Pipe Support Types & Shimming Guide

Overview of Pipe Support Types

Pipeline and process piping systems use various types of supports to carry the weight of the pipe, control thermal movement, and resist dynamic loads. Each support type has different shimming requirements based on its function and the loads it carries.

Rest Supports (Simple Supports)

Rest supports are the most basic type. The pipe or pipe shoe simply rests on a structural steel beam or concrete pedestal. The pipe is free to move laterally and axially on the support surface.

Shimming Considerations

• Shims are placed between the pipe shoe and the support steel to achieve design elevation
• Full-width shims are required to distribute load evenly across the bearing surface
• Shim material should match the support steel material to prevent galvanic corrosion
• Rest supports are the most common type requiring shimming on pipeline projects

Guide Supports

Guide supports allow the pipe to move axially (along its length) while preventing lateral movement. They typically consist of steel plates or angles welded to the structural steel that straddle the pipe or pipe shoe.

Shimming Considerations

• Vertical shims under the pipe shoe set the elevation, same as rest supports
• Lateral clearance between the guide plates and pipe shoe must be maintained per specification
• Over-shimming can change the effective clearance if the pipe shoe geometry shifts
• Document both vertical shim dimensions and lateral clearance measurements

Anchor Supports

Anchor supports fix the pipe in all directions, preventing both axial and lateral movement. They are critical stress control points in the piping system and are typically located near equipment nozzles and expansion loops.

Shimming Considerations

• Elevation accuracy is critical because anchor points directly affect nozzle loading on equipment
• Tighter tolerances are typically specified at anchor supports compared to rest supports
• Shim packs must be secured to prevent movement under thermal and dynamic loads
• Some anchor designs require shims to be welded or tack-welded in place

Slide Plate Supports

Slide plate supports use low-friction bearing surfaces (often PTFE or graphite-coated plates) to allow the pipe to move with minimal resistance. They are used where thermal expansion would create excessive friction on standard rest supports.

Shimming Considerations

• Shims are placed below the slide plate assembly, not between the sliding surfaces
• The sliding surface must remain flat and level after shimming to function properly
• Check that shim installation does not create a tilt that would bind the slide plate
• Record the slide plate orientation along with shim dimensions for as-built records

Spring Hangers and Supports

Spring hangers support the pipe from above and allow vertical movement during thermal expansion. Variable spring hangers and constant spring hangers each have specific shimming requirements.

Shimming Considerations

• Spring hangers are typically set at a cold load position during installation
• Shims at the connection point to structural steel affect the spring's operating range
• Incorrect shimming can cause the spring to top out or bottom out during operation
• Travel stops must be removed after shimming is verified and before system startup

Trunnion and Dummy Leg Supports

Trunnion supports are welded directly to the pipe and rest on structural steel. Dummy legs (also called pipe stanchions) are short pipe sections welded to the main pipe that act as support legs.

Shimming Considerations

• Shims are placed under the trunnion or dummy leg base plate
• The weld connecting the trunnion to the pipe means elevation adjustments can only be made at the base
• Ensure shims provide full bearing under the base plate to prevent point loading
• Critical for elevated pipe rack installations where structural steel tolerances create gaps

Tracking Shims Across Support Types

ShimSheet allows you to organize pipe supports by type, label, and location within your project. Whether you are shimming rest supports on a pipe rack or precision-shimming anchor points near equipment, every shim dimension is captured digitally and available for instant reporting.

Frequently Asked Questions

Which pipe support type requires the most precise shimming?

Anchor supports and supports near equipment nozzles typically require the tightest tolerances, often plus or minus 1-2 mm, because they directly affect equipment loading and piping stress.

Do slide plate supports need shims?

Yes. Shims are placed below the slide plate assembly to set elevation. The sliding surfaces themselves must remain flat and unobstructed for proper operation.

Can I track different support types in ShimSheet?

Yes. ShimSheet lets you label and organize supports by any naming convention. You can group supports by type, area, line number, or any other project-specific categorization.