TM 9-4940-444-14 & P
Q. Vent Stack.
Piping from blast chamber to baffle type abrasive trap in horizontal line shall be of a heavier gage sheet metal than is
used in the standard piping. The gage of metal for the vent stack is as follows:
Diam of Pipe
Up to 8" inclusive
8" to 18" inclusive
18" to 30" inclusive
Pipe directly from blast chamber vent stack to
baffle trap shall be:
Diam of Pipe
Up to 8" incl.
8" to 18" incl.
18" to 30" incl.
1. Vent stack shall be two times the outlet
pipe diameter in height and tapered so the
inlet end is equal to two times the pipe
area at the outlet end. There shall be a
circular opening into blast chamber of
2. The pipe from vent stack is standard
construction and as noted, is of a heavier
gage metal than standard pipe.
3. The elbow from pipe is standard
construction and, as noted, is of a heavier
gage metal than standard elbow.
4. The pipe from elbow to diverging section
of pipe shall be the same as "2".
5. The diverging section of pipe shall be
standard construction and the same gage
as for the vent stack. It shall also be two
times the inlet pipe diameter in length and
shall be two times the inlet pipe diameter
at the outlet end.
6. The size of the baffle type line trap shall be twice the diameter of the stack pipe.