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3M, E-A-RCAL Laboratory
3M's E-A-RCAL Acoustical Laboratory, established in 1979, has offered contract testing since 1992. The principal service offered is the measurement of the real-ear attenuation at threshold (REAT) of hearing protection devices (HPDs). Additional services include objective hearing protector and earphone measurements utilizing either KEMAR or the ANSI S12.42-2010 or ISO/TR 4869-3 acoustical test fixtures, or miniature microphones and/or probe microphones placed in real ears. Previous clients include Mobil Research and Development Corp., Quest Electronics, Etymotic Research, Welch Allyn, and other corporations and government agencies.
The facility
Testing is conducted in a 113-m3 double-wall structure with isolated
outer and inner foundations. The Sound Transmission Class (STC)
of the  combined
structure exceeds 75 dB, providing noise levels in the room of <16
dBA (approximately 20 dB in the 125-Hz octave band). REAT measurements
can be conducted over an extended frequency range, from 80 Hz to
16 kHz. Insertion-loss measurements cover an even wider frequency
range, extending from 50 Hz to 16 kHz.
All of the electroacoustic aspects of the facility and instrumentation comply with ANSI S3.19-1974 and S12.6-2008.
Accreditation
E-A-RCAL Laboratory was the first facility accredited by the Department of Commerce, National Institute of Standards and Technology, National Voluntary Laboratory Accreditation Program (NVLAP)
to conduct tests in conformance with ANSI S3.19-1974, and is also accredited for S12.6-2008. In achieving accreditation the laboratory has demonstrated competence and adherence to a rigorous set of procedural, quality-control, and recordkeeping requirements. Accreditation is maintained via regular audits by NVLAP assessors.
History of the facility
The E-A-RCAL facility was designed by and constructed under the supervision of Elliott H. Berger in 1977, and has been utilized for hearing protector testing since 1979. During the past 31 years more than 1800 REAT evaluations have been conducted. E-A-RCAL laboratory participated in an EPA interlaboratory comparison study of hearing protector attenuation measurements which was conducted in the early 1980s, and in 1990 was one of four participants in the interlaboratory comparison research conducted under the auspices of the Acoustical Society of America's accredited standards working group S12/WG11, Hearing Protector Attenuation and Performance. This work led to the development of ANSI S12.6-1997, "Methods for measuring the real-ear attenuation of hearing protectors."
Personnel
Elliott H. Berger, M.S., Division Scientist.
Elliott conducts research and development into hearing protector performance,
design, and utilization. He has written over 60 articles on hearing
protection/conservation, and was the principal editor for the 5th edition
of the AIHA Noise Manual. Elliott chairs ANSI working group S12/WG11
on hearing protector performance, and is also involved with numerous
other standards committees. For additional details see Elliott Berger.
Ronald W. Kieper, A.A.S., COHC, Senior Acoustical Technician.
Ron has been conducting hearing protector tests for E-A-R, Aearo
Company, and what is now part of 3M for more than 28 years and thus
has experience with a wide variety of products and procedures. He participated
in the WG 11 interlaboratory comparison study mentioned above.
Contact and fees
To discuss your testing requirements and/or retain E-A-RCAL services,
contact Cyd Kladden.
The fee for standardized REAT
evaluations per S3.19 or S12.6 is $2400 per 10-subject test and $2600
for 20-subject tests; custom earmold tests are billed at a 15% premium.
The typical turnaround time is 4-5 weeks. Quotations will be provided
for nonstandardized testing.
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