RECOMMENDATIONS FOR REDUCING NOISE LEVELS

RECOMMENDATIONS FOR REDUCING NOISE LEVELS

The following are among the recommendations for reducing noise levels in the Brookline (MA) Fire Department contained in the Local 950, International Association of Fire Fighters “Hearing Screening and Sound Level Survey” (1990). Many of these suggestions are applicable to all fire departments.

Stations

Eliminate alarm bells while leaving the tapper in the patrol area. Remove all unnecessary alarm bells. Relocate the remaining bells to areas out of the path of travel of a firefighter leaving the area to report to the apparatus floor to respond to an emergency. No other alarm bells should be along that path of travel, and none shall be on the apparatus floor near the patrol area or apparatus. Attenuate all alarm bells to a level not exceeding 80 db(A) when a box alarm is struck. This recommendation with regard to the alarm bells in conjunction with the recommendations concerning the tapper, vocal alarm, radio, and telephone system ensures the redundancy of the emergency communication system while reducing the potential for hearing damage that may now exist.

• Relocate still horns in a similar manner. Place them in the areas where they are most likely to be needed, and reduce the horn sound levels to 75 to 80 db(A). Replace one long blast on the still horn with intermittent taps.
• Relocate vocal alarm speakers and install more, if necessary, to provide a “distributed system,” where the volume would be 75 to 80 db(A) throughout the building. If the current system is incapable of accepting more speakers, relocate existing speakers to more advantageous locations. Each in-house PA system should be reviewed and modified as necessary, within the capabilities of the existing system.
• Place maximum volume limits on radios, including portables, in stations. A maximum of 80 db(A) seems reasonable.
• Forbid sirens and air horns to be used in quarters, especially when children are present. This will become even more important in the future as sirens and air horns are moved to the front bumper.
• Reword the department directive that says that air bottles will be recharged when they contain 3,000 psi of air. Personnel attempting to bleed the last 100 or 200 psi from the bottle so that it does not contain more than 3,000 psi of air when it is sent to be recharged are exposed to 115.5 db(A) of noise. Make it clear that the pressure should not be allowed to fall below 3.000 psi and that discharging air from the bottle so diat it is not above 3,000 psi no longer will be done. In other words, it is acceptable to send a bottle that reads 3,100 or 3,200 psi to be recharged.
• Where necessary, insulate the watch areas from the noise of the apparatus This can be achieved by installing partitions, doors, or other physical barriers. This also will help to alleviate some of the problems of diesel exhaust emissions in the stations.
• Train fire alarm dispatchers to
• repeat emergency alarm broadcasts over the vocal alarm system to better ensure that the broadcast has been correctly understood.

Apparatus

• Use warning devices only when necessary. People are more perceptually aware of changes in stimuli than of stimuli that are constant. Intermittent taps of the air horn are more effective than constantly sounding the horn.
• Discourage the use of the air horn by any company following a tiller-equipped ladder truck.
• Move sirens and air horns to or below the front bumper so that the vehicle acts as a sound shield.
• Modify sirens moved to the front bumper with longer horns that direct sound waves away from the workers. When compared with the conventional siren, “The high-directivity 40° by 20° horn covers nearly four times the distance, giving almost four times more warning time to motorists and pedestrians without raising sound levels indiscriminately. By using adapters for the horns, you can use existing siren drivers, reducing the cost of upgrading existing equipment.”² Consider replacing narrow-band, high-frequency devices with broader-band, lower-frequency warning devices.³
• Use sound-absorbing insulation to reduce exposure to noise in the cab and jumpseats. Wrap exhaust pipes with a heat-resistant material that reduces engine noise. Doing this may not provide adequate protection on some vehicles. Consider the age and condition of the vehicle before retrofitting an existing vehicle in this manner and assess how much attenuation may be achieved through tli is process.
• When purchasing new apparatus, consider models that have been engineered to reduce worker exposure to excessive noise. Newly purchased vehicles should not exceed 90 db(A) with warning devices operating, to meet NFPA 1500 specifications.⁴

General

• Hearing-protection devices are recommended for any activity, emergency, or nonemergency where the noise level exceeds or is suspected of exceeding 85 db(A). This includes riding on apparatus, training, performing maintenance checks, using auxiliary equipment, and operating on the fireground.
• Hearing-protection devices— carmulfs, earplugs, or a combination of them—should be worn when entering buildings with activated alarm systems. The department should buy these devices and consider them part of the firefighters’ protective gear. It is ironic that a firefighter entering a building with an activated alarm system is wearing more than 50 pounds of protective gear costing about S3,000 to protect against a multitude of hazards that may be present and yet is not guarded against noise, the one hazard that is present.
• Survey all stations and alarmed buildings to which you frequently respond with a sound level meter to identify problem areas and determine the appropriate remedial action needed to attenuate in-station problem areas and the level of hearing protection personnel require in specific buildings.
• Establish a “Code H” response classification for responses to buildings where the alarm system is known or suspected to be in excess of 85 db(A), indicating that hearing-protection devices are warranted when inside the building. Consider “Code H-2” response classification for buildings where the alarms are so loud that a combination of earplugs and earmuffs is necessary to protect firefighters.
• Develop a standard operating procedure that addresses the issue of when to silence audible alarms. The standard should address issues such as the need to alert residents, the wisdom of allowing horns to sound for the duration of the incident, the communication problems caused by the alarm system’s remaining activated, and any legal ramifications that such a policy might foster.
• Develop a hearing-conservation program that includes yearly audiometric testing, a continuing education program, and a mechanism for continually researching and implementing noise-exposure reduction practices.
• Train all firefighters to understand die effects of noise and the hardships caused by hearing loss. Every firefighter should strive to reduce occupational and recreational exposure to noise. Remember, noiseinduced hearing loss can be prevented, but it cannot be cured.

References

1. R. L. Tubbs, Health Hazard Evaluation: Memphis Eire Department, HETA 86-138-2017, p.12.
2. B. Mckinnon, “New Technology for Emergency Vehicle Sirens,” Fire Engineering, November 1990, 72.
3. R. L. Tubbs 12.
4. National Fire Protection Association, NFPA 1500 Standard on Eire Department Occupational Safety and Health Program (Quincy, Mass.: 1987), chap. 5-8.