TWI has designed, built and commissioned a pressure containment facility, which enables large components to be subject to high internal and/or external pressure, in combination with axial or bending loads. It adds to TWI’s capabilities of designing test machines, fixtures and fittings and enabling a range of specimen shapes and sizes to be tested with internal pressure.
Applications for the pressure pit include:
- carrying out large, full-scale tests of components with internal water pressure to check for leak tightness and/ or determine burst pressure
- performing proof of concept tests on new component design
- 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 29,000psi
- testing components under axial loads (static or cyclic) whilst containing internal water pressure
The pressure containment facility allows 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 usually does not satisfy the safety concerns of oil and gas companies, who require the level of assurance that only full-scale tests can provide.
Specification
The pit is 3.7m wide and 3.45m tall. Its total length is 13.5 metres. A partition can be added to make two shorter facilities. It has a blast proof lid for 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, so tensile, compressive and bending loads can be applied to specimens. Components such as sections of pipeline and other pressure containing equipment up to 10m in length can be tested. Shorter lengths can be tested across the width of the pit.
Capabilities
The facility is designed to safely apply axial tensile or compressive loads of up to 1500 tonnes (15,000kN) (static) and 500 tonnes (5000kN) (cyclic), and vertical loads on each of the cross beams up to 1000 tonnes (10,000kN) (static) can be applied. Test fixtures can be designed which allow combined loads (axial plus bending) to be applied to components. During all of these load scenarios, internal pressures up to 2000bar (29,000psi) can be applied to the specimens inside.
It is fully serviced by an overhead crane with two hooks of five tonnes each (ten tonnes total capacity). There are also video cameras within the pit so that tests can be viewed remotely, as they take place.
To find out more about the specialised testing services at TWI please email contactus@twi.co.uk.