Fire Alarm Systems
Having the proper fire safety systems is crucial to providing safety to your facility and its occupants. The first line of defense in a fire is an active alert or alarm system. It is important as a building owner to understand the difference between a smoke alarm and smoke detector. A smoke alarm is single unit that is disconnected from an overall system. It has an alarm and detector all in one. A smoke detector is connected to an overall fire alarm system is usually works in conjunction with other detectors throughout your building. It is recommended to have a complete fire alarm system within your building for optimal safety.
The following information is an excerpt from the National Electrical Manufacturers Association’s Guide for Proper Use of System Smoke Detectors:
Smoke detectors offer the earliest warning of fire possible. They have saved thousands of lives in the past and will save more in the future. For this reason, detectors should be located on every level of a building.
Ionization detectors are better at detecting fast and flaming fires than slow, and smoldering fires. Photoelectric smoke detectors sense smoldering fires better than flaming fires.
To provide effective early warning of a developing fire, fire (smoke) detectors should be installed in all areas of the protected premises. Total (complete) coverage, as described by NFPA 72, should include all rooms, halls, storage areas, basements, attics, lofts, and spaces above suspended ceilings, including plenum areas utilized as part of the HVAC system. In addition, this should include all closets, elevator shafts, enclosed stairways, dumbwaiter shafts, chutes, and other subdivisions and accessible spaces.
Fire detection systems installed to meet local codes or ordinances may not be adequate for early warning of fire. A user should weigh the costs against the benefits of installing a total (complete) fire detection system when any detection system is being installed.
“Total Coverage,” as described in NFPA 72, is a complete fire detection system. In some of the specified areas of coverage, such as attics, closets, and under open loading docks or platforms, a heat detector may be more appropriate than a smoke detector.
Careful consideration should be given to the detector manufacturer’s instructions and the following recommendations:
Smoke detectors shall not be installed if any of the following ambient conditions exist:
- Temperature below 32°F (0°C)
- Temperature above 100°F (38°C)
- Relative humidity above 93 percent
- Air velocity greater than 300 ft/min (1.5 m/sec)
Detector Placement—Air Supply and/or Return
Placement of detectors near air conditioning or incoming air vents can cause excessive accumulation of dust and dirt on the detectors. This dirt can cause detectors to malfunction. Detectors should not be located closer than 3 feet from an air supply diffuser or return air opening.
Where Not to Place Detectors
- In damp or excessively humid areas, or next to bathrooms with showers. Tiny water droplets can accumulate inside the sensing chamber and make the detector overly sensitive.
- Do not place in or near areas where combustion particles are normally present, such as in kitchens or other areas with ovens and burners; in garages, where particles of combustion are present.
- Do not place in or near manufacturing areas, battery rooms, or other areas where substantial quantities of vapors, gases, or fumes may be present.
- Do not place near fluorescent light fixtures. Electrical noise generated by fluorescent light fixtures may cause unwanted alarms. Install detectors at least 6 feet (1.8 meters) away from such light fixtures
To read the full guide, which includes technical guidance on proper practices for fire alarm systems, you may download it for free
Prevention of Arcing Ignited Fires
The following information is intended to help prevent undesirable electrical arcing from potentially starting a building fire. Fire investigation studies indicate that electrical arcing between wires or between wires and grounded metal surfaces cause 20-40% of all electrically ignited fires. Electrical arcing can occur through loose wire connections, by physical damage to extension cord insulation, wire insulation damaged by long term exposure to moderate or high heat, electrical surges, or even from a misplaced drywall screw or picture hanger nail. Arc Fault Circuit Interrupter (AFCI) protection can detect and interrupt arcing to help prevent fire ignition. The National Electrical Code® requires AFCI protection in new construction, but existing buildings are more prone to faults due to wear and tear on electrical systems. AFCI protection can be installed at the breaker panel or in the first receptacle of each branch circuit. To get the best arc fault protection from AFCI circuit breakers, install combination-type AFCI circuit breakers, not branch/feeder-type AFCI circuit breakers.
AFCI devices should be regularly tested for proper operation using the test and reset buttons clearly marked on the devices. AFCI receptacles should be installed within reach so you can easily test and reset the devices on a regular basis to ensure they are functioning properly. To identify if your circuit breakers or outlets contain AFCI protection, look for the “AFCI” identification mark on the circuit breaker or outlet face. If you do not have AFCI protection in your building, install it as soon as possible for added fire protection. Many new buildings will have these advanced arc fault circuit interrupters in place, but even new buildings can increase their level of protection. Updating the circuits from standard devices to those that are designed to detect arcing and sparking that may cause electrical fires provides that additional level of protection against arcing faults. Use a qualified electrician to ensure a proper, safe installation.
In photovoltaic (PV) solar electricity generation systems, loose connections have caused a number of building fires. Safe PV systems should be protected with AFCI in the inverter to open the output circuit if arcing occurs.
The best solution is not to only detect arcing with AFCI technology, but to identify faults before they begin to arc and cause damage. You can do so by regularly inspecting for hazards and following these tips:
Hire a qualified electrical contractor who is trained on the equipment and on electrical safety to help you perform a safety check in your building.
When plugging and unplugging appliances, inspect the cords. Look for any signs of damage due to wear and tear including cracked, cut or crushed insulation, discoloration or melting due to heat. Sometimes plugs can be crushed between furniture and the wall, weakening the conductor insulation. Cords can also be damaged through abuse by improperly removing them from the receptacle outlet, being stepped on, or placed under the leg of chairs or other types of furniture.
Extension cords should never by placed underneath carpets or area rugs or tucked under baseboard molding. Extension cords are not designed as permanent wiring for appliances or equipment. Compare the sum of all electrical rating(s) of appliance loads with the extension cord capacity. If the load exceeds the cord capacity, then reduce the load for that cord. Inspect cords for visible damage such as strain at plug connections, cuts or crushed insulation, and discoloration or melting caused by high temperature exposure. Dispose of any cords with these dangerous signs.
Regularly inspect appliance cords, connections and parts for signs of damage. Heat damage can appear as pitted or corroded electrical contacts, discolored wire insulation or plastic, and melted or deformed plastic. Ensure you are using appliances in the manner intended by the manufacturer. Consult the manufacturer if needed. Repair or replace questionable appliances.
An arc fault is an unintended arc caused by current flowing through and unintended path. Usually this is caused by damage to the electrical conductor insulation. These arcs can cause intense heat at the point of the arc resulting in property damage and fire. These fires can cause extensive damage to property as well as loss of life. According to the National Fire Protection Association (NFPA), arc-faults are “the principle electrical failure mode resulting in fire.”
Arc-fault circuit interrupters (AFCIs) come in both outlet and circuit breaker forms and operate by using advanced technology to detect dangerous arcing conditions while allowing normal arcing such as is caused by a light switch or electric motor. These devices provide an increased level of protection from electrical fires for your building. An AFCI can detect an arc-fault, which creates high-intensity heat that could ignite a building’s inner structural walls or insulation. Arc-faults can occur from damaged, overheated, or stressed electrical wiring, worn/old electrical insulation, and damaged appliances. When an arc-fault is detected, the AFCI can immediately shut-off the power to that circuit before an electrical fire has a chance to start.
While AFCIs are not typically required for commercial buildings, many architects, engineers, and building owners recognize the added safety that they provide. AFCIs can be found at electrical distributors, hardware stores, and home centers. Even though AFCIs cost a little more than traditional outlets and circuit breakers, they provide an extra level of protection to your building and business.
Make sure to test your AFCI devices once a month.
Photo Credit: Legrand
Available in both single- and multiple-gang version, in both steel and nonmetallic fabrications, fire-rated floor boxes preserve the two-hour fire rating of floors in which they have been installed. When properly installed, Fire Classified Floor Boxes can save time and money for general contractors and installers by eliminating the need for spraying to fireproof floors. Be sure to only install floor boxes that meet or exceed the UL Fire Classification Standard for Floor Boxes (look for the UL or Warnock Hersey mark on the product).
Photo Credit: Legrand
In order to protect the integrity of a firewall, without adding caulk or putty after cables are installed, you can use a fire-rated, thru-wall fitting. They meet UL tests for flame, temperature, and smoke, as well as for use in air handling spaces (plenums) and are made with fire-stopping intumescent material with an enclosed thru-wall penetration. Once installed, these fittings let you add or remove cables easily, without risking the unseen and potentially dangerous gaps or voids that can occur with caulks or putty. If the temperature reaches approximately 375°F, the material expands, creating a hard char that fills voids around the cables and stops flame from penetrating the opening. This prevents further damage to the cabling and your networks. Be sure to only install devices that meet or exceed UL standards (look for the UL or Warnock Hersey mark on the product).
The following companies can help you get started with your project: