Determining risk tolerance of building clients
The Fire Safety Concepts Tree can help fire protection engineers quantify the level of fire risk in a building.
For many design professionals, the primary objective for the client is to provide a code-complying building in a cost-effective manner. The client generally assumes that code compliance results in an acceptable level of risk. However, there are clients that want to better quantify the level of fire risk that exists within their facilities.
Several years ago, Koffel Associates worked with a hospital client. Questions were asked of the hospital administration as to what would be an acceptable outcome should a fire occur in the facility. For the most part, they wanted the fire contained to the room of origin. Using their fire experience and data shown in the NFPA's Fires in Health Care Facilities report, one could determine what the likelihood would be that a fire would spread beyond the room of origin over a period of time.
NFPA 550: Guide to the Fire Safety Concepts Tree was then used to identify ways in which the risk could be reduced to an acceptable level. Hospital administration could then make a risk-informed decision as to whether they wanted to invest additional funds and provide a level of safety beyond that which was required by the applicable codes. In this instance, they did. The investment was in enhanced fire detection and not passive fire protection features. The enhanced fire detection also impacted the "Manage Exposed" branch of the tree, especially for the occupants (patients) within the room of origin. Again, the decision was reached based on looking at the overall Fire Safety Concepts Tree.
In today's market, when looking for alternative compliance methods or a means to reduce the fire risk, design professionals typically will do a qualitative risk assessment by comparing the level of risk to some known factor, such as a code-compliant building. This would be an appropriate method to ensuring that there remains some balance between passive and active fire protection features. It should be noted that this could result in increasing either the passive or active fire protection features at the "expense" of the other; but in the end, they should be proportioned to provide an acceptable level of risk.
William E. Koffel is president of Koffel Associates, a fire protection engineering design/consulting firm, and is recognized as an expert in the fire protection/life safety aspects of codes and standards. He is a member of the Consulting-Specifying Engineer editorial advisory board.