Recent advances in fire-detection technology and fire-suppression systems and the ongoing development of international and national codes and standards have made possible the "greening" of facility fire-safety systems, which increasingly is becoming a priority for building owners. The installation of environmentally friendly fire-protection technology can help a new or retrofitted building earn credits under the U.S. Green Building Council's Leadership in Energy and Environmental Design (LEED) Green Building Rating System.

Fire protection plays an important role in overall building design and construction. Building owners and fire-protection engineers need to be able to navigate the complex waters governing code compliance, LEED certification, and system suitability for protected hazards.

First steps

When choosing an appropriate fire-protection system, it is important to identify the critical physical areas of building operation and function. Business continuity and the ability to return quickly to normal operation is vital because uptime is at a premium, and excessive downtime can herald the untimely demise of an otherwise healthy business. Building areas that are critical to daily business functions can include data centers, control rooms, power-generation facilities, plant rooms, and flammable-liquid-storage areas. A building's operation can be crippled if any of these areas is rendered inoperable by fire. Key areas that provide a building's day-to-day functions demand fire protection above and beyond the minimum regulated requirements, such as sprinkler systems and portable extinguishers.

Once an area is identified as critical and requiring additional protection, a multifaceted hazard analysis should be performed. Understanding types of potential fires and differentiating among Class A (combustible materials, such as paper or plastics), B (flammable liquids), and C (energized electrical equipment) ignition sources can aid in the selection of the most efficient detection and suppression technology for a building's specific hazards. A thorough review of potential ignition sources enables not only selection of an appropriate fire-protection system, but the possible elimination of ignition sources. For example, good housekeeping can eliminate some fire hazards.

Upon the completion of a hazard analysis, a fire-protection engineer, building owner, or other responsible party should determine which codes and standards apply to the facility and select the most suitable fire-protection system. Because a fire-protection system includes fire-detection and suppression elements, it is likely multiple standards will apply.

Codes and Standards

The three most relevant national codes that relate to green-building fire-protection systems are published by the National Fire Protection Association (NFPA): NFPA 72, National Fire Alarm Code; NFPA 2001, Standard on Clean Agent Fire Extinguishing Systems; and NFPA 750, Standard on Water Mist Fire Protection Systems. While these codes are not mandatory in all jurisdictions, they are valuable because they are written to provide maximum safety for property and personnel.

NFPA 72. NFPA 72 governs the design, installation, operation, and maintenance of fire-detection and alarm systems. It includes requirements for detector spacing, occupant notification, and control-panel functionality.

NFPA 2001. NFPA 2001 governs the design, installation, operation, and maintenance of clean-agent systems. It includes requirements for determining design concentrations, safe personnel-exposure levels, and system-discharge times. The standard also requires that an agent be included on the U.S. Environmental Protection Agency's (EPA's) Significant New Alternatives Policy list.

NFPA 750. NFPA 750 governs water-mist-system classification and includes requirements for water-mist-system design, installation, operation, and maintenance.

LEED Contributions

Fire-suppression systems are referenced only indirectly in LEED-certification documents. LEED for New Construction (LEED-NC) V 2.2 Energy & Atmosphere (EA) Credit 4, Enhanced Refrigerant Management, and LEED for Existing Buildings (LEED-EB) V 2.0 EA Credit 4, Additional Ozone Protection, indicate that credits can be earned with the installation/operation of fire-suppression systems that do not contain ozone-depleting substances, such as chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and halons.

LEED credits in the Innovation and Design category also can be obtained for fire-suppression systems. To earn those points, it is necessary to document and substantiate the innovation and design processes used. By outlining modern clean agents' environmental properties (zero ozone-depletion and low to negligible global-warming potential), unique benefits (electrically nonconductive), and safety characteristics (when used in accordance with EPA guidelines and NFPA 2001), a strong case can be made for Innovation and Design points.

Fire-Detection Technology

Fire-detection systems play an important role in green buildings. By detecting a fire quickly and accurately (i.e., by not sacrificing speed or causing false alarms) and providing early warning notification, a fire-detection system can limit the emission of toxic products created by combustion, as well as global-warming gases produced by the fire itself. These environmental effects often are overlooked, but undoubtedly occur in all fire scenarios. Therefore, reducing the likelihood of a fire is an important part of designing a green building.

Aspirating smoke-detection systems, which can detect the early stages of combustion, are 1,000 times more sensitive than conventional smoke detectors, giving early warning to building occupants and owners. Early warning allows emergency responses to occur well before a fire causes serious damage. It is not uncommon for these types of systems to detect smoldering cables or overheating circuit boards. Early detection helps limit damage and downtime.

A complete fire-protection system typically includes spot smoke detectors, such as ionization and photoelectric types. These smoke detectors can signal a fire control panel to deploy a fire-suppression system. Aspirated systems should not be the sole source of smoke detection when using fire-suppression systems, making spot detectors a necessary part of an overall green-building fire-protection system.

Fire-Suppression Technology

Introduced during the mid-1960s, bromotrifluoromethane, commonly known as Halon 1301, was the industry-standard clean agent for protecting high-value assets from the threat of fire. A fast-acting fire-suppression agent, Halon 1301 is safe for people and assets and requires minimal storage space. Its major drawback is that it depletes atmospheric ozone.

The Montreal Protocol on Substances that Deplete the Ozone Layer, introduced in 1987, initiated the demise of Halon 1301. Installation of new Halon systems is rare. In those cases in which Halon 1301 is used, such as in select aviation, military, and "essential-use" applications, it has been reclaimed and recycled. Replacing an existing Halon system with a newer, environmentally friendlier agent can contribute to the "greening" of a building.

In general, the most commonly used special-hazard fire-suppression systems fall into two categories: clean agents or water mist (Table 1).

Clean agents. Clean agents include fluorinated ketone, halocarbons, and inert gases. The most recently developed agent is fluorinated ketone fire-protection liquid. With a global-warming potential of 1 and an atmospheric lifetime of five days, it has the most favorable environmental profile of all chemical clean agents. Liquid fire-suppression systems increasingly are becoming the choice of most environmentally conscious building owners.

Halocarbons are active agents that extinguish fires by interacting directly with them. Various types of halocarbon agents are alike in many respects, although each has subtle differences. All halocarbon agents are electrically nonconductive, and most require some form of super-pressurization with nitrogen. The typical discharge time of a halocarbon system is 10 sec, providing rapid discharge and extinguishment.

The most popular halocarbon agent is heptafluoropropane, or HFC-227ea. Because of its low global-warming and zero ozone-depletion potential, HFC-227ea has been used widely in green buildings for more than a decade. The EPA chose HFC-227ea to protect its National Computer Center, a LEED Silver facility built in Research Triangle Park, N.C.

In contrast with the previously mentioned agents, inert gases are considered passive agents because they alter the atmosphere around a fire and do not interact with it directly. Typically, inert gases are used to lower the oxygen content within an enclosure to 10 to 14 percent. (An oxygen concentration below 12 to 14 percent will not sustain combustion.) A number of different inert-gas blends have been used in fire suppression (Table 1). Inert gases are electrically nonconductive, are stored as high-pressure gases, and have discharge times under 60 sec. Because oxygen levels are reduced, a protected space's occupancy typically is restricted post-discharge.

Inert gases IG-55 and IG-541, commonly known as argonite and inergen, have zero global-warming potential and have been used in green buildings for many years. Because of the inability to store inert gases as compressed liquids, systems that use inert gases require significantly larger space requirements than those that use fire-protection liquid. This can preclude inert-gas systems from many applications. However, if storage space can be planned in advance, these systems are viable options for green-building owners.

Water mist. Water-mist systems are green by definition because they use water as a suppression media and have zero global-warming or ozone-depletion potential. The application of fine water drops, or mist, utilizes water's maximum fire-extinguishing capabilities while conserving the quantity used. Thus, significantly less water typically is used in a water-mist system than a traditional sprinkler system. Although caution is required in the operation and use of popular high-pressure water-mist systems, risks can be mitigated with appropriate training and ongoing maintenance.

Conclusion

Green buildings have many fire-protection-system options. Careful consideration of a facility and its anticipated hazards will determine areas needing protection. Codes and standards can help guide system design and installation. Because of advances in technology, fire-detection and suppression systems can support and sustain a modern green-building philosophy. The methodical selection of a clean-agent or water-mist system can help contribute to LEED-certification credits for building owners.


Kate Houghton is the director of marketing for Kidde Fire Systems, a UTC Fire & Security company, in Ashland, Mass. Previously an applications engineer, product manager, and marketing manager, she is responsible for new-product development, product introduction, applications engineering, and technical support. She has bachelor's degrees in engineering and marketing from Monash University in Australia.