By James G. Munger, Ph.D., MIFireE, CFPS, and Robert A. Neale
An emerging new philosophy in modern building designs may mean big changes are in store for fire suppression personnel. For many years, fire officials have performed preincident surveys and developed strategic and tactical plans to identify and mitigate hazards in buildings and facilities constructed under “prescriptive” building and fire codes. Now, architects, engineers, fire marshals, and building officials are exploring new ways to construct buildings that employ modern materials, nontraditional construction methods, alternative fire protection systems, and creative new designs. This new approach is known as performance-based designs.
Performance-based designs employed in sophisticated and challenging construction projects may not adhere to traditional building codes, and the fire protection features on which we have learned to rely may not exist. Consequently, comprehensive preincident planning and regular inspection are imperative to ensure fire departments protect lives and property—including their own.
Firefighters may discover that the fire protection features with which they have been familiar—such as fire separation walls and smoke management systems—don’t exist in these new buildings. Many incident commanders have made successful defensive stands at four-hour-rated fire walls, and if those walls don’t exist, alternate plans must be made.
PRESCRIPTIVE CODES AND PERFORMANCE DESIGNS
Fire suppression personnel should not suspect that buildings are becoming less safe with these new designs. In fact, the opposite may be true.
Many local, state, and national building codes have evolved in the past century based on observed events and public demand for improvement. When 492 people died in Boston’s Cocoanut Grove, building codes changed to require that doors swing in the direction of exit. Fire codes addressed combustible interior decorations. After 64 people died in the Hotel LaSalle in Chicago and another 119 died in Atlanta’s Winecoff Hotel, the codes addressed the issues of enclosing vertical openings to minimize fire and smoke spread.
Other recent changes have been based on hazardous-materials regulations, improvements in fire detection and protection systems, and an overall better understanding of fires and how they perform in buildings. However, not all of these code changes have been based on scientific or engineering principles. Many of these code changes have resulted in what are called “prescriptive” requirements. The building and fire codes prescribe exactly what fire protection or life safety strategy must be employed to meet the intent of the code.
For example, most building codes require two- or four-hour-rated area separation or fire walls to divide the floor area of buildings into spaces where the fire department can be expected to control a fire. Some structures, based on their size or use, require the installation of fire sprinklers. Others, because of their height, require standpipe systems to make the firefighters’ job easier by not having to string fire hose up stairways.
Over time, firefighters learn to rely on these features and include them in their preincident plans. Look at the preincident plans in your station. Not only do they include the access roads, building footprint, and fire hydrants, but they probably include fire wall and door locations, fire department sprinkler and standpipe connections, smoke management system controls, and known locations of hazardous materials and processes.
Some plans even might include preincident strategic and tactical instructions. In one case, the strategy might be to confine a fire to one-quarter of the building, while the tactics to be employed include supplementing the sprinklers, establishing secondary water supplies, starting fire pumps, and setting up defensive master streams.
A common tactic in high-rise firefighting is to connect hoselines to a standpipe system in a fire-rated stair enclosure before entering the floor to attack the fire.
These tactics have become common because of the consistency among building and fire code requirements for structures based on their size and use. With prescriptive building codes, fire departments operating in any state or territory can predict how a building will be erected and outfitted for fire protection.
Traditional code requirements may be tossed aside, however, where performance-based designs and codes are employed. Rather than using prescriptive lists of requirements, performance designs apply scientific data on fire and smoke spread, combustion principles, and human behavior to building designs and construction. Firefighters should not expect to find all of the same fire protection features to which they are accustomed in these buildings, but alternate methods likely are provided. Essentially, designers may be creating their own building code for each unique structure.
For example, as part of a performance design, the architect and engineer may be able to show that all occupants can be evacuated within a specific period of time, thereby eliminating the need for fire resistive exit enclosures. Or, more commonly, they may show through fire testing that sprinklers would not be effective in an extremely tall ceiling configuration and therefore could be omitted.
Before a performance design is implemented, those persons interested in the successful outcome get together to discuss their goals and objectives for the project. These participants are called stakeholders and should include the local fire officials (prevention, engineering, and suppression), emergency medical services, hazardous-materials emergency response teams, and preincident planning specialists.
This is an important time for fire suppression personnel to look at the proposal and offer their comments. Address significant fire suppression concerns (water supply, access roads, hydrant placement, and fire suppression equipment) early in the discussion so they can become part of the preincident plan.
THE IMPORTANCE OF PREINCIDENT PLANS
All fire officials know it is better to be prepared than to be sorry. Information gathered and evaluated before an incident can be the difference between a successful and unsuccessful outcome.
An important part of preincident planning when dealing with performance-based designs is to visit the property regularly and update the plan as needed. To assist the fire department as well as the owners and occupants of buildings, the National Fire Protection Association developed NFPA 1620, Recommended Practice for Preincident Planning. This document was first published in 1993 as NFPA 1420, Preincident Planning for Warehouse Occupancies. Since its original issue, the document has been expanded to cover all types of occupancies. It is anticipated that in the near future this document will be revised from a “recommended practice” to a “standard.”
As NFPA 1620 points out, a preincident plan is one of the most valuable tools available for aiding emergency responders in effectively controlling an emergency. A preincident plan should not be confused with inspections, which are intended to identify fire hazards and monitor code compliance. Proper planning involves evaluating the protection systems, building construction, contents, and operating procedures that can impact emergency operations. Unlike fire prevention or fire safety inspections, a preincident plan assumes that some type of incident will occur.
Performance-based designs often are based on scientific or engineering studies and computerized fire modeling programs that predict what should happen in the event of a fire. To ensure the models are valid and the project stays within safe limits, these designs incorporate “bounding conditions.” A bounding condition is one that, if changed, would result in a significantly different outcome.
As a hypothetical example, the bounding conditions on a high school chemistry lab design might include the fact that no more than two gallons of denatured alcohol are stored in the room. The fire protection system then would be designed to control a fire in that space with that amount of fuel. If 20 gallons of alcohol are brought into the room, the fuel load is increased substantially. This situation would exceed the bounding conditions and perhaps result in a fire protection system failure.
Preincident plans should identify the bounding conditions, and fire personnel should have a method to identify and report changes to get them corrected.
PREINCIDENT PLANNING CONSIDERATIONS
Key considerations for preincident planning of performance designs include many of the factors already identified in NFPA 1620.
- Physical elements and site considerations. There are three major factors identified in physical elements and site considerations: building construction, building services, and external conditions. Building construction includes not only the critical structural elements, combustibility, and size but also window and door access, roof construction, opening protection (fire doors), and significant design features such as atria that may allow smoke and fire to spread vertically through many stories. Building services include water (fire protection and domestic), sewer, electric, gas, steam, liquid fuels, emergency power, and elevators. Site considerations include exposures, road and bridge access, slopes, security features, and potential environmental impact of an incident and how it might be mitigated.
- Occupant considerations. Occupant issues include the number and “type” of persons who may be in or around the facility at any time. How many people will be there at any time? Are workers or visitors limited to specific time shifts, or is there around-the-clock use? Are people capable of escaping an incident on their own? Do they need staff assistance because they are bedridden or incarcerated? Does the facility have its own emergency evacuation and care plan that coincides with the fire department’s?
- Water supplies and fire protection systems. NFPA 1620 recommends a thorough assessment of the water supply and fire protection systems. The preincident plan should identify on-site water supplies and locate alternate sources in the neighborhood. The estimated fire flow should be computed beforehand using recognized formulas and water supplies capable of delivering that flow clearly identified. Fire protection equipment features—such as fire department connections for sprinklers and standpipes, main control valves, fire pump controls, fire alarm systems, and smoke management systems—should be included in the plan and operating sequences for sophisticated systems explained in easy-to-understand descriptions.
- Special hazards. One of the key elements of any preincident plan is the recognition and identification of special hazards. This is especially important in the area of performance-based designs where alternate means of protection may have been employed. Special hazards include obvious items such as explosives or toxic materials and some less-obvious ones such as electrical or mechanical hazards, confined spaces, inert atmospheres, openings between floors, complex product piping systems, and unique architectural features.
Fire departments have recognized the value of preincident planning for a long time. It is better to arrive on the scene of an incident prepared to address its unique hazards than to let the incident control the response. With performance-based designs, the potential variations in building layout, means of access and egress, and fire protection features may vary dramatically from those with which fire officers are familiar.
Do you want a better understanding of performance-based design? The United States Fire Administration’s National Fire Academy offers a new six-day course called “Evaluating Perfor-mance-Based Designs.” The course is intended to help local fire and building officials obtain familiarity with performance-based design concepts so they may feel confident reviewing plans submitted for their approval. Performance Technologies International, Inc., of Annandale, Virginia, developed the pilot materials. The Internation-al Fire Marshals Association, Society of Fire Protection Engineers (SFPE), and National Institute of Standards and Technology made significant contributions to course content.
Course content includes a comparison of prescriptive and performance design and building codes, an introduction to fire dynamics, an overview of available fire models, the SFPE “Process Method” for fire safe design, and the importance of documentation and ongoing inspection to the success of performance-based design.
Fire service and allied professionals interested in taking the regularly scheduled courses should check their 2003 National Fire Academy Catalog of Activities for a course synopsis, prerequisites, and upcoming dates.
James G. Munger, Ph.D., MIFireE, CFPS, is a fire protection and life safety consultant from Cullman, Alabama, and a frequent contract instructor at the National Fire Academy. He is a member of the NFPA technical committee on preincident planning.
Robert A. Neale is the U.S. Fire Administration training specialist responsible for the Fire Prevention: Technical series at the National Fire Academy in Emmitsburg, Maryland. He is a member of the NFPA technical committee on fire inspector and plan examiner professional qualifications.
