Clearances - hdbk1132990180

DOE-HDBK-1132-99

1.3.2

Clearances.

Adequate clearances should be provided between pipe and other piping

systems, ductwork, structural steel and concrete, equipment, and cable

trays to permit interference-free erection and allow for maintenance and

in-service inspection and reduces the possibility of impact during a

seismic event.

Proper clearances will allow for the removal of valves and other

equipment. Piping should not be routed across floors, walkways, or

working spaces if that location could be a hazard.

Overhead clearance to the bottom of piping or pipe racks should address

the following guidelines:

7 feet, 6 inches over walkways inside buildings,

15 feet elevated yard piping and/or pipe racks over roadways,

22 feet over railroad tracks.

Vents and Drains . Vents and drains facilitate the filling, hydrostatic testing, and

1.3.3

draining of piping systems. The following guidelines provide the piping system

with adequate venting and draining.

Where possible, the piping system should be designed with only one high

point and one low point; vent and drain connections should be provided

at these locations.

Liquid systems 2.5 inches and larger in diameter should be vented and

drained at all high and low points.

Liquid systems 2 inches and smaller in diameter should be vented and

drained at the highest and lowest points in the system. Piping of this size

self-purges any intermediate high and low points.

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