Re-evaluating Evaluation : New Materials, New Methods

In today’s world of energy-efficient building requirements, structural insulated panels (SIPs) remain an attractive option. Modern SIPs combine the strength of wood with the energy-saving attributes of cutting-edge foam plastic insulation, to create a cost-effective solution for construction professionals. These sandwiched panels stand ready to meet the building codes of tomorrow, but many fear that the lack of adequate, systematic testing of these new materials may hinder their popularity and stifle their widespread implementation.

The Forest Products Laboratory (FPL), APA – The Engineered Wood Association, and the Structural Insulated Panel Association are on a mission to change this. Because of their unique construction, researchers believe SIP walls must be tested differently than more common light-frame walls. Unlike traditional walls, SIP walls are required to bear weight on their cap and sill plates, so that vertical loads from the story above are effectively transferred down to the foundation.

Creep test setup for a structural insulated panel.

A structural insulated panel undergoing performance testing at FPL.

This “restrained” method of evaluation yields the most accurate data for SIP performance.

Until recently however, SIP walls have been evaluated in the same way as their conventional light-frame counterparts, using an “unrestrained” configuration. Researchers fear that these tests may not realistically reflect the lateral load-bearing ability of the SIPs.

SIPtest

A diagram illustrating how the 24 full-size SIPs will be tested.

Between May 2015 and August 2016, 24 full-size SIP walls will undergo a carefully monitored regime of restrained, lateral load performance tests, which represent the most common configurations used by industry professionals. Researchers will consider a wide range of variables — from the obvious, such as wall thickness and type — to the minute, such as nail size and nail spacing. The final report will be prepared by December 2016.

Results of this project will not only increase the accuracy SIP performance data, it may help guide further evaluations of similar building materials in the future. Most importantly, it will provide construction and design professionals with the data they need to make informed choices when considering these new building materials, so that they can keep tomorrow’s buildings efficient and safe.

For more information, please see this Research in Progress.