TM 9-4940-444-14 & P
EXHAUST PIPING INSTRUCTIONS - cont 'd.
WEATHER CAP SPECIFICATIONS
DIA. D.
NO BRACKETS
SIZE STEEL
DIA. OF RIVETS
THICKNESS OF GALV STL.
REQ'D
REQD.
FOR WEATHER CARD U.S.
GAUGE NO.
6" & UNDER
3
" x 1/8"
3/16" 0
22 GA.
OVER 6" 0
TO 12" 0
3
1 x 3/16"
3/16" 0
22 GA.
OVER 12" 0 TO 10" 0
4
1 x 3/16"
3/16" 0
20 GA.
OVER 18"
NOT LESS THAN 4
1" X 1" X 3/16" <
" 0
18 GA.
WITH MAX SPACING
NOT TO EXCEED 19"
AROUND
CIRCUM
OF STACK.
K. Automatic Discharge Stack Dampers.
Automatic dampers may be used in the discharge stack of an exhaust system if it is necessary to prevent cold air from
entering the building during the time the system is not in operation. Installation of such dampers should be limited to
the larger size stacks.
The dampers shall be automatic in operation so the air or gas created by the air flow producing equipment shall hold
the damper open while in operation and they will close of their own weight when there is no air flow.
- continued -
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