Ingangsdatum: 01-07-1999
Geldig tot en met: 19-05-2011
Definitions8.2.1 In this section and in 6.2.1 to
6.2.7 of part 2, the following definitions apply:
- Actuating force means
the force required to set the actuating mechanism.
- Actuating mechanism means the mechanism which, when operated, allows
the liferaft to be released automatically.
- Automatic release mechanism means the mechanism which opens the hook
automatically to release the liferaft.
- Hook means a hook to be used for the launching of liferafts which can
be activated to automatically release the liferaft when it is waterborne.
- Load limit for automatic release means the minimum load at which the
automatic release mechanism opens the hook and automatically and completely
releases the liferaft.
- Manual release force means the force required at the actuating
mechanism to release the hook manually.
- Safe working load means the load for which the hook is to be approved.
- Securing force means the force required to close the hook manually.
- Testing establishment means an establishment accepted by the
Administration having the equipment and the qualifications necessary for the
testing and approval of liferaft release hooks.
Hook and
documents required for tests8.2.2 The following should be submitted
to the testing establishment for the prototype testing of the hook:
- two
hooks which have been passed for delivery; and
- a functional description of the hook together with any other documents
necessary to carry out the tests.
Corrosion resistance test8.2.3 Two hooks should be submitted to
a corrosion resistance test which should be made in a salt mist chamber in
accordance with ISO 3768:1976 for 1,000 h or equivalent national standard. Any
corrosion effects and other damage to the hooks should be recorded.
8.2.4 Both hooks should then be subjected
five times to the tests required by 8.2.5 to 8.2.17.
Load test8.2.5 The maximum load on the hook to
allow for automatic release loads should be determined as follows:
- the
hook should be loaded with a mass of 200 kg and the actuating mechanism set;
- the load should be reduced gradually in stages until the hook releases
automatically, but at not more than 30 kg, to establish load F; and
- the load F should be measured and recorded. The minimum allowable load
F is the minimum obtained at release which should be not less than 5 kg.
8.2.6 The hook should be loaded with a mass of 200 kg and the
actuating mechanism set. The hook should then be subjected to cyclic loading
between 30 kg and 200 kg using a frequency of 1 + 0.2 Hz. The hook should not
release before 300 cycles. The number of cycles at which the hook opened or
whether the test was discontinued at 300 cycles should be recorded.
8.2.7 The hook should then be reloaded to
200 kg and the actuating mechanism set. The hook should be subjected to a cyclic
loading, the upper limit of which is +200 kg, and the lower limit being F1 using a
frequency of 1 + 0.2 Hz. The automatic release mechanism should operate within
three cycles. The number of cycles at which the hook opened or whether the test
was discontinued after three cycles should be recorded. F1 is to be taken as the
minimum load on the hook to allow for automatic release, as established in
8.2.5.2, reduced by 2 kg.
8.2.8 The
hook should be attached to a short wire rope fall, approximately 1.5 m, and loaded
with a mass of 10 kg. The weight should be secured and then lifted 1 m. From this
position it should be released to perform a free fall before it is abruptly
stopped by the wire rope fall. The hook should not release as a result of this
test.
8.2.9 The automatic release hook
should be attached to a test load equal to 1.1 times the safe working load, with
the actuating mechanism in the locked position. The load should be raised to a
height of at least 6 m and then be lowered at a speed of 0.6 m/s. When the load is
1.5 m above the ground or water surface, the actuating mechanism should be set for
automatic release, and the lowering completed. The automatic release hook should
release the load when it strikes the ground or water surface. The test should be
repeated with a test load equal to 2.2 times the safe working load.
8.2.10 The automatic release hook should
be attached to a test load of 1.1 times its maximum working load using an approved
launching appliance. The test load should be lowered at maximum lowering speed
through a distance of at least 3 m and stopped by applying the hand brake sharply.
This test should be conducted twice, once with the release mechanism set for
automatic release, and again with the mechanism set to closed. The release
mechanism should not open in either test.
8.2.11 The hook should be loaded to 0, 25%, 50%, 75% and 100% of the
safe working load of the hook. At each load level, the actuating force required at
the actuating mechanism should be measured and recorded. The actuating force
should be between 150 and 250 N if the hook is lanyard-operated, or the action
required to set the actuating mechanism should be readily performed by a single
person without difficulty.
8.2.12 The
securing force, which should be less than 120 N, should be determined with an
unloaded hook and should be recorded.
8.2.13 The manual release force should be determined as follows:
- the hook should be loaded with a mass of 150 kg;
- the actuating mechanism should be set;
- the force required to release the hook manually should he established
and recorded; and
- the manual release force for a mass of 150 kg on the hook should be at
least 600 N for lanyard-operated designs. Alternative designs should be
demonstrated to the satisfaction of the Administration to provide adequate
protection from inadvertent release under load.
8.2.14 The
automatic release hook should be attached to a test load equal to the mass of the
lightest liferaft for which the automatic release hook is to be approved, with the
actuating mechanism in the locked position (i.e. not set for automatic release).
The load should then be raised so that it is clear of the ground. The actuating
mechanism should be set to automatic release. This should be easily accomplished
by a single person and should not release the load.
8.2.15 The hook should be released 100 times without
failure by each of its modes of release using the maximum load permitting release
for that mode. It should then be disassembled and the parts examined. There should
be no evidence of excessive wear on any part.
8.2.16 The hook should be arranged in a cold store at -30°C to simulate
operational readiness and loaded with 25 kg. A 3.5 cm thick uniform layer of icing
should be built onto it by spraying cold fresh water from angles above 45° from
horizontal, with intermittent pauses to let icing form. The hook should then be
actuated and as a result release the hold without failure.
8.2.17 It should be demonstrated that the hook is not
damaged as a result of 10 impacts at a horizontal speed of 3.5 m/s on to a
structure resembling a vertical ship's side. As far as practical all sides of the
hook, especially areas with exposed controls, should impact the structure. The
hook should not sustain any damage which will interfere with the normal function
of the hook.
Compatibility of liferaft and
release hook8.2.18 Where automatic release hooks
are supplied for use with liferafts made by different manufacturers, operational
tests with each type and size of lifting or attachment fitting used by the
different manufacturers of the liferafts should be carried out before the
particular combination of liferaft and release hook is accepted by the
Administration.