WHY DO WE TEST fire alarm systems? To ensure that the system providing early warning of fire to the occupants operates reliably during a fire.
Once technicians have installed or repaired a fire alarm system, testing that system represents one of the most important things that needs to happen. NFPA 72®, National Fire Alarm and Signaling Code
, provides specific reasons why a building owner must test a fire alarm system after an initial installation or when changes are made to the system and periodically thereafter.
Conducting initial system tests helps verify that the installation complies with the design documents and meets all the applicable requirements found in NFPA 72 and any other applicable codes or standards. In addition, professional installers conduct initial testing to ensure that every portion of the system operates in accordance with the detailed sequence of operation.
Based on a thorough understanding of the stakeholder-developed goals for the system, the technician and the authority having jurisdiction should make sure that the operational tests conducted will show whether the system meets its goals. To do so, they must make certain that conditions during the testing accurately represent the building’s normal operational environment. Initial tests of a fire alarm system that occur when the building is not occupied or before other equipment is operating, for example, may skew the maximum average or peak values of normally present ambient noise. Testing under such conditions may affect the system’s ability to meet the code’s audibility requirements. If the designer has documented the design audibility levels appropriately and taken into consideration the expected ambient noise level, however, the technician can take measurements with these design levels in mind.
The initial testing should verify that the fire alarm system interfaces properly with other systems. Some believe that the only way to ensure a properly interfaced system operation is to witness the system in operation. However, exercising an interfaced system every time an interfaced fire alarm device operates might not be practical or necessary. It may not even be allowed. To accommodate testing but prevent problems that may arise when physically evaluating an interfaced system, the code allows the fire alarm system to be tested up to the point where it connects with the interfaced system.
The code requires technicians to visually inspect fire alarm systems periodically to ensure that there is no obvious damage, that no unauthorized changes to the system have been made, and that changes to the building or facilities have not impaired the system. The code also requires the operational testing of devices, appliances, and control equipment to verify that the components function reliably.
With new systems operated by software, testing after any software change becomes even more important. The code specifically states that “when changes are made to site-specific software.., all functions known to be affected by the change, or identified by a means that indicates changes, shall be 100 percent tested.”
In addition to code requirements, technicians must remain aware of a host of practical information that can affect fire alarm system testing and maintenance. For example, earlier versions of software used DOS operating systems. While this may not seem important, changes to the fire alarm system software on these older systems will be difficult if not impossible unless the installer has maintained a computer that still uses the DOS operating system.
Wayne D. Moore, P.E., FSFPE, is a principal with Hughes Associates