4-36. MBU-12/P OXYGEN MASK SELECTION - CONTINUED.
b. FACEMASK SELECTION. To
select the appropriate facemask
part number from figure 3-2,
proceed as follows:
To insure accurate measurements, sub-
ject shall relax facial muscles with jaw
Measure distance from tip on
underside of subject's chin to the
maximum nasal root depression,
using caliper, P/N 834-800.
When indicated caliper is not
available, use alternate caliper,
P/N 450-100 or other suitable
Measure caliper gap obtained in
step (1) using a ruler.
Find measurement obtained in
step (2) in the dimensional
ranges contained in the tabular
format on figure 3-3.
Proper facemask fit requires the
selected mask to fit comfortably and
conform to facial contours. Individuals
with borderline facial dimensions (i.e.
4.4, 4.8, etc.) shall select mask that
conforms to proper fit requirements.
Select mask size required
(i.e. small, regular, etc.).
Using mask size obtained in
step (4), select part number
required from tabular data in
4.0 - 4.4
4.4 - 4.8
4.8 - 5.1
5.1 - 5.5
Figure 3-3. Measurement Procedure for