Page 512
CHAPTER 5
May/12
9107
SERVICE MANUAL
CHAPTER 5
Page 512
Feb/11
283
SERVICE MANUAL
ISO 9650
4.3 Necessary Additional Pressure (NAP) test
4.3.1 Carry out a NAP test as follows:
(a) Install the caps on both relief valves (FIGURE 504).
4.3.2 Inflate the liferaft slowly to twice the working pressure.
4.3.3 Let it stand for a minimum of 5 minutes after which there should be
no seam slippage or cracking or other defects.
4.3.4 If the pressure decreases, allowing for temperature or barometric
changes, by more than 5% the liferaft has failed the NAP test.
Look for leaks and porous fabric. If possible, repair the liferaft
within the limits given, refer to Chapter 6. Carry out a re-test of the
buoyancy tubes again.
4.3.5 If the pressure decreases abruptly during the NAP test and there is
audible ‘cracking’ from the liferaft, condemn the liferaft.
4.3.6 Sounds from the liferaft with no drop in pressure may be ignored.
4.3.7 After testing remove both PRV caps together.
NOTE:
After the raft has been deployed, the threads on the
nut which clamps the foil bag to the Operating Head
should be inspected, along with the corresponding
male threads on operating head. If either thread form
is damaged, or appears to be cross-threaded, the
complete operating head should be replaced, with the
old item to be discarded.
