Higher MAOP not a wrap

By Stephen Barlas, Washington Editor | September 2008 Vol. 63 No. 9

Pipeline companies who have been pressing PHMSA to increase maximum allowable operating pressures (MAOPs) in three class areas have some problems with the proposal on that subject the agency released in March, raising questions about whether the Bush administration will issue a final rule before it leaves office.

Pipelines want PHMSA clearance to increase MAOP routinely as a means of increasing throughput and decreasing operating costs.

The proposed rule PHMSA issued last March would have allowed pipelines to increase MAOP to 80, 67 and 60 percent of specified minimum yield strength (SMYS) in Class 1, 2 and 3 areas as long as they meet certain preconditions having to do with the type of pipe used, how it is coated, how the companies check for dents and many, many other issues. Currently, the MAOP for sparsely populated Class 1 locations is a maximum of 72 percent of SMYS of the steel. The operating pressures in more populated Class 2 and Class 3 locations are limited to 60 and 50 percent of SMYS, respectively.

PHMSA has granted Special Permits to pipelines allowing the higher limits. But the agency wants to move away from those permits, which are labor intensive, and revise its policy in a new federal regulation. Alan Mayberry, director, engineering and emergency support at PHMSA, made a presentation at the June 10 meeting of the Technical Pipeline Safety Standards Committee. He outlined some of the changes PHMSA was considering making to the proposed rule it issued in March as a result of suggestions made by pipeline companies. But it was clear that while the impending changes were welcome, they did not go far enough for some of the representatives at the meeting.