Shim Installation Procedure & Safety Guide for Pipe Supports

Pre-Installation Safety Requirements

Before any shim installation work begins at a pipe support, field crews must complete several safety checks. Pipe support shimming often involves working at height on pipe racks, working near heavy suspended loads, and handling sharp metal plates that can cause cuts.

Safety Checklist Before Shimming
PPE requirements: Hard hat, safety glasses, steel-toe boots, cut-resistant gloves, high-visibility vest
Fall protection: Required when working above 1.8m (6 feet) on pipe racks or elevated structures
Lockout/tagout: Verify the pipe is depressurized and isolated if working on a live system
Load verification: Confirm the pipe is properly supported before removing or adjusting shims
Rigging inspection: Check all temporary supports, chain falls, or jacks before lifting pipe
Hot work permit: Required if grinding or welding is needed near the shim location

Step-by-Step Shim Installation Procedure

Step 1: Review Engineering Documents

Before going to the field, review the pipe support detail drawing, isometric drawing, and shim specification. Identify the required shim thickness, material, dimensions, and any special requirements such as welding the shim to the support steel.

Step 2: Inspect the Support Location

At the pipe support, inspect the bearing surface for damage, debris, rust, or irregularities. The shim bearing surfaces must be clean, flat, and free of burrs or weld spatter that could create point loading or prevent proper seating.

Step 3: Measure the Gap

Using feeler gauges, tapered gap gauges, or a measuring tape, determine the exact gap between the pipe shoe and the support steel. Measure at multiple points across the width to check for any tilt or unevenness in the support.

Step 4: Select and Prepare Shims

Select shim plates that match the required thickness within the project tolerance. Verify the shim material matches the specification. Deburr any sharp edges and verify the shim dimensions cover the required bearing area.

Step 5: Install the Shims

Place the shim pack on the support steel, centering it under the pipe shoe or clamp. If multiple shims are stacked, place the thickest shim on the bottom for stability. Verify the shims are seated flat with no rocking or gaps between plates.

Step 6: Verify and Document

After installation, verify the pipe alignment is within the specified tolerance. Record the shim thickness, material, number of shims in the pack, and the final measured elevation. Take a photo if required by the project QC plan.

Common Installation Mistakes to Avoid

Overhanging shims: Shims must not extend beyond the support bearing surface where they can be struck or dislodged
Too many thin shims: Avoid stacking more than 4 to 5 individual shims. Combine into fewer, thicker plates when possible
Mismatched materials: Using carbon steel shims on stainless steel supports creates galvanic corrosion risk
Unsecured shims: On vibrating systems or vertical surfaces, shims must be tack-welded or mechanically retained
Dirty surfaces: Rust, dirt, or paint between shims reduces load capacity and can cause settling over time

When to Tack Weld Shims

Tack welding shims to the support steel is required in several situations: when the pipe operates at elevated temperatures causing thermal cycling, when the support is subject to vibration from rotating equipment, when the shim could slide out due to thermal movement of the pipe, or when the project specification requires it for all permanent shim installations.

Tack welds should be small fillet welds placed at the corners of the shim. The welder must have the appropriate qualifications and the welding must comply with the project welding procedure specification.

Temporary vs Permanent Shim Installation

During construction, temporary shims may be used to set pipe elevation while waiting for final alignment verification. Temporary shims are often made from scrap material and are replaced with permanent, specification-compliant shims before system turnover.

All permanent shims must meet the project material specification, be properly documented, and be included in the as-built records. ShimSheet helps field crews track both temporary and permanent shims so nothing falls through the cracks during the transition.

Track Every Shim Installation in the Field

Use ShimSheet to document shim installations at every pipe support. Record dimensions, materials, and generate professional reports for QC handover.

Try ShimSheet Free

Frequently Asked Questions

What PPE is required for shim installation?

Minimum PPE includes hard hat, safety glasses, steel-toe boots, and cut-resistant gloves. Fall protection is required when working above 1.8m (6 feet). Additional PPE may be required by site-specific safety plans.

How many shims can be stacked at one support?

Most project specifications limit shim packs to 4 or 5 individual plates with a maximum total height of 50mm to 100mm. If more height is needed, the engineering team should evaluate alternatives.

Do shims need to be welded to the support?

Tack welding is required when the pipe is subject to vibration, thermal cycling, or when the shim could slide out of position. Many project specifications require tack welding for all permanent shim installations.