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NIOSH Hearing Loss Research Program Review NIOSH Publications on Noise and Hearing The National Academies - Advisors to the Nation on Science, Engineering, and Medicine

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R&D Portfolio - Research Goal 1.10 : Develop a hearing protector device compendium

Research has demonstrated HPDs will not be worn unless, among other factors, they are comfortable, convenient, and do not prevent users from communicating with one another or from hearing other important sounds such as warning signals. The wrong hearing protector can be a safety hazard. HPDs that provide too little protection will not prevent noise-induced hearing loss. HPDs that over protect will inhibit effective voice communication and interfere with the ability to hear other important sounds.

Because no single HPD can be appropriate for all situations or for all workers, it is important to have a variety of HPDs from which to choose. Currently, more than 300 different models of hearing protectors are sold in the U.S., but workers may not know how to choose the HPD that is best for their work tasks and environments. It can be equally difficult for persons responsible for purchasing HPDs for a company to know what HPDs to order. An accessible collection of data about HPDs and their characteristics, as well as guidance regarding the selection process, was needed to assist individuals and organizations in making informed decisions about HPDs.

NIOSH collected and published a collection of data regarding HPD characteristics and selection guidance in 1976, 1984, and 1995[14],[15],[16]  In 2000, NIOSH researchers initiated a new effort to collect data published by manufacturers of hearing protectors sold in the United States to augment or replace the data collected for the 1994 Hearing Protector Compendium. The data included the mean attenuations and standard deviations of the attenuations provided by the manufacturers on labeling required by the Environmental Protection Agency (EPA). Data were also provided about HPD materials, HPD construction and other features that may aid in selection of protectors for specific situations. All companies listed in various industries, technical, and professional directories were invited to submit data. Many companies that were listed in the 1994 compendium have merged with other companies or have ceased to manufacturer or sell hearing protectors. The present compendium contains data from 23 manufacturers nationwide (down from 53 in the 1994 compendium) on 292 hearing protectors (up from 241 in the 1994 compendium). Although only 23 of the 67 companies contacted responded to the request for data, these 23 represent a majority of the market share. There are no data in the compendium other than those provided by the manufacturers. In the pursuit of completeness, we maintain open invitations for all manufacturers to submit their data.

The current compendium has been designed to be responsive to changes in the production and availability of HPD models. Thus, it has been published on the NIOSH hearing loss prevention web site: The electronic version contains updated information on the use of the real ear attenuation at threshold (REAT) attenuation values and standard deviations for the purpose of calculating the attenuation. Additional information is provided for special cases where HPDs are worn for high-level noise environments such as target shooting or hunting. There is also a complete tutorial on how the NRR and other rating systems are calculated. Development of this compendium was partially supported through an interagency agreement with EPA (DW 75-9390401-3).

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