Commercial Construction Considerations: Performance Based Design Process

July 30, 2008

Since this series started, we have discussed the general commercial construction process along with several of the key components in a commercial building. We started by looking at the design process and building layout. Then, we began a more in-depth look at steel, concrete, and wood as the primary structural components of a commercial structure.

.,p> Last month, we explored the construction of roofs and how they play into fire attack, mainly with ventilation. This month I want to take a look at something a little different -- performance based fire protection.

Buildings are typically designed around the code for the jurisdiction where they are being constructed, and this is an example of a prescriptive design.

.,p> The designer knows the construction type and occupancy and follows a prescription to insure that the design is met. According to Hurley and Roesnbaum, University of Maryland 2008, there are two disadvantages to using these prescriptive codes: "They can only protect against events of a type that have occurred in the past. Major fires are low probability/high consequence events. Because of their nature some types of rare events have not yet occurred." They go on to say that "They can stifle innovation. By specifying certain types of methods and materials, it can be difficult to introduce new methods and materials into the marketplace."

So what is performance based design and what does it mean to the firefighter on the street? The SFPE Engineering Guide to Performance-Based Fire Protection, 2007 edition, defines it as "an engineering approach to fire protection design based upon agreed upon fire safety goals and objectives, deterministic and/or probabilistic analysis of fire scenarios, and quantitative assessment of design alternatives against the fire safety goals using accepted fire engineering tools, methodologies, and performance criteria.

Performance based design is a method to determine what the fire protection goals for a given facility are based on a number of factors including use, occupancy, construction type, layout, and fire department response. Then using that data to analyze the facility to determine what type of fire scenario could develop. Once scenarios are developed the designer will then determine if the goals are met by using calculations, real life models or computer models, or a combination the all three. Performance Based design is a method of fire protection design that should provide a fire protection system that addresses the specific needs of the building, the owner and the responding fire department."

It should be noted that this method of fire protection design does have several codes that govern its use. The International Code Council (ICC) Performance Code for Buildings and Facilities, the NFPA 101: Life Safety Code and NFPA 5000: Building Code provide guidance for designers using this method of design.

The SFPE Engineering Guide to Performance-Based Fire Protection, 2007 outlines the process for this to be completed and it should include you, as members of the fire service. The fire department needs to be included throughout the design process. From the determination of goals and the review of the testing of the design the fire department should be able to sign off.

One of the very first tasks the fire protection designer must complete when using a Performance Based Design is developing a list of stakeholders. Stakeholders should include the fire department and the authority having jurisdiction over building construction. Numerous other stakeholders include other designers and the building owner.

The building owner's goals will generally be the most influential. It is very important the fire department is aware of the goals for the facility. This is a good time for firefighters to share what they think some of the possible goals should be. For example, the need to have the building remain structurally sound for the duration of rescue and suppression operations. The design team, which includes the fire department, may determine that since a particular building is a warehouse and the goods stored inside are of little value that there is not need to try to save the building and only the exposures need to be protected.

It is very important that units responding to that location are aware of this. If the fire protection design simply calls for exposure protection, there is most likely limited fire protection of the structural members inside the building. This could lead to rapid collapse of the facility which could be extremely dangerous if firefighters are in the facility.

Another reason fire departments need to be involved in all portions of the performance based design is the assumptions that are made in order for the calculations and models to prove that the design will work. To complete the calculations and models it is necessary to assume many things about the building, including combustible loading, occupancy and the proper operation of the fire detection and sprinkler systems if present. Buildings designed using a performance based method need to maintain the same occupancy, fire load and fire protection system for the life of the building.

For example, if a building is designed to be office space, you cannot relocate a day care center into one of the spaces. The original designer intended there to be mobile adults in the building who were familiar with how to exit. If you change to a daycare the occupants will generally need assistance leaving the space due to their age. The same can be said of fire load, we will use the office space example again, if a building is designed for office space it cannot become a medical records storage facility without dramatically changing the outcome of a fire. When conducting walk-throughs or inspections of buildings that have been designed using the performance method insure that the building remains the same unless a redesign is completed.

Performance based design is another method of designing the fire protection systems for new or renovated facilities. It requires the input of many stakeholders and none is more important than the fire department. Buildings in your response area that have been designed using this method should be flagged to insure inspections occur and the firefighters or inspectors know what to look for. I believe performance based design will provide more appropriate fire protection for firefighters and building occupants, however you need to work with the local code officials to insure you are involved with the process from the very beginning.

The Society of Fire Protection Engineers has published The Code Officials' Guide to Performance Based Design Review for those of you charged with enforcing codes. Which will provide detailed information on how to work through the process.

MATTHEW STIENE, a Contributing Editor, is a project manger for the Mecklenburg County Real Estate Services Department, and a firefighter with Robinson Volunteer Fire and Rescue, in Charlotte, NC. He is a licensed professional engineer in North Carolina, New York and Pennsylvania, and is a certified facility management professional. To read Matthew's complete biography and his archived articles, click here. You can reach Matthew by e-mail at [email protected].

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