Performance-based structural fire design
In the codes and standards reviewed, there is general agreement that the performance goals of structural design against fire are to limit risks to the individual and society, to directly exposed or neighboring property, and to the environment. Satisfactory performance can be demonstrated by engineering analysis or qualification testing. To achieve these overall goals, many countries are currently developing performance-based standards that would allow designers flexibility in the use of new materials and technology, while possibly reducing cost. According to Buchanan (2001), performance-based design starts with the setting of general, high-level goals, and then gets more specific with the definition of functional objectives and performance requirements that guide the designers to meet these goals. At the design level, performance-based standards recommend acceptable solutions and approved calculation methods, but leave open the possibility of alternative designs, provided these can be proven to meet the performance goals. Compliance with performance-based codes can be attained by using either prescriptive methods (sometimes called acceptable solutions or approved calculation methods), or performance-based design (PBD).
Society for Fire Protection Engineering (SFPE)
The SFPE Guide provides a general framework for performance-based design against fire.
The First step is to define performance objectives, which are to mitigate the consequences of fire in buildings in terms of loss of life, financial cost on the property, impact on operations and the environment, or maximum allowable conditions. These conditions include stability of the structure, the integrity of partitions, maximum temperature, the extent of the fire and smoke spread, and the spread of combustion products.
The second step is to develop performance criteria, i.e., assign threshold values for the temperature of materials and gases, toxic gas emission, thermal effects on structures, fire spread, fire barrier damage, structural integrity, damage to exposed properties and the environment, etc. These can be stated as either deterministic criteria, e.g., preventing flashover in the room of fire origin, or probabilistic criteria, e.g., reducing the probability of flashover below a threshold value.
The third step is to develop design fire scenarios
The fourth step is to develop trial designs for fire protection systems, construction features such as fire barriers, and operational procedures that meet the specified performance criteria for the design of fire scenarios.
The fifth and final step is to evaluate the trial designs and select the final design based on effectiveness, reliability, availability, and cost.
