350
Plumbing Distribution: Design Criteria
Figure 350-4.
FLOOR DRAIN DIMENSIONS
To these dimensions must be added the potential maximum fall of the
drain (dimension B in Figure 350-4). Assuming one main drain run
between each pair of girders, the minimum structural span of 40'6" would
require a maximum fall of 10-1/8", and the maximum span of 58'6" would
require 14-5/8", at " fall per foot run. On this basis the maximum depth
of the subzone would be 28-5/8". But this would allow the extreme case of
a floor sink with horizontal vent at the furthest position from the main drain.
However, these sinks, and such a run, would be extremely rare. Also,
most drains will be standard two-inch floor drains or sinks, therefore a
subzone depth of the order of 20" to 24" will usually be sufficient. This
range would also comfortably contain the depth necessary for any trap
(dimension C in Figure 350-4).
In the calculations for space required by drainage, any structural members
that are necessary for transferring lateral forces transversely across the
beams will need to be taken into account. (See Section 316.2 and Figure
310-5.)
1 - 211
Previous Page
