Nevada Administrative Code

NAC 455C.190 General requirements. (NRS 455C.110) 1. Upon completion of the installation or at the time of an inspection, each boiler or pressure vessel must be stamped, tagged or numbered as close as practicable to the nameplate or stamping of the manufacturer with a number of t…

NAC 455C.192 Stamping and restamping: Compliance with code. (NRS 455C.110) The stamping or restamping of a boiler or pressure vessel must comply with the applicable provisions of the code. (Added to NAC by Div. of Industrial Relations by R101-02, eff. 12-15-2004)

NAC 455C.194 Numbering of boiler or pressure vessel requiring manufacturer’s data report; signing and filing of copy of report. (NRS 455C.110) A boiler or pressure vessel for which a manufacturer’s data report is required pursuant to the code must bear a number beginning with “NB…

NAC 455C.200 Decrease in working pressure or temperature: Determination by inspector or special inspector; contest of decision. (NRS 455C.110) 1. An inspector or special inspector may require a decrease in the working pressure or temperature of a boiler or pressure vessel if he o…

NAC 455C.202 Removal or alteration of appliance for safety or device or valve for relief of pressure; removal of appliance for repair. (NRS 455C.110) 1. A person shall not attempt to remove or do any work on any required appliance for safety while a boiler or pressure vessel is s…

NAC 455C.204 Platforms and runways. (NRS 455C.110) 1. If valves and other appurtenances require frequent manipulation and are so located that they cannot be reached or operated from the floor, a platform or other safe means of operation must be provided. If a platform or runway i…

NAC 455C.206 Gas burners; emergency shut-off valve. (NRS 455C.110) For installations which are gas-fired: 1. The burners used must conform to the applicable requirements of the National Fuel Gas Code, as adopted by reference in NAC 455C.108; and 2. An emergency shut-off valve mus…

NAC 455C.208 Supports. (NRS 455C.110) Each boiler and pressure vessel must be supported by masonry or structural supports of sufficient strength and rigidity to support safely the boiler or pressure vessel and its contents. There must not be an excessive vibration in the boiler, …

NAC 455C.210 Connective pipes. (NRS 455C.110, 455C.112) All connective pipes that are subjected to pressure emanating from: 1. A heating boiler; 2. A hot water supply boiler; 3. A fired storage water heater; 4. A power or process boiler; 5. The equipment and apparatuses used in c…

NAC 455C.212 Doors, latches and fastenings. (NRS 455C.110) 1. A watertube boiler must have firing doors which open inward, unless the doors are provided with substantial and effective latching or fastening devices or are so constructed as to prevent them from being blown open by …

NAC 455C.214 Backflow prevention devices. (NRS 455C.110) Except as otherwise provided in this section, the pipe that is used to feed water into a boiler or pressure vessel must not be installed or connected to any domestic water supply unless a backflow prevention device that is …

NAC 455C.216 Repairs and alterations. (NRS 455C.110) 1. Repairs and alterations to all boilers and pressure vessels must conform to the applicable provisions of the code. 2. If a repair or alteration to a boiler or pressure vessel is necessary, an inspector or special inspector m…

NAC 455C.218 Repair of safety valves. (NRS 455C.110) A person who is in the business of repairing safety valves must hold a certificate of authorization from the National Board for the use of a National Board Pressure Relief Valve Repair stamp, designated by the National Board as…

NAC 455C.220 Lap-seam crack. (NRS 455C.110) 1. The shell or drum of a boiler or pressure vessel with a lap-seam crack along a longitudinal riveted joint must be immediately discontinued from use. The crack may not be repaired. 2. As used in this section, “lap-seam crack” means a …

NAC 455C.222 Automatically controlled boilers; repair or replacement of fittings or appliances. (NRS 455C.110) 1. Each automatically controlled boiler must be provided with a control for water level that automatically maintains the water level in the boiler within the range desig…

NAC 455C.224 Repair or replacement of fitting or appliance. (NRS 455C.110) The replacement or repair of a fitting or appliance must be made in compliance with the requirements for the initial installation of a fitting or appliance. (Added to NAC by Div. of Industrial Relations by…

NAC 455C.226 Capacity ratings of certain valves. (NRS 455C.110) The capacity rating of: 1. A safety valve that is designed primarily for use in steam or vapor service must be rated in pounds per hour. 2. A relief valve that is designed primarily for use in liquid service must be …

NAC 455C.228 Power boilers: Safety valves. (NRS 455C.110) 1. The use of weighted-lever safety valves or safety valves having the seat or disc of cast iron is prohibited. Valves of this type or construction must be replaced by direct spring-loaded, pop-type valves that conform to …

NAC 455C.230 Steam heating boilers: Safety valves. (NRS 455C.110) 1. Each low-pressure steam boiler must have one or more safety valves certified by the American Society of Mechanical Engineers or the National Board which is of the spring-pop type, adjusted and sealed to discharg…

NAC 455C.232 Hot water boilers: Safety relief valves. (NRS 455C.110) 1. Each hot water heating boiler must have at least one safety relief valve, certified by the American Society of Mechanical Engineers or the National Board, set to relieve pressure at or below the maximum allow…

NAC 455C.234 Potable water heaters: Relief valves. (NRS 455C.110) 1. A potable water heater must have at least one pressure and temperature relief valve that is: (a) Not smaller than three-fourths of an inch standard pipe size; and (b) Marked with the symbol V or HV to ensure com…

NAC 455C.236 Discharge piping. (NRS 455C.110) The discharge of safety valves, blowoff pipes and other outlets of a boiler or pressure vessel must be full sized to the point of discharge and be piped to a safe point of discharge. (Added to NAC by Div. of Industrial Relations by R1…

NAC 455C.240 Period of operation for nonstandard boiler. (NRS 455C.110) 1. A boiler having a longitudinal joint that is other than lap-riveted may be continued in operation beyond 30 years at the working pressure determined by the formula set forth in NAC 455C.242 if it is thorou…

NAC 455C.242 Working pressure for nonstandard boiler. (NRS 455C.110) 1. Except as otherwise provided in this section, the maximum allowable working pressure of a nonstandard boiler is determined by the following formula: TStE —— = maximum allowable working pressure, in PSIG RFS w…

NAC 455C.244 Working pressure for boiler made of cast iron. (NRS 455C.110) The maximum allowable working pressure for any boiler made of cast iron, except a hot water boiler, is 15 PSIG. (Added to NAC by Div. of Industrial Relations by R101-02, eff. 12-15-2004)

NAC 455C.246 Working pressure for watertube boiler. (NRS 455C.110) The maximum allowable working pressure on a watertube boiler which has: 1. Tubes secured in headers made of cast iron or malleable iron; or 2. Mud drums made of cast iron, Ê must not exceed 160 PSIG. (Added to NAC…

NAC 455C.248 Maximum age. (NRS 455C.110) The maximum age at which a standard boiler may be operated is the age determined pursuant to the code in effect when the boiler was constructed and stamped, if it is thoroughly inspected, by an internal inspection and an external inspectio…

NAC 455C.250 Clearance: Generally. (NRS 455C.110) Except as otherwise provided in NAC 455C.252 and 455C.254, if boilers are replaced or new boilers are installed in existing or new buildings, a minimum height of at least 3 feet must be provided between the top of the boiler, excl…

NAC 455C.252 Clearance: Fired storage and fired coil water heater. (NRS 455C.110) The clearance between a wall or other structure and a fired storage and fired coil water heater must be not less than the clearance specified by the manufacturer. (Added to NAC by Div. of Industrial…

NAC 455C.254 Clearance and access: Copper watertube boilers. (NRS 455C.110) 1. A copper watertube boiler that is used for domestic hot water or comfort heating must have a clearance of not less than the clearance recommended by the manufacturer of the boiler between each side or …

NAC 455C.256 Feeding. (NRS 455C.110) 1. Each boiler must have a supply of feed water that will allow it to be fed at any time while under pressure. 2. A boiler having more than 500 square feet of water heating surface must have at least two means of feeding water, one of which mu…

NAC 455C.258 Feed water connections. (NRS 455C.110) 1. Feed water, make-up water or water treatment must be introduced into a boiler through the return piping system or through an independent feed water connection which does not discharge against the parts of the boiler exposed t…

NAC 455C.260 Return pipe loop connections. (NRS 455C.110) The return water connections to all low-pressure steam heating boilers supplying a gravity return heating system must be arranged to form what is known as the “return pipe loop connection,” so that the water cannot be forc…

NAC 455C.262 Steam gauges. (NRS 455C.110) 1. Each steam boiler must have a steam gauge connected to the steam space or to the steam connection to the water column. The steam gauge must have a dial range that is graduated to approximately double the pressure at which the safety va…

NAC 455C.264 Stop valves and check valves. (NRS 455C.110) 1. Each outlet for steam from a boiler, except connections for a safety valve and water column, must be fitted with a stop valve that is located as close as practicable to the boiler. 2. If a stop valve is so located that …

NAC 455C.266 Water level indicators. (NRS 455C.110) 1. Outlet connections, except for damper regulators, feed water regulators, low-water fuel cutouts, drains, steam gauges or such apparatus that does not permit the escape of an appreciable amount of steam or water therefrom, mus…

NAC 455C.268 Qualifications of attendant. (NRS 455C.110) A person is qualified to attend a power boiler or a high-pressure, high-temperature water boiler, where such attendance is required pursuant to NAC 455C.274, if the person has: 1. The technical training, experience and know…

NAC 455C.270 Air and ventilation. (NRS 455C.110) 1. A permanent source of outside air must be provided for the room in which the boiler is located to allow satisfactory combustion of the fuel as well as proper ventilation of the room under normal operating conditions. Air used fo…

NAC 455C.272 Exits. (NRS 455C.110) Any room for a boiler exceeding 500 square feet in floor area and containing one or more boilers having a capacity to burn fuel of 1,000,000 British thermal units per hour, or the equivalent electrical input of heat, must have at least two means…

NAC 455C.274 Supervision. (NRS 455C.110) 1. Except as otherwise provided in subsection 4, a high-pressure, high-temperature water boiler and a power boiler must be attended by an operator who meets the qualifications set forth in NAC 455C.268. 2. The operator shall personally che…

NAC 455C.276 Hot water heating boilers: Pressure or altitude gauge. (NRS 455C.110) 1. Each hot water heating boiler must have a pressure or altitude gauge connected to it or to its flow connection in such a manner that it cannot be shut off from the boiler except by a cock with a…

NAC 455C.278 Hot water boilers: Thermometer; operating control and secondary high limit control; stop valve and drain valve. (NRS 455C.110) 1. Each hot water boiler must have a thermometer so located and connected that it is easily readable when observing the burner of the boiler…

NAC 455C.280 Device for feeding water; automatic cutoff for fuel. (NRS 455C.110) 1. Except as otherwise provided in subsections 4 and 5, each automatically fired steam, vapor system or hot water heating boiler with an input of fuel in excess of 199,999 British thermal units per h…

NAC 455C.282 Pressure-reducing valves. (NRS 455C.110) 1. Where pressure-reducing valves are used, at least one relief or safety valve must be provided on the low-pressure side of the reducing valve if the piping or equipment on the low-pressure side does not meet the requirements…

NAC 455C.284 Blowoff piping and fittings. (NRS 455C.110) 1. The construction of the setting around each blowoff pipe must allow free expansion and contraction. The openings for the setting must be sealed without restricting the movement of the blowoff piping. 2. All blowoff pipin…

NAC 455C.286 Blowoff equipment. (NRS 455C.110) 1. A blowdown from a boiler that enters a sanitary sewer system or a blowdown which is considered by an inspector or special inspector to be a hazard to life or property must pass through blowoff equipment that will reduce pressure a…

NAC 455C.290 Working pressure for formed heads and nonstandard pressure vessels. (NRS 455C.110) The maximum allowable working pressure allowed for: 1. Formed heads and their tensile strength and factors of safety; and 2. Nonstandard pressure vessels subjected to external pressure…