[Code of Federal Regulations]
[Title 10, Volume 3]
[Revised as of January 1, 2005]
From the U.S. Government Printing Office via GPO Access
[CITE: 10CFR434.404]
[Page 390-392]
TITLE 10--ENERGY
CHAPTER II--DEPARTMENT OF ENERGY
PART 434_ENERGY CODE FOR NEW FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH
RISE RESIDENTIAL BUILDINGS--Table of Contents
Subpart D_Building Design Requirements_Electric Systems and Equipment
Sec. 434.404 Building service systems and equipment.
404.1 Service Water Heating Equipment Efficiency. Equipment must
satisfy the minimum performance efficiency specified in Table 404.1 when
tested in accordance with RS-37, RS-38, or RS-39 (incorporated by
reference, see Sec. 434.701). Omission of equipment from Table 404.1
shall not preclude the use of such equipment. Service water heating
equipment used to provide additional function of space heating as part
of a combination (integrated) system shall satisfy all stated
requirements for the service water heating equipment. All gas-fired
storage water heaters that are not equipped with a flue damper and use
indoor air for combustion or draft hood dilution and that are installed
in a conditioned space, shall be equipped with a vent damper listed in
accordance with RS-42 (incorporated by reference, see Sec. 434.701).
Unless the water heater has an available electrical supply, the
installation of such a vent damper shall not require an electrical
connection.
Table 404.1--Minimum Performance of Water Heating Equipment
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Input to Thermal
Category Type Fuel Input VT VT ratio Test Method Energy efficiency Standby
rating Btuh/gal a factor Et% loss %/HR
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NAECA......................... all.............. electric......... 12 kW all\c\ .......... DOE Test 0.93-0.0013
2V
Covered....................... storage.......... gas.............. 75,000 all\c\ .......... Procedure 10 0.62-0.0019
Btuh V
Water......................... instantaneous.... gas.............. 200,000 all .......... CFR Part 430 0.62-0.0019
V
Heating....................... storage.......... oil.............. Btuh\c\ all .......... 430 0.59-0.0019
V
Equipment\b\.................. instantaneous.... oil.............. 105,000 all .......... Appendix E 0.59-0.0019
Btuh V
pool heater...... gas/oil.......... 210,000 all .......... ANSI Z21.56 ........... 78
Btuh
all ....... .......... (RS-38) *
--------------------------------------------------- electric all all
Heating....................... .......... ....... .......... Z21.10.3 ........... 78 .030+27/
VT
Equipment\d\.................. storage/......... gas/oil.......... 155m999 all <4,000 (RS-39)* ........... 78 1.3+114//
instantaneous.... Btuh VT
all <4,000 ............ ........... 80 1.3+95/VT
155,000
Btuh
10 4,000 ............ ........... ........... 2.3+67/VT
-------------------------------====================
Storage
Tanks
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a For detailed references see Subpart E.
b Consistent with National Appliance Energy Conservation Act (NAECA) of 1987.
c DOE Test Procedures apply to electric and gas storage water heaters with rated volumes 20 gallons and gas instantaneous water heaters with input
ratings of 50,000 to 200,000 Btuh.
d All except those water heaters covered by NAECA.
* Incorporated by reference, see Sec. 434.701.
[[Page 391]]
404.1.1 Testing Electric and Oil Storage Water Heaters for Standby
Loss.
(a) When testing an electric storage water heater, the procedures of
Z21.10.3-1990 (RS-39, incorporated by reference, see Sec. 434.701),
Section 2.9, shall be used. The electrical supply voltage shall be
maintained with 1% of the center of the voltage
range specified on the water heater nameplate. Also, when needed for
calculations, the thermal efficiency (Et) shall be 98%. When
testing an oil-fired water heater, the procedures of Z21.10.3-1990 (RS-
39 incorporated by reference, see Sec. 434.701), Sections 2.8 and 2.9,
shall be used.
(b) The following modifications shall be made: A vertical length of
flue pipe shall be connected to the flue gas outlet of sufficient height
to establish the minimum draft specified in the manufacturer's
installation instructions. All measurements of oil consumption shall be
taken by instruments with an accuracy of 1% or
better. The burner rate shall be adjusted to achieve an hourly Btu input
rate within 2% of the manufacturer's specified
input rate with the CO2 reading as specified by the
manufacturer with smoke no greater than 1 and the fuel pump pressure
within 1% of the manufacturer's specification.
404.1.2 Unfired Storage Tanks. The heat loss of the tank surface
area Btu/(h[middot]ft\2\) shall be based on an 80[deg]F water-air
temperature difference.
404.1.3 Storage Volume Symbols in Table 404.1. The symbol ``V'' is
the rated storage volume in gallons as specified by the manufacturer.
The symbol ``VT'' is the storage volume in gallons as
measured during the test to determine the standby loss. VT
may differ from V, but it is within tolerances allowed by the applicable
Z21 and Underwriters Laboratories standards. Accordingly, for the
purpose of estimating the standby loss requirement using the rated
volume shown on the rating plate, VT should be considered as
no less than 0.95V for gas and oil water heaters and no less than 0.90V
for electric water heaters.
404.1.4 Electric Water Heaters. In applications where water
temperatures not greater than 145[deg]F are required, an economic
evaluation shall be made on the potential benefit of using an electric
heat pump water heater(s) instead of an electric resistance water
heater(s). The analysis shall compare the extra installed costs of the
heat pump unit with the benefits in reduced energy costs (less increased
maintenance costs) over the estimated service life of the heat pump
water heater. Exceptions are as follows: Electric water heaters used in
conjunction with site-recovered or site-solar energy sources that
provide 50% or more of the water heating load or off-peak heating with
thermal storage.
404.2 Service Hot Water Piping Insulation. Circulating system piping
and noncirculating systems without heat traps, the first eight feet of
outlet piping from a constant-temperature noncirculating storage system,
and the inlet pipe between the storage tank and a heat trap in a
noncirculating storage system shall meet the provisions of subsection
403.2.9.
404.2.1 Vertical risers serving storage water heaters not having an
integral heat trap and serving a noncirculating system shall have heat
traps on both the inlet and outlet piping as close as practical to the
water heater.
404.3 Service Water Heating System Controls. Temperature controls
that allow for storage temperature adjustment from 110[deg]F to a
temperature compatible with the intended use shall be provided in
systems serving residential dwelling units and from 90[deg]F for other
systems. When designed to maintain usage temperatures in hot water
pipes, such as circulating hot water systems or heat trace, the system
shall be equipped with automatic time switches or other controls that
can be set to turn off the system.
404.3.1 The outlet temperature of lavatory faucets in public
facility restrooms shall be limited to 110[deg]F.
404.4 Water Conservation. Showerheads and lavatory faucets must meet
the requirements of 10 CFR 430.32 (o)-(p).
404.4.1 Lavatory faucets in public facility restrooms shall be
equipped with a foot switch, occupancy sensor, or similar device or, in
other than lavatories for physically handicapped persons, limit water
delivery to 0.25 gal/cycle.
[[Page 392]]
404.5 Swimming Pools. All pool heaters shall be equipped with a
readily accessible on-off switch.
404.5.1 Time switches shall be installed on electric heaters and
pumps. Exceptions are as follows:
(a) Pumps required to operate solar or heat recovery pool heating
systems.
(b) Where public health requirements require 24-hour pump operation.
404.5.2 Heated swimming pools shall be equipped with pool covers.
Exception: When over 70% of the annual energy for heating is obtained
from a site-recovered or site-solar energy source.
404.6 Combined Service Water Heating and Space Heating Equipment. A
single piece of equipment shall not be used to provide both space
heating and service water heating. Exceptions are as follows:
(a) The energy input or storage volume of the combined boiler or
water heater is less than twice the energy input or storage volume of
the smaller of the separate boilers or water heaters otherwise required
or
(b) The input to the combined boiler is less than 150,000 Btuh.