52 THE SAN FRANCISCO EARTHQUAKE AND FIRE. 
Of perhaps thirty fireproofs of good height with reenforced- 
concrete floors, all but two had steel frames. Steel beams and 
columns were generally protected with metal lath and plaster, cinder 
concrete, or terra-cotta tile. Practically all floor construction con- 
sisted either of hollow terra-cotta tile or reenforced concrete. Ceil- 
ings of light angles and metal lath, plastered, suspended from floors, 
served as additional means of fireproofing, by keeping the fire from 
coming into direct contact with the flooring material. Steel beams 
in many buildings had no protection, even where concrete filled, 
except this subceiling. The lower webs of floor tile came off to per- 
haps a greater extent than in the Baltimore fire. It is said to be 
impossible to procure a suitable hard-wood sawdust on the Pacific 
coast, such as is required in the manufacture of porous terra-cotta 
tile. The tile used is therefore denser and of poorer quality. The 
behavior of reenforced-concrete floors was most excellent. 
Partition walls were in a very few buildings of brick. As a rule, 
however, they were either of 3-inch hollow terra-cotta tile or metal 
lath, plastered. 
The matter of column protection is very important, as the number 
of failures in the San Francisco fire was particularly large, especially 
in the Fairmount Hotel (PI. XXXIV). Unprotected cast-iron col- 
umns failed as a result of unequal expansion caused by the lugs. A 
few light cast-iron columns filled with concrete came through without 
damage, and at the Academy of Sciences (PL XXIV, A), as already 
described, cast iron failed around a concrete core, which carried the 
load. Brick-filled columns gave fair satisfaction, but concrete-pro- 
tected columns afforded the best results. The question of fireproof- 
ing, however, is one of degree, being dependent on the intensity and 
duration of the fire. A column may be fireproofed sufficiently for an 
office building, but entirely too little for a warehouse; or a column 
which may be suitable for the upper stories may fail in the basement, 
as in the Kamra Building (p. 40). Again, the practice of running 
piping back of the fireproofing on columns, especially if the fireproof- 
ing is of hollow tile, is extremely bad. Many failures were caused by 
the expansion of such piping throwing off the terra-cotta tile. Con- 
crete is probably the best fireproofing material, because, as shown by 
experience, its stiffness will enable it to support not only the steel 
within, if the latter is softened by the heat, but perhaps the structure 
itself. The following types of column protection were used in San 
Francisco buildings : ( 1 ) Plaster on wire lath, both single and double 
layers, the latter having a dead air space; (2) single terra-cotta tile; 
(3) concrete; (4) concrete covered with terra-cotta tile; (5) brick. 
Of the fire loss, perhaps 75 per cent was in the trim and ornamental 
work. Inflammable woodwork in the corridors, doors, and windows 
proved a source of great loss, and should be eliminated for orna- 
