(a) As used in subpart B, all terms not defined here have the meaning given them in the Act or in subpart A of Part 211.

(b) ANSI Z24.22-1957. A measurement procedure published by the American National Standards Institute (ANSI) for obtaining hearing protector attenuation values at nine of the one-third octave band center frequencies by using pure tone stimuli presented to ten different test subjects under anechoic conditions.

(c) ANSI S3.19-1974. A revision of the ANSI Z24.22-1957 measurement procedure using one-third octave band stimuli presented under diffuse (reverberant) acoustic field conditions.

(d) Carrying Case. The container used to store reusable hearing protectors.

(e) Category. A group of hearing protectors which are identical in all aspects to the parameters listed in §211.210-2(c).

(f) Claim. An assertion made by a manufacturer regarding the effectiveness of his product.

(g) Custom-molded device. A hearing protective device that is made to conform to a specific ear canal. This is usually accomplished by using a moldable compound to obtain an impression of the ear and ear canal. The compound is subsequently permanently hardened to retain this shape.

(h) Dispenser. The permanent (intended to be refilled) or disposable (discarded when empty) container designed to hold more than one complete set of hearing protector(s) for the express purpose of display to promote sale or display to promote use or both.

(i) Disposable Device. A hearing protective device that is intended to be discarded after one period of use.

(j) Ear Insert Device. A hearing protective device that is designed to be inserted into the ear canal, and to be held in place principally by virtue of its fit inside the ear canal.

(k) Ear Muff Device. A hearing protective device that consists of two acoustic enclosures which fit over the ears and which are held in place by a spring-like headband to which the enclosures are attached.

(l) Headband. The component of hearing protective device which applies force to, and holds in place on the head, the component which is intended to acoustically seal the ear canal.

(m) Hearing Protective Device. Any device or material, capable of being worn on the head or in the ear canal, that is sold wholly or in part on the basis of its ability to reduce the level of sound entering the ear. This includes devices of which hearing protection may not be the primary function, but which are nonetheless sold partially as providing hearing protection to the user. This term is used interchangeably with the terms, “hearing protector” and “device.”

(n) Impulsive Noise. An acoustic event characterized by very short rise time and duration.

(o) Label. That item, as described in this regulation, which is inscribed on, affixed to or appended to a product, its packaging, or both for the purpose of giving noise reduction effectiveness information appropriate to the product.

(p) Manufacturer. As stated in the Act “means any person engaged in the manufacturing or assembling of new products, or the importing of new products for resale, or who acts for, and is controlled by, any such person in connection with the distribution of such products.”

(q) Noise Reduction Rating (NRR). A single number noise reduction factor in decibels, determined by an empirically derived technique which takes into account performance variation of protectors in noise reducing effectiveness due to differing noise spectra, fit variability and the mean attenuation of test stimuli at the one-third octave band test frequencies.

(r) Octave Band Attenuation. The amount of sound reduction determined according to the measurement procedure of §211.206 for one-third octave bands of noise.

(s) Over-the-Head Position. The mode of use of a device with a headband, in which the headband is worn such that it passes over the user's head. This is contrast to the behind-the-head and under-the-chin positions.

(t) Package. The container in which a hearing protective device is presented for purchase or use. The package in some cases may be the same as the carrying case.

(u) Primary Panel. The surface that is considered to be the front surface or that surface which is intended for initial viewing at the point of ultimate sale or the point of distribution for use.

(v) Spectral uncertainty. Possible variation in exposure to the noise spectra in the workplace. (To avoid the underprotection that would result from these variations relative to the assumed “Pink Noise” used to determine the NRR, an extra three decibel reduction is included when computing the NRR.)

(w) Tag. Stiff paper, metal or other hard material that is tied or otherwise affixed to the packaging of a protector.

(x) Test Facility. For this subpart, a laboratory that has been set up and calibrated to conduct ANSI Std S3.19-1974 tests on hearing protective devices. It must meet the applicable requirements of these regulations.

(y) Test Hearing Protector. A hearing protector that has been selected for testing to verify the value to be put on the label, or which has been designated for testing to determine compliance of the protector with the labeled value.

(z) Test Request. A request submitted to the manufacturer by the Administrator that will specify the hearing protector category, and test sample size to be tested according to §211.212-1, and other information regarding the audit.

(aa) Random Incident Field. A sound field in which the angle of arrival of sound at a given point in space is random in time.

(bb) Real-Ear Protection at Threshold. The mean value in decibels of the occluded threshold of audibility (hearing protector in place) minus the open threshold of audibility (ears open and uncovered) for all listeners on all trials under otherwise identical test conditions.

(cc) Reverberation Time. The time that would be required for the mean-square sound pressure level, originally in a steady state, to fall 60 dB after the source is stopped.