34 BULLETIN 801, TJ. S. DEPARTMENT OF AGRICULTURE. 
The ordinary beam system of reinforced concrete design is illus- 
trated by tbe photograph, Plate XVI, which shows the interior of 
a compartment similar to those of the warehouse design in figure 2. 
In this last design the distance between the line of columns and the 
division wall is 25 feet, the compartment being 50 feet wide. The 
story height is 8J feet, which permits the storage of cotton to a height 
of only one bale on end, and consequently a limitation in load of 
from 50 to 75 pounds per square foot. This extremely light floor load 
in combination with the rather long span of 25 feet between the 
column and wall are distinctly favorable to the beam system of con- 
struction. 1 
The combination of clay tile with reinforced concrete has not 
the advantages for warehouse construction that it has in ordinary 
domestic building. Its only advantage for the warehouse is that of 
reducing the amount of concrete and steel required for a given 
strength of floor or roof. In the case of the most economical design 
for the warehouse floor there is no advantage in the use of tile. 2 
FAILURE OF POORLY CONSTRUCTED FLOORS AND ROOFS FROM 
FIRE. 
It is interesting to note the degTee of success with which the 
types of construction here described have withstood the tests of 
fire. A view of a building which successfully withstood one of the 
1 In this instance the columns are loeated under alternate beams, while the 
intervening beam is carried by a cross beam, or girder. The beams are spaced 
8 feet apart, which is a very effective spacing with this light load, considering 
the proportions necessary for both the beam and slab. The best fire resistance 
for beams is secured when the beam is no thinner than necessary, a good pro- 
portion being secured when the breadth, or thickness, of the beam is not 
more than half the drop, or distance from the bottom of the slab to the bottom 
of the beam : but in no case should the thickness of the beam be less than 6 
incites, while S inches is to be preferred as a minimum thickness. 
2 For the roof slab, economy may sometimes be effected by the use of the 
tile, depending entirely on the local cost of materials. When it is tised the 
blocks should be arranged end to end in a single row and with a space be- 
tween rows of not less than 6 inches for the concrete joists, which are cast 
between. The whole top surface should be troweled over with cement mortar 
after casting to receive the roofing material. Even with the best of work- 
manship this construction is not as good as solid concrete, and the chances 
of poor workmanship are much greater than with the latter. Only a sub- 
stantial saving in cost would justify a departure from the solid concrete for 
this particular character of building. The semi-porous clay tile is best for 
this use. 
For all of these designs, columns should receive very careful attention. 
They may be round, octagonal, or square. The round is the best shape, but 
usually requires the use of metal forms. The octagonal shape is practically as 
good and is readily secured by use of wooden forms, The square column, 
