gases or vapors as a measure of the protection afforded the wearer in high concentrations of these gases or vapors at high rates of breathing. The minimum life requirements of these tests have been chosen so that canisters that meet the requirements should meet the life requirements of the man tests.

(b) Table 3 lists the conditions for the high-concentration and highrate-of-flow tests.

(iv) Tests on filters for protection against particulate matter. (a) Gasmask canisters containing filters for protection against dust, fumes, mists, fogs, and smokes in combination with gases or vapors will be tested to determine the adequacy of the protection afforded in emergencies. No canister will be tested under the regulations in this part for use in dusts, fumes, mists, fogs, TABLE 3-HIGH-CONCENTRATION AND HIGH-RATE-OFFLOW TESTS

[Relative humidity of test atmosphere: 50+5 percent. Temperature: Room temperature (approximately 25° C.). Concentration of gas or vapor: Concentration for which approval is requested.1 Rate of air flow: 64 liters per minute, continuous flow. Number of canisters: 2 for each test atmosphere]

and smokes alone. All filters designed for this purpose will be tested under Part 14 of this subchapter.

4

(b) Three canisters containing the filters will be tested as follows: Air containing specially prepared tobacco smoke will be admitted to the canister at a rate of 85 liters per minute. The minimum filtering efficiency shall be 50 percent. Efficiency will be determined during the first 5 (approximately) minutes of test.

(3) Indicator for service-life of canister. Gas masks for protection against carbon monoxide must have a suitable means of indicating when the protection afforded by the canister against carbon monoxide has ended. Tests of such indicators will be arranged by the Bureau to suit the particular case. This requirement does not pertain to the selfrescue devices.

(h) Requirements and tests for complete gas masks-(1) Check valve. The gas mask shall have a check valve which will prevent exhaled air from entering the canister.

(2) Resistance to air flow. The maximum resistance requirements of the complete gas mask, including facepiece, breathing tube, timer (if part of the gas mask), and canister, to a continuous flow of air at a rate of 85 liters per minute are as follows: Inhalation, 3.5 inches of water (3.75 for Type N or those with canisters with special mechanical filters); exhalation, 1.25 inches of water. (3) Man tests. The final criterion for judging a gas mask for approval will be the protection afforded by the complete gas mask when worn by men.

(i) Gases and vapors. (a) The complete gas mask will be tested against each of the gases or vapors at the concentrations for which approval is requested, within the limits imposed by § 13.4 (a) and (b). Self-rescue devices for protection against carbon monoxide will be tested against 1 percent of carbon monoxide. These tests will be made in duplicate, starting with unused canisters for testing against each gas or vapor. If the test

Katz, S. H., Smith, G. W., and Meiter, E. G., Dust Respirators, Their Construction and Filtering Efficiency: Bureau of Mines Tech. Paper 394, 1926, 52 pp.

atmosphere does not cause marked discomfort through irritation of the skin or poisoning by absorption through the skin, as by hydrocyanic acid gas," two men will wear the complete masks in the test atmosphere. Otherwise the men will wear the mask for 2 minutes (1 minute in hydrocyanic acid gas) in the test atmosphere; and immediately following this the test will be continued with the canister of the mask attached to a source of the test atmosphere, so that the men are in uncontaminated air.

(b) During these tests the men will perform the schedule of exercise listed in table 4 below.

(c) The average breathing rate of each man while wearing the gas mask and performing the above schedule of exercise will be about 25 liters per minute.

(d) To meet the requirements of this test the gas masks shall give complete respiratory protection to wearers for 30 minutes for all types except Type N, which shall give complete respiratory protection against carbon monoxide for 30 minutes, organic vapors for 25 minutes, acid gases for 15 minutes, and ammonia for 15 minutes. Excessive fogging of the eyepieces must not occur, and undue discomfort must not be experienced because of fit or other physical or mechanical features of the gas mask.

(ii) Particulate matter. Gas masks designed for protection against dusts, fumes, mists, fogs, and smokes will be

tested by two men wearing them under the conditions set forth below:

(a) Cotton smoke. (1) Two men will wear the gas masks for 10 minutes in a room of about 1,000 cubic feet capacity filled with the smoke from the smudgeburning of 1 pound of cotton waste.

(2) To meet the requirements of this test, the gas masks must afford such protection to the wearers that they will experience no ill effects, such as discomforting irritation of the eyes or respiratory system during or after the test period.

(b) Tin tetrachloride. (1) Two men will wear the gas masks for 20 minutes with the canister connected to a room of about 1,000 cubic feet capacity in which is an atmosphere prepared by vaporizing enough tin tetrachloride to give a calculated concentration of 500 p. p. m. by volume of tin tetrachloride in the air. (Vaporized tin tetrachloride hydrolyses rapidly in moist air to form hydrogen chloride and a dense cloud of stannic hydroxide.)

(2) To meet the requirements of this test, the gas masks must afford such protection to the wearers that they will experience no ill effects, such as discomforting irritation of the eyes or respiratory system, during or after the test period.

[Sched. 14F, 20 F.R. 2710, Apr. 23, 1955; 20 F.R. 6552, Sept. 7, 1955]

tests, a formal written notification of approval or disapproval of the gas mask will be supplied to the applicant by the Bureau. If the device meets all requirements of this part, the notification will not be accompanied by test data or detailed results of tests. If the device fails to meet any of the requirements of this part, notification of such failure will be accompanied by details of the failure with a view to possible remedy of the defect or defects in gas masks subImitted in the future. Otherwise, results of tests of gas masks that fail to meet the requirements will not be made public by the Bureau.

(b) No verbal reports of the Bureau's decisions concerning the investigations will be given, and no informal approvals will be granted.

(Name of atmospheric contaminant) (b) Appropriate instruction and caution statements on the use and limitations of the gas mask will be included in these labels.

(c) One label shall be reproduced on the outside of the container of the gas mask. It shall be attached securely and, if a paper label is used, be waterproofed.

(d) The approval label for the canisters shall be suitably reproduced on each canister. If a paper label is used it must be attached to the canister with heat-proofed cement. Should the approval label for the canister not be plainly visible when the latter is attached to the canister harness, it may be necessary to attach a similar label to the canister harness.

(e) The main parts of the gas mask, such as the facepiece, canister harness, and canister, shall be marked by stamp

ing, stenciling, or labeling in a legible and permanent manner with the appropriate approval number in letters and figures at least 8 inch high placed in a position plainly visible.

(f) Full-scale designs or reproductions of approval labels and markings and a sketch or description of their position shall be submitted to the Central Experiment Station for approval before final adoption.

(g) Permission to place the Bureau's marks of approval on his gas mask obligates a manufacturer to maintain the quality of his product and to have each mask, and all parts thereof, strictly according to the drawings and records that have been accepted by the Bureau for that mask and are in the Bureau's files. Gas masks that exhibit changes in design or include parts that have not been approved for use with the gas mask are not permissible gas masks and must not bear the Bureau's approval label.

§ 13.10 Material required for Bureau of Mines record.

In order that the Bureau may know exactly what it has tested and approved, detailed records of each investigation are kept. These include drawings and actual equipment, as follows:

(a) Drawings and specifications. Drawings and specifications submitted with application for tests and final drawings and specifications that the applicant must submit to the Bureau before approval is granted to show the details of the gas mask as approved, will be retained by the Bureau. The company receiving the approval shall keep an exact duplicate of the set of drawings and specifications that are in the Bureau's records. These are to be adhered to in commercial production of the approved device.

(b) Actual equipment. (1) Parts of the gas mask or a complete mask used in the tests may be retained by the Bureau as a permanent record of the investigation and of the mask submitted. Material not required for record will be returned to the applicant at his expense on written shipping instructions to the Central Experiment Station.

(2) If the gas mask is approved, the applicant shall deliver to the Central Experiment Station, gratis, one complete gas mask in the form in which it is to be sold, to serve as a record of the commercial product.

The regulations in this part set forth the requirements for certification of respirators designed to remove particulate matter from inhaled air as permissible for use in atmospheres that are contaminated with certain dusts, fumes, or mists, or combinations thereof; procedures for applying for such certification; and fees. § 14.2 Definitions.

As used in this part

(a) "Permissible," as applied to a dust, fume, or mist respirator, means that the respirator conforms to the requirements of this part, and that a certificate of approval to that effect has been issued. (b) "Bureau" means the United States Bureau of Mines.

(c) "Certificate of approval" means a formal document issued by the Bureau stating that the respirator has met the requirements of this part for a dust, fume, or mist respirator and authorizing the use and attachment of an official approval label or marking so indicating.

(d) "Respirator” means a completely assembled device designed to provide respiratory protection against dusts, fumes, or mists, or combinations thereof by removing these contaminants from the air inhaled by the wearer.

(e) "Applicant" means an individual, partnership, company, corporation, organization, or association that designs, manufactures, assembles, or controls the assembly of a respirator, and seeks a certificate of approval thereof.

(f) "TLV" means the most recent Threshold Limit Value adopted by the American Conference of Governmental Industrial Hygienists.

(g) "Concentration limits for radionuclides" means the concentration limits set forth in Appendix B, Table I, Column 1 of Title 10 CFR Part 20 by the Atomic Energy Commission.

(h) "DOP" means a homogeneous liquid aerosol, having a particle diameter of 0.3 micron, which is generated by vaporization and condensation of dioctyl phthalate.

(i) "Protection factor" means the ratio of the concentration of dust, fume, or mist present in the ambient atmosphere to the concentration of dust, fume, or mist within the facepiece while the respirator is being worn.

By appointment, applicants or their representatives may visit the Bureau of Mines facility at 4800 Forbes Avenue, Pittsburgh, Pennsylvania, 15213, and discuss with qualified Bureau personnel proposed designs of respirators to be submitted in accordance with the requirements of the regulations of this part. No charge is made for such consultation and no written report thereof will be submitted to the applicant.

§ 14.4 Types of respirators for which certificates of approval will be issued. (a) Certificates of approval will be issued only for completely assembled respirators. Certificates will not be issued for component parts or subassemblies.