acoustical calibrator shall be within ±5 percent of the frequency stated by the applicant.

(c) If the acoustical calibrator operates at more than one sound pressure level, means shall be provided to indicate which sound pressure level is in use. The accuracy of the calibration sound pressure level of the acoustical calibrator shall be accurate to within ±1 dB, utilizing any corrections for atmospheric pressure specified by the instruction manual.

(d) If the acoustical calibrator is battery operated, means shall be provided to indicate whether battery voltage is adequate to maintain the performance specified for the acoustical calibrator. The requirements described in paragraphs (b) and (c) of this section shall be tested under minimally adequate battery voltage (i.e., the minimum battery voltage necessary to ensure adequate operation).

(e) The tests of frequency and sound pressure level shall be made with a compatible microphone whose calibration has been transferred from a laboratory standard microphone calibrated by the reciprocity technique described in ANSI S1.10-1966, "Method for the Calibration of Microphones".

(f) If the acoustical calibrator operates at multiple sound pressure levels or frequencies, then the preferred frequency and sound pressure level, if any, shall be specified by the applicant for use in calibrating the industrial sound level meter for testing for compliance with the requirements of § 82.64.

§ 82.64 Requirements and tests for industrial sound level meters.

Each industrial sound level meter submitted for certification shall meet the following requirements and tests. All tests shall be performed with the industrial sound level meter set to Aweighted, "SLOW" response unless otherwise specified.

(a) The industrial sound level meter shall have an A-weighting-network with the frequency characteristics and design specified for Type 2 sound level meters in sections 3.1, 3.1.1, and 3.1.3. of ANSI S1.4-1971. The A-weighted response of the sound level meter shall

be verified by the tests described in paragraph (b) of this section.

(b) The total tolerance limits of the industrial sound level meter for sound at random incidence shall be as specified for Type S2A sound level meters in section 3.2.1 of ANSI S1.4-1971. Testing shall be performed in an anechoic chamber to determine if the industrial sound level meter meets the required frequency response characteristics and total tolerance limits. The method of test shall be as described in sections 4.1 and 4.2.1 of ANSI S1.41971. Testing shall be performed with no observer present in the anechoic chamber. Tests to determine that the industrial sound level meter meets acoustic low frequency response tolerances will be performed using a low frequency calibration chamber at the Testing and Certification Laboratory. Supplementary diffuse field or freefield tests will be performed by the Testing and Certification Laboratory as required to verify overall random incidence response tolerance limits.

(c) The maximum deviation of the free-field relative response level as a function of angle or incidence with respect to the random-incidence relative response level shall be as specified for Type S2A sound level meters in section 4.2.2 of ANSI S1.4-1971. Testing shall be performed in an anechoic chamber with no observer present in the chamber.

(d) The sensitivity range attenuator of the industrial sound level meter, if provided, shall meet the requirements specified for Type 2 sound level meters in section 3.2.2 of ANSI S1.4-1971. The accuracy of the settings of the sensitivity range attenuator shall be determined by inserting a sinusoidal voltage of adjustable amplitude in series with the microphone of the industrial sound level meter. The microphone shall be acoustically shielded to make the acoustic pickup negligible. The test shall be performed at least at the frequencies 63 Hz, 1000 Hz, and 8000

Hz.

(e) The internal noise of those industrial sound level meters supplied with amplifier output connections shall meet the Type 2 sopund level meter requirements specified in section 3.3.1 of ANSI S1.4-1971. However, in order

to properly test sound level meters having very wide scale spans, the last sentence of section 3.3.1 of ANSI S1.41971 shall be modified and interpreted as follows: "In addition, the internal noise equivalent sound level, when measured in octave bands for all range attenuator settings that include any portion of the range 80 dBA to 115 dBA, shall not exceed either of the following: (1) 40 decibels below full scale, (ii) 20 decibels below the lower limit of the fully graduated scale. Each octave band level shall be expressed relative to a sinusoidal signal, centered in the octave band, having full scale level."

(f) In an acoustic environment in which the sound level is less than 30 dBA, the industrial sound level meter reading shall not exceed 55 dBA if the industrial sound level meter has a sensitivity range attenuator setting to allow such a measurement within the fully graduated scale. If such a sensitivity range attenuator setting is not provided, the industrial sound level meter, when placed on its most sensitive range attenuator setting, shall indicate a reading less than 1 dBA above the lower limit of the fully graduated scale.

(g) The amplifier distortion of the industrial sound level meter shall meet the requirements for Type 2 sound level meters specified in section 3.3.3 of ANSI S1.4-1971. The response to electrical sine waves shall be determined by inserting a sinusoidal voltage in series with the microphone of the industrial sound level meter to produce a full scale deflection reading. The microphone shall be acoustically shielded to make the acoustic pickup negligible. The signal shall then be increased until the electrical signal is 10 dBA above the voltage equivalent of full scale deflection. Any deviation from linearity in the response of the industrial sound level meter shall be noted. The test shall be performed at least at the frequencies 63 Hz, 1000 Hz, and 8000 Hz.

(h) The amplifier overload distortion of the industrial sound level meter shall meet the requirements of section 3.3.4 of ANSI S1.4-1971 except that the specified data shall be required only for the A-weighting mode.

(i) The industrial sound level meter scale marking and accuracy shall meet the requirements specified for Type 2 sound level meters in Section 5.1 of ANSI S1.4-1971. In section 5.1.3 of ANSI S1.4-1971 the phrase "full scale" shall mean the upper limit of the fully graduated scale. Table I below provides the permitted error for scales graduated from -5 decibels to +10 decibels as required by section 5.1.3 of ANSI S1.4-1971. If the scale is graduated otherwise, the formula specified for Type 2 sound level meters in section 5.1.3 of ANSI S1.4-1971 is to be applied to obtain a similar table. The accuracy of the indicating instrument scale shall be determined by inserting a sinusoidal voltage in series with the microphone of the industrial sound level meter. The microphone shall be acoustically shielded to make the acoustic pickup negligible. The amplitude of the inserted signal shall be adjusted so that the indicating instrument reads full scale deflection. Then the signal shall be attenuated so as to reduce the indicated sound level in one decibel steps. The required attenuation shall be precisely measured and used to determine the accuracy of the indicating instrument. The test shall be performed at least at the frequency of 1000 Hz.

TABLE 1.--Permitted scale error

(1) One-third octave bands of noise shall be used. Octave bands of noise shall not be used.

(2) The voltage developed across the resistor shall be applied as an electrical input to the industrial sound level meter in series with the microphone, with the acoustic pickup made negligible.

(3) Only A-weighting shall be used in the measurement procedure.

(4) Only the "SLOW" meter characteristic of the industrial sound level meter shall be used in the measurement procedure.

(k) The industrial sound level meter shall employ an indicating system equally responsive to instantaneous sound pressures both above and below ambient static pressure (i.e., full-wave or true square law rectification shall be employed).

(1) The industrial sound level meter shall have the slow dynamic characteristic specified for Type 2 sound level meters in section 5.4 of ANSI S1.4-1971, with the exception of section 5.4.4 which need not apply. The phrase "full-scale reading" in section 5.4.3 of ANSI S1.4-1971 means the upper limit of the fully graduated scale. If the scale of the meter is not graduated from -5 decibels to +10 decibels, suitable testing levels other than that specified in section 5.4.3 of ANSI S1.4-1971 may be chosen by the Institute. The test described in section 5.4.2 of ANSI S1.4-1971 shall be performed at least at the frequencies 63 Hz, 1000 Hz, and 8000 Hz.

(m) The industrial sound level meter shall have a battery indicator, if battery operated, as specified in section 5.5 of ANSI S1.4-1971. The accuracy of the industrial sound level meter with minimally adequate battery voltage shall be checked by first inserting a sinusoidal signal in series with the microphone with normal battery voltage and then with the minimally adequate voltage. The microphone shall be acoustically shielded to make the acoustic pickup negligible. The variation in the meter reading shall not exceed +.5 dBa. If the industrial sound level meter has more than one battery, the various combinations of

will be used to perform the above test.

(n) Each industrial sound level meter shall meet the requirements specified in section 6.2.2 of ANSI S1.41971 except that the industrial sound level meter, as part of a set, shall be designed so that its sensitivity can be checked with an acoustical calibrator of the coupler type.

(0) The industrial sound level meter shall meet the temperature requirements specified in section 7.1 of ANSI S1.4-1971. The effect of temperature on the electronic circuitry of the industrial sound level meter shall be determined by placing the industrial sound level meter in a temperature controlled chamber and then inserting a sinusoidal voltage in series with the microphone to produce a steady meter reading 6 decibels down from full scale deflection. If the scale of the indicating instrument is not graduated from -5 decibels to +10 decibels, other suitable testing levels may be chosen by the Institute. The microphone shall be acoustically shielded to make the acoustic pickup negligible. The temperature shall then be varied and the deviation in reading noted. The test shall be performed at least at the temperatures -10° C, 10° C, 30° C, and 50° C. The effect of temperature upon the entire instrument including the microphone shall also be determined. The test just described shall be repeated, utilizing an acoustical tone in place of electrical insertion. If the industrial sound level meter is battery operated, the tests shall be performed under battery power.

(p) The industrial sound level meter shall meet the humidity requirements for Type 1 sound level meters specified in section 7.2 of ANSI S1.4-1971 except that the range of relative humidity over which there is less than 0.5 decibel variation in sensitivity shall be that stated by the applicant. The effect of humidity on the industrial sound level meter operation shall be determined by using an acoustical tone to produce an indicated sound level 6 decibels down from full scale deflection. If the scale of the indicating instrument is not graduated from -5 decibels to +10 decibels, other suitable testing levels may be chosen by

the Institute. The relative humidity shall then be varied and the deviation in reading noted.

(q) The industrial sound level meter shall meet the vibration requirements for Type 1 sound level meters specified in section 7.3 of ANSI S1.4-1971 except that the tests shall be performed and the manufacturer shall be required to state readings for the Aweighting network only. The symbol "0.1g," in ANSI S1.4-1971 means that the root-mean-square acceleration shall be 0.1g where g=9.80 m/sec2. The tests shall be performed by placing the industrial sound level meter in contact with a vibrating surface. The surface shall be vibrated at least at the frequencies 63 Hz, 250 Hz, and 1000 Hz.

(r) The industrial sound level meter shall meet the requirements for magnetic fields specified in section 7.5 of ANSI S1.4-1971 except that:

(1) Tests shall be performed and the manufacturer shall be required to state the magnetic field sensitivity for the A-weighting network only.

(2) Testing shall be performed using 60 Hz and 400 Hz magnetic fields.

(3) The A-weighted levels (in decibels) for 1 oersted, 60 Hz and 400 Hz magnetic fields shall be stated for each sensitivity range attenuator setting, if provided. If no sensitivity range attenuator is provided, the indicated reading under these test conditions shall be stated.

Any term defined in the Occupational Safety and Health Act of 1970 and not defined below shall have the meaning given it in the Act. As used in this part:

(a) "Act" means the Occupational Safety and Health Act of 1970 (29 U.S.C. 651 et seq.).

(b) "Institute" means the National Institute for Occupational Safety and Health established under the Act.

(c) "Applicant" means an individual, partnership, company, corporation, association, or other organization that designs, manufactures, assembles, or markets a gas detector tube unit or component and seeks a certificate therefor.

(d) "Gas detector tube" means a tube containing a chemically impreg

nated packing which indicates the concentration of a contaminant in the air by means of a chemically produced color change.

(e) “Tube unit" means a device for measuring or signaling the presence of one or more gaseous contaminants in the atmosphere of a working environment which consists of (1) a gas detector tube and (2) an aspirating pump and which may also include (3) an oxidation tube or pyrolyzer or any other component which changes the nature of the contaminant so that it may be measured by the tube, or (4) any other device such as an automatic stroke counter which enhances the convenience or usability of the tube unit.

(f) "Component" means any gas detector tube, aspirating pump, or device which changes the nature of the contaminant so that it may be measured by the tube, and is designed to operate as a constituent of the tube unit in such a way that the entire unit meets the requirements of this part.

(g) "Independent tube reader" means a person measuring the length of stain or comparing the color or stain in a tube unit in accordance with the instructions furnished by the applicant who (1) is not aided by another person in reading the tube, (2) has no knowledge of other reader results, and (3) has no prior knowledge of the actual contaminant concentration other than from tube unit readings.

(h) "Test standard" means the contaminant concentration in air which is adopted by the Institute for each contaminant for the purpose of defining the concentration range to be measured by the tube.

(i) “MIL-STD” means a specific military standards document approved by the U.S. Department of Defense.

(j) "Batch" means a quantity of material as defined in MIL-STD-105D and MIL-STD-414.

[38 FR 11459, May 8, 1973, as amended at 38 FR 14940, June 7, 1973]

§ 84.3 Applications; tube units; compo

nents.

(a) From time to time, the Institute will publish a notice in the FEDERAL REGISTER Specifying the dates during which applications will be accepted for the testing and possible certification

of tube units and components thereof which are intended to measure specific gases. This notice shall also list the test standard adopted by the Institute for each specific gas. Information concerning the test standards for specific gases is available at the address given in paragraph (b) of this section.

(b) No testing of a tube unit or components thereof will be undertaken by the Institute except pursuant to a written application filed in accordance with the requirements of this subpart. The application and all related materials and correspondence concerning it shall be sent to the National Institute for Occupational Safety and Health, Department of Health, Education, and Welfare, Testing and Certification Laboratory, Appalachian Center for Occupational Safety and Health, 944 Chestnut Ridge Road, Morgantown, W. Va., 26505, and shall be accompanied by a check, bank draft, or money order in the amount specified in § 84.12, payable to the National Institute for Occupational Safety and Health.

(c) Tube units or compatible components thereof submitted for certification shall be made from those materials specified in the application, on regular production tooling, using only those operations which are a part of regular production processing.

(d) The applicant shall describe the way in which each lot or batch of components will be sampled and tested to maintain their quality in the manufacturing and distribution process pursuant to Subparts B and C of this part.

(e) The applicant shall furnish to the Institute without charge the tube units required for testing. The Institute may require such number of units and components as it deems necessary for adequately testing such units.

(f) The applicant shall submit fullscale designs or reproductions of proposed labels specifying storage instructions, batch number, and expiration date, and a sketch or description of the position of the proposed labels on each tube unit or component thereof. The proposed position of the certification seals issued by the Institute shall also be shown.

(g) The applicant shall submit a statement based upon tests prescribed