Spring Hanger Installation: Travel Stops, Hydrotest and Commissioning

A correctly sized spring hanger can still end up carrying the wrong load — most spring support problems we see traced back to site are installation and commissioning errors, not sizing errors. This note walks through the field procedure for variable spring hangers and constant supports, from crate to hot operation.

Step 1 — receiving and pre-installation checks

• Match the tag. Each unit is tagged to one support location and preset to that tag's cold load. Units are not interchangeable, even within the same size.
• Check the data sheet values — hot load, cold load, travel and direction — against the hanger schedule and the latest stress revision.
• Inspect for transit damage: casing, load scale window, indicator, rod threads and the travel stops themselves.
• Do not remove the travel stops at receiving. They protect the preset during handling and installation.

Step 2 — installation

• Lift by the designated attachment points — never by the indicator, scale plate or stop brackets.
• Make up the top attachment (beam clamp, welded lug or bolted plate per the arrangement letter) and the bottom connection (rod, turnbuckle, clamp or pipe shoe) as shown on the support drawing.
• Keep the assembly plumb. Rod angularity is commonly limited to a few degrees from vertical in industry practice — offsets consume travel and side-load the casing. Where the pipe moves horizontally as well, the offset should be pre-set opposite the movement so the rod comes plumb in the hot position, per the support drawing.
• Leave adjustment thread engagement per the data sheet — you will need turnbuckle range later for load adjustment.

Step 3 — hydrotest with stops in

During hydrotest the line carries water weight far above the operating load. The travel stops turn the spring unit into a rigid support so that this temporary load bypasses the spring:

• Verify every spring support on the test loop has its stops fitted before filling.
• After the test, drain fully before releasing anything.
• Constant supports ship with equivalent locking devices — same rule, same sequence.

Step 4 — releasing the stops

• Release after hydrotest and drain-down, with insulation substantially complete (insulation is real weight — releasing before it is fitted shifts the cold position).
• Remove stops progressively and keep them tagged and stored — they go back in for any future hydro or major maintenance.
• After release, the indicator should sit at the cold position marked on the scale. A small deviation is normal; significant deviation means weight differs from design — check water left in the line, missing insulation, or interference at other supports before touching the turnbuckle.

Step 5 — hot position check

• At stable operating temperature, walk the line: each indicator should sit at the hot position.
• An indicator hard against either end of the scale means the support is topped or bottomed out — it is carrying the wrong load or the line is moving more than designed. Flag it for engineering; do not simply crank the turnbuckle.
• Record cold and hot readings per tag in the commissioning dossier — they are the baseline for every future outage inspection.

Field mistakes we see most often

Related reading: Spring hanger selection guide with worked example · Variable vs constant spring hangers · MSS SP-58 hanger types, explained