Current through Register Vol. 43, No. 02, November 27, 2024
(1)
Automatic Low-Water Fuel Cutoff and/or Water Feeding Device
(a) Each automatically fired steam or vapor
system boiler shall be equipped with an automatic low-water fuel cutoff so
located as to automatically cut off the fuel supply when the surface of the
water falls to the lowest safe waterline. 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. The lowest safe waterline should not be lower than the
lowest visible part of the water glass.
(b) Such fuel or feedwater control devices
may be attached directly to a boiler or for low pressure boilers, to the tapped
openings provided for attaching a water glass directly to a boiler, provided
that such connections from the boiler are nonferrous tees or Ys not less than
1/2 in. pipe size between the boiler and the water glass, so that the water
glass is attached directly and as close as possible to the boiler; the
straightway tapping of the Y or tee to take the water glass fittings, the side
outlet of the Y or tee to take the fuel cutoff or water-feeding device. The
ends of all nipples shall be reamed to full size diameter.
(c) Designs embodying a float and float bowl
shall have a vertical straightaway valve drain pipe at the lowest point in the
water equalizing pipe connections by which the bowl and the equalizing pipe can
be flushed and the device tested.
(2)
Pressure Reducing Valves
(a) Where pressure reducing valves are used,
one or more safety or safety relief valves shall be provided on the
low-pressure side of the reducing valve when the piping or equipment on the
low-pressure side does not meet the requirements for the full initial pressure.
The safety or safety relief valves shall be located adjoining or as close as
possible to the reducing valve. Proper protection shall be provided to prevent
injury or damage caused by the escaping fluid from the discharge of safety or
safety relief valves if vented to the atmosphere. The combined discharge
capacity of the safety or safety relief valves shall be such that the pressure
rating of the lower pressure piping or equipment shall not be exceeded in case
the reducing valve fails in the open position.
(b) The use of hand-controlled bypasses
around reducing valves is permissible. If a bypass is used around the reduction
valve, the safety valve required on the low- pressure side shall be of
sufficient capacity to relieve all the fluid that can pass through the bypass
without over-pressuring the low-pressure side.
(c) A pressure gage shall be installed on the
low-pressure side of a reducing valve.
(3)
Boiler Blowoff Equipment
(a) The blowdown from a boiler or boilers
that enters a sanitary sewer system or blowdown that is considered a hazard to
life or property shall pass through some form of blowoff equipment that will
reduce pressure and temperature as required hereinafter.
(b) The temperature of the water leaving the
blowoff equipment shall not exceed 140°F.
(c) The pressure of the blowdown leaving any
type of blowoff equipment shall not exceed 5 psig.
(d) All blowoff equipment shall be fitted
with openings to facilitate cleaning and inspection.
(e) Blowoff equipment shall conform to the
provisions set forth in the recommended rules for National Board Boiler Blowoff
Equipment.
(4)
Location of Discharge Piping Outlets. The discharge of safety
valves, blowoff pipes, and other outlets shall be located and supported as to
prevent injury to personnel.
(5)
Supports. Each boiler and pressure vessel shall be supported by
masonry or structural supports of sufficient strength and rigidity to safely
support the boiler or pressure vessel and its contents. There shall be no
excessive vibration in either the boiler, pressure vessel, or its connecting
piping.
(6)
Boiler Door
Latches
(a) A watertube boiler shall
have the firing doors of the inward opening type, unless such doors are
provided with substantial and effective latching or fastening devices or
otherwise so constructed as to prevent them, when closed, from being blown open
by pressure on the furnace side.
(b) These latches or fastenings shall be of
the positive self-locking type. Friction contacts, latches, or bolts actuated
by springs shall not be used. The foregoing requirements for latches or
fastenings shall not apply to coal openings of downdraft or similar
furnaces.
(c) All other doors,
except explosion doors, not used in the firing of the boiler may be provided
with bolts or fastenings in lieu of self-locking latching devices.
(d) Explosion doors, if used and if located
in the setting walls within 7 ft. of the firing floor or operating platform,
shall be provided with substantial deflectors to divert the blast.
(7)
Clearance
(a) All boilers and
pressure vessels shall be so located that adequate space will be provided for
the proper operation of the boilers and pressure vessels and their
appurtenances, for the inspection of all surfaces, tubes, waterwalls,
economizers, piping, valves, and other equipment, and for their necessary
maintenance and repair and replacement of tubes.
(b) When boilers are replaced or new boilers
are installed in either existing or new buildings, a recommended minimum height
of 3 ft. should be provided between the top of the boiler proper and the
ceiling and between all sides of the boiler and adjacent walls or other
structures. Boilers and pressure vessels having manholes should have a
recommended 5 ft. clearance from the manhole opening and any wall, ceiling, or
piping that will prevent a person from entering the boiler or
vessel.
(8)
Ladders
and Runways. When necessary for safety, there shall be a steel runway or
platform of standard construction installed across the tops of adjacent boilers
or pressure vessels or at some other convenient level for the purpose of
affording safe access. All walkways shall have at least two means of exit, each
to be remotely located from the other.
(9)
Exit from Boiler Room. All
boiler rooms exceeding a 500 square foot floor area and containing one or more
boilers having a fuel-burning capacity of 1 million BTU or equivalent
electrical heat input shall have at least two means of exit. Each exit shall be
remotely located from the other. Each elevation in such boiler room shall have
two means of exit, each remotely located from the other.
(10)
Suggestions for Operation.
It is suggested that the Recommended Rules for Care of Power Boilers, Section
VII, and the Recommended Rules for Care and Operation of Heating Boilers,
Section VI, of the ASME Code be used as a guide for proper and safe operating
practices.
(11)
Air and
Ventilation Requirements - Combustion Air Supply and Ventilation of Boiler
Room
(a) A permanent source of outside
air shall be provided for each boiler room to permit satisfactory combustion of
the fuel as well as proper ventilation of the boiler room under normal
operating conditions.
1. The total
requirements of the burners for all fired pressure vessels in the boiler room
must be used to determine the net louvered area in square feet:
|
BTU/HOUR |
REQUIRED AIR CU/FT/MIN |
MIN. NET LOUVERED AREA, SQ.
FT____
|
|
500,000 |
125 |
1.0 |
|
1,000,000 |
250 |
1.0 |
|
2,000,000 |
500 |
1.6 |
|
3,000,000 |
750 |
2.5 |
|
4,000,000 |
1,000 |
3.3 |
|
5,000,000 |
1,250 |
4.1 |
|
6,000,000 |
1,500 |
5.0 |
|
7,000,000 |
1,750 |
5.8 |
|
8,000,000 |
2,000 |
6.6 |
|
9,000,000 |
2,250 |
7.5 |
|
10,000,000 |
2,500 |
8.3 |
(BTU/10,000) X 2.5= CFM - 300 CFM per sq. ft. of net req.
area
2. When mechanical
ventilation is in lieu of paragraph 1, the supply of combustion and ventilation
air to the boiler room and the firing device will not operate with the fan off.
The velocity of the air through the ventilating fan shall not exceed 500 feet
per minute, and the total air delivered shall be equal to or greater than shown
in paragraph 1 above.
(12)
Carbon Monoxide (CO) Monitors in
Boiler/Equipment Rooms.
(a) For new
construction/installation, Carbon Monoxide (CO) monitors are mandatory in
Boiler/Equipment Rooms where fired boilers and/or water heaters are located per
NBIC Part I, 1.6.9 2021 Edition.
The following parameters for CO monitors in new
Boiler/Equipment Rooms are being established in accordance with the State of
Alabama Boiler and Pressure Vessel Administrative Code.
1. CO monitor shall be hard wired with
battery backup in new construction.
2. CO monitor shall be installed on the wall
5 feet or above from the floor of the Boiler/Equipment Room.
3. CO monitor shall have an audible alarm
which can be heard outside of the Boiler/Equipment Room.
4. CO monitor shall alarm at 200
PPM.
5. Inspectors shall verify the
installation and operational status of the CO monitor during routine
inspections.
(b) For
existing fired boilers and/or water heaters, the following parameters for CO
monitors are highly recommended:
1. Existing
Boiler/Equipment Rooms: the monitor should be hard wired, plug-in type with
battery backup or battery powered with 10-year battery.
2. CO monitor shall be installed on the wall
5 feet or above from the floor of the Boiler/Equipment Room.
3. CO monitor shall have an audible alarm
which can be heard outside of the Boiler Equipment Room.
4. CO monitor shall alarm at 200
PPM.
5. Inspectors shall verify the
installation and operational status of the CO monitor during routine
inspections.
Author: Board of Boilers & Pressure Vessels,
Dr. David Dyer, Chairman
Statutory Authority:
Code of Ala.
1975, §§
25-12-4, -6,
-14.
