Tests show charring helps cross-laminated lumber resist fire

Full-scale tests by the National Research Council of Canada have shown that cross laminated timber assemblies have good fire resistance, even when they are unprotected and under full loading conditions.

The NRC recently launched a study with FPInnovations to develop a methodology to encourage the design of buildings using cross-laminated timber (CLT), which is a relatively new building system in North America.

In its newsletter, Construction Innovation, NRC reports that the charring of the wood helps it to keep its strength: “As wood burns it forms a thick char layer which acts as a low-density insulator that protects the wood underneath it from elevated temperatures. Understanding charring rates (a measure of the char depth over time) is fundamental to estimating the remaining thickness of full strength wood, which in turn designers can use to calculate the residual strength of members for a given fire exposure.”

The article provides results of eight full-scale experiments with tables of results.

To view the article, click here.

www.nrc-cnrc.gc.ca/ci