Current through Register Vol. 47, No. 12, March 26, 2025
(a)
All boilers hereafter installed with gas, oil or mechanical firing, shall be
provided with an automatic low water fuel cutout of the manual reset type. All
boilers installed after the effective date of this Part shall be provided with
two automatic low water cutouts of the manual reset type except as follows:
(1) boilers of 1,500 square feet or more of
heating surface when there is an attendant present during boiler
operation;
(2) boilers of 100
square feet or less of heating surface when the boiler is operated with no
extraction of steam (closed system), provided that the boiler is on the same
floor or the floor immediately below the steam using equipment and provided
that the total length of connected steam piping does not exceed 50 feet;
and
(3) boilers of 20 square feet
of heating surface or less (see section
14-11.12 of this Part).
(b) Fuel cutouts, water feeding
and regulating devices of the float type hereafter installed, shall comply with
the following requirements:
(1) The float
chamber of a water feeder or regulator shall be set at a level that will start
feeding when the water level drops below the predetermined water level of that
particular boiler.
(2) A fuel
cutout switch, if installed, shall be so set or adjusted that it will shut off
the fuel supply before the water drops lower than one-quarter inch above the
lowest visible level of the gage glass. The design and material of the float
chamber shall comply with the requirements of section
14-9.22 of this Part and be
properly marked for pressure. Float chambers made of cast iron in accordance
with specifications SA-278 may be used for maximum boiler pressures not
exceeding 250 pounds per square inch. Float chambers made of malleable iron in
accordance with specifications SA-395 may be used for maximum boiler pressures
not exceeding 350 pounds per square inch. For higher pressures steel
construction shall be used.
(3) The
float shall have a displacement adequate to insure positive movement of the
mechanism operating the feed valve and/or the cutout switch. It shall be tested
against collapse at a pressure of at least twice the boiler pressure. Bearings,
shafts, water valves and seats and other similar parts shall be of material
that is resistant to corrosion.
(4)
Electric switches shall be designed to prevent deterioration from atmospheric
conditions and be approved by the Underwriters' Laboratories. Accessibility for
inspection, cleaning and repairing shall be provided for all parts.
(5) The steam connection to a float chamber,
including pipe, fittings, and valves, if any, shall comply with the
requirements of sections
14-9.22 and 14- 9.23 of this Part.
There shall be no sag or offset in the piping which will permit the
accumulation of water.
(6) The
water connection to a float chamber and drains from the float chamber,
including pipe, fittings and valves, if any, shall comply with the requirements
of sections
14-9.22 and
14-9.23 of this Part.
(7) The water connections shall be provided
at each right angle turn with a cross or a fitting with a back outlet to permit
cleaning in both directions. The upper edge of the water connection at the
boiler shall not be above the lowest visible water level in the gage glass. No
part of this pipe connection shall be above point of connection at the float
chamber.
(8) The minimum size of
pipes connecting the float chamber to a boiler shall be one inch for the
connection below the water line and three-quarters inch for the steam
connection. When shutoffs are used on the connection pipes, they shall be
either outside-screw-and-yoke gate valves or stopcocks or valves with levers
permanently fastened thereto and marked in line with their passage, or of such
other through flow construction as 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; and such 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. Connecting the float chamber to gage glass
connections is not recommended unless the gage glass connections are at least
one inch pipe size below the water line and three-quarters inch for the steam.
Exception:For boilers of less than 50 square feet of
heating surface the minimum size pipe shall be three-quarters inch for the
connection below the water line and one-half inch for the steam
connection.
(9) No outlet
connection, except for damper regulation, drains, steam gages or such apparatus
which does not permit the escape of an appreciable amount of steam or water
therefrom, shall be placed on the float chamber or pipes connecting the float
chamber to a boiler.
(10) The float
chamber shall be fitted with a drain valve having a suitable connection to the
ashpit, or other safe point of waste, and if the water connection thereto has a
rising bend or pocket which cannot be drained by means of the float chamber
drain, an additional drain shall be placed on this connection in order that it
may be blown off to clear any sediment from the pipe. The float chamber blowoff
pipe shall be at least three-quarters inch pipe size, except for boilers of 50
square feet or less of heating surface, when it can be one-half inch.
(11) Feed water regulator and low water
cut-off shall be tested daily and maintained in good working
condition.
(12) Boilers consisting
of continuous piping affording no reservoir or water level practicable for the
operation of a low water cutoff may be equipped with a flow valve or other
suitable control which has been tested and approved in accordance with a code
or standard commonly applied in the industry, e.g., AGA or UL.