Latest news
Summer 2018/19
energysafe issue 52
Gas cylinder valve change
to cut leaks
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By Jason Treseder, Senior Gas Engineer
The connection on an LP Gas cylinder has a known weakness
that enables dangerous gas leaks to occur. This contributes to over
100 LP Gas barbecue fires over the summer in Victoria. Standards
Australia are looking at rectifying this issue through a change to a new
safer connection, known as CGA 791 Quick Connect Coupling (QCC).
In October, Standards Australia held a
stakeholder forum in Sydney to discuss
the future of the LP Gas cylinder valve.
The forum discussed a proposal to
amend relevant standards and change
the LPG cylinder valve connection from
its current type 21 ‘POL’ design to the
CGA 791 Quick Connect Coupling
(QCC) for leisure LPG cylinders ranging
4.5kg up to 9kg.
The significant number of incidents
involving portable LPG appliances
like barbecues each year drove the
appeal for change. A common cause
of these incidents is a gas leak from
the connection to the cylinder valve,
which eventually ignites and explodes
damaging property and injuring anyone
nearby.
The Type 21 cylinder valve outlet
connection has been the default LPG
cylinder connection for many years.
The outlet connection on the cylinder
valve consists of an internal thread
leading to an internal cone. The mating
fitting on the hose assembly consists of
a matching external thread and a round
nipple with a 19mm radius. A leak tight
seal is achieved by compression of the
radius against the internal cone.
Historically, the nut fitting was provided
with spanner flats and tightening
was achieved by using a spanner
to apply sufficient torque to the nut.
The connection was subsequently
revised to permit soft seals on the
nipple to assist with sealing, enabling
a hand wheel to make a leak tight seal
this resulted in making the connection
process easier for consumers.
However, over time, consumer
expectations for the connection have
changed and the number of incidents
involving the cylinder valve connection
has made it clear that the Type 21
connection is no longer an appropriate
connection for leisure use. The QCC
fitting is considered a reasonable and
effective alternative to the Type 21 fitting.
Step towards safety:
the new QCC safety valve
10
This fitting has a number of additional
safety advantages over the current
Type 21 connection.
» The cylinder valve incorporates a check
valve that will only enable gas to flow
when a gas tight connection is made.
» The connection is a large diameter right
handed thread that is able to be made
without the use of tools.
» All perishable rubber seals are located
within the body of the gas valve. so it
can be assessed as part of the refilling
process and replaced with the cylinder
valve as part of the cylinder test process.
» The connection is widely used
internationally including New Zealand
and the USA.
» The connection incorporates a thermal
fuse that will melt when exposed to heat.
This allows the internal check valve to
close and shut off gas flow in the event
the connection is exposed to a fire.
» The QCC valve is compatible with
existing appliances that use the Type
21 connection, which will assist in the
transition process.
Standards Australia will now start the
process to amend a range of relevant
standards as part of the normal
consensus process. A proposed
transition timeframe will be confirmed
in the near future along with further
details of the transition.