Knowledge Base

T15.00 - Pedestal Strength

The horizontal load test.

The T15.00 Horizontal Load Test forms part of the PSA MOB PF2 PS/SPU specification for raised access flooring. It is used to assess the ability of a pedestal and its fixing to resist horizontal loading without unacceptable movement, deformation or failure.

Unlike vertical load testing, T15 applies a lateral force to the pedestal, creating an overturning force at the pedestal base.

These forces can result from pedestrian traffic, movement of wheeled equipment, rolling server racks, installation activities, maintenance operations, accidental impacts and thermal movement within the building. The Horizontal Load Test verifies that the complete pedestal system can safely withstand these real-world conditions.

How the Test is Performed

The test is carried out using a pedestal installed on a representative subfloor in accordance with the StarFix installation instructions, including the specified adhesive and curing period.

Once the pedestal has fully cured, a calibrated horizontal load is applied to the pedestal head using a controlled test rig. The force is introduced at a specified height above the subfloor to create a realistic overturning moment, replicating the lateral loads experienced during normal service.

The load is applied gradually and maintained for the required duration while measurements are taken to assess the pedestal's behaviour under stress.

What is Being Evaluated?

The purpose of the Horizontal Load Test is to assess the overall stability of the pedestal assembly rather than simply the strength of an individual component.

During testing, engineers evaluate:

Resistance to lateral movement
Stability of the pedestal under horizontal loading
Integrity of the adhesive bond to the subfloor
Strength of the pedestal structure
Permanent deformation following loading
Any signs of cracking, loosening or bond failure

To achieve a successful result, the pedestal must resist the specified horizontal force without unacceptable movement or structural damage.

Why Adhesive Performance is Critical

A pedestal is only as secure as the bond anchoring it to the subfloor. Even the strongest steel pedestal cannot perform correctly if the adhesive is unable to transfer horizontal forces effectively.

StarFix® pedestal adhesives are specifically formulated to provide:

Exceptional shear strength
High resistance to peel and lateral forces
Excellent long-term adhesion to common construction substrates
Outstanding durability under repeated loading
Reliable performance throughout the service life of the floor

By maintaining a secure bond between the pedestal base and the substrate, StarFix® adhesives help ensure the complete raised access flooring system remains stable under both vertical and horizontal loading conditions.

Understanding a Failed T15 Test

A failed horizontal load test does not automatically indicate adhesive failure. The failure surface should always be examined to determine where the system has actually failed.

If adhesive remains firmly attached to the pedestal but brings away concrete, laitance or part of the subfloor surface, the adhesive bond may have exceeded the strength of the substrate itself. This is a substrate failure rather than an adhesive bond failure. Similarly, if adhesive remains bonded to the subfloor but separates cleanly from the steel pedestal, the pedestal surface or its coating should be investigated. Only where the adhesive itself separates internally should cohesive failure of the adhesive be considered.

Real-World Performance

The Horizontal Load Test represents one of the most demanding assessments of pedestal stability because it evaluates the complete installation rather than individual components in isolation. Passing this test demonstrates that the adhesive, pedestal and fixing system work together to resist the prescribed horizontal loading conditions.

Combined with rigorous quality control and independent testing, the StarFix® range of pedestal adhesives provides specifiers, contractors and building owners with confidence that pedestals are securely bonded and capable of maintaining the stability required in modern raised access flooring installations.