Fighting Fires ... Before and After They Start
Contrary to what many industry professionals might think, a fire-protection engineer is neither the pump controls operator on a fire engine nor a sprinkler system designer. Practitioners of a relatively new and specialized discipline, fire-protection engineers today are licensed and recognized as P.E.
Contrary to what many industry professionals might think, a fire-protection engineer is neither the pump controls operator on a fire engine nor a sprinkler system designer. Practitioners of a relatively new and specialized discipline, fire-protection engineers today are licensed and recognized as P.E.s in almost every U.S. state. And they are found in a variety of settings, including research and development, jurisdictional organizations, property insurance companies and A/E and other types of consulting firms.
By virtue of education, training and experience, fire-protection engineers are able to:
understand the nature and characteristics of fire and associated products of combustion.
understand how fires originate, spread within and outside built structures, and how they can be detected, controlled and extinguished.
anticipate the behavior of materials, structures, machines, apparatus and processes in a fire event.
More importantly, a fire-protection engineer ensures that all of these abilities come together as a system to combat a single phenomenon: fire.
As buildings and their systems become more sophisticated, engineers with specific knowledge of structural fire resistance, detection and suppression systems, egress systems and fire-alarm systems have become indispensable.
And fire-protection engineers also have a host of modern tools at their disposal. These include computer models using finite element analysis that predicts smoke movement, temperatures, heat detector and sprinkler actuation, occupant egress times, fire and toxicological effects—and even human behavior.
Computerized modeling software is particularly useful when dealing with more unconventional building architecture, which does not lend itself easily to prescriptive requirements contained in most codes. Above all else, it's the fire-protection engineer's understanding of the codes and how they work that leads to a cost-efficient yet effective system.
Cracking the codes
The primary goal of building and fire codes is to ensure a reasonable level of public safety, and then, to ensure minimum damage to a building and its contents. These priorities are especially true for industrial and storage occupancies. For these facilities, loss of life has historically been low when compared with other occupancies, but has accounted for a high percentage of property loss.
Faced with increasing competition, however, companies cannot tolerate high risk to property. Over the past century, insurance companies have developed standards for protection of property, usually referred to as highly protected risk (HPR). Fire-protection engineers with HPR knowledge are in the best position to ensure that a maximum level of protection is provided for operations and to minimize downtime.
Fire-protection engineers are also often called on to help a company or building owner ensure that a facility complies with current code requirements, or with an internal corporate standard, especially in older facilities that have been modified many times.
Another area where a fire-protection engineer can provide valuable benefits is in dealing with local jurisdictions and code interpretations. They speak the same language as jurisdictional officials. A fire-protection engineer who is in charge of and familiar with a project will not only be able to answer officials' questions, but can also provide code interpretations and other expert opinions. This is becoming more important as jurisdictions increasingly retain fire-protection engineers as consultants or even have them on staff.
A consulting fire-protection engineer not only can ensure that building specifications are compatible with applicable codes, they can also save the building owner money in the long run.
Saving the owner money
One important way the fire-protection engineer saves the owner money is by making sure that funds are spent wisely on necessary systems, rather than merely following code requirements. Traditionally, building and fire codes have been prescriptive. However, during the past decade, we've been hearing more about performance-based codes (see "The Importance of Performance-Based Design," left).
Other than allowing some trade-offs when providing a higher level of fire protection, such as increased travel distances and hazardous material storage in sprinklered buildings vs. unsprinklered buildings, code requirements are insensitive to potential returns on investment. Similarly, insurance company recommendations are typically drawn from the company's standards, which are based on opinions or loss experience, not cost-benefit analysis.
The best cost-benefit approach is a quantitative risk analysis, based not only on a before-and-after scenario of providing the protection, referred to as severity, but also on the probability of a particular fire event occurring, referred to as frequency. The product of severity and frequency is risk. Fire-protection engineers quantify the risk over a given time span— usually the useful life of a facility—on an annual dollar basis with and without the contemplated protection. Then, they compare the risk reduction to the amortized cost of providing the protection. If the ratio of the two is greater than one, the benefit outweighs the cost. If the ratio is less than one, the cost outweighs the benefit. Needless to say, accuracy and relevance of the analysis depends on the analyst's knowledge and skills.
For example, HSB was contacted by a utility that operates aqueducts equipped with various pumping or "lift" stations. Because these pumping stations were built at different times to different standards and by different firms, they had varying levels of fire protection. The utility wanted to establish a uniform standard to ensure that all stations had adequate levels of protection. They also needed a prioritized list of improvements and a study of how each improvement affected the overall risk.
Our firm performed field engineering surveys at the lift stations, selected appropriate engineering standards and developed recommendations for various improvements. In addition, we performed a risk-based analysis for each capital expenditure improvement and prioritized each improvement according to its impact on overall risk, including variables such as property damage, business interruption and public image. The results of the study concluded that some improvements based on "conventional wisdom" actually had less risk-reduction effect than others that were identified as deficiencies but had been typical practice for the utility.
A/E firms often make the mistake of providing vague specifications in a bid specification document. For example, in today's design-build environment, a typical specification for a building's sprinkler system may include instructions to "design and install an automatic sprinkler system in accordance with NFPA and local codes." Such a vague specification leaves all important design and engineering decisions up to the contractor and the local jurisdiction. Depending on these individuals' qualifications, the result may be a fire-protection system that at best meets minimum code requirements but presents significant operational problems or inflexibility in future occupancy changes or building expansion. At worst, it fails to provide an adequate level of protection during a fire.
And this is where the fire-protection engineer comes in. Detailed specifications—the type of system, the design density, location and types of risers, coverage areas, material specifications and other details—are the engineer's responsibility, with input coming from the building owner and the A/E firm. They not only provide specific guidance to the contractor, but also ensure that individual contractor bids are based on the same fundamentals.
The fire-protection engineer should also review plans and calculations before they are submitted for approval, perform site inspections to ensure material and installation compliance, witness acceptance testing of systems to ensure flawless system performance and provide guidance to the building's future maintenance and operations personnel about the protection systems.
The Importance of Performance-Based Design
Performance-based design essentially means that the code specifies an objective rather than the type and level of protection. Examples of standards that allow performance-based alternatives are the Life Safety Code (NFPA 101), NFPA's Guide on Alternative Approaches to Life Safety (NFPA 101A) and the new Building Construction and Safety Code (NFPA 5000). While the migration to performance-based codes and standards is a very slow transition, it will ultimately result in equal or better levels of safety at potentially lower costs by eliminating some traditionally required protection features that are not justified, and also increasing protection in other areas. However, performance-based design requires an increasing level of decision-making, agreements with jurisdictional officials, expert knowledge and decisions on the building owner's part.
Example: Approximately 10 years ago, HSB was contacted by an architectural firm for a national "big box" home improvement store to provide code compliance consulting regarding heat and smoke venting requirements in addition to complete automatic sprinkler protection by local codes in several jurisdictions throughout the U.S. Our proposed alternate method of protection included the installation of ESFR (early-suppression fast-response) sprinklers. Because full-scale test results indicate that heat and smoke vents actually work against ESFR sprinklers and result in higher ceiling temperatures and damage levels within the building, we presented our alternative protection method to the various jurisdictions, including a formal Board of Appeals for a code variance hearing, and were able to obtain code variances for our client at an estimated savings in excess of $600,000 by not providing the heat and smoke vents.