The Plastics Industry Pipe Association of Australia discusses the importance of standards, the role of industry guidelines and the importance of welder competence for PE pipelines.
Polyethylene (PE100) pipe is a material of choice, with well over 100,000 tonnes of PE pipe installed across Australia every year. PE100 piping is used for critical infrastructure including gas reticulation networks, water supply for drinking water reticulation, irrigation, and extensively used for industrial and mining applications for water and process fluids.
PE pipes in Australia are manufactured in a range of diameters from 20mm through to 2000mm.
The two most common installation techniques to connect pipe and fittings are electrofusion and butt fusion. Both techniques are safe, economical and an efficient means of installation of underground and above ground piping systems.
Electrofusion was first used in the 1970’s and has grown in popularity. Millions of electrofusion joints are installed worldwide each year. In larger diameters, butt fusion is the most common jointing technique.
With a wide range of sustainability benefits, these engineered products are safe, durable and play a critical role in delivering essential services reliably everyday day to homes and communities. To achieve a service life in excess of 100 years, it’s important for materials and products to meet Australian standards and be installed correctly by a qualified welder in accordance with industry best practice guidelines.
Australian standards and industry guidelines
Australian PE pipe manufacture centres on a suite of Australian standards that were first developed in the early 1960’s and have been constantly updated since. Relevant Australian standards include AS/NZS 4131 PE compounds for pressure pipes and fittings, AS/NZS 4130 PE pipes for pressure applications and AS/NZS 4129 Fittings for PE pipes for pressure applications.
In terms of requirements for PE100, the Australian standard for PE materials aligns closely with the PE100+ Association in Europe – an organisation that has set benchmark standards above the International Organization for Standardization requirements to showcase the high-end capabilities of the best PE pipe materials. The Plastics Industry Pipe Association of Australia (PIPA)’s technical guideline POP004 – Polyethylene pipe and fittings compounds, lists PE pipe compounds evaluated against the requirements of Australian standards.
Complementing Australian standards, industry best practice guidelines are developed to provide additional information outside of the standard.
“As the industry organisation, PIPA brings together industry experts to form committees and working groups focused on addressing industry priorities,” PIPA Executive General Manager Cindy Bray said.
“Collaborating with global counterparts and industry professionals, we develop and publish robust guidelines and specifications for plastic pipes and fittings.”
Identifying the importance of industry best practice for welding, PIPA has published technical guidelines POP001- Electrofusion jointing of PE pipe and fittings for pressure applications. It provides guidance on industry best practice techniques for safe and reliable jointing of PE pipe using electrofusion jointing. It includes building an understanding of electrofusion and providing vital information on all the critical factors for successful fusion, quality requirements, welder certification and training, and appropriate tools and equipment. The guideline also provides an overview on the considerations of installation, including post fusion quality checks and quality control records.
POP003 – Butt fusion jointing of PE pipes and fittings, provides recommendations on butt fusion jointing parameters and best practices for butt fusion jointing.
These guidelines are referenced in relevant Australian standards, water industry codes and the coal seam gas code of practice.
Welder competence
It is critical to have competent welders.
“The biggest single contribution to a successful electrofusion or butt fusion weld is the competency of the welder and their dedication to correct surface preparation and weld procedures,” Bray said.
As per AS/NZS 2033 Design and Installation of polyolefin pipe systems, installers must be trained and certified to the standard PMBWELD302E – Electrofusion Weld Polyethylene Pipelines for electrofusion and PMBWELD301E – Butt weld polyethylene pipelines and hold a current installer’s certificate before undertaking any welding practices.
“It’s important that the competency level of the welder be considered in relation to the criticality of the pipeline,” Bray said.
“Specifying the minimum competency level required also ensures that quotes or tenders can be assessed on an equal basis.”
A welding crew will normally contain people with a range of skills and experience, from unskilled workers through to trained welders with extensive experience. When developing a project specification, the composition of the welding and installation crew needs to be defined in terms of expected skill and experiences.
Typically for a major project, the welding supervisor on site should be a trained and experienced welder (a person trained by a registered training organisation) and be able to provide objective evidence of at least three years relevant experience. This experience should include welding pipe of similar or larger sizes to those in the current project.
The remainder of the crew would typically be trained welders (where training was provided by a registered training organisation within the last three years) assisted by unskilled workers.
PIPA recommends the reaccreditation of welders every two to three years to ensure the welder maintains understanding of current standards, procedures, and technical advances. It also ensures the welder skills are reviewed and current.
PE pipes play such a critical role in society, so it is important they are manufactured to relevant standards and, just as importantly, installed in accordance with industry best practice guidelines and by competent and qualified welders.
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This feature also appears in the November edition of The Australian Pipeliner.