Sec.

12.1

12.2

12.3

12.4

12.5

12.6

12.7

12.8

12.9

PART 12-SUPPLIED-AIR

RESPIRATORS

Definition of a permissible supplied-
air respirator.

Types of supplied-air respirators.
Purpose of testing for permissibility.
Conditions under which supplied-air
respirators will be tested.

Requirements for Bureau of Mines
approval.

Changing details of tests.

Notification of approval or disapproval.

Approval markings.

Material required for Bureau of
Mines record.

12.10 Changes subsequent to approval.
12.11 Withdrawal of approval.

AUTHORITY: The provisions of this Part 12 issued under secs. 2, 3, 5, 36 Stat. 370, as amended, sec. 212, 66 Stat. 709; 30 U.S.C. 3, 5, 7, 482.

SOURCE: The provisions of this Part 12 contained in Schedule 19B, 20 F.R. 2564, Apr. 19, 1955, unless otherwise noted. § 12.1

Definition of a permissible supplied-air respirator.

(a) A supplied-air respirator is permissible for use in harmful or objectionable atmospheres encountered in its field of industrial usage if all the materials and details of construction are the same as and its performance in all respects is equal to or better than that required by applicable portions of this part.

(b) Bureau of Mines approval applies only to a complete supplied-air respirator and not to the integral parts thereof.

(c) The devices are designated by names other than the usual trade names. This change provides logical nomenclature for such devices, obviating dependence on a multiplicity of trade names, and provides for the naming of devices developed in this field in the future. The manufacturer, of course, may continue to advertise his device as a hose mask, air-line respirator, or abrasive blasting device.

[Sched. 19B, 20 F.R. 2564, Apr. 19, 1955]

§ 12.2 Types of supplied-air respirators. With regard to design and approval, supplied-air respirators are subdivided into the following types:

(a) Type A supplied-air respirator. (1) The Type A supplied-air respirator is commonly called a hose mask. This respirator is designed to require the presence of a man (safety man or blower

operator) in addition to the wearer; to permit the wearer to inspire air through the hose, connections, and air-supply device (blower) by his lungs alone when the blower is not operated; and to permit the wearer to be drawn to safety by a life line, or, if necessary, the hose in case of accident. It is the only supplied-air respirator that will be approved for use in immediately harmful atmospheres or those from which the wearer could not escape without the aid of the respirator. (2) The principal parts of a Type A supplied-air respirator are: A handoperated or motor-driven blower that shall permit free entrance of air to the hose when the blower is not operated; a strong, large-diameter hose having a low resistance to flow of air; a strong harness to which the hose and life line are attached; and a tight-fitting facepiece.

(b) Type B supplied-air respirator. (1) The type B supplied-air respirator is similar to the type A, with the main exception that it has no blower.

(2) It will not be approved for use in immediately harmful atmospheres or those from which the wearer could not escape without the aid of the device.

(3) The principal parts of a type B supplied-air respirator are: A strong, large-diameter hose having a low resistance to flow of air; a harness to which the hose is attached; and a tight-fitting facepiece.

(c) Type C supplied-air respirator. (1) The type C supplied-air respirator is designed for routine use in protecting workers against harmful or objectionable atmospheres that are not immediately dangerous to life or from which the wearer could escape without the aid of the respirator. It may be used with either a low- or high-pressure air-supply system. It is the responsibility of the user to provide respirable air either by a compressor that does not use an internal lubricant that could produce gases or mists that may be objectionable or injurious to health, or by one that is protected by suitable filters, temperature regulators, and alarms.

(2) Type C supplied-air respirators are divided into three classes: (i) Continuous-flow, (ii) demand, and (iii) pressure-demand. Type C respirators of the continuous-flow class supply respirable air to the respiratory-inlet covering continuously, even when the wearer exhales. Type C respirators of

the demand class supply respirable air to the respiratory-inlet covering only when the wearer inhales. Type C respirators of the pressure-demand class supply respirable air to the respiratoryinlet covering until a predetermined pressure is established in the respiratoryinlet covering and then supply additional respirable air when the wearer inhales.

(3) The principal parts of a type C supplied-air respirator, continuous-flow class, are: A positive-pressure air-supply system; a hose; a detachable coupling; a control valve or orifice; an arrangement for attaching hose to wearer; and a respiratory-inlet covering. Where the supply pressure exceeds 125 pounds per square inch gage, a pressure-release mechanism is required.

(4) The principal parts of a type C supplied-air respirator, demand class, are: A positive pressure air-supply system; a hose; a detachable coupling; a demand valve; an arrangement for attaching the respirator to the wearer; and a tight-fitting respiratory-inlet covering. A maximum air pressure of 125 pounds per square inch gage is allowed at the point of attachment of the air-supply hose to the air-supply system.

(5) The principal parts of a Type C supplied-air respirator, pressure-demand class, are: A positive pressure air-supply system; a hose; a detachable coupling; a pressure-demand valve; an arrangement for attaching the respirator to the wearer; and a tight-fitting respiratoryinlet covering that has provision for establishing a predetermined pressure in it. A maximum air pressure of 125 pounds per square inch gage is allowed at the point of attachment of the airsupply hose to the air-supply system.

(6) The general term "respiratoryinlet covering" is used for the covering worn over the face or head by the wearer of the respirator, when otherwise it would be necessary to use an expression such as "facepiece, half facepiece, helmet, or hood."

(d) Types AE, BE, and CE suppliedair respirators. Supplied-air respirators

may be modified for use in abrasive blasting. The letter E added to the regular-type letter indicates that the type of respirator designated by the first letter has been modified or provided with additional equipment to make it suitable for use in abrasive blasting. Such changes or additions consist primarily of providing a suitable covering to protect the head and neck against impact and abrasion by the rebounding material.

(e) Types A, AE, B, BE, C, or CE respirator in combination with another type of respiratory protective device. (1) A respirator of this type may consist of a supplied-air respirator in combination with a self-containeed breathing apparatus or with an air-purifying respirator such as a gas mask, dispersoid respirator, or chemical-cartridge respirator. A combination supplied-air respirator and selfcontained breathing apparatus which meets the applicable requirements of this part and of Part 11 of this chapter may be worn in atmospheres immediately harmful to life. A combination suppliedair respirator and air-purifying respirator which meets the requirements of this part and of other applicable parts will not be approved to be worn in atmospheres which exceed the limitations prescribed by the Bureau for use of the airpurifying respirator.

(2) Respiratory protective devices combining the characteristics of a supplied-air respirator and another type of respiratory protective device shall meet the requirements of this part as well as the requirements of any other part which is applicable to the total purpose of the device for which approval is sought. The approval, if granted, will be issued under the other applicable part(s). The Bureau will specify, in the certificate of approval and on the approval label, the limitations which shall apply to the use of the combination respiratory protective device.

[Sched. 19B, 20 F.R. 2564, Apr. 19, 1955; 20 F.R. 6552, Sept. 7, 1955, as amended at 28 F.R. 12121, Nov. 14, 1963; 33 F.R. 11817, Aug. 21, 1968]

§ 12.3 Purpose of testing for permissibility.

(a) The Bureau of Mines conducts tests of supplied-air respirators for the purpose of determining their permissibility for use in air containing contaminants such as harmful gases, vapors, and particulate matter.

(b) This part is for the information and guidance of those who may desire to submit supplied-air respirators for approval and also to inform consumers and other interested persons regarding the qualities the Bureau of Mines believes such devices should have.

[Sched. 19B, 20 F.R. 2565, Apr. 19, 1955] § 12.4 Conditions under which suppliedair respirators will be tested.

(a) Consultation. By appointment, applicants or their representatives may visit the Bureau's Health and Safety Research and Testing Center, 4800 Forbes Avenue, Pittsburgh, Pa. 15213 to discuss with qualified Bureau personnel proposed supplied-air respirators to be submitted in accordance with the regulations of this part. No charge is made for such consultation and no written report thereof will be made to the applicant.

(b) Application. No investigating or testing (including retesting of a respirator that has been previously tested and disapproved) will be undertaken hereunder by the Bureau except pursuant to a written application, in duplicate, accompanied by all drawings, specifications, descriptions, and related matters and also a check, bank draft, or money order, payable to the Bureau of Mines to cover the fees. The application and all related matters and correspondence concerning it shall be addressed to the Bureau of Mines, Health and Safety Research and Testing Center, 4800 Forbes Avenue, Pittsburgh, Pa. 15213, Attention: Approval and Testing.

4. Types C or CE supplied-air respirators, demand class (complete) – (i) Air-supply line (hose) –– (ii) Respiratory-inlet covering (facepiece)

5. Types C or CE supplied-air respirators, pressure-demand class (complete)

covering

(i) Air-supply line (hose)
(ii) Respiratory-inlet
(facepiece)

6. Additional examination and tests of respirator in connection with other tests, per man-day required

7. Fees for tests of unusually complicated apparatus, for unusual tests or tests not included in this list, or for tests required for extensions of approval, will be based on the actual costs of testing, which will be determined in advance by the Bureau. The applicant will be notified accordingly, and the fee shall be paid before the tests are begun.