TM 10-8415-208-12
NOTE
The following procedure is an optional procedure that is not intended to replace the Army's standard face
piece fit test. Face piece fitting should be conducted in accordance with local standard operating
procedures (SOP)
NOTE
Perform the following procedure using the accompanying test fixture illustration
a.
Construct a manometer by taping an eight foot long piece of 1/4-inch vinyl tubing (1) to a wall approximately four
feet above the floor
b.
Insert one end of a short piece of copper tubing (2) into a #6 one-hole rubber stopper (3).
c.
Insert the other end of copper tubing (2) into the 1/4-inch vinyl tubing (1).
d.
Add water to the 1/4-inch vinyl tubing (1) until both columns are about half full.
e.
Tap with a finger or squeeze the 1/4-inch vinyl tubing (1) to remove any air bubbles in the water.
f.
Tape a one foot ruler (4) to the wall between the two columns of water such that the six-inch mark on ruler (4)
aligns with the water level in the two columns of water
g.
Fully extend head harness straps (5), (6), and (7).
h.
Place chin into the lower part of face piece (8).
i.
Pull head harness straps (5), (6), and (7) back over the head.
j.
Ensure all straps lie flat on the head.
k.
Tighten chin straps (5).
I.
Tighten temple straps (6).
m.
Tighten top head strap (7).
n.
Insert the #6 one-hole rubber stopper (3) into exhalation hose connector (9) on face piece (8).
o.
Take a deep breath and slowly exhale.
p.
Note the level of water in both columns of the 1/4-inch vinyl tubing (1) when leakage first occurs around face
piece (8)
q.
Stop exhaling and read the water level position when the water comes to rest in both columns of the 1/4-inch
vinyl tubing (1) using the one foot ruler (4)
r.
For a good face piece (8) fit, there should be a total displacement of at least six inches between the levels of
water in the two columns of 1/4-inch vinyl tubing (1) when the water comes to rest
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