In the "fire risk characterization" step of the new PBFPD process, fire protection engineers (FPEs) collected the system targets (i.e. elements of the system which contribute to its overall performance). Then, in the "damage criteria estimation" step, for each considered targets, FPEs have to quantify how these targets are affected by direct and indirect effects of fire events, events involving a fire and defined between two "chronic" states of the system.

After reviewing the two decades of worldwide experience using standards, codes and guidelines related to PBPFD for buildings [1], we concluded that the performance criteria gathered in the current codes, standards and guides and guidelines:
- should be called "damage criteria" as they quantify more a threshold value at which building occupants (and contents) are damaged than the performance of the considered project to withstand fires,
- only include the direct effects of a fire (people and building contents are affected by high temperatures, high toxic fire effluents and low visibility preventing occupant evacuation or rescue).

As the new engineering process is target oriented, it is essential to get the metrics allowing the estimation of the potential damage to the targets. Damage criteria metrics would have to include:
- typical criteria related to fire effects to humans (due to thermal threat, toxic threat and loss of visibility which impedes evacuation),
- damage criteria related to stampede,
- damage criteria related to indirect fire threat to people,
- damage criteria related to safety equipment, building contents (e.g. for heritage preservation) and
- damage criteria related to the use of fire protection measures (sprinkler, fire fighting) on building contents and systems.

These damage criteria have to be collected and the process by which the damage is assessed has to be a result of an agreement within the scientific community not only involving fire protection engineers but also:
- toxicologists, psychologists, etc. when the targets are related to the life safety objective,
- operators, electronics engineers, etc. when the targets are related to the business continuity objective,
- Structural engineers, etc. when the targets are related to the property protection objective.

[1] A. Alvarez, B.J. Meacham, N.A. Dembsey, J.R. Thomas, 20 Years of Performance-Based Fire Protection Design: Challenges Faced and a Look Ahead, Journal of Fire Protection Engineers, submitted Aug, 12th 2012, submission number: JFE-12-0035

Alberto Alvarez - W3PI (2012-10-02)