# Heat Release Rates of Burning Items in Fires

A paper by Hyeong-Jin Kim and David Lilley (Heat Release Rates of Burning Items in Fires, AIAA 2000-0722, January 2000) summarizes experimentally measured heat release rates for more than 60 different items that could be involved in fires. The data sets used by Kim and Lilley include FASTLite, HAZARD, and the Building and Fire Research Laboratory data sets. As part of preparing PyroSim examples, we developed a spreadsheet that calculates the heat release rates using the data and method described in the paper.

Of course, a fire protection engineer is responsible for determining the appropriate heat release rate for any specific application and the data in the paper should not be used without careful evaluation. However, the paper does serve as a valuable guide to:

1. Provide reference data that helps understand fire behavior.
2. Show the extremely large range of heat release values that can be obtained for similar household items (for example chairs).

As part of preparing PyroSim examples, we developed a spreadsheet that calculates the heat release rates using the data and method described in the paper. In the Kim and Lilley paper, the experimental results are represented using t2 fires for the growth and decay periods, with a constant maximum heat release rate between these two periods.

During each time period, the heat release rate is calculated by:

The paper provides input parameters for each case.

Typical calculations for two different chairs from the FASTLite data set are shown below. Chair 1 is made of one-piece wood-reinforced urethane foam and Chair 6 has a wood frame with California foam and polyolefin fabric. As can be seen, the total duration of the fires (1900 compared to 315 seconds) and peak heat release rates (422.5 compared to 1960 kW) are very different. However, the total energy released is similar (270 compared to 231.9 MJ).

The HRR calculator is an Excel spreadsheet that can be downloaded from the PyroSim Resources page and from the following link. Heat Release Rate Calculator

## References

Hyeong-Jin Kim and David Lilley (Heat Release Rates of Burning Items in Fires, AIAA 2000-0722, January 2000).