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U.S. Department of Health and Human Services

Recognized Consensus Standards

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Part B: Supplementary Information Sheet (SIS)
FR Recognition List Number 028 Date of Recognition 03/16/2012 
FR Recognition Number 4-186
ANSI ASA S12.2-2008 (Revision of ANSI S12.2-1995)
American National Standard Criteria for Evaluating Room Noise
This Standard provides three primary methods for evaluating room noise: a survey method, an engineering method, and a method for evaluating low-frequency fluctuating noise. Two methods for evaluating room noise-RC (room criterion) and NCB (balanced noise criterion) curves-were the basis of the previous ANSI S12.2-1995 standard, and RC is included briefly for informational purposes in Annex D. All of the methods assume that the measured noise is free of tones. (ANSI S1.13-2005 Annex A gives an accurate method for assessing the presence of prominent discrete tones using

narrow band analysis.)

The three primary methods are:

1. The survey method that employs the A-weighted sound level;

2. The engineering method that employs noise criteria (NC) curves; and

3. The method for evaluating low-frequency fluctuating noise using room noise criteria (RNC)


This Standard also contains one ancillary set of criteria curves for evaluating acoustically induced vibrations or rattles.

Requirements are given in the body of the Standard for determining whether a:

1. Measured or estimated A-weighted sound level satisfies a specified noise criterion.

2. Set of octave-band sound pressure levels satisfies a specified noise criterion (NC) curve.

3. Time-series of octave-band sound pressure levels satisfies a specified room noise criterion (RNC) curve.

4. Table of octave-band sound pressure levels that, when modulated by fluctuations at low frequencies, may cause perceptible vibrations or rattles in lightweight constructions.

Extent of Recognition
Complete standard
Rationale for Recognition
This standard is relevant to medical devices and is recognized on its scientific and technical merit and/or because it supports existing regulatory policies.
Public Law, CFR Citation(s) and Procode(s)
Regulation Number Device Name Device Class Product Code
§874.3950 Hearing Aid, Air Conduction, Transcutaneous System Class 2 NIX
§874.3400 Masker, Tinnitus Class 2 KLW
§874.3300 Hearing Aid, Air Conduction Class 1 ESD
§874.3300 Hearing Aid, Bone Conduction Class 2 LXB
§874.3300 Hearing Aid, Bone Conduction, Implanted Class 2 MAH
§874.1090 Tester, Auditory Impedance Class 2 ETY
§874.1090 Tympanometer Class 2 NAS
§874.1080 Set, Audiometer Calibration Class 1 EWA
§874.1050 Audiometer Class 2 EWO
Unclassified Implant, Auditory Brainstem Class 3 MHE
Unclassified Implant, Cochlear Class 3 MCM
Unclassified Implant, Hearing, Active, Middle Ear, Partially Implanted Class 3 MPV
§874.3950 Hearing Aid, Air Conduction, Transcutaneous System Class 2 NIX
Relevant FDA Guidance and/or Supportive Publications
Class II Special Controls Guidance Document: Transcutaneous Air Conduction Hearing Aid System (TACHAS); Guidance for Industry and FDA. Document issued November 7, 2002

Guidance for Industry and FDA Staff Implantable Middle Ear Hearing Device Document issued on: August 1, 2003

Draft Guidance for Industry and FDA Staff Class II Special Controls Guidance Document: Tinnitus Masker Devices. Documenet issued on November 8, 2005

Guidance for Industry - Noise Claims in Hearing Air Labeling Document issued on: October 21, 1998
FDA Technical Contact
 Vasant Dasika
Standards Development Organizations
ANSI American National Standards Institute https://www.ansi.org/
ASA Acoustical Society of America http://acousticalsociety.org/
FDA Specialty Task Group (STG)