Description

The thicknesses of concrete elements required to achieve various Fire Resistance Ratings (FRR) in New Zealand are notional and based on overseas building codes and test results. Because of variation in the properties of the constituent aggregates, a test program was undertaken to determine the reliability of the notional ratings when applied to concretes contianing locally produced aggregates. The results showed that the current Fire Resistance Ratings used in New Zealand are adequate for the thickness tested. Indicative information has been collected on damage to concrete after firing and a technique for the measurement of residual compressive strength has been evaluated. Recommendations are made for further work in the extrapolation of data to other concrete thicknesses for both walls and floors; the assessment of the influence of loading, and performance of high stength concrete; and the use of techniques for assessing post-fire loadbearing capacity.