Industrial model

The National Research Council’s Institute for Research in Construction (IRC) has developed a new fire protection model that promises to play an important role in the design of fire protection systems in light industrial buildings.

The model, called FIERAsystem, was developed by researchers in IRC’s Fire Risk Management Program in collaboration with partners such as the Department of National Defence. The impetus came from the evolution occurring in Canada and other countries from prescriptive-based building codes to performance- or objective-based codes. The new type of code created the need for new design tools to demonstrate compliance. With an emphasis initially on warehouses and aircraft hangars, the FIERAsystem is intended to assist engineers and building officials in evaluating whether a selected building design meets established objectives for life safety and property protection.

FIERAsystem complements the capabilities of FiRECAM, a computer fire-risk cost assessment model developed for apartment and office buildings. In developing FIERAsystem, researchers recognized early that substantial differences exist between those residential types of buildings and light industrial buildings, hence the need for the new model.

While life safety remains a vital concern in light industrial buildings, the protection of property and need to continue operations become extremely important. Many more fire scenarios can occur in industrial buildings because of the available fuel. Occupant response and evacuation may take a less prominent role, while environmental impact and fire spread to adjacent buildings become more important. In addition, because light industrial buildings are each a unique situation depending on the building geometry as well as the processes and materials that they contain, we have to rely much more on experiments and sophisticated computer models rather than on statistical information to evaluate the effectiveness of their detection and suppression systems.

In the next stage of their work, researchers will expand FIERAsystem’s capabilities by increasing the fire scenarios it can handle, and by improving its ability to model the unique aspects of other industrial plants, arenas and shopping malls.

How FIERAsystem works

In using the new computer model, designers set fire safety objectives and describe the building, its components and contents. They select various fire scenarios, and evaluate each scenario’s impact on life safety, the protection of the property and interruptions to business. They compare the calculations with established objectives to ensure design options are adequate. If necessary they can then make design changes and re-run the models.

FIERAsystem models deal with fire growth and spread, smoke movement, structural behaviour in response to fire attack, and occupant response and evacuation. To define the project, FIERAsystem guides the user through a series of six steps. The first step is to define Building Characteristics and the second is to describe Occupant Characteristics — the factors which affect people’s abilities to receive and interpret fire cues and warnings and evacuate. The user then identifies Fire Safety Objectives and Appropriate Performance Criteria. These are based on the building’s characteristics and functions, as well as the owner’s fire safety expectations. He or she then chooses from a variety of Potential Fire Scenarios, including: solid fuel fires in a small compartment; liquid pool fires in open or enclosed spaces; storage rack fires; and generic fires represented by t2 Heat Release Rate (HRR) curves.

The next step is to select Fire Protection Options, including passive, automatic and manual systems, and finally to select Calculation Options to determine the type of analysis and the submodels required. These submodels can be used independently to evaluate individual design components such as activation time of heat detectors or sprinklers, or they can be used in conjunction with other submodels to perform a complete risk analysis.

The overall results for each fire scenario are the expected deaths, property losses and number of days that business will be interrupted. These results are then compared to established objectives and criteria to determine if the design options are adequate.

FIERAsystem enhancements will continue, further improving the model’s usefulness to engineers. CCE

For more information contact Dr. George Hadjisophocleous, Institute for Research in Construction/NRC, tel. 613-993-4757.