6
Operation and settings
54
6924-en_V1.3_09/20
6.6
Breath resistance test based on EN 149
The following values are saved in the testing routine
Breath Resistance
:
Volume flow rate 1 when inhaling (curvature of respiratory mask up): 95 l/
min.
Volume flow rate 2 when inhaling (curvature of respiratory mask up): 30 l/
min.
Volume flow rate when exhaling (curvature of respiratory mask down): 160 l/
min.
Note
To be able to compare the test results with a reference value (mask data
sheet), the face velocity may need to be converted. The face velocity de-
pends on the flow rate and the face area.
The face velocity with a face area of 100 cm
2
(0.01 m
2
) is:
0.1583 m/s at 95 l/min.
0.05 m/s at 30 l/min.
0.2667 m/s at 160 l/min.
Formula for calculating face velocity W [m/s]:
W = Q / A
Q = flow rate [m
3
/s], A = face area [m
2
]
Testing sequence
1. Measuring with respiratory mask, with the outside of the mask facing up
(with concave masks: curvature up)
2. Measuring with respiratory mask, with the outside of the mask facing
down
(with concave masks: curvature down)