Existing Systems: Upgrades & Alterations
When evaluating an existing fire detection and alarm system, the first question that should be asked is: Evaluating for what? Most evaluations are done to determine if the existing system meets local code requirements. That simply requires some knowledge of, or research into, the local codes.
Another reason to evaluate an existing system is to determine if the system should be replaced or upgraded to help control life-cycle costs. Just like people, as fire detection and alarm systems age, some require a greater amount of maintenance. Smoke detectors may accumulate dust and dirt even when they are regularly cleaned using manufacturer's instructions. Eventually, their sensitivity might drift to the point where replacement is warranted. A higher sensitivity could directly result in a false alarm as the unit approaches its response threshold. Higher sensitivity can also increase the likelihood of nuisance alarms from sources such as cooking odors, steam or tobacco smoke that normally might not be sufficient to alarm the detector. There is no code requirement for the replacement of aging system smoke detectors. This is because a regular inspection and testing program is an effective method of assuring detector operability.
NFPA 72, the National Fire Alarm and Signaling Code, requires owners to keep records of system activations and operation for a period of one year after the next regular test.2 Owners should be encouraged to keep records for longer periods to assist in evaluating aging effects on system performance
Another reason to evaluate an existing system is to determine if the system should be replaced or upgraded to help control life-cycle costs. Just like people, as fire detection and alarm systems age, some require a greater amount of maintenance. Smoke detectors may accumulate dust and dirt even when they are regularly cleaned using manufacturer's instructions. Eventually, their sensitivity might drift to the point where replacement is warranted. A higher sensitivity could directly result in a false alarm as the unit approaches its response threshold. Higher sensitivity can also increase the likelihood of nuisance alarms from sources such as cooking odors, steam or tobacco smoke that normally might not be sufficient to alarm the detector. There is no code requirement for the replacement of aging system smoke detectors. This is because a regular inspection and testing program is an effective method of assuring detector operability.
NFPA 72, the National Fire Alarm and Signaling Code, requires owners to keep records of system activations and operation for a period of one year after the next regular test.2 Owners should be encouraged to keep records for longer periods to assist in evaluating aging effects on system performance
