Why this test matters
A welded joint is often the most critical point in a gas or water pipeline: a weak or poorly executed weld can lead to leaks, sudden failure, or a costly recall. We verify PE (polyethylene) welded assemblies following the Synergrid procedures, the standard used by Belgian gas and water network operators, covering the joint types most common in distribution networks: butt-fused joints, and electrofused sleeves and saddles. This test applies to PE thermoplastics used in gas and water distribution, and matters most for utility companies, fitting manufacturers, and installers who need to prove a weld will hold under real network conditions.
How the test works
We run six distinct tests, each matched to a specific joint type. Pullout tests place a saddle or seat under tension to pull it off the tube, with a matching test for electro-welded tube-and-seat assemblies. Peeling tests cut sleeve fittings into 4 or 8 samples and load them to peel the weld apart, either the tube itself fractures, which means the weld held, or the weld gives way and can be analysed, with the same approach used for electro-welded tube-and-sleeve assemblies, including fracture surface analysis when the weld fails. Tensile tests on butt joints use 4 to 7 samples, depending on tube diameter, pulled in tension until failure: a sudden, brittle fracture signals a poorly made weld, while ductile failure, where the PE itself stretches, signals a good one. Compression tests on sleeves cut the assembly lengthwise and through the middle of the sleeve to produce 4 samples, each compressed between plates to check the joint's integrity.
What you learn from this test
For every test, the result comes down to where the failure happens: in the base PE material, which means the weld itself was strong enough, or in the weld or fusion interface, which points to a problem with the welding process or parameters. Where a weld does fail, we can analyse the fracture surface to help identify the cause. This lets utility companies, fitting manufacturers, and installers validate welding procedures, qualify welders and equipment, and confirm that joints will perform safely under real network pressure and stress before they go into the ground.
