square foot of heating surface to heat 76 L 20 gallons or more of
water in 1 hour from 4 to 82 degrees C 40 to 180 degrees F using
steam at atmospheric pressure. [Cast-iron] [bronze] heads shall
be used. Tubing shall be light-drawn copper tubing conforming to
ASTM B 75M ASTM B 75. Heating elements shall withstand an
internal hydrostatic pressure of 1551 kPa 225 psig for not less
than 15 seconds without leaking or any evidence of damage.
2.13.2
Instantaneous Water Heater
Heater shall be crossflow design with service water in the coil and [steam]
[hot water] in the shell. An integral internal controller shall be
provided, anticipating a change in demand so that the final temperature can
be maintained under normal load conditions when used in conjunction with a
[pneumatic control system] [pilot-operated temperature control system].
Normal load conditions shall be as specified by the manufacturer for the
heater. Unit shall be manufactured in accordance with ASME BPVC SEC VIII D1,
and shall be certified for 1034 kPa 150 psi working pressure in the shell
and 1034 kPa 150 psi working pressure in the coils. Shell shall be carbon
steel with copper lining. Heads shall be [cast iron] [bronze] [carbon
steel plate with copper lining]. Coils shall be [copper] [copper-nickel].
Shell shall have metal sheathed fiberglass insulation, combination pressure
and temperature relief valve, and thermometer. Insulation shall be as
specified in Section 15080A THERMAL INSULATION FOR MECHANICAL SYSTEMS.
2.13.3
Phenolic Resin Coating
**************************************************************************
NOTE: If interior erosion of the tubes at or near
the tube sheet is expected to be a severe problem,
change the wording of this paragraph and its
subparagraphs to require the coating to be applied
to the first 125 to 200 mm (5 to 8 inches) inside
the tubes by brushing.
**************************************************************************
The phenolic resin coating shall be applied at either the coil or coating
manufacturer's factory. The coil shall be chemically cleaned to remove any
scale if present and to etch the metal surface. The exposed exterior
surface of the coil shall be abrasively cleaned to white metal blast in
accordance with SSPC SP 5. The coating shall be a product specifically
intended for use on the material the water heating coils are made of and
shall be acceptable for use in potable water systems. The coating
components shall be capable of withstanding temperatures up to 204 degrees
C 400 degrees F dry bulb and shall meet the requirements of 21 CFR 175.
The entire exterior surface and the first 125 to 200 mm 5 to 8 inches
inside the tubes of each coil shall be coated with the three-component
phenolic resin coating system. The system shall consist of the following:
the wash primer, the pigmented base coat, and the clear top coat.
Immediate and final cure times and temperatures shall be as recommended by
the coating manufacturer.
2.13.3.1
Coating Coil Interiors
One coat of the wash primer component shall be applied by brushing or
flooding. Two coats of the pigmented base component shall be applied by
brushing, immersion, or flooding. Two coats of the clear top
(non-pigmented) component shall be applied by brushing, immersion, or
flooding, with exception of the final coat which may be applied by spraying.
SECTION 15405A
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