New test chamber comes alive
17/12/2010
Extremely high pressure testing at TWI’s Cambridge laboratories entered a new era recently with the completion of a large subterranean pressure test pit. Serving the engineering needs of the oil and gas sector in particular, it is believed to be one of the best equipped facilities of its type in Europe.The advent of the new test facility has largely been triggered by the start of a group sponsored project on strain-based assessment of pipeline girth welds. The specimen under test will be both strained in bending and pressurised simultaneously.
“The idea is not necessarily to take it to destruction,” explains Project Consultant Henryk Pisarski. “But we’re applying very high loads at extremely high pressure, up to 1000 bar. The pipe will be bent considerably, in a four point loading test. It’ll be strained beyond its yield point. There’ll be an intentional crack within it…so the potential exists for things to go wrong. Without a remote pit like this you run the risk of damaging adjacent laboratory equipment, so we decided now is a perfect opportunity to build a dedicated facility.”
Pisarski believes that what puts TWI’s facility in the forefront is the huge back-up support offered behind any test work it performs: “We’ll pressurise it of course, but perhaps the client will want it to be strain gauged and instrumented. We can do that. We can carry out all the material behaviour analysis, if and when it fails. Whatever happens, we can do all the post-test investigation under one roof because we have all the metallurgists and engineers and equipment we need here at TWI. We can also compare the reality of the test with the results of numerical modelling.”
For a third of a million pounds TWI certainly has an impressive installation. Measuring eight metres by three in plan, the 2.5 m-deep reinforced concrete bunker comprises a metre-thick floor with 700 mm-thick walls.
Now that it has an established controlled facility, rather than building a temporary structure for each new project, it is expecting a number of short notice projects related to internal pressure testing and external loading. Already there are half a dozen jobs on the waiting list related to last year’s destructive testing of electrical resistance welded pipe.
To learn more about TWI’s new pressure test facility, contact henryk.pisarski@twi.co.uk or phil.robinson@twi.co.uk
