Raise the mask to your outthrust chin and
bring the head harness over the back of
Center the head harness pad on the back
of your head and adjust the bottom straps
as necessary for proper fit.
Close the outlet valve with the heel of the
hand and exhale forcibly to clear the mask
of contaminated air.
Test the mask for possible leakage by
placing your palms over the canisters and
inhaling normally until the mask collapses
against your face and remains collapsed for
approximately 10 seconds.
Resume normal breathing.
Replace headgear and close the carrier flap.
The protective mask outlet valve sometimes
sticks closed because saliva or sweat has dried on
it. If this occurs, you may loosen the valve by
blowing into the valve or by massaging the valve.
The valve may be massaged with the valve cover
partially removed as shown in figure 6-4.
CANISTER REPLACEMENT. A pair of
replacement canisters for the ND Mk V mask is
provided in a hermetically sealed coffee can
container. While sealed in this container, the
canisters have an indefinite shelf life. Therefore,
the container seal should not be broken until the
canisters are to be mounted on the mask. Once
unsealed, the container should not be resealed,
and the canisters should be permanently removed
The following procedures are used for
removing and replacing canisters on the ND
Mk V mask. To remove each canister from
the facepiece, you should take the following
1. Roll approximately one-third of the rubber
apron back over the edge of the canister.
2. Slide the canister off the holder.
To install new canisters on the facepiece, you
should proceed as follows:
Remove the canisters from the hermetically
Roll the rubber apron of each canister
completely over the outer edge of the
Position each canister snugly against its
holder so that the holder contacts the
perforated plate of the canister at all points
of its outer edge.
Roll the rubber apron of each canister over
the back of the canister holder.
CARE OF THE ND MK V MASK. Because
of the importance of the mask, it should be
maintained in an efficient operating condition.
Careful attention should be given to stowing,
cleaning, handling, and inspecting the mask to
prolong its useful life.
The mask should be stowed in a cool, dry,
dark area free from solvents and their vapors. Oil
Figure 6-4.-Correcting sticking outlet
valve with cover
and gasoline vapors weaken the rubber and are
especially damaging to the activated charcoal
in unsealed canisters. The mask must be kept
dry. Moisture causes rotting of parts, corroding
metal, deteriorating canisters, and mildewing
The mask should be thoroughly cleaned with
soap and water and dried before it is stowed. If
the mask was previously used and is to be issued
to another person, it should be sterilized with a