Signaling for the Blind
Audible signals must be of sufficient audibility to alert blind persons. Section 7.4.2 of NFPA 72 provides performance-based requirements for the sound pressure level (SPL) of fire alarm signals. The minimum SPL for public mode operation is 15 dBA above the average SPL, or 5 dBA above the maximum SPL lasting a minute or longer, whichever is greater, throughout the protected space. A good dispersion of lower-powered audible devices throughout the protected space will help ensure a uniform distribution of the signal. It is best to design the system so that a signal does not need to penetrate more than one wall or door. Hotels and apartments should be designed with at least one audible appliance in each unit. High-noise environments may require the use of tactile pagers to alert occupants.
Considerations for Limited Mobility
Persons using wheelchairs or other similar devices cannot generally reach more than 48 inches above the finished floor when facing the object they are trying to reach, and they cannot usually reach more than 54 inches when approaching an object from the side. According to the ADAAG, manual fire alarm boxes must be mounted not more than 48 inches high for front reach and 54 inches high for side reach. Manual fire alarm boxes mounted with the top of the back box at 48 inches will generally satisfy both sets of requirements, and complies with Section 2-8.1 of NFPA 72.
The Access Board has developed a new draft of the ADAAG, which was released on April 2, 2002. According to the Access Board's newsletter, the draft contains significant changes relating to fire alarms. It incorporates the ADAAG with the Architectural Barriers guidelines and also incorporates a new numbering system. But one of the most significant technical changes is found in Section 702.1, which directly references NFPA 72 (1999 edition). This change will make compliance with the ADA much easier. The one exception to NFPA 72 is for the maximum sound pressure level, which the ADAAG draft has set at 110 dBA.
It is unclear when the draft will clear the necessary hurdles, but the final rule will not be published for a while. Given the current administration's track record on rule making, expect to see a final rule no earlier than late 2003.
Compliance with the ADA is not that difficult. The real issue is that we need to have knowledge firmly planted in two documents. But once the current draft of the ADAAG becomes final, compliance will get a whole lot easier. In the meantime, we need to navigate our way through the labyrinth of regulations, guidelines, codes, and standards. A qualified consultant can help you better understand these issues for specific projects.
Merton Bunker is a senior consulting engineer with Rolf Jensen & Associates' Fairfax, Va. office. He can be reached by e-mail at firstname.lastname@example.org. To learn more about RJA, visit their Web site at www.rjagroup.com.