Hence, if a fatigue safety factor of 10 is used on the experimental data, the range of design life is between 2,000 cycles and 77,000 cycles considering a stress range of 36% SMYS
* Pre-1970 pipe in high consequence areas (HCA) that operates at greater than 20 percent of specified minimum yield strength (SMYS
* Pre-1970 pipe in high consequence areas (HCA) operating at greater than 20% of specified minimum yield strength (SMYS
Service need and use among SMYs
is poorly understood, partly because of limited large-scale data collection efforts that include sexual minority populations.
* Type B gathering lines include metallic lines with an MAOP of less than 20% of SMYS
, as well as nonmetallic lines with an MAOP of 125 psig or less, in a Class 2 location (as determined under one of three formulas) or in a Class 3 or Class 4 location.
Six months after giving pipelines the green light to use high-stress pipelines more widely, the Pipeline and Hazardous Materials Safety Administration (PHMSA) is now highlighting safety concerns with new pipelines operating at 80 percent of specified minimum yield strength (SMYS
Pipe 15% below the mandated SMYS
was found on several new pipeline projects.
Department of Transportation Pipeline and Hazardous Materials Safety Administration (PHMSA) finalized new rules allowing transmission companies to operate pipeline segments in Class 1 locations at 80 percent of specified minimum yield strength (SMYS
) of the steel.
Many operators perform an engineering evaluation to determine how susceptible the pipeline is to seam failures based on operational parameters that include the percent of SMYS
at M(A)OP, the severity of pressure cycling, and the data associated with historical pressure tests.
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.
However, this exception only applies to steel pipelines to be operated at 30% or more of SMYS
. A similar exception is not allowed if the component other than pipe is being replaced or added to steel pipelines that operate at less than 30% of SMYS
([section][section] 192.507 and 192.509), service lines ([section] 192.511) or plastic pipelines (CFR 192.513).
Currently, the MAOP for sparsely populated Class 1 locations is a maximum of 72 percent of the specified minimum yield strength (SMYS
) of the steel.