Mine Safety and Health Administration
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U.S. Department of Labor Mine Safety and Health Administration Protecting Miners' Safety and Health Since 1978 |
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PROGRAM POLICY LETTER NO. P06-V-2 FROM: RAY McKINNEY  Administrator for Coal Mine Safety and Health MARK E. SKILES  Director of Technical Support SUBJECT: Interpretation of 30 CFR 75.1100-1 and 2 Regarding Water Delivery Capability of Coal Mine Waterlines When Fighting a Fire with a Firehose and Nozzle Scope This Program Policy Letter (PPL) applies to all miners, miner's representatives, Coal Mine Safety and Health (CMS&H) enforcement personnel, and underground coal mine operators. Purpose This PPL clarifies the performance test requirements used by the Mine Safety and Health Administration (MSHA) for determining compliance with Title 30 Code of Federal Regulations (30 CFR) �.1100-1(a) concerning the water delivery capability of waterlines used for fighting a fire with a firehose and attached nozzle. This PPL also clarifies the intent of the MSHA Program Policy Manual (PPM), Volume V, Section 75.1100-1 regarding this standard. The PPL is intended to answer questions, eliminate inconsistencies, and provide guidance to enforcement personnel and the mining industry. MSHA will be re-evaluating water lines used for fighting a fire with a fire hose to assure that adequate fire protection is afforded under the standard. Policy The standards contained in �.1100 are derived from the statutory provisions in Section 311(a) of the Federal Mine Safety and Health Act of 1977. The statutory provision states that: "Each coal mine shall be provided with suitable firefighting equipment adapted for the size and conditions of the mine. The Secretary shall establish minimum requirements for the type, quality, and quantity of such equipment." Standard 75.1100-1(a) requires that: "Waterlines shall be capable of delivering 50 gallons of water a minute at a nozzle pressure of 50 pounds per square inch." This is a minimum performance standard and is commonly referred to as the "50/50" rule. The current PPM policy addressing �.1100-1(a) states that: "Waterlines, with hoses attached, shall be of sufficient size to deliver 50 gallons of water per minute at a nozzle pressure of 50 psig." (psig means pounds per square inch gage) Although the current policy indicates that hose is to be included in the performance evaluation, it does not define the length, size (diameter), or type of hose to be considered. This PPL revises the policy to state that the length of hose used for determining compliance depends upon the location in the mine, which will fall into two categories: the "the working section of the mine" and "all other areas of the mine." The length, size, and type of hose affect compliance with the performance standard because water flowing through a hose will create pressure loss along the hose due to friction. The magnitude of this friction pressure loss will depend upon the water flow rate and the length, size, and type of hose. To compensate for pressure friction loss, the available pressure in the waterline at each valved firehose outlet (VFO) must be equal to or greater than the required nozzle pressure plus the expected friction pressure loss. The valved firehose outlet is the point where the firehose is connected to the waterline and is also commonly referred to as a firehose outlet, hose tap, fire tap, fire valve, outlet valve, or fire hydrant. For the intent and purpose of the fire protection regulations for underground coal mines (30 CFR, Part 75, Subpart L) all of these terms are synonymous. However, this list is not intended to be all inclusive as some mines may have additional terms for this equipment. Consideration must also be given to increases in elevation between the VFO and the fire hose nozzle. For each twelve (12) feet of increase in elevation, an additional five (5) psi should be available at the VFO to compensate for the change in elevation. Where elevation changes may be a concern, mine operators should contact their local MSHA field office or the MSHA district office for guidance. MSHA personnel can contact Technical Support for assistance in evaluating the need for elevation pressure adjustments. Detailed information on calculating friction pressure losses in various hose arrangements, and in making adjustments for elevation, can be found in Appendix A of this PPL. The Working Section of the Mine For the working section of the mine, the length and size of hose used for determining compliance with the 50/50 rule shall be the length and size of the continuous miner water supply hose if this hose is also intended for use as a fire fighting hose. As an example, consider 700 feet of 1.25 inch diameter continuous miner hose also intended to be used for fighting a fire at the face area with negligible elevation change. The calculated friction pressure loss in the hose when flowing 50 gpm is 140 psi. In order to provide 50 psig at the nozzle, the waterline pressure at the VFO must be 190 psig when flowing the required 50 gpm. When miner hose is also intended for fire fighting, a nozzle must be stored at a readily accessible strategic location and any adapters needed to connect the nozzle to the miner hose should be stored with the nozzle. For fighting purposes on the section, MSHA prefers the use of dedicated firehose over the use of the continuous miner hose. When such firehose is provided on the section, its size shall be used for determining compliance. The length of firehose stored shall be at least the same length as that of the continuous miner hose. Continuous miner hoses often exceed 500 feet in length. The 700 feet of 1.25 inch hose in the cited example above represents a typical continuous miner hose arrangement. Additional technical considerations in using miner hoses for fighting a fire on the working section are discussed in Appendix B. All Other Areas of the Mine For all other areas of the mine, the length and size of firehose considered in the compliance determination shall be 500 feet of the size and type of firehose being stored along the belt conveyor line. For belt conveyors, �.1100-2(b) requires a minimum of 500 feet of firehose to be stored at a strategic location along each belt flight. To effectively utilize this hose, valved firehose outlets connected to the waterline must be provided at a spacing of no greater than every 300 feet along the belt entry. Furthermore, �.1100-2(c) requires that each haulage track entry must also have valved firehose outlets spaced no greater than every 500 feet apart. When the haulage track entry is adjacent to the belt entry, the belt entry hose outlets can often fulfill the track entry hose outlet requirement as long as the maximum travel distances between hose outlets is not exceeded for either entry. Operators should contact their local MSHA field or district offices for additional guidance on this issue. In order to fight a fire in areas other than the working section, it may be necessary to connect the full 500 feet of firehose stored at one location into a single hose lay with attached nozzle. Therefore, MSHA requires that 500 feet of firehose be included when evaluating the compliance of the waterline with the performance standard. As another example, consider 500 feet of 1.5 inch diameter firehose with negligible elevation change. The calculated friction pressure loss when flowing 50 gpm is 30 psi. Therefore, in order to provide 50 psig at the nozzle, the waterline pressure at the VFO must be 80 psig when flowing the required 50 gpm. Additional important information on issues involving firehose sizes, lengths, and types can be found in Appendix B. Appendix B also includes several examples of compliance determination. Water Flow Measurements The PPM for �.1100-1 states that, "Water flow through the nozzle can be measured by a pitot tube instrument if the diameter of the nozzle orifice is known." The revised policy now includes additional recognized test methods and devices, such as in-line flow meters and pressure gages in conjunction with known orifices, as acceptable for determining compliance with the performance standard. Appendix C describes an example of one test device that may be used by MSHA compliance officers and technical support personnel. Background Questions have been raised concerning the important need for testing and evaluating the capability of mine water systems to supply adequate water for fire fighting purposes in light of the number of recent belt conveyor fires. The performance standard in �.1100-1(a) requires that waterlines be capable of delivering 50 gpm at a nozzle pressure of 50 psig. Neither the performance standard nor the Program Policy Manual provides details on how to determine compliance with this rule. Of particular concern has been the use of undersized waterlines in some coal mines (typically three-inch diameter and smaller pipes, but in some cases also four-inch lines). While small waterlines may be capable of providing sufficient water for dust control during mining operations, these smaller lines typically create excessive pressure losses at water flow rates adequate for fighting a mine fire. The use of either small waterlines or small firehoses, or both, increases the difficulty of complying with the 50/50 rule. It is important to note that compliance with the 50/50 rule does not waive compliance requirements with other fire protection water supply performance standards. These include the requirements established for deluge-type water spray systems (�.1101-1(b)), and water sprinklers systems (�.1101-8(c)) used to protect belt conveyor drives. It also includes requirements for sprinkler or water spray systems used to protect electrical equipment containing hydraulic fluids (�.1107-1). Determination of compliance with these other fire protection water requirements may require additional considerations, methods, equipment, and/or analysis. Authority The Federal Mine Safety and Health Act of 1977, and 30 CFR Ё 75.1100-1(a), 75.1100-2(b), and 75.1100-2(c). Filing Instructions This policy letter should be filed behind the tab marked "Program Policy Letters" at the back of Volume V of the Program Policy Manual. Internet Availability This policy letter may be viewed on the Internet by accessing the MSHA Home Page (http://www.msha.gov) and then choosing "Compliance Info" and "Program Policy Letters." Issuing Office and Contact Persons Coal Mine Safety and Health, Safety Division Terry L. Bentley, (202) 693-9521 E-mail: bentley.terry@dol.gov Salwa El Bassioni, (202) 693-9525 E-mail: el-bassioni.salwa@dol.gov; Technical Support - Approval & Certification Center Derrick M. Tjernlund (304) 547-2301 E-mail: tjernlund.derrick@dol.gov Michael Hockenberry (304) 547-2075 E-mail: hockenberry.michael@dol.gov Distribution Underground Coal Mine Operators Miners' Representatives Independent Contractors Mining Product Manufacturers Special Interest Groups Coal and All-Volume Program Policy Manual Holders Appendices  |
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