A pipe bent consists of a vertical column or columns and a horizontal structural member or members that carry piping systems, usually above headroom.

The line sizes that are installed in the rack establish the bent spacing. Generally 2” is the smallest line size we use in the pipe rack to avoid intermediate supports.

Below is a typical pipe span chart and shows how far a particular line can span on the basis of size, schedule, liquid or vapor, and insulated or bare pipe.

Pipe racks are tailored to a specific plant; pipe sizes in chemical plants are smaller than those found in refinery units.

If a plant requires a 16-ft (4,900-mm) spacing, the variation in following drawing allows for a 32-ft (9,700-mm) spacing by adding intermediate bents supported from spandrels.

Spandrels are horizontal structural members located along the longitudinal centerline that are used for structural stability, pipe support, or intermediate pipe bents.

Doubling the column spacing as shown in 2A of following figure may be required to cross roadways or avoid underground obstructions.

The civil and structural engineers should be consulted to review the economics of the approach.

Each bay between two passing columns shall have secondary structural members at a span of 3m to enable supporting of small bore lines.

The spacing between pipe rack portals shall be taken as 6M in general. However it can be increased to 8M depending on the size of the pumps to be housed below pipe rack, in which case an intermediate structural member may be provided in pipe rack for tier depending on line size.