Section 7.504 - Refuge alternatives and components; general requirements(a)Refuge alternatives and components:(1) Electrical components that are exposed to the mine atmosphere shall be approved as intrinsically safe for use. Electrical components located inside the refuge alternative shall be either approved as intrinsically safe or approved as permissible.(2) Shall not produce continuous noise levels in excess of 85 dBA in the structure's interior.(3) Shall not liberate harmful or irritating gases or particulates into the structure's interior or airlock.(4) Shall be designed so that the refuge alternative can be safely moved with the use of appropriate devices such as tow bars.(5) Shall be designed to withstand forces from collision of the refuge alternative structure during transport or handling.(b) The apparent temperature in the structure shall be controlled as follows:(1) When used in accordance with the manufacturer's instructions and defined limitations, the apparent temperature in the fully occupied refuge alternative shall not exceed 95 degrees Fahrenheit (°F).(2) Tests shall be conducted to determine the maximum apparent temperature in the refuge alternative when used at maximum occupancy and in conjunction with required components. Test results including calculations shall be reported in the application.(c) The refuge alternative shall include:(1) A two-way communication facility that is a part of the mine communication system, which can be used from inside the refuge alternative; and accommodations for an additional communication system and other requirements as defined in the communications portion of the operator's approved Emergency Response Plan.(2) Lighting sufficient for persons to perform tasks.(3) A means to contain human waste effectively and minimize objectionable odors.(5) Materials, parts, and tools for repair of components.(6) A fire extinguisher that-(i) Meets the requirements for portable fire extinguishers used in underground coal mines under part 75;(ii) Is appropriate for extinguishing fires involving the chemicals used for harmful gas removal; and(iii) Uses a low-toxicity extinguishing agent that does not produce a hazardous by-product when deployed.(d) Containers used for storage of refuge alternative components or provisions shall be-(1) Airtight, waterproof, and rodent-proof;(2) Easy to open and close without the use of tools; and(3) Conspicuously marked with an expiration date and instructions for use.