The head harness consists of a thin rubber pad
from which the inelastic top strap, two elastic side
straps, and two elastic bottom straps extend.
These straps, secured to buckles on the facepiece,
hold the facepiece against the face.
The mask is issued with a carrier in which the
mask should be stowed when not in use. The
carrier is equipped with straps that keep the
carrier snug against the body to prevent inter-
ference with normal work routine. The flap on
the carrier pouch is held closed by a snap latch
that can be quickly and easily opened in
emergency situations. A metal shield is sewn
into the front of the carrier to protect the eyepiece
of the mask when the mask is properly placed in
the carrier. The only authorized equipment that
should be placed in the carrier with the mask is
nerve agent antidote (when issued) and anti-
fogging solution. The antifogging solution reduces
fogging of the mask eyepiece when properly
applied to its interior.
FITTING AND TESTING THE ND MK V
MASK. The amount of protection provided by
the Mk V mask depends greatly on the wearer.
Careful attention to proper fitting of the mask
is required to provide maximum protection and
The following steps outline the procedure for
properly fitting the protective mask:
1. Let the harness straps out to their full
2. Don the mask by inserting your chin in the
lower end of the facepiece and pulling the
head harness over your head.
3. While holding the head harness pad against
the center of the back of your head, pull
back on the top strap tab until the mask
rests lightly under your chin.
4. Pull back on the two side strap tabs until
the upper sides of the mask rest lightly
against your face.
5. Pull back on the bottom strap tabs until
the lower sides of the mask rest lightly
against your face.
6. Check the mask for an airtight seal by
placing your hands over the canisters so
that no air can enter and by inhaling
normally until the mask collapses. Hold
your breath for about 10 seconds to see if
the mask remains collapsed. If the mask
does not collapse, or does not remain
Figure 6-3.-Securing the top and side straps for permanent
collapsed, the mask is defective or the
straps are not properly adjusted.
NOTE: A leakproof fit cannot be expected
unless the wearer is smooth shaven.
After the foregoing tests have been made and
the strap adjustments are correct, adjust the top
and side straps for a permanent fit. Permanently
fit the mask by threading the loose ends of the
top and side straps through the buckles between
the body and the sliding member, as shown in
figure 6-3. These straps will then be permanently
adjusted to the individual. Only the two bottom
straps will have to be loosened each time the mask
is removed or donned. Both the mask and the
carrier should be securely marked with the name
of the person on whom the mask has been fitted.
DONNING THE ND MK V MASK. To
train your personnel in the proper procedures for
donning and removing the mask, you should
conduct periodic drills. During these drills, you
should emphasize speed as well as accuracy in
donning the mask. The general procedures for
donning and removing the mask are as follows:
At the command GAS, take the following
1. Stop breathing and remove your headgear.
2. Yank open the carrier flap and remove the
mask from the carrier.
3. Insert your thumbs under the head harness
straps and grasp the top of the facepiece.