Current through August, 2024
(a) Feedwater.
(1) Steam heating boilers. Feedwater or water
treatment shall be introduced into a boiler through the return piping system.
Alternatively, feedwater or water treatment shall be introduced through an
independent connection. A cross or equivalent fitting shall be placed in the
water piping connection at every right angle turn to facilitate cleaning and
inspection. The water flow from the independent connection shall not discharge
directly against parts of the boiler exposed to direct radiant heat from the
fire. Feedwater or water treatment shall not be introduced through openings or
connections provided for inspection or cleaning, safety valve, water column,
water-gage glass, or pressure gage. The feedwater pipe shall be provided with a
check valve, or a backflow preventer containing a check valve, near the boiler
and a stop valve or cock between the check valve and the boiler, or between the
check valve and the return pipe system;
(2) Hot-water heating boilers. Makeup water
may be introduced into a boiler through the piping system or through an
independent connection. The water flow from the independent connection shall
not discharge directly against parts of the boiler exposed to direct radiant
heat from the fire. Makeup water shall not be introduced through openings or
connections provided exclusively for inspection or cleaning, safety relief
valve, pressure gage, or temperature gage.
The makeup water pipe shall be provided with a check valve,
or a backflow preventer containing a check valve, near the boiler and a stop
valve or cock between the check valve and the boiler, or between the check
valve and the piping system; and
(3) The following shall apply to potable
water heaters:
(A) Water supply shall be
introduced into a water heater through an independent water supply connection.
Feedwater shall not be introduced through openings or connections provided for
cleaning, safety relief valves, drain, pressure gage, or temperature gage;
and
(B) If the water supply
pressure to a water heater exceeds seventy-five per cent (75%) of the set
pressure of the safety relief valve, a pressure reducing valve is
required.
(b)
Stop valves. Stop valves shall conform with the applicable portions of an
acceptable code of construction and may be ferrous or nonferrous. The minimum
pressure rating of all stop valves shall be at least equal to the pressure
stamped upon the boiler, and the temperature rating of such stop valves shall
be not less than 250 degrees Fahrenheit.
(1)
The following shall apply to steam heating, hot-water heating, and hot-water
supply boilers:
(A) When a stop valve is used
in the supply pipe connection of a single steam boiler, there shall be one
installed in the return pipe connection;
(B) Stop valves for single hot-water heating
and hot-water supply heating boilers shall be located at an accessible point in
the supply and return pipe connections as near to the boiler as possible, to
permit draining the boiler without emptying the system; and
(C) stop valves shall be used in each supply
and-return pipe connection for boiler installations of two or more heating
boilers connected to a common system; and
(2) Potable water heaters. Stop valves shall
be installed in the supply and discharge pipe connections of a water heater
installation to permit draining the water heater without emptying the
system.
(c) Fuel. Fuel
systems shall be installed in accordance with jurisdictional and environmental
requirements, manufacturer's recommendations, and industry standards, as
applicable.
(d) Electrical. The
following shall apply to steam heating, hot-water heating, and hot-water supply
boilers:
(1) All wiring for controls, heat
generating apparatus, and other appurtenances necessary for the operation of
the heating boilers shall be installed in accordance with the provisions of
national or international standards and shall comply with the applicable local
electrical codes;
(2) A
disconnecting means capable of being locked in the open position shall be
installed at an accessible location at the boiler so that the boiler can be
disconnected from all sources of potential. This disconnecting means shall be
an integral part of the boiler or adjacent to it;
(3) A manually operated remote shutdown
switch or circuit breaker shall be located just outside the equipment room door
and marked for easy identification. Consideration should also be given to the
type and location of the switch to safeguard against tampering;
(4) If the equipment room door is on the
building exterior, the shutdown switch should be located just inside the door.
If there is more than one door to the equipment room, there shall be a shutdown
switch located at each door of egress;
(5) For atmospheric-gas burners, and oil
burners where a fan is on a common shaft with the oil pump, the complete burner
and controls should be shut off; and
(6) For power burners with detached
auxiliaries, only the fuel input supply to the firebox need be shut
off.
(e) Potable water
heaters. The following shall apply to potable water heaters:
(1) All wiring for controls, heat generating
apparatus, and other appurtenances necessary for the operation of the potable
water heaters shall be installed in accordance with the provisions of national
or international standards and comply with the applicable local electrical
codes;
(2) A disconnecting means
capable of being locked in the open position should be installed at an
accessible location at the heater so that the heater can be disconnected from
all sources of potential. This disconnecting means shall be an integral part of
the heater or adjacent to it;
(3)
For atmospheric-gas burners, and oil burners where a fan is on a common shaft
with the oil pump, the complete burner and controls should be shut off;
and
(4) For power burners with
detached auxiliaries, only the fuel input supply needs be shut off.
(f) Controls and heat generating
apparatus. The following shall apply to controls and heat generating apparatus:
(1) Oil and gas-fired and electrically heated
heating boilers and water heaters shall be equipped with suitable primary
(flame safeguard) safety controls, safety limit controls, and burners or
electric elements as required by a nationally or internationally recognized
standard; or as specified by the National Fire Protection Association (NFPA)
standards for oil and gas burning installations for the particular job
conditions, or one (1) square inch of free area per 2000 Btu per hour (586 W)
maximum fuel input of the combined burners located in the equipment room. The
equipment room supply openings shall be kept clear at all times;
(2) The symbol of the certifying organization
that has investigated such equipment as having complied with a nationally
recognized standard shall be affixed to the equipment and shall be considered
as evidence that the unit was manufactured in accordance with that standard;
and
(3) These devices shall be
installed in accordance with jurisdictional and environmental requirements,
manufacturer's recommendations, and industry standards, as
applicable.
(g)
Ventilation and combustion air. The following shall apply to ventilation and
combustion air:
(1) The equipment room shall
have an adequate air to permit clean, safe combustion, minimize soot formation,
and maintain a minimum of nineteen and a half per cent (19.5%) oxygen in the
air of the equipment room and sufficient to maintain ambient temperatures as
recommended by the boiler, heater, or vessel manufacturer. The combustion and
ventilation air should be supplied by either an unobstructed air opening or by
power ventilation or fans. When combustion air is supplied to the boiler by an
independent duct, with or without the employment of power ventilators or fans,
the duct shall be sized and installed in accordance with the manufacturer's
recommendations. However, ventilation for the equipment room must still be
considered;
(2) When combustion air
is supplied to the boiler, heater, or vessel by an independent duct, with or
without the employment of power ventilators or fans, the duct shall be sized
and installed in accordance with the manufacturer's recommendations. However,
ventilation for the equipment room must still be considered;
(3) Unobstructed air openings shall be sized
based on the manufacturer's recommendations, or as specified by the National
Fire Protection Association (NFPA) standards for oil and gas burning
installations for the particular job conditions, or one (1) square inch of free
area per 2000 Btu per hour (586 W) maximum fuel input of the combined burners
located in the equipment room. The equipment room supply openings shall be kept
clear at all times;
(4) Power
ventilators or fans shall be sized based on 0.2 cfm for each 1000 Btu per hour
(293 W) of maximum fuel input for the combined burners of all heating boilers
and heaters located in the equipment room. Additional capacity may be required
for other fuel burning equipment in the equipment room;
(5) When power ventilators or fans are used
to supply combustion air, they shall be installed with interlock devices so
that burners will not operate without an adequate number of ventilators/fans in
operation;
(6) When power
ventilators or fans are used to supply combustion air, they shall be installed
with interlock devices so that burners will not operate without an adequate
number of ventilators/fans in operation;
(7) The size of openings specified in (3) may
be reduced when special engineered air supply systems approved by the
jurisdiction are used; and
(8) Care
should be taken to ensure that steam, water and fluid lines are not routed
across combustion air openings, where freezing may occur.
(h) Breeching and dampers. Breeching and
dampers shall be installed in accordance with jurisdictional and environmental
requirements, manufacturer's recommendations, and industry standards, as
applicable.
(i) Burners and
stokers. Burners and stokers shall be installed in accordance with
jurisdictional and environmental requirements, manufacturer's recommendations,
and industry standards, as applicable.
(j) Lighting. The equipment room shall be
well-lit and have an emergency light source for use in the case of a power
failure.
(k) Emergency valves and
controls. All emergency shut-off valves and controls shall be accessible from a
floor, platform, walkway, or runway. Accessibility shall mean within a six (6)
feet elevation of the standing space and not more than twelve (12) inches
horizontally from the standing space edge.
(l) Chimney or stack. Chimneys or stacks
shall be installed in accordance with jurisdictional and environmental
requirements, manufacturer's recommendations, and industry standards, as
applicable.
(m) Ash removal. Ash
removal systems shall be installed in accordance with jurisdictional and
environmental requirements, manufacturer's recommendations, and industry
standards, as applicable.
(n)
Return pipe connections. The following shall apply to return pipe connections:
(1) The return pipe connections of each
boiler supplying a gravity return steam heating system shall be so arranged as
to form a loop so that the water in each boiler cannot be forced out below the
safe water level; and
(2) Provision
shall be made for cleaning the interior of the return piping at or close to the
boiler. Washout openings should be used for return pipe connections and the
washout plug placed in a tee or a cross so that the plug is directly opposite
and as close as possible to the opening in the boiler.
(o) Bottom blowoff and drain valves. The
following shall apply to bottom blowoff and drain valves of steam heating,
hot-water heating, and hot-water supply heating boilers:
(1) Each steam boiler shall have a bottom
blowoff connection fitted with a valve or cock connected to the lowest water
space practicable with a minimum size as shown in the NBIC. The discharge
piping shall be full size to the point of discharge. Heating boilers having a
capacity of twenty-five (25) gallons or less are exempt from the above
requirements, except that they shall have a NPS three-fourths (3/4) minimum
drain valve;
(2) Each steam or
hot-water boiler shall have one or more drain connections, fitted with valves
or cocks connecting to the lowest water containing spaces. All parts of the
boiler must be capable of being drained (the boiler design will dictate the
number and size of drains). The minimum size of the drain piping, valves, and
cocks shall be NPS 3/4. The discharge piping shall be full size to the point of
discharge. When the blowoff connection is located at the lowest water
containing space, a separate drain connection is not required; and
(3) The minimum pressure rating of valves and
cocks used for blowoff or drain purposes shall be at least equal to the
pressure stamped on the boiler but in no case less than thirty (30) psig. The
temperature rating of such valves and cocks shall not be less than 250 degrees
Fahrenheit.
(p) Each
potable water heater shall have a bottom drain pipe connection fitted with a
valve or cock connected with the lowest water space practicable. The minimum
size bottom valve shall be NPS three-fourths (3/4). Any discharge piping
connected to the bottom drain connection shall be full size to the point of
discharge.
(q) Provisions for
thermal expansion of expansion tanks and piping for steam heating, hot-water
heating, and hot-water supply heating boilers shall comply with the following:
(1) Expansion tanks for hot-water heating and
hot-water supply heating boilers shall be installed so that all hot-water
heating systems incorporating hot-water tanks or fluid relief columns prevent
freezing under normal operating conditions;
(2) Heating systems with an open expansion
tank shall have an indoor overflow from the upper portion of the expansion tank
in addition to an open vent, the indoor overflow shall be carried within the
building to a suitable plumbing fixture or drain;
(3) In closed heating systems an expansion
tank shall be installed in a closed heating system that will be consistent with
the volume and capacity of the system. If the system is designed for a working
pressure of thirty (30) psig or less, the tank shall be suitably designed for a
minimum hydrostatic test pressure of seventy-five (75) psig. Expansion tanks
for systems designed to operate above thirty (30) psig shall be constructed in
accordance with an acceptable code of construction. Provisions shall be made
for draining the tank without emptying the system; and
(4) Hot-water supply systems. If a system is
equipped with a check valve or pressure-reducing valve in the cold-water inlet
line, consideration should be given to the installation of an airtight
expansion tank or other suitable air cushion. Otherwise, due to the thermal
expansion of the water, the safety relief valve may lift periodically. If an
expansion tank is provided, it shall be constructed in accordance with an
acceptable code of construction. Except for pre-pressurized tanks, which should
be installed on the cold-water side, provisions shall be made for draining the
tank without emptying the system.
(r) Piping for steam heating, hot-water
heating, and hot-water supply boilers. Provisions shall be made for the
expansion and contraction of steam and hot water mains connected to boiler(s)
so there will be no undue strain transmitted to the boiler(s).
(s) Expansion tanks and piping for potable
water heaters. The following shall apply to expansion tanks and piping for
potable water heaters:
(1) If a system is
equipped with a check valve or pressure-reducing valve in the cold-water inlet
line, consideration should be given to the installation of an airtight
expansion tank or other suitable air cushion. Otherwise, due to the thermal
expansion of the water, the safety relief valve may lift periodically. If an
expansion tank is provided, it shall be constructed in accordance with an
acceptable code of construction. Except for pre-pressurized diaphragm-type
tanks, which should be installed on the cold-water side, provisions shall be
made for draining the tank without emptying the system; and
(2) Piping. Provisions shall be made for the
expansion and contraction of hot water mains connected to potable water
heater(s) so that there will be no undue stress transmitted to the potable
water heater(s).
