(g) Tests 6, 7, and 8. The work schedule for Test 5, given in Table 2, is repeated for each of these tests. (i) Tests 10 and 11. The work schedule for Test 9, given in Table 3, is repeated for each of these tests. 1 Continue sitting quietly and take samples and readings at the same listed intervals until the supply of compressed oxygen or compressed air is exhausted; record the time when the supply is exhausted. (m) Test 15 is made to determine the maximum length of time that the apparatus will supply the needs of the wearer when in a quiescent state. The wearer will remain as far as possible in a sitting posture throughout the test and perform no work. He will be allowed to manipulate the devices controlling the compressed-oxygen or compressedair supply to conserve such compressedoxygen or compressed-air supply to the greatest advantage. § 11.8 Approval of regenerators. (a) The Bureau will, on application, make separate tests, identical with the foregoing tests, of regenerators manufactured for use with any breathing apparatus that it has approved under the regulations of this part. (b) Regenerators that fulfill the requirements of the foregoing tests will be approved for use only with that particular type of apparatus for which they are designed and that has previously been approved by the Bureau. § 11.9 Notification of approval or disapproval. (a) After the Bureau has considered the results of the investigation and suitable drawings and specifications have been placed on file, it will supply the applicant with a formal written notification of approval or disapproval of the self-contained breathing apparatus. If the breathing apparatus meets all requirements of this part, the notification will not be accompanied by test If the data or detailed results of tests. apparatus fails to meet any requirements of this part, the notification will be accompanied by details of the failure, with a view to possible remedying of the defect or defects in self-contained breathing apparatus submitted for testing and approval in the future. Results of tests of self-contained breathing apparatus that fail to meet the requirements will not be made public by the Bureau. (b) When an application for testing an apparatus is received and within a period not exceeding 10 days one or more additional applications for testing apparatus are received from sources different from the first application, the Bureau will not announce approval of the first apparatus unless approval can be announced for the other apparatus within a period not exceeding the interval of time between receipt of the first and subsequent applications. This exception is contingent upon the apparatus submitted with each application successfully meeting all of the requirements prescribed in this part. If an apparatus does not meet all of the requirements prescribed in this part it will not delay announcement of approval of such apparatus as have met the requirements. (c) When an applicant or manufacturer receives formal notification of approval, he shall be free to advertise the type of successfully tested self-contained breathing apparatus as "permissible" and to use the approval inscription described in § 11.10. The inscription shall be stamped, cast, or molded into the supplemental part of the breathing apparatus or shall be on a plate attached to the supplemental part. § 11.11 Changes subsequent to approval. All approvals are granted with the understanding that the manufacturer will make the approved self-contained breathing apparatus according to final drawings and specifications submitted to the Bureau. Therefore, before making any change in an approved apparatus, the manufacturer shall first obtain the Bureau's approval of the change. This procedure is as follows: (a) The manufacturer shall write to the Central Experiment Station, Bureau of Mines, 4800 Forbes Avenue, Pittsburgh, Pa., 15213, requesting an extension of the original approval and stating the change or changes desired. He shall send 2 sets of revised drawings and specifications showing the changes in detail, and 1 each of the apparatus parts affected to the Central Experiment Station. (b) The Bureau will consider the application and inspect the drawings and parts to determine whether it will be necessary to make tests. (c) If tests are unnecessary, the applicant will be notified formally by the Bureau of the approval or disapproval of the change. (d) If tests are necessary, the applicant will be notified of the fee and material required. 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. § 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 ɔbjectionable 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 provid ing a suitable covering to protect the head and neck against impact and abrasion by the rebounding material. [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] § 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. § 12.4 Conditions under which suppliedair respirators will be tested. (a) Consultation. Manufacturers or their representatives may visit or communicate with the Central Experiment Station, Bureau of Mines, 4800 Forbes Avenue, Pittsburgh, Pennsylvania, 15213, to obtain criticisms of proposed designs or to discuss the requirements of this part in connection with a device to be submitted. No charge is made for this consultation and no written report will be made to the manufacturer. (b) Application. An application for investigation under this part shall be in the form of a letter (in duplicate) addressed to the Central Experiment Station, Bureau of Mines, 4800 Forbes Avenue, Pittsburgh, Pennsylvania, 15213, which contains: (1) Duplicate descriptions and complete drawings of the device (supplemented with any available printed matter); (2) a statement that the device is completely developed and of the design and materials which the manufacturer believes suitable for a finished marketable device; (3) a statement that the device has been subjected to inspections and tests of the nature described in this part and that it has met these requirements when tested by the applicant or his testing agency; (4) two copies of the results of the applicant's inspection and tests; (5) a statement describing the nature, adequacy, and continuity of control of the quality of the respirator (see paragraph (e) of this section); (6) a request that the necessary inspections and tests leading 66-067 0-67-3 |