Dead leg definition

From: <M.>
Date: Thu Dec 13 2007 - 14:42:00 EST

Dear Colleagues

The definition of dead legs in API 570 is "Components of a piping system that normally have no significant flow. Examples include the following: blanked branches, lines with normally closed block valves, lines with one end blanked, pressurized dummy support legs, stagnant control valve bypass piping, spare pump piping, level bridles, relief valve inlet and outlet header piping, pump trim bypass lines, high-point vents, sample points, drains, bleeders, and instrument connections". My question here:

Part of designing the piping system in hydrocarbon facility is the inclusion of vents (welding boss+nipple+cap) at the highest point and drains at lowest point, although those vents and drains are small in size 3/4 or 1 inch most of the times and very short in distance, however, they might be considered dead leg per API 570 definition since the they are points of stagnations. Can some one tell me other industry standard which specifies the minimum length of branch piping in order to be considered as dead leg. How can we overcome such conflict? Appreciate your assisstance

Khaled Mahmoud
Jeddah Refinery Received on Thu Dec 13 14:42:00 2007

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