Consequential rupture of gas pipeline

In the earlier part of the year 2003, various pipeline ruptures were caused by sabotage activities in the southern part of Pakistan. The event being presented in this paper was fascinating because a pipe, which was blasted with the help of explosives, subsequently caused another pipe (buried 20 ft away) to rupture through slow and gradual consequential erosion. On 8 April 2003, two parallel-running gas pipelines (30 and 24-in. diameters), in the main gas transmission pipelines-network of Pakistan, were ruptured. The 30-in. line was the first to rupture (at about 3.30 AM), while after a time interval of about 80 min the 24-in. line also developed a rupture. At the site of the rupture, the 30-in. line passed over an irrigation canal, while the 24-in. line was buried a few feet below the canal-bed at a horizontal distance of about 20 ft from the 30-in. line. The above-ground 30-in. line was ruptured with the help of an explosive device that had been placed in the space between the pipe and the top of the canal-bank. The blast created an opening of about 4 x 10 in. at about 5 o'clock position. The leaking gas (a gas-jet, to be exact), which was co-incidentally directed towards the nearby-buried 24-in. line, caused a 'sand-blasting' action on the surface of the 24-in. pipe. The slow but persistent abrasion of the 24-in. pipe by the 'sand-blasting' caused a gradual reduction in the wall-thickness of the pipe with the result that when the wall-thickness had been reduced to a level that it was unable to support the inside gas-pressure of 1000 psi, the pipe developed a longitudinal rupture. (c) 2005 Elsevier Ltd. All rights reserved.