Saving cash and ensuring maximum safety were the sole considerations of one oil and gas contractor when, at short notice, it mobilised TWI to solve a problem.
'The customer had built an LNG tank and installed associated pipework between 50 and 600mm diameter when, during commissioning, they detected ferritic contamination in the weld pipelines.' recall project leaders Tat-Hean Gan and Alan Day.
'We were given a few day's notice to mobilise and were out there for a month' recalls Gan. 'TWI prides itself on being able to respond quickly. We were established on site within five days, and performing an inspection rate of 100 welds per day within the week.'
The material was a 304L stainless steel. Simple inspection by the client using magnets revealed early on that some of the welds were ferritic material.
'But magnets are not an entirely accurate way of positioning the flawed areas so the client came to us with a request to devise a technique using eddy current equipment to inspect for contamination' says Gan. 'They wanted to be able to position the flawed regions accurately'.
The client was quick to acknowledge that the contamination was not caused intentionally. 'Accidents happen' says Gan. 'Occasionally sub-contractors, unfamiliar with the specific requirements of a job, pick up the wrong consumable. We were able to identify the troubled regions on time and to budget to the satisfaction of the client.'