TM 5-822-11/AFP 88-6, Chap. 7
b. Seal Width. Using the joint width from the
previous example, the following results are ob-
tained:
(1) Seal Widthmax = (0.440X5.0) = 2.20
inches
(2) Seal Widthmin = (0.584X1.2) = 0.70
inches The width of the seal selected should be
approximately the average of these two extremes
(1.45 inches). A general rule of thumb is to select
a seal twice the joint width at the time of sealing
if it meets the above criteria. In this case, a 1-inch
seal would meet the requirements. The working
range of the seal would be:
(a) Max = 1.0 - (0.2)(1.0) =0.80 inches
(20 percent compression)
Again, the working range of the seal must be
(b) Mm = 1.0 - (0.6)(1.0) = 0.40 inches
larger than the working range of the joint for the
(60 percent compression)
seal to perform properly.
The working range of the seal is illustrated in
c. A seal width of 3/4 inch would also meet the
table C-3.
range requirements at a cheaper cost although it
would be very close to being undercompressed.
These guidelines must be followed if the seals are
to perform properly. If the size restrictions are not
properly considered, the seal in even the most well
prepared joint will not exhibit a normal life span.
C-3
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