Purpose-built pressure testing facility opens for business at TWI


TWI industrial members now have a new supplier for their pressure testing requirements. In combination with TWI capabilities in project management, welding, specimen preparation, strain gauging, bespoke testing, fracture testing and resonance fatigue testing, the addition of a new purpose-built containment facility means that the organisation can provide a one-stop shop for full-scale component testing.

There is a growing need from industry for the testing of pressure-containing equipment, such as pipelines, risers and pressure vessels. These components are subject to complex loading conditions during their lifetimes and highly-specialised testing is required to accurately reproduce the environment in which they operate. While results from small-scale tests can, to some extent, be extrapolated to predict the behaviour of larger components, this method does not usually satisfy the safety concerns of oil & gas companies, which require a level of assurance that only full-scale tests can provide.

In response, TWI designed, built and commissioned a new pressure containment facility, which enables large components to be subject to high internal and/or external pressure, in combination with axial or bending loads. The facility is now available for use.

Applications for the pressure pit include: carrying out large, full-scale tests on components with internal water pressure to check for leak tightness and/ or determine burst pressure; performing proof-of-concept tests on new component designs; testing new connector designs in line with the requirements in ISO 13628-7 Annex I or API 17G; carrying out bend tests on components containing internal water pressure of up to 29,000 psi; and testing components under axial loads (static or cyclic) while containing internal water pressure.

The new facility is designed to safely apply axial tensile or compressive loads of up to 1500 tonnes (15,000 kN) (static) and 500 tonnes (5000 kN) (cyclic), as well as vertical loads on each of the crossbeams of up to 1000 tonnes (10,000 kN) (static). Test fixtures that allow combined loads (axial plus bending) to be applied to components can be designed. During all of these load scenarios, internal pressures of up to 2000 bar (29,000 psi) or external pressures of up to 1000 bar (14,500 psi) can be applied to specimens inside the facility.

The facility is fully serviced by an overhead crane with two hooks of five tonnes each (ten tonnes total capacity). There are video cameras within the pit so that tests can be viewed remotely, as they take place.

The facility adds to TWI’s existing capabilities of designing test machines, fixtures and fittings and so a range of specimen shapes and sizes can now be tested with internal pressure.

The pit is 3.7 m wide and 3.45 m tall. Its total length is 13.5 m. A partition can be added to create two shorter containment facilities if necessary. It has a blast-proof lid for the containment of fragments and pressure, allowing burst tests to be carried out. There are a number of attachment points on all four walls and I-beams across the pit; therefore tensile, compressive and bending loads can be applied to specimens. Components such as sections of pipeline and other pressure-containing equipment up to 10 m in length can be tested in the facility. Shorter lengths can be tested across the width of the pit.