476 Issue date: 17 November 2006 52 of 80
Observe and listen
20.82 Observe and listen to:
(a) The electronic low pressure warning and the ‘red’ and ‘blue’ LEDs flashing (operates at
84 bar).
and
(b) The pneumatic low pressure warning (whistle operates at 74 bar +/- 5 bar).
Note: due to the design of the BA set it may not be achievable for the wearer to accurately check
the actuation pressures for both devices although they must be heard to actuate. The pressure
settings will be tested during any routine maintenance/repair of the BA set by OSG.
20.83 When zero is displayed (0 bar) open the cylinder valve slowly and fully and breathe normally,
note this pressure and round down for entry onto the BA tally.
20.84 Take a deep breath and hold, close the cylinder valve, continue to hold onto the valve.
20.85 Breathe steadily until the air is exhausted (0 bar displayed) and the face mask collapses onto
your face.
20.86 Continue holding your breath for approximately 8 seconds whilst moving your
head slowly up, down and side-to-side to ensure the face mask is not leaking
inwardly (negative pressure), this will be noted by the face mask failing to remain
‘sucked down’ onto your face.
20.87 After 8 seconds, breathe out slightly, release sliding buckles and remove the face
mask.
20.88 Extend straps, wipe the face mask seal and inner mask with a damp PALTECH wipe.
20.89 Check and ensure the two inner mask non-return valves are in place and are seated correctly,
restow the face mask into its bag (face mask bag must be cleaned using a mild detergent solution
and then dried ).
Note: do not attach neck loop to the retaining stud. This will prevent the reflex seal becoming
permanently distorted.
20.90 Fill out the BA tally – the pressure to be inserted is that noted in paragraph 20.84 above and
rounded down. i.e. 292 bar would be entered as 290 bar. Ensure that printed details on the BA
tally are clear and enter rank and name.
Note: if there is a leak as a result of the breathe down sequence above the wearer should repeat
the ‘B’ test ‘breathe down sequence’ from 20.73 above paying particular attention to correctly
fitting the face mask and the adjustment of the head harness. The straps should not be over-
tightened.
20.91 If the wearer continues to find a leak they should try another BA set and if there is still a leak they
should inform the OIC.
20.92 Extreme movement of the head may in some cases cause some leakage, but this should cease
once the head is returned to a more central position and/or the head movement is less severe. A
continuous leak that does not stop even when the head is in the central position is not
acceptable.
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