process. 
