Pipe Support Design Flashcards

What is the primary purpose of a pipe anchor in a piping system?

Answer: To restrain all pipe movement in all directions at a fixed point

An anchor restrains all translational and rotational degrees of freedom, fixing the pipe completely at that location.

Which type of pipe support allows axial movement but restricts lateral movement?

Answer: Guide

A guide restrains lateral (transverse) movement while permitting axial displacement along the pipe centerline.

Which MSS standard governs the materials, design, and manufacture of pipe hangers and supports?

Answer: MSS SP-58

MSS SP-58 specifically covers pipe hangers and supports — materials, design, and manufacture, including component types and load ratings.

What is the primary advantage of a variable spring hanger over a rigid rod hanger?

Answer: It accommodates vertical thermal movement while continuously supporting pipe weight

Variable spring hangers compress or extend as the pipe moves thermally, maintaining a changing but continuous support load throughout the travel range.

Which pipe support device allows slow thermal movements but locks up rigidly under dynamic loads such as vibration or seismic events?

Answer: Snubber

Snubbers (hydraulic or mechanical) permit gradual thermal displacement but engage and provide rigid restraint when subjected to rapid dynamic loading.

What is a 'dummy leg' in pipe support design?

Answer: A short pipe extension welded to the main pipe to transfer load to a structural support

A dummy leg is a stub pipe section welded perpendicular to the main pipe (often at elbows) to transfer pipe loads directly to grade or structural steel.

According to MSS SP-69, support spacing tables are primarily based on which variables?

Answer: Pipe size, fluid specific gravity, and allowable sag

MSS SP-69 span tables account for pipe outside diameter, pipe schedule, fluid weight (specific gravity), and a standard allowable mid-span deflection to limit sag.