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Gas news
Multi-layered composite pipe forum
By Enzo Alfonsetti , Manager Type A Gas Appliance & Component Safety
ESV recently held a forum with suppliers of multi-layered ( composite ) pipe and other stakeholders to discuss installation in bushfire-prone areas and other topics of interest .
Participants included gas technical regulators , Plastics Industry Pipe Association of Australia ( PIPA ), Australasian Fire and Emergency Service Authorities Council ( AFAC ) and members of the Standards Australia committee FP020 , which is responsible for the standard AS3959 : Construction of buildings in bushfire-prone areas .
The main aim was to discuss the installation of exposed composite pipe in bushfire-prone areas . Participants also took the opportunity to discuss a number of other issues including :
»» conducting hot work ( e . g . brazing ) on metal pipe while connected in line to composite pipe
»» providing identification adjacent to gas meters or LPG cylinders / tanks for composite pipe
»» colour of composite pipe and fitting markings
»» reversion fittings
»»
UV degradation and protection from physical damage
»» use in mobile applications or boats .
Composite pipe exposed above ground in bushfire-prone areas
The group considered a 2005 investigation report into the 2003 ACT bushfires . The report indicated flexible polymer coated gasfitting lines had ruptured as a result of low level flame contact .
Furthermore , simulated fire testing organised by the ACT Gas Technical Regulator was able to show that when composite pipe was subjected to sustained flame contact , the outer and inner polyethylene layers melted . This caused the aluminium core to become malleable and ultimately rupture as it could no longer sustain the gas pressure within the pipe .
AS / NZS5601.1 currently allows for the installation of composite pipe outdoors and above ground provided that the pipe is protected from UV degradation and from physical damage where this is likely to occur . AS3959 , on the other hand , includes clauses that require that both gas and water supply pipes be made of metal where the piping is above ground and exposed . It is unclear whether composite pipe would be considered metal piping in the context of AS3959 .
Although composite pipe has an aluminium core , it is the view of the Gas Technical Regulators that composite pipe should be considered as plastic piping in the context of exposed above ground installation in bushfire-prone areas . There was unanimous support for the Gas Technical Regulators interpretation from stakeholders .
As a result , the FP020 committee that is currently revising AS3959 will consider providing some clarification in that standard . Similarly the
Emerging problem : Non-compliant use of multi-layer pipe is an issue in residential developments .
AG006 committee is currently revising AS / NZS5601.1 and consideration will be given to the introduction of a clause that will strictly prohibit the installation of exposed composite pipe above ground in bushfire-prone areas .
Hot working metal piping connected in line with composite pipe
It was acknowledged during the forum that some suppliers provide instructions for conducting hot work ( e . g . brazing ) metal piping connected in line to composite pipe while others prohibit the practice . The concern is that the heat generated from conducting hot work on metal piping in line with composite pipe could damage the proprietary system . The AG006 committee will consider this issue at its next meeting .
Identification adjacent to gas meters or LPG cylinders / tanks for composite pipe
Clause 4.5.4 of AS / NZS5601.1 states “ A label shall be attached adjacent to the gas meter or LP Gas tank or cylinder ( s ) indicating the make or trade-name of the proprietary system .” Suppliers have indicated that they supply identification labelling for their products however it appears that not all retail outlets supply these labels . Gasfitters are encouraged to contact composite pipe suppliers where they are unable to purchase identification labels .
Colour of composite pipe and markings for fittings
It was noted that the product standard for composite pipe AS4176.8 does not include a colour requirement to identify composite pipe as gas piping . On the other hand , cross-linked polyethylene complying with AS / NZS2492 ( which does not have an aluminium layer ) includes a requirement for gas piping to be coloured yellow . The AG006 committee will consider whether composite pipe to AS4176.8 should be yellow or marked with yellow striping for identification .
Furthermore , it was acknowledged that where a gasfitter uses more than one proprietary system there is the potential for the fittings to be mixed . There are currently no marking requirements for composite pipe fittings and it was acknowledged that the product standard should in future include a requirement for composite pipe fittings to be marked so that they are easily identifiable and are not used with another proprietary piping system .
Reversion fittings
Clause 5.2.13 of AS / NZS5601.1 requires reversion fittings be used in class 1 buildings where there is more than one appliance installed . Future consideration will be given to whether reversion fittings should apply also where only one appliance is installed and for buildings that are other than class 1 buildings . Accessibility to reversion fittings will also need to be considered .
UV and mechanical protection The Gas Technical Regulators have noted installations where exposed composite pipe above ground is not protected from UV degradation . Table 4.1 of AS / NZS5601.1 requires composite pipe be protected from UV degradation and clause 5.3.17 requires protection from UV and physical damage where this is likely to occur . Given the number of non-compliant installations encountered by the Gas Technical Regulators the AG006 committee will be asked to consider if it should continue to allow the installation of exposed composite pipe above ground external to a building when it next revises AS / NZS5601.1 .
Use in mobile applications or boats
It was acknowledged that composite pipe is not used in boats or mobile applications such as caravans and that this is not common practice overseas either . Clause 5.1.4.4 of AS / NZS5601.2 prohibits the use of composite pipe in these applications .
ESV and the Victorian Building Authority ( VBA ) are in the process of developing information sheets for multi-layered composite pipe .