Section 74.7 - Design and construction requirements(a)General requirement. Continuous Personal Dust Monitors (CPDMs) shall be designed and constructed for coal miners to wear and operate without impeding their ability to perform their work safely and effectively, and shall be sufficiently durable to perform reliably in the normal working conditions of coal mines.(b)Ergonomic design testing. Prior to submitting an application under § 74.13 , the applicant shall develop a testing protocol and test the CPDM to assure that the device can be worn safely, without discomfort, and without impairing a coal miner in the performance of duties throughout a full work shift. The results of the test shall also demonstrate that the device will operate consistently throughout a full work shift under representative working conditions of underground coal miners, including representative types and durations of physical activity, tasks, and changes in body orientation.(1) The testing protocol shall specify that the tests be conducted in one or more active mines under routine operating conditions during production shifts.(2) The applicant shall submit the testing protocol, in writing, to NIOSH for approval prior to conducting such testing.(3) The applicant shall include the testing protocol and written test results in the application submitted to NIOSH as specified in § 74.13 .(4) NIOSH will advise and assist the applicant, as necessary, to develop a testing protocol and arrange for the conduct of testing specified in this paragraph.(5) NIOSH may further inspect the device or conduct such tests as it deems necessary to assure the safety, comfort, practicality, and operability of the device when it is worn by coal miners in the performance of their duties.(6) NIOSH may waive the requirement for the applicant to conduct testing under paragraph (b) of this section if NIOSH determines that such testing is unnecessary to assure the safety, comfort, practicality, and operability of the device when it is worn by coal miners in the performance of their duties.(c)Maximum weight. A CPDM shall not add more than 2 kg to the total weight carried by the miner. CPDMs that are combined with other functions, such as communication or illumination, may exceed 2 kg provided that the total added weight carried by the miner does not exceed 2 kg.(d)Dust concentration range. The CPDM shall measure respirable coal mine dust concentrations accurately, as specified under § 74.8 , for an end-of-shift average measurement, for concentrations within a range from 0.2 to 4.0 mg/m3 for respirable coal mine dust. For end-of-shift average concentrations exceeding 4.0 mg/m3, the CPDM shall provide a reliable indication that the concentration exceeded 4.0 mg/m3.(e)Environmental conditions. The CPDM shall operate reliably and accurately as specified under § 74.8 , under the following environmental conditions:(1) At any ambient temperature and varying temperatures from minus 30 to plus 40 degrees centigrade;(2) At any atmospheric pressure from 700 to 1000 millibars;(3) At any ambient humidity from 10 to 100 percent relative humidity; and(4) While exposed to water mists generated for dust suppression and while monitoring atmospheres including such water mists.(f)Electromagnetic interference. The CPDM shall meet the following standards for control of and protection from electromagnetic interference.(1) For emissions control, operators must follow: IEEE Std C95.1-2005, (IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz) and 47 CFR 15.1 through 15.407 (FCC Radio Frequency Devices). Persons must proceed in accordance with IEEE Std C95.1-2005 (IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz).(i) The Director of the Federal Register approves this incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Persons may obtain a copy from: American National Standards Institute (ANSI), 25 West 43rd Street, New York, NY 10036. http://www.ansi.org.(ii) Persons may inspect a copy at MSHA, Office of Standards, Regulations, and Variances, 201 12th Street South, Arlington, VA 22202-5452, 202-693-9440, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.(2) For immunity/susceptibility protection, operators must follow: IEC 61000-4-6, International Standard (Electromagnetic compatibility-Part 4-6: Testing and measurement techniques-Immunity to conducted disturbances, induced by radio-frequency fields), Edition 3.0, 2008-10. Persons must proceed in accordance with IEC 61000-4-6, International Standard (Electromagnetic compatibility-Part 4-6: Testing and measurement techniques-Immunity to conducted disturbances, induced by radio-frequency fields), Edition 3.0, 2008-10. The Director of the Federal Register approves this incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.(i) Persons may obtain a copy from the International Electrotechnical Commission at the address provided below:International Electrotechnical Commission, IEC Central Office, 3, rue de Varembe, P.O. Box 131, CH-1211 GENEVA 20, Switzerland. http://www.standardsinfo.net.
(ii) Persons may inspect a copy at MSHA, Office of Standards, Regulations, and Variances, 201 12th Street South, Arlington, VA 22202-5452, 202-693-9440, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.(g)Durability testing. The CPDM shall be designed and constructed to remain safe and measure respirable coal mine dust concentrations accurately, as specified under § 74.8 of this section after undergoing the following durability tests, which NIOSH will apply to test devices prior to their use in further testing under § 74.8 of this-subpart:| Vibration | Mil-Std-810F, 514.5 | U.S. Highway Vibration, Restrained Figure 514.5C-1 | 1 Hours/Axis, 3 Axis; Total Duration = 3 Hrs, equivalent to 1,000 miles. |
| Drop | 3-foot drop onto bare concrete surface | In standard in-use configuration | 1 drop per axis (3 total). |
(1) Persons must proceed in accordance with Mil-Std-810F, 514.5, Department of Defense Test Method for Environmental Engineering Considerations and Laboratory Tests, 1 January 2000. The Director of the Federal Register approves this incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 . Persons may obtain a copy from the U.S. Department of Defense at the address provided below.ASC/ENOI, Bldg. 560, 2530 Loop Road West, Wright-Patterson AFB OH 45433-7101. http://www.dtc.army.mil/navigator/.
(h)Reporting of monitoring results.(1) The CPDM shall report continuous monitoring results legibly or audibly during use. A digital display, if used, shall be illuminated and shall provide a minimum character height of 6 millimeters. Other forms of display (e.g., analogue) must provide comparable visibility. Auditory reporting, if used, shall be clear, have adjustable volume, and provide means for the user to obtain data reports repetitively. The CPDM shall also report end-of-shift results using computer software compatible with current, commonly used personal computer technology.(2) The CPDM shall report results as cumulative mass concentration in units of mass per volume of air (mg/m3) with two significant figures of accuracy rounded as customary.(i)Power requirements. The power source of the CPDM shall have sufficient capacity to enable continuous sampling for 12 hours in a coal mine dust atmosphere of up to 4.0 mg/m3. If the CPDM uses a rechargeable battery, the battery charger shall be operated from a 110 (VAC) (nominal), 60 Hz power line.(j)Flow stability and calibration of pump. If a pump is used, the flow shall not vary more than ±5 percent of the calibrated flow for 95 percent of samples taken for any continuous duration for up to 12 hours. The flow calibration maintenance interval to assure such performance shall be specified in the calibration instructions for the device.(k)Battery check. If the CPDM uses a rechargeable battery, the CPDM shall have a feature to indicate to the user that the device is sufficiently charged to operate and provide accurate measurements for an entire shift of 12 hours under normal conditions of use.(l)Integration with other personal mining equipment.(1) If the CPDM is integrated or shares functions with any other devices used in mines, such as cap lights or power sources, then the applicant shall obtain approvals for such other devices, prior to receiving final certification of the CPDM under this section.(2) A CPDM that is integrated with another device shall be tested, according to all the requirements under this part, with the other device coupled to the CPDM and operating.(m)Tampering safeguards or indicators. The CPDM shall include a safeguard or indicator which either prevents intentional or inadvertent altering of the measuring or reporting functions or indicates that the measuring or reporting functions have been altered.(n)Maintenance features. The CPDM shall be designed to assure that the device can be cleaned and maintained to perform accurately and reliably for the duration of its service life. 75 FR 17523 , Apr. 6, 2010, as amended at 80 FR 52990 , Sept. 2, 2015