Section 12-222.1-7 - Power boiler appurtenances(a) Water level indicators. The following shall apply to water level indicators: (1) Each steam boiler having a fixed waterline shall have at least one water gage glass, except that boilers operated at pressures over 400 psig shall be provided with two water gage glasses that may be connected to a single water column, or connected directly to the drum. The gage glass and pipe connections shall be not less than NPS 1/2. Each water gage glass shall be equipped with a drain valve;(2) The lowest visible water level in a gage glass shall be at least two inches above the lowest permissible water level as determined by the manufacturer;(3) Gage glasses shall be connected directly to the shell or drum of the boiler or to an intervening water column;(4) The lower edge of the steam connection between a water column, gage glass, or water level sending device in the boiler, shall not fall below the highest visible water level in the gage glass. In addition, there shall be no sag of offset in the piping that will permit accumulation of water;(5) The upper edge of the water connection between water column, gage glass, or water level sensing device in the boiler, shall not be above the lowest visible water level in the gage glass. In addition, no part of the pipe connection shall be above the point of connection at the water column;(6) For installations where the water-gage glass or glasses are not easily viewed by the operator, consideration should be given to install a method of remote transmission of the water level to the operating floor;(7) Boilers of the horizontal firetube type shall be so set that when the water is at the lowest reading in the water-gage glass, it shall be three (3) inches above the lowest permissible water level as determined by the manufacturer. Horizontal firetube boilers that do not exceed sixteen (16) inches in inside diameter shall have the lowest visible level in the gage glass at least one (1) inch above the lowest permissible level as determined by the manufacturer,(8) Each water-gage glass shall be equipped with a top and a bottom shutoff valve of such through-flow construction as to prevent blockage by deposits of sediment and to indicate by the position of the operating mechanism whether they are in the open or closed position. The pressure-temperature rating shall be at least equal to that of the lowest set pressure of any safety valve on the boiler drum and the corresponding saturated stream pressure; provided that: (A) Boilers having a maximum allowable working pressure of four hundred (400) psi or less shall always have at least one gage glass in service; or(B) Boilers having maximum allowable working pressure greater than 400 psi shall always have two gage glasses in service: (i) When two gage glasses are required, both may connect to a single water column;(ii) Instead of one of the two required gage glasses, two independent remote water level indicators (two discrete systems that continuously measure, transmit, and display water level) may be provided. In addition, minimum water levels shall be clearly marked; (iii) When both remote level indicators are in reliable operation, the remaining gage glass may be shut off, but shall be maintained in serviceable condition; and(iv) When the water level in at least one gage glass is not readily visible to the operator in the area where control actions are initiated, either a fiber optic cable (with no electrical modification of the optical signal) or mirrors shall be provided to transfer the optical image of the water level to the control area. Provided that alternatively any combination of either an independent remote water level indicator or an independent continuous transmission and display of an image of the water level in a gage glass may be used. If the latter is used, then the display of a remote water level indicator shall have a clearly marked minimum water level reference at least two (2) inches above the lowest permissible water level, as determined by the manufacturer;
(9) Gage glass assemblies with multiple sections, whether of tubular or other construction, shall: (A) Ensure a one-foot overlap of all adjoining sections so the water level is visible; or(B) Ported or reflex gages using refractive light to aid determination of water level may omit the requirement of overlapping sections;(10) The gage class cock connections shall not be less than one-half (1/2) of an inch NPS;(11) Each gage glass, externally mounted water level, or water level controlling device shall be fitted with a drain cock or valve having an unrestricted drain opening of not less than one-fourth (1/4) of an inch in diameter to facilitate cleaning;(12) Connections for gage glasses connected directly to the boiler or to an intervening water column shall be at least NPS one-half (1/2);(13) Connections from the boiler to a remote water level indicator shall be at least NPS three-fourths (3/4), including the isolation valve; and from there to the remote level indicator at least one-half (1/2) of an inch in OD tubing;(14) Water level connections shall be completely independent of other connections for any function other than water level indication; and(15) Electric steam boilers shall have at least one water-gage glass. On electrode type electric boilers, the gage glass shall be located as to indicate the water levels both at startup and maximum steam load conditions, as established by the boiler manufacturer. On resistance element type electric steam boilers, the lowest visible part of the gage glass shall be located at least 1 inch above the lowest permissible water level established by the boiler manufacturer.(b) Low-water fuel cutoffs and water feeding devices. The following shall apply to low-water fuel cutoffs and water feeding devices:(1) Each automatically fired steam or vapor system boiler shall have an automatic low-water fuel cutoff device so located as to automatically cut off the fuel supply when the surface of the water falls to the lowest visible part of the water-gage glass. If a water feeding device is installed, it shall be so constructed that the water inlet valve cannot feed water into the boiler through the float chamber and so located as to supply requisite feedwater; provided that such a fuel cutoff or water feeding device may be attached directly to the boiler. A fuel cutoff or water feeding device may also be installed in the tapped openings available for attaching a water glass directly to the boiler, provided the connections are made to the boiler with nonferrous tees or Ys not less than NPS one-half (1/2) inch between the boiler and water glass so that the water glass is attached directly and as close as possible to the boiler, the run of the tee or Y shall take the water glass fittings, and the side outlet or branch of the tee or Y shall take the fuel cutoff or water feeding device. The ends of all nipples shall be reamed to full-size diameter. In addition, a secondary low-water fuel cutoff with manual reset shall be provided on each automatically fired steam or vapor system boiler;(2) Functioning of the lower of the two controls shall cause safety shutdown and lockout. The manual reset may be incorporated in the lower cutoff control. Where a reset device is separate from the low-water fuel cutoff, a means shall be provided to indicate actuation of the low-water fuel cutoff. The manual reset device may be of the instantaneous type or may include a time delay of not more than three (3) minutes after the fuel has been cut off;(3) The fuel cutoff device may be inserted internally or attached externally to the boiler. An external cutoff device may be attached on piping connecting a water column to the boiler or combined with a water column;(4) Water column piping and connections shall be at least NPS 1 (DN 25). If the low-water fuel cutoff is connected to the boiler by pipe or fittings, no shutoff valves of any type shall be placed in such piping. The steam and water connections to a water column shall be readily accessible for internal inspection and cleaning. Some acceptable methods of meeting this requirement are by providing a cross-fitting with a back outlet at each right-angle turn to permit inspection and cleaning in both directions or by using pipe bends or fittings of a type that does not leave an internal shoulder or pocket in the pipe connection and with a radius of curvature that will permit the passage of a rotary cleaner. Fuel cutoff devices embodying a separate chamber shall have a vertical drainpipe and blowoff valve, not less than NFS 3/4, located at the lowest point of the chamber or water-equalizing pipe connections, so that the chamber and the equalizing pipe can be flushed and the device tested;(5) Fuel cutoffs and water feeding devices embodying a separate chamber shall have a vertical drainpipe, extended to a safe point of discharge, and a blowoff valve not less than NFS 3/4, located at the lowest point in the water equalizing pipe connections so that the chamber and the equalizing pipe can be flushed and the device tested;(6) Each miniature boiler, except electric boilers of the electrode type, shall have at least one low-water fuel cutoff device;(7) Each electric steam boiler of the resistance element type shall be equipped with an automatic low-water cutoff so located as to automatically cut off the power supply to the heating elements before the surface of the water falls below the visible part of the glass. No low-water cutoff is required for electrode-type boilers; (8) These devices shall be installed in such a manner that they cannot be rendered inoperative by the manipulation of any manual control or regulating apparatus;(9) In boilers with a fixed water line, the low-water fuel cutoff devices shall be tested regularly by lowering the water level sufficiently to shut off the fuel supply to the burner when the water level reaches the lowest safe level for operation. Boilers that do not have a fixed water line shall be equipped with a flow sensing device, thermal couple or expansion ring that is listed by a nationally recognized testing agency to prevent burner operation at a flow rate inadequate to protect the boiler unit against overheating;(10) Boilers with single drain electronic solenoid valve shall be fitted with a manual by-pass drain line to facilitate testing of the low-water cutoff safety device;(11) The low-water cutoff shall be rated for a pressure and temperature equal to or greater than the MAWP and temperature of the boiler;(12) For high-temperature water boilers requiring forced flow circulation, an approved flow sensing device shall be installed on the outlet, as close to the boiler as possible;(13) When a low-water fuel cutoff and feedwater pump control is combined in a single device, an additional separate low-water fuel cutoff shall be installed. The additional control shall be wired in series electrically with the existing low-water fuel cutoff;(14) When a low-water fuel cutoff is housed in either the water column or a separate chamber it shall be provided with a blowdown pipe and valve not less than 3/4 inch NPS. The arrangement shall be such that when the water column is blown down, the water level in it will be lowered sufficiently to activate the lower-water fuel cutoff device; and(15) If a water feed device is utilized, it shall be constructed to prevent feedwater from entering the boiler through the water column or separate chamber of the low-water fuel cutoff.(c) Pressure gages. The following shall apply to pressure gages:(1) Each steam boiler shall have a pressure gage connected to the steam space or to the steam connection to the water column. When a pressure-reducing valve is installed in the steam supply piping, a pressure gage shall be installed on the low pressure side of the pressure-reducing valve;(2) The dial range shall not be less than 1.5 times and no greater than approximately two times the pressure at which the lowest pressure relief valve is set;(3) For a steam boiler, the gage or connection shall contain a siphon or equivalent device that will develop and maintain a water seal that will prevent steam from entering the gage tube. A valve or cock shall be placed in the gage connection adjacent to the gage. An additional valve or cock should be located near the boiler providing it is locked or sealed in the open position. No other shut-off valves shall be located between the gage and the boiler; and(4) Pressure gage connections shall be suitable for the maximum allowable working pressure and temperature, but if the temperature exceeds 406°F, brass or copper pipe or tubing shall not be used. The connections to the boiler, except for the siphon, if used, shall not be less than NPS 1/4 inch Where steel or wrought iron pipe or tubing is used, it shall not be less than 1/2 inch inside diameter. The minimum size of a siphon, if used, shall be 1/4 inch inside diameter.(d) Water columns. The following are requirements for water columns:(1) The water column shall be directly connected to the boiler. Outlet connections (except for damper regulator, feedwater regulator, low-water fuel cutoff, drains, steam gages, or such apparatus that does not permit the escape of an appreciable amount of steam or water) should not be placed on the piping that connects the water column to the boiler;(2) Straight-run globe valves of the ordinary type shall not be used on piping that connects the water column to the boiler. Where water columns are seven (7) feet or more above the floor level, adequate means for operating gage cocks or blowing out the water glass shall be provided;(3) When automatic shutoff valves are used on piping that connects the water column to the boiler, they shall conform to the requirements of the code of construction for the boiler;(4) When shutoff valves are used on the connections to a water column, they shall be either outside-screw and yoke or lever-lifting-type gate valves or stop cocks with levers permanently fastened thereto and marked in line with their passage, or of such other through-flow constructions to prevent stoppage by deposits of sediment and to indicate by the position of the operating mechanism whether they are in open or closed position; provided that the valves or cocks shall be locked or sealed open; (5) The water column shall be fitted with a drain cock or drain valve of at least three-fourths (3/4) of an inch nominal pipe size and shall be piped to a safe point of discharge;(6) Connections from the boiler to the water column shall be at least NPS 1;(7) The steam and water connections to a water column or a water gage glass shall be readily accessible for internal inspection and cleaning; and(8) Shutoff valves shall not be used in the pipe connections between a boiler and a water column, or between a boiler and the shutoff valves required for the gage glass, except:(A) Outside screw-and-yoke or lever-lifting-type gate valves or stopcocks with lever permanently fastened thereto and marked in line with their passage; and(B) Another through-flow construction that prevents stoppage by deposits of sediment, and to indicate by the position of the operating mechanisms whether they are in open or closed position. These valves or cocks shall be locked or sealed open. Where stopcocks are used, they shall be of a type with the plug held in place by a guard or gland.Haw. Code R. § 12-222.1-7
[Eff and comp 12/21/2019] (Auth: HRS § 397-4) (Imp: HRS § 397-4)