Fire Safety Systems
Fire Sprinkler Systems
Many areas of the country have local fire codes that apply to sprinkler systems. The system must comply with local codes, and the property manager or maintenance supervisor must remain aware of any changes to the code. Some code changes may require that the property be retrofitted with current systems.
Wet pipe sprinkler systems are the most common sprinkler system. As the name implies, a wet pipe system is one in which water is constantly maintained within the sprinkler piping. When a sprinkler activates, this water is immediately discharged onto the fire.
The main disadvantage of these systems is that they are not suited for subfreezing environments. Another concern is in locations where piping is subject to severe impact damage and could consequently leak, e.g., warehouses.
A dry pipe sprinkler system is one in which pipes are filled with pressurized air or nitrogen, rather than water. The air or nitrogen holds a remote valve, known as a dry pipe valve, in a closed position. Located in a heated space, the dry pipe valve prevents water from entering the pipe until a fire causes one or more sprinklers to operate. Once that happens, the air escapes and the dry pipe valve releases. Water then enters the pipe, flowing through open sprinklers onto the fire. The main advantage of dry pipe sprinkler systems is their ability to provide automatic protection in spaces where freezing is possible. Typical dry pipe installations include unheated warehouses and attics, parking garages, outside exposed loading docks, and inside commercial freezers.
A pre-action sprinkler system employs the basic concept of a dry pipe system in that water is not normally contained within the pipes. The difference, however, is that water is held from the piping by an electrically operated valve, known as a pre-action valve. Valve operation is controlled by independent flame, heat, or smoke detection.
Two separate events must happen to initiate sprinkler discharge. First, the detection system must identify a developing fire and then open the pre-action valve. This allows water to flow into the system’s piping, which effectively creates a wet pipe sprinkler system. Second, individual sprinkler heads must release to permit water to flow onto the fire. This feature provides an added level of protection against inadvertent discharge. For this reason, pre-action systems are frequently employed in water-sensitive environments such as archival vaults, fine art storage rooms, rare book libraries, and computer centers.
Fire sprinkler heads have two types of activation devices:
- One device is a filament, which melts when the temperature reaches a certain level. The sprinkler head is then activated.
- The second device has a small solder link or a glass tube. Heat melts the solder or the liquid expands causing the glass tube to shatter and the sprinkler head is activated.
Fire Sprinkler Concerns
In the past 10 years, corrosion-related failures have increased in fire sprinkler systems. Systems installed before the 1970s commonly used thicker wall, extra strong schedule 80 piping. Since then, thinner wall schedule 40 piping has been used, and over the last 20 years, the schedule 40 piping has been replaced with an even thinner wall schedule 10 piping. The problem with using thinner wall piping is that very little pipe wall is available to corrode before the pipe reaches minimal acceptable thickness limits.
Schedule 10 piping has less than half the wall thickness of schedule 80 piping, and it can provide from 10 to 20 years of service. However, depending on the system and corrosion, failure can occur in as little as 5 years or less.
For high-pressure applications, schedule 10 piping will only provide acceptable service if there is no corrosion, which is almost an impossibility. Carbon black piping is traditionally used for fire sprinkler systems, and the water used in the systems is not chemically treated. Corrosion, then, is a real and serious condition that affects sprinkler systems.
Other factors that influence a system’s operation are pipe location, material, age, and how frequently the pipe is drained and refilled. Systems that are frequently drained, extended, or modified suffer greater corrosion than systems in which water is left standing. In standing water, the oxygen level depletes and corrosion stops. A fire sprinkler system should never have a constant flow of water running through it.
A frequently running jockey pump (the jockey pump keeps a high positive pressure on the discharge side of fire pumps) or a cold, sweaty fire sprinkler pipe is a sign of a leak somewhere in the system. The worst situation is when an underground water leak goes undetected and continues for years.
If a pipe is cold, water is likely to be entering the system, as a stagnant pipe will have an ambient temperature. Rust and moisture condensation are also indications that water is entering the system.
Microbiologically influenced corrosion (MIC) can destroy a fire sprinkler system in just a few years. MIC is difficult to identify and requires metallurgical and microbiological testing. The cause and prevention of MIC are also not known at this time. MIC is a serious problem for clamped joint piping systems because microbes tend to flourish in small gaps between pipe ends. Systems should always be cleaned and sterilized when installed. Water flow should be minimized. Once MIC is firmly established in a system, most corrosion authorities consider it impossible to correct.
Buildup of iron oxide deposits is another serious threat to fire sprinkler systems. These deposits are created by corrosion, which can add thousands of pounds of moveable rust debris. The debris can dislodge and move through the system to control and actuating valves and eventually to sprinkler heads.
There are new concerns for fire sprinkler systems that did not exist previously. Property managers must inspect sprinkler systems and carefully plan for their maintenance. Annual testing of sprinkler systems is a good idea.
Fire extinguishers must be inspected frequently (usually annually or semiannually). To inspect a fire extinguisher:
- Ensure access to the extinguisher is not blocked and that the cabinet door, if any, opens easily.
- The pressure should be within the recommended level on extinguishers equipped with a gauge. The needle should be in the green zone. If the needle is not in the green zone, the extinguisher requires professional maintenance. This should be noted on the inspection report.
- Verify the locking pin is intact and the tamper seal is not broken.
- Visually inspect the hose and nozzle to ensure they are in good condition.
- Visually inspect the extinguisher for dents, leaks, rust, chemical deposits, or other signs of abuse or wear and note any findings on the inspection report. If the extinguisher is damaged or needs recharging, remove it from service and note this on the inspection report.
- Fire extinguishers must be pressure tested (a process called hydrostatic testing) every six years to ensure the cylinder is safe to use. The inspection sheet has all hydrostatic testing dates noted. If an extinguisher requires this service, this should be noted in the comments.
The property manager or maintenance supervisor must ensure the following:
- Fire hoses are free of debris.
- Fire hoses have no evidence of mildew, rot, or damage by chemicals, burns, cuts, abrasions, or vermin.
- Fire cabinets are not obstructed and the latches work.
- Nozzles are not damaged.
- No parts are missing.
- Shutoff valve works.
- Fire hoses are not for tenant or building personnel to use (for safety reasons).
Fire Alarm Systems
Facility maintenance personnel usually don’t possess the experience and knowledge that manufacturer’s service technicians do. A factory service agreement can range from a basic on-call agreement to regularly scheduled service visits. Most service agreements offer optional 24-hour-a-day emergency service with 4-hour and 8-hour response times. This service usually provides response within the specified time, along with repair and replacement of the equipment. Rapid emergency response is almost universal for the health-care and lodging industries because of around-the-clock occupancy by staff, patients, and guests.
Before signing a maintenance agreement, the property manager must ensure that technicians are certified by the National Institute for the Certification of Engineering Technologies (NICET), and that they specialize in life safety.
Most system manufacturers recommend at least one full annual test and inspection after initial installation and acceptance. Various agencies, organizations, and local authorities recommend, and in some cases, mandate, testing intervals. The National Fire Protection Association (NFPA) provides the National Fire Alarm Code, NFPA 72. This standard covers the application, installation, performance, and maintenance of protective signaling systems and their components.
The local authority having jurisdiction (AHJ) and insurance companies also influence, recommend, or set forth standards they deem necessary for the proper operation of life safety systems. AHJs may establish guidelines that exceed NFPA guidelines.
Fire Alarm System Test
A test of the alarm system should include the following:
- Test and calibrate alarm sensors, such as flame and smoke detectors, per manufacturer specifications. This requires knowledge about the different sensors and their testing requirements, failure modes, and reinstallation requirements.
- Simulate inputs and test the annunciators. This requires specific knowledge of the system under test.
- Set sensitivity. This requires an understanding of the particular system, the specific application, and fire detection theory.
- Coordinate with the fire department to test the input to their system.
- Check the battery for corrosion and expiration date, and take appropriate action, as necessary.
Smoke Evacuation Systems
Just as with fire alarm systems, smoke evacuation systems should be maintained and tested on a scheduled basis by certified technicians.
Smoke-proof towers are used in high-rise buildings and are designed to allow people to leave a floor without smoke following them and filing up the stairway. This is accomplished because the smoke-proof stairway has an intermediate vestibule, open to the outside atmosphere. Any smoke that follows people exiting the building will rise in the atmosphere instead of following people into the fire stairway.
Fire drills are an important part of an overall fire safety plan. They should be conducted on an annual basis in conjunction with the Fire Department. The main purpose of a fire drill is to help tenants understand how they should respond in the event of an emergency. Fire drills also allow tenants to hear what the fire alarm sounds like, hear the public address system (where provided), and to learn where the exits/stairs are located.