Welcome to "disaster area"
I know compressor operators bang
on about cylinders being in test but as you will see, there is a good reason for it.
INCIDENT
NEWSFLASH “Gas
Bottle Explosion”
1
of 1
Summary
Of Incident A gas bottle
exploded in a lifeboat of a vessel during the process of charging it up from the Breathing Apparatus Air Compressor.The Master of the 8 years-old vessel was in proximity of the
lifeboat and he was very seriously wounded. The bottle was quite old with different numbers/dates.The photographs below speak for themselves. Unfortunately one person was injured
– imagine the results if this happened on the deck area with more people around.
Lessons Learnt
(1) The incident related to Life Saving Equipment, which indicated
the lack of inspections and maintenance programs.
(2)
Ensure air cylinders or gas bottles are all in good condition. Guidelines are:Visual inspections every 2.5 years and pass hydro-test requirements every
5 years (3)
Cylinder(s) in poor condition should not be moved or depressurized and should be roped off and warning sign(s) clearly displayed
| Gas explosion on lifeboat!!! |
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The standard American DOT 3AL 3000 aluminum
scuba tank manufactured by the Luxfer and Catalina companies, represents an amazing piece of metallurgical technology. The
single piece seamless construction manufacturing technique, plus subsequent heat treatment results in a structure containing
20 times more strength than the original aluminium billet from which it was made. Rough handling, miss-use, corrosion and
many other factors can critically effect the strength and integrity its construction. The end result is an explosion, that
usually occurs during refilling, killing the compressor operator and destroying the dive shop.
Further opportunity for death and destruction occurs during scuba tank inspection, when untrained technicians
try to remove the pillar valve without testing that the tank is truly un-pressurized. In 2003, a dive instructor
working at Koh Tao, Thailand suffered critical injury when a scuba tank pillar valve plus the removal clamp was jettisoned
through his leg during a servicing action; the aluminium tank went through a few concrete walls off into the jungle. A well-trained-medic
saved the dive instructors life.
Even
for those Dive Operators attempting an visual inspection, few realize that an aluminum tank is susceptible to Sustained
Load Cracking or SLC cracks in the neck area or carry out effective pillar valve thread inspections or gauging, or understand
what 'Eddy Current' NDT testing is.
Further confusion exists in the scuba
industry, in that the hydrostatic test is somehow believed to be the usual way a dodgy scuba tank is identified and removed
from service. The paradox is that scuba tanks rarely fail hydrostatic test and It is the Visual Inspection where most scuba
tanks are identified as having critical defects and condemned or otherwise removed from service.
| Another crack in neck failure!! |
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| BANG!! |
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| What can happen when a testing date is passed by |
Steel tanks are also not without their own problems as anyone who has been near the sea
with ferrous materials will testify. If there is one truth in the world it is 'that rust never sleeps' A flooded steel
scuba tank lying on its side can exhibit corrosion accelerated by the high pressure of air in the tank, that can lead to critical
weakening of the cylinder wall sufficient to cause an explosion within a few months.
| Corrosion |
|
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| Look, the moons surface in a bottle!!! |
