The ADA's impact on fire alarm systems.
In general, the owner is responsible for accommodations in common areas, including hallways, elevators, etc., and tenants are responsible for accommodations in leased premises. The first step in deciding who will perform renovations in a tenant's space to comply with the ADA is to look at the lease. You should find an allocation of this kind of responsibility in the clause concerning compliance with laws, in the use clause, or even in the repairs and maintenance clause.
In July 1991, the Justice Department issued the Americans with Disabilities Act Accessibility Guidelines (ADAAG), which state what building components and construction features define accessibility. One provision requires that all fire alarm systems be made accessible. Elements of a fire detection and alarm system to be considered are the manual fire alarm stations (pull stations), audible warning devices (horns and speakers), and visual warning devices (strobe lights).
Manual Fire Alarm Stations
Manual fire alarm stations, where provided, must be accessible. This requires the pull station to be installed so the operating mechanism is no more than 54 inches above the floor when approach is available from the side by a wheelchair, or no more than 48 inches above the floor when the approach is straight on. Also, the pull station's design must be accessible, which requires that the activation mechanism be easily graspable.
Audible Warning Devices
Fire alarm horns and speakers are required to provide the minimum audibility levels. The ADAAG requires a horn or speaker to provide an alarm sound level that is 15 dbA (decibels) above the prevailing sound level. However, if the prevailing sound level is greater than 105 dbA, which is considered damaging to ears, then the alarm shall sound for 60 seconds at a level of 5 dbA above the prevailing sound level. In no case shall the alarm sound level be greater than 120 dbA, either intermittent or constant.
The sound-level characteristics of fire alarm horns now are published for the use of designers to determine proper placement of devices. Also, typical sound obstruction values of wall construction are available. Sound levels drop off exponentially as distance from the device increases. To test an area, engineers set off the alarm, and using sound meters, take calibrations of the sound level to determine if it is accurate. Normally, sound levels are quieter than they should be. Most speakers never operate at the highest level, but are designed with numerous levels available, so that they may be "tapped" to the level needed. Designers can calculate anticipated sound levels that are lost through distance and different wall assembly and be able to increase the sound level and space speakers appropriately (50 to 100 feet apart) to meet requirements.
Visual Warning Devices
The ADAAG requires strobe lights be installed in all general usage areas and any other area for common use. This includes restrooms, meeting, conference, and dining rooms, hallways, lobbies, and cafeterias. In general, all areas of a building must be provided with strobe lights, with the exception of private offices, mechanical spaces, and exit stairs.
Strobe lights also have very strict installation requirements. They must be installed 80 inches above the highest floor level or six inches below the ceiling, whichever is lower. In corridors, strobe lights must be within 15 feet of the end of a corridor and no more than 100 feet from one another.
In open rooms, the ADAAG requires strobe lights to be within 50 feet of all parts of the floor. In large rooms, greater then 100 feet across and with no obstructions greater than six-feet high, strobe lights may be placed around the room's perimeter. The strobe lights can be no more than 100 feet apart along the walls. This rule can be used in auditoriums, exhibit halls, and other spaces without columns. The ADAAG allows strobe lights to be installed on the ceiling, but they must be suspended to meet the height requirements and flash at a rate of between one and three hertz (one to three times per second). These flash rates must be maintained to attract people's attention.
Practical Barriers to Strobe Light Installation
Strobe lights use a considerably greater amount of energy than other fire alarm devices. Also, in many applications strobe lights outnumber other fire alarm devices.
In order for strobe lights to flash at the required frequency, the minimum voltage must be maintained. Since the resistance through exceptionally long runs of wires cannot be overcome, remote power supplies are used. These power supply panels also are provided with emergency power batteries to maintain the flash rate for the required operation times during a power loss.
Since strobe lights use so much power, the battery capacity must be calculated to provide the required voltage throughout the operation time. Many designers include a reduction of battery capacity to account for degradation of the battery capacity due to aging.
In high-rise buildings, a typical fire alarm installation includes a fire alarm control panel in the main fire control room. Remote transponders are provided for every three floors. This reduces the lengths of wire runs to strobe lights and keeps resistance at a minimum. Typically, the remote transponders are small fire alarm control panels that can act independently of a main fire alarm control panel. This improves overall system reliability since the small control panel continues to function if communications to the main fire alarm control panel or other panels is lost.
In existing buildings, it often is desirable to use the existing fire alarm system and only add fire alarm strobe lights. This can be accomplished only if there are adequate output relays at the main fire alarm control panel to send a signal to the new fire alarm system. This is made more difficult by the need to evacuate three or four floors above the alarm. This multiple output matrix is more difficult to achieve than the old method of evacuating the entire building when an alarm is received. Individual alarm outputs are required since all notification circuits must be supervised by the use of a small current to ensure proper functions.
The use of relays that monitor an existing fire alarm notification circuit for a change in polarity or increase in voltage, as the signal to activate the strobe lights, is not permitted since this does not completely supervise all circuits. All fire notification circuits must be supervised to ensure proper function, as required by NFPA 72.
One permissible arrangement is to install a new fire alarm panel with remote power panels that operate all the older system notification devices. This new panel gets all the output alarm functions from the old fire alarm system, but still operates all the detection devices. The alarm output signals are taken from the old fire alarm notification circuits. This arrangement allows for a phased replacement of the fire alarm system. The new fire alarm control panel can be upgraded in the future to include all the alarm initiation devices when the old panel must be replaced.
Costs differ from building to building, depending on various factors including height, the number of stories, and building design. A typical high-rise fire alarm system replacement can cost anywhere from $9,000 to $12,000, depending on the actual square footage of the building, quality of finishes, and local cost differentials
The fire alarm industry has rapidly responded to the requirements of the ADA with a number of new technologies. Fire alarm pull stations are uniformly located to allow easy access to all persons. The design of audible systems has become more uniform and testing includes the use of sound meters.
Strobe lights have had the largest impact on fire alarm system design. They have increased the number of devices and control units beyond what was typical prior to the enactment of the ADA. Initially, the strobe light requirements were very strict, but due to Underwriters Laboratories research, more flexible designs are now available. The ADA will undergo periodic changes to incorporate new technologies. As this occurs, even more flexible designs will be available.
This article reprinted and adapted with permission from the April 1998 issue of Security Technology and Design, published by Locksmith Publishing Corp. located in Park Ridge, Ill.
Andrew Valente is a registered professional engineer with Rolf Jensen Associates Inc., based in Houston.
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|Title Annotation:||Americans with Disabilities Act|
|Publication:||Journal of Property Management|
|Date:||Jan 1, 1999|
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