Specialized fire protection equipment
Automatic sprinklers are an effective means of controlling many common fire hazards in buildings. But sprinklers can do more harm than good in certain situations. Sprinklers can damage sensitive electronics, spread flammable liquids, create electrical hazards, or just not respond quickly enough to control the fire. These situations call for special-hazard fire protection.
Start With the Hazard, Not the Equipment
Fire protection for special hazards isn’t limited to one type of equipment or system. It’s an approach to assessing the potential fuel sources, the rate of fire growth, other materials present in the space and the best fire suppression agent to extinguish the fire while causing as little collateral damage as possible.
Examples of special hazards include:
- Fuel and chemical storage
- Electrical switchgear and control rooms
- Rooms with irreplaceable materials such as records and archives
- Commercial kitchen equipment
- Rooms with data and communications equipment
- Industrial processing equipment
- Solvent, paint and coating operations
The goal of special-hazard fire protection is to control fires without causing more damage to the building’s operations, equipment and assets. That includes extinguishing the fire, preventing re-ignition and minimizing heat and smoke exposure.
Match the Suppression Agent to the Fuel
Types of special-hazard fire protection systems include:
Special-hazard fire suppression system
Clean agent systems use agents that extinguish fires without leaving a residue like powder, foam or water. These systems are common in enclosed spaces with electrical, data and controls equipment and other sensitive or valuable equipment and materials. These systems are engineered for specific enclosed spaces and those spaces have to be able to retain the fire suppression agent long enough to reach and maintain the design extinguishing concentration. Seals around doors, cable and duct penetrations, ceiling openings and fire dampers in ventilation systems are among the enclosure-integrity considerations that Cannistraro Special Hazard Fire Protection evaluates before finalizing the suppression design.
Foam systems blanket flammable and combustible liquid fires, smothering the fuel source and keeping vapors from igniting. These systems are common in areas where flammable or combustible liquids are processed, loaded or stored and there’s a risk of a spill or fire with a pool of liquid fuel. Drainage and cleanup are important considerations for these systems. Discharged foam solution and contaminated drainage from firefighting activities may need to be captured and can’t necessarily be allowed to drain to floor drains.
Dry chemical agents quickly interrupt the chemical reaction of combustion. These systems are common in areas with industrial process equipment and other hazards involving flammable and combustible liquids. Wet chemical systems are common in commercial kitchens and are designed to smother and cool fires involving hot cooking oils and grease. When these systems are activated, fuel and/or electrical service to cooking equipment needs to be interrupted. Exhaust systems may need to continue operating depending on the design.
Select Detection That Fits the Conditions
Detection systems for special hazards include:
- Heat detection systems that aren’t affected by dust, humidity or other conditions present during normal operations
- Flame detection systems that quickly identify rapidly growing fires from flammable and combustible liquid hazards
- Highly sensitive smoke detection systems to identify slow, smoldering fires common in electrical equipment
- Air sampling systems to identify fires before they get big
- Gas detection systems
Coordinate Suppression With Building Systems
Special-hazard fire protection systems also need to be carefully designed and integrated with other building systems. Depending on the application, ventilation systems, air handlers, space layout, machinery locations, ceiling heights and air movement can all affect fire protection system performance. Clean agent systems, covered in the overview at en.wikipedia.org/wiki/Gaseous_fire_suppression, typically require supply and return air-handling equipment to shut off automatically when the fire protection system activates so the agent can reach and remain at extinguishing concentrations.
- Will people be able to leave the area before the fire protection system activates?
- Are vents needed to relieve pressure and protect the enclosure?
- Can agents reach concealed spaces like under raised floors?
- Do machines and pieces of equipment need to automatically shutoff?
- Are there any signage, alarms, testing/inspection or emergency operation requirements from local fire code?
Add Complexity Only When the Risk Justifies It
Special-hazard fire protection systems are likely overkill for a small room without unusual or significant fuel/hazard loads, without extremely valuable or critical equipment and when adequately protected by sprinklers. There should be a compelling reason to add the complexity of designing and integrating special-hazard fire protection systems.
Special-hazard fire protection systems require routine inspections and testing to make sure they’ll operate when needed. Depending on the type of system, items to inspect can include the amount of extinguishing agent, condition of pressure vessels/cylinders, piping, detection devices, control equipment, alarm devices, manual activation equipment and automatic shutoff equipment. Facility modifications can also affect special-hazard fire protection system performance. Adding/removing partition walls, relocating equipment, significant changes to storage practices, new ceiling penetrations, changes to air handlers and adding server racks are all examples of facility changes that can impact special-hazard fire protection system performance.
The best special-hazard fire protection systems start with an understanding of the hazard being protected (types of fuels, ignition sources, valuable/critical equipment, occupancy/use of area, impact of downtime, etc.) instead of starting with a specific fire protection solution. Potential extinguishing media could include water, foam, clean agents, dry chemicals, wet chemicals, etc.