[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: 10CFR434.403]
[Page 380-390]
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. 434.403 Building mechanical systems and equipment.
Mechanical systems and equipment used to provide heating,
ventilating, and air conditioning functions as well as additional
functions not related to space conditioning, such as, but not limited
to, freeze protection in fire projection systems and water heating,
shall meet the requirements of this section.
403.1 Mechanical Equipment Efficiency. When equipment shown in
Tables 403.1a through 403.1f is used, it shall have a minimum
performance at the specified rating conditions when tested in accordance
with the specified reference standard. The reference standards listed in
Tables 403.1a through 403.1f are incorporated by reference, see Sec.
434.701. Omission of minimum performance requirements for equipment not
listed in Tables 403.1a through 403.1f does not preclude use of such
equipment.
Table 403.1a--Unitary Air Conditioners and Condensing Units, Electrically Operated, Minimum Efficiency
Requirements
----------------------------------------------------------------------------------------------------------------
Subcategory or Minimum Test procedure
Equipment type Size category rating condition Efficiency \2\ \1\
----------------------------------------------------------------------------------------------------------------
Air Conditioners, Air Cooled.... < 65,000 Btu/h.... Split system...... 10.0 SEER......... ARI 210/240
Single Package.... 9.7 SEER.......... (RS-15)*
= Split System and 8.9 EER \3\....... ARI 210/240
65,000 Btu/h and Single Package. 8.3 IPLV \3\...... (RS-15)*
< 135,00.
Btu/h.............
= Split System and 8.5 EER\3\........ ..................
135,000 Btu/h and Single Package. 7.5 IPLV\3\.......
< 240,000 Btu/h.
= Split System and 8.5 EER\3\........ ARI-340/360
240,000 Btu/h and Single Package. 7.5 IPLV\3\....... (RS-16)*
< 760,000 Btu/h.
= Split System and 8.3 EER\3\........ ARI-340/360
760,000 Btu/h. Package. 7.5 IPLV\3\....... (RS-16)*
[[Page 381]]
Air Conditioners, Water and < 65,000 Btu/h.... Split System and 9.3 EER\3\........ ARI 210/240
Evaporatively Cooled. Single Package. 8.4 IPLV\3\....... (RS-15)*
= Split System and 10.5 EER\c\....... ARI 210/240
65,000 Btu/h and Single Package. 9.7 IPLV\c\....... (RS-15)*
< 135,000 Btu/h.
= Split System and 9.6 EER\c\........ ARI-340/360
135,000 Btu/h and Single Package. 9.0 IPLV\c\....... (RS-16)*
< 240,000 Btu/h.
= Split System and 9.6 EER\c\........ ARI-340/360
240,000 Btu/h. Single Package. 9.0 IPLV\c\....... (RS-16)*
Condensing Units, Air Cooled... 135,000 Btu/h..... .................. 9.9 EER........... ARI 365
11.0 IPLV......... (RS-29)*
Condensing Units, Water or 135,000 Btu/h..... .................. 12.9 EER.......... ARI 365
Evaporatively Cooled. 12.9 IPLV......... (RS-29)*
----------------------------------------------------------------------------------------------------------------
\1\ See Subpart E for detailed references
\2\ IPLVs are only applicable to equipment with capacity modulation.
\3\ Deduct 0.2 from the required EERs and IPLVs for units that have a heating section.
* Incorporation by reference, see Sec. 434.701
Table 403.1b--Unitary and Applied Heat Pumps, Electrically Operated, Minimum Efficiency Requirements
----------------------------------------------------------------------------------------------------------------
Subcategory or Minimum efficiency
Equipment type Size category rating condition 2 Test procedure 1
----------------------------------------------------------------------------------------------------------------
Air Cooled (Cooling Mode)....... <65,000 Btu/h..... Split System...... 10.0 SEER......... ARI 210/240
Single Package.... 9.7 SEER.......... (RS-15)*
=65,000 Split System and 8.9 EER 3......... ARI 210/240
Btu/h and Single Package. 8.3 IPLV 3........ (RS-15)*
<135,000 Btu/h.
=135,00 Split System and 8.5 EER 3......... ARI-340/360
0 Btu/h and Single Package. 7.5 IPLV 3........ (RS-16)*
<240,000 Btu/h.
=240,00 Split System and 8.5 EER 3......... ARI-340/360
0 Btu/h. Single Package. 7.5 IPLV 3........ (RS-16)*
Water Source.................... <65,000 Btu/h..... 85 [deg]F Entering 9.3 EER........... ARI-320
(Cooling Mode).................. Water. 10.2 EER.......... (RS-27)*
75 [deg]F Entering
Water.
=65,000 85 [deg]F Entering 10.5 EER.......... ARI-320
Btu/h and Water. 11.0 EER.......... (RS-27)*
<135,000. 75 [deg]F Entering
Btu/h............. Water.
Groundwater-Source (Cooling <135,000 Btu/h.... 70 F Entering 11.0 EER.......... ARI 325
Mode). Water. 11.5 EER.......... (RS-28)*
50 F Entering
Water.
Ground Source (Cooling Mode).... <135,000 Btu/h.... 77 F Entering 10.0 EER.......... ARI 325
Water. 10.4 EER.......... (RS-28)*
70 F Entering
Water.
Air Cooled (Heating Mode)....... <65,000 Btu/h Split System...... 6.8 HSPF.......... ARI 210/240
(Cooling Single Package.... 6.6 HSPF.......... (RS-15)*
Capacity).
65,000 Btu/h and 47 F db/43 F wb 3.00 COP.......... ARI 210/240
<135,000 Btu/h Outdoor Air. 2.00 COP.......... (RS-15)*
(Cooling 17 F db/15 F wb
Capacity). Outdoor Air.
135,000 Btu/h 47 F db/43 F wb 2.90 COP.......... ARI-340/360
(Cooling Outdoor Air. 2.00 COP.......... (RS-1/)*
Capacity). 17 F db/15 F wb
Outdoor.
Water-Source (Heating Mode)..... <135,000 Btu/h 70 F Entering 3.80 COP.......... ARI-320
(Cooling Water. 3.90 COP.......... (RS-27)*
Capacity). 75 F Entering
Water.
Groundwater-Source (Heating <135,000 Btu/h 70 F Entering 3.40 COP.......... ARI 325
Mode). (Cooling Water. 3.00 COP.......... (RS-28)*
Capacity). 50 F Entering
Water.
Ground Source (Heating Mode).... <135,000 Btu/h 32 F Entering 2.50 EER.......... ARI-330
(Cooling Water. 2.70 EER.......... (RS-45)*
Capacity). 41 F Entering
Water.
----------------------------------------------------------------------------------------------------------------
\1\ See Subpart E for detailed references.
\2\ IPLVs are only applicable to equipment with capacity modulation.
\3\ Deduct 0.2 from the required EERs and IPLVs for units that have a heating section.
* Incorporation by reference, see Sec. 434.701.
[[Page 382]]
Table 403.1c--Water Chilling Packages, Minimum Efficiency Requirements
----------------------------------------------------------------------------------------------------------------
Subcategory or Minimum efficiency
Equipment type Size category rating condition \2\ Test procedure \1\
----------------------------------------------------------------------------------------------------------------
Air-Cooled, With Condenser, <150 Tons......... 2.70 COP.......... 2.50 COP.......... ARI 550
Electrically Operated. =150 2.80 IPLV......... 2.50 IPLV......... Centrifugal/
Tons. Rotary Screw (RS-
30)* or ARI 590
Reciprocating (RS-
31)*
Air-Cooled, Without Condenser, All Capacities.... .................. 3.10 COP
Electrically Operated. 3.20 IPLV.........
Water Cooled, Electrically All Capacities.... .................. 3.80 COP
Operated, Positive Displacement 3.90 IPLV.........
(Reciprocating).
Water Cooled, Electrically <150 Tons 3.80 COP
Operated, Positive Displacement =150 .................. 3.90 IPLV.........
(Rotary Screw and Scroll). Tons and <300 4.20 COP..........
Tons. 4.50 IPLV.........
=300 5.20 COP..........
Tons. 5.30 IPLV.........
Water-Cooled, Electrically <150 Tons......... 3.80 COP.......... ARI 550
Operated, Centrifugal. 150 Tons and <300 .................. 3.90 IPLV......... (RS-30)*
Tons. .................. 4.20 COP..........
300 Tons.......... 4.50 IPLV.........
5.20 COP..........
5.30 IPLV.........
Absorption Single Effect........ All Capacities.... .................. 0.48 COP..........
Absorption Double Effect, All Capacities.... .................. 0.95 COP.......... ARI 560
Indirect-Fired. 1.00 IPLV......... (RS-46)*
Absorption Double-Effect, Direct- All Capacities.... .................. 0.95 COP
Fired. 1.00 IPLV ........
----------------------------------------------------------------------------------------------------------------
\1\ See Subpart E for detailed references.
\2\ Equipment must comply with all efficiencies when multiple efficiencies are indicated.
*Incorporation by reference, see Sec. 434.701.
Table 403.1d--Packaged Terminal Air Conditioners, Packaged Terminal Heat Pumps, Room Air Conditioners, and Room
Air-Conditioner Heat Pumps Electrically Operated, Minimum Efficiency Requirements
----------------------------------------------------------------------------------------------------------------
Subcategory or Minimum efficiency
Equipment type Size category rating condition \2\ Test procedure \1\
----------------------------------------------------------------------------------------------------------------
PTAC (Cooling Mode)............. All Capacities.... 95[deg]F db 10.0- (0.16 x Cap/ ARI 310/380
Outdoor Air. 1,000) \3\EER. (RS-17)*
.................. 12.2-(0.20 x Cap/ ARI 310/380
82[deg]F db 1,000) \3\EER. (RS-17)*
Outdoor Air.
PTHP (Cooling Mode)............. All Capacities.... 95[deg]F db 10.0-(0.16 x Cap/
Outdoor Air. 1,000) \3\ EER.
.................. 12.2-(0.20 x Cap/
82[deg]F db 1,000) EER.
Outdoor Air.
PTHP (Heating Mode)............. All Capacities.... .................. 2.90-(0.026 x CAP/
1,000) \3\ COP.
Room Air Conditioners, With <6,000 Btu/h...... .................. 8.0 EER........... ANSI/AHAM RAC-1
Louvered Sides. =6,000 8.5 EER........... (RS-40)*
Btu/h and <8,000 ..................
Btu/h. 9.0 EER...........
=8,000 ..................
Btu/h and 8.8 EER...........
lt;14,000 Btu/h. ..................
=14,000 8.2 EER...........
Btu/h and <20,000
Btu/h.
=20,000
Btu/h.
Room Air Conditioner, Without <6,000 Btu/h...... .................. 8.0 EER........... ANSI/AHAM RAC-1
Louvered Sides. =6,000 8.5 EER........... (RS-40)*
Btu/h and <20,000 ..................
Btu/h. 8.2 EER...........
=20,000
Btu/h.
Room Air-Conditioner Heat Pumps All Capacities.... .................. 8.5 EER........... ANSI/AHAM RAC-1
With Louvered Sides. (RS-40)*
Room Air-Conditioner Heat Pumps All Capacities.... .................. 8.0 EER........... ANSI/AHAM RAC-1
Without Louvered Sides. (RS-40*
----------------------------------------------------------------------------------------------------------------
\1\ See Subpart E for detailed references.
\2\ Equipment must comply with all efficiencies when multiple efficiencies are indicated. (Note products covered
by the 1992 Energy Policy Act have no efficiency requirement for operation at other than standard rating
conditions for products manufactured after 1/1/94).
[[Page 383]]
\3\ Cap means the rated capacity of the product in Btu/h. If the unit's capacity is less than 7,000 Btu/h, use
7,000 Btu/h in the calculation. If the unit's capacity is greater than 15,000 Btu/h, use 15,000 Btu/h in the
calculation.
* Incorporation by reference, see Sec. 434.701.
Table 403.1e--Warm Air Furnaces and Combination Warm Air Furnaces/Air Conditioning Units, Warm Air Duct Furnaces
and Unit Heaters, Minimum Efficiency Requirements
----------------------------------------------------------------------------------------------------------------
Subcategory or Minimum
Equipment type Size category rating condition efficiencyb,e Test procedure\a\
----------------------------------------------------------------------------------------------------------------
Warm Air-Furnace, Gas-Fired..... < 225,000 Btu/h... .................. 78% AFUE or 80% Et DOE 10 CFR 430
Appendix N
= Maximum Capacity c 80% Et............ ANSI Z21.47
225,000 Btu/h. Minimum Capacityc. 78% Et............ (RS-21)*
Warm Air-Furnace, Oil-Fired..... < 225,000 Btu/h... .................. 78% AFUE or 80% DOE 10 CFR 430
Et\d\. Appendix N
= Maximum Capacity c 81% Et............ U.L. 727
225,000 But/h. Minimum Capacity.. 81% Et............ (RS-22)*
Warm Air Duct Furnaces, Gas- All Capacities.... Maximum Capacity c 78% Et............ ANSI Z83.9
Fired. Minimum Capacity.. 75% Et............ (RS-23)
Warm Air Unit Heaters, Gas Fired All Capacities.... Maximum Capacity c 78% Et............ ANSI Z83.8
Minimum Capacity.. 74% Et............ (RS-24)*
Oil-Fired....................... All Capacities.... Maximum Capacity c 81% Et............ U.L. 731
Minimum Capacity.. 81% Et............ (RS-25)*
----------------------------------------------------------------------------------------------------------------
\a\ See Subpart E for detailed references.
\b\ Minimum and maximum ratings as provided for and allowed by the unit's controls.
\c\ Combination units not covered by NAECA (Three-phase power or cooling capacity = 65,000 Btu/h) may
comply with either rating.
\d\ Et = thermal efficiency. See referenced document for detailed discussion.
\e\ Ec = combustion efficiency. Units must also include an IID and either power venting or a flue damper. For
those furnaces where combustion air is drawn from the conditioned space, a vent damper may be substituted for
a flue damper.
* Incorporation by reference, see Sec. 434.701
Table 403.1f--Boilers, Gas- and Oil-Fired, Minimum Efficiency Requirements
----------------------------------------------------------------------------------------------------------------
Subcategory or Minimum efficiency
Equipment type Size category rating condition \b\ Test procedure \a\
----------------------------------------------------------------------------------------------------------------
Boilers, Gas-Fired............. <300,000 Btu/h.... Hot Water......... 80% AGUE.......... DOE 10 CFR 430
Appendix N
.................. Steam............. 75% AGUE.......... DOE 10 CFR 430
Appendix N
<300,000 Btu/h.... Maximum Capacity c 80% Ec............ ANSI Z21.13
Minimum Capacity.. 80% Ec............ (RS-32)*
Boilers, Oil-Fired.............. <300,000 Btu/h... .................. 80% AGUE.......... DOE 10 CFR 430
(RS-20)*
<300,000 Btu/h.... Maximum Capacity c 83% Ec............ U.L. 726
Minimum Capacity.. 83% Ec............ (RS-33)*
Oil-Fired (Residual)............ <3000,000 Btu/h... Maximum Capacity c 83% Ec............
Minimum Capacity.. 83% Ec ...........
----------------------------------------------------------------------------------------------------------------
\a\ See Subpart E for detailed references.
\b\ Minimum and maximum ratings as provided for and allowed by the unit's controls.
\c\ Ec = combustion efficiency (100% less flue losses). See reference document for detailed information.
* Incorporation by reference, see Sec. 434.701.
403.1.1 Where multiple rating conditions and/or performance
requirements are provided, the equipment shall satisfy all stated
requirements.
403.1.2 Equipment used to provide water heating functions as part of
a combination integrated system shall satisfy all stated requirements
for the appropriate space heating or cooling category.
403.1.3 The equipment efficiency shall be supported by data
furnished by the manufacturer or shall be certified under a nationally
recognized certification program or rating procedure.
403.1.4 Where components, such as indoor or outdoor coils, from
different manufacturers are used, the system designer shall specify
component efficiencies whose combined efficiency meets the standards
herein.
403.2 HVAC Systems.
403.2.1 Load Calculations. Heating and cooling system design loads
for the purpose of sizing systems and equipment shall be determined in
accordance with the procedures described in RS-1 (incorporated by
reference, see Sec. 434.701) using the design parameters specified in
subpart C of this part.
[[Page 384]]
403.2.2 Equipment and System Sizing. Heating and cooling equipment
and systems shall be sized to provide no more than the loads calculated
in accordance with subsection 403.2.1. A single piece of equipment
providing both heating and cooling must satisfy this provision for one
function with the other function sized as small as possible to meet the
load, within available equipment options. Exceptions are as follows:
(a) When the equipment selected is the smallest size needed to meet
the load within available options of the desired equipment line.
(b) Standby equipment provided with controls and devices that allow
such equipment to operate automatically only when the primary equipment
is not operating.
(c) Multiple units of the same equipment type with combined
capacities exceeding the design load and provided with controls that
sequence or otherwise optimally control the operation of each unit based
on load.
403.2.3 Separate Air Distribution System. Zones with special process
temperature and/or humidity requirements shall be served by air
distribution systems separate from those serving zones requiring only
comfort conditions or shall include supplementary provisions so that the
primary systems may be specifically controlled for comfort purposes
only. Exceptions: Zones requiring only comfort heating or comfort
cooling that are served by a system primarily used for process
temperature and humidity control need not be served by a separate system
if the total supply air to these comfort zones is no more than 25% of
the total system supply air or the total conditioned floor area of the
zones is less than 1000 ft2.
403.2.4 Ventilation and Fan System Design. Ventilation systems shall
be designed to be capable of reducing the supply of outdoor air to the
minimum ventilation rates required by Section 6.1.3 of RS-41
(incorporated by reference, see Sec. 434.701) through the use of return
ducts, manually or automatically operated control dampers, fan volume
controls, or other devices. Exceptions are as follows: Minimum outdoor
air rates may be greater if:
(a) Required to make up air exhausted for source control of
contaminants such as in a fume hood.
(b) Required by process systems.
(c) Required to maintain a slightly positive building pressure. For
this purpose, minimum outside air intake may be increased up to no
greater than 0.30 air changes per hour in excess of exhaust quantities.
403.2.4.1 Ventilation controls for variable or high occupancy areas.
Systems with design outside air capacities greater than 3,000 cfm
serving areas having an average design occupancy density exceeding 100
people per 1,000 ft\2\ shall include means to automatically reduce
outside air intake to the minimum values required by RS-41 (incorporated
by reference, see Sec. 434.701) during unoccupied or low-occupancy
periods. Outside air shall not be reduced below 0.14 cfm/ft\2\. Outside
air intake shall be controlled by one or more of the following:
(a) A clearly labeled, readily accessible bypass timer that may be
used by occupants or operating personnel to temporarily increase minimum
outside air flow up to design levels.
(b) A carbon dioxide (CO2) control system having sensors
located in the spaces served, or in the return air from the spaces
served, capable of maintaining space CO2 concentrations below
levels recommended by the manufacturer, but no fewer than one sensor per
25,000 ft\2\ of occupied space shall be provided.
(c) An automatic timeclock that can be programmed to maintain
minimum outside air intake levels commensurate with scheduled occupancy
levels.
(d) Spaces equipped with occupancy sensors.
403.2.4.2 Ventilation Controls for enclosed parking garages. Garage
ventilation fan systems with a total design capacity greater than 30,000
cfm shall have automatic controls that stage fans or modulate fan volume
as required to maintain carbon monoxide (CO) below levels recommended in
RS-41.
403.2.4.3 Ventilation and Fan Power. The fan system energy demand of
each HVAC system at design conditions shall not exceed 0.8 W/cfm of
supply air for constant air volume systems and 1.25 W/cfm of supply air
for variable-
[[Page 385]]
air-volume (VAV) systems. Fan system energy demand shall not include the
additional power required by air treatment or filtering systems with
pressure drops over 1 in. w.c. Individual VAV fans with motors 75 hp and
larger shall include controls and devices necessary for the fan motor to
demand no more than 30 percent of design wattage at 50 percent of design
air volume, based on manufacturer's test data. Exceptions are as
follows:
(a) Systems with total fan system motor horsepower of 10 hp or less.
(b) Unitary equipment for which the energy used by the fan is
considered in the efficiency ratings of subsection 403.1.
403.2.5 Pumping System Design. HVAC pumping systems used for comfort
heating and/or comfort air conditioning that serve control valves
designed to modulate or step open and closed as a function of load shall
be designed for variable fluid flow and capable of reducing system flow
to 50 percent of design flow or less. Exceptions are as follows:
(a) Systems where a minimum flow greater than 50% of the design flow
is required for the proper operation of equipment served by the system,
such as chillers.
(b) Systems that serve no more than one control valve.
(c) Systems with a total pump system horse power <=10 hp.
(d) Systems that comply with subsection 403.2.6.8 without exception.
403.2.6 Temperature and Humidity Controls.
403.2.6.1 System Controls. Each heating and cooling system shall
include at least one temperature control device.
403.2.6.2 Zone Controls. The supply of heating and cooling energy to
each zone shall be controlled by individual thermostatic controls
responding to temperature within the zone. For the purposes of this
section, a dwelling unit is considered a zone. Exceptions are as
follows: Independent perimeter systems that are designed to offset
building envelope heat losses or gains or both may serve one or more
zones also served by an interior system when the perimeter system
includes at least one thermostatic control zone for each building
exposure having exterior walls facing only one orientation for at least
50 contiguous ft and the perimeter system heating and cooling supply is
controlled by thermostat(s) located within the zone(s) served by the
system.
403.2.6.3 Zone Thermostatic Control Capabilities. Where used to
control comfort heating, zone thermostatic controls shall be capable of
being set locally or remotely by adjustment or selection of sensors down
to 55[deg]F or lower. Where used to control comfort cooling, zone
thermostatic controls shall be capable of being set locally or remotely
by adjustment or selection of sensors up to 85[deg]F or higher. Where
used to control both comfort heating and cooling, zone thermostatic
controls shall be capable of providing a temperature range or deadband
of at least 5[deg]F within which the supply of heating and cooling
energy to the zone is shut off or reduced to a minimum. Exceptions are
as follows:
(a) Special occupancy or special usage conditions approved by the
building official or
(b) Thermostats that require manual changeover between heating and
cooling modes.
403.2.6.4 Heat Pump Auxiliary Heat. Heat pumps having supplementary
electric resistance heaters shall have controls that prevent heater
operation when the heating load can be met by the heat pump.
Supplemental heater operation is permitted during outdoor coil defrost
cycles not exceeding 15 minutes.
403.2.6.5 Humidistats. Humidistats used for comfort purposes shall
be capable of being set to prevent the use of fossil fuel or electricity
to reduce relative humidity below 60% or increase relative humidity
above 30%.
403.2.6.6 Simultaneous Heating and Cooling. Zone thermostatic and
humidistatic controls shall be capable of operating in sequence the
supply of heating and cooling energy to the zone. Such controls shall
prevent: Reheating; recooling; mixing or simultaneous supply of air that
has been previously mechanically heated and air that has been previously
cooled, either by mechanical refrigeration or by economizer systems; and
other simultaneous operation of heating and cooling systems to
[[Page 386]]
the same zone. Exceptions are as follows:
(a) Variable-air-volume systems that, during periods of occupancy,
are designed to reduce the air supply to each zone to a minimum before
heating, recooling, or mixing takes place. This minimum volume shall be
no greater than the larger of 30% of the peak supply volume, the minimum
required to meet minimum ventilation requirements of the Federal agency.
(0.4 cfm/ft\2\ of zone conditioned floor area, and 300 cfm).
(b) Zones where special pressurization relationships or cross-
contamination requirements are such that variable-air-volume systems are
impractical, such as isolation rooms, operating areas of hospitals and
clean rooms.
(c) At least 75% of the energy for reheating or for providing warm
air in mixing systems is provided from a site-recovered or site-solar
energy source.
(d) Zones where specified humidity levels are required to satisfy
process needs, such as computer rooms and museums.
(e) Zones with a peak supply air quantity of 300 cfm or less.
403.2.6.7 Temperature Reset for Air Systems. Air systems supplying
heated or cooled air to multiple zones shall include controls that
automatically reset supply air temperatures by representative building
loads or by outside air temperature. Temperature shall be reset by at
least 25% of the design supply air to room air temperature difference.
Zones that are expected to experience relatively constant loads, such as
interior zones, shall be designed for the fully reset supply
temperature. Exception are as follows: Systems that comply with
subsection 403.2.6.6 without using exceptions (a) or (b).
403.2.6.8 Temperature Reset for Hydronic Systems. Hydronic systems
of at least 600,000 Btu/hr design capacity supplying heated and/or
chilled water to comfort conditioning systems shall include controls
that automatically reset supply water temperatures by representative
building loads (including return water temperature) or by outside air
temperature. Temperature shall be reset by at least 25% of the design
supply-to-return water temperature difference. Exceptions are as
follows:
(a) Systems that comply with subsection 403.2.5 without exception or
(b) Where the design engineer certifies to the building official
that supply temperature reset controls cannot be implemented without
causing improper operation of heating, cooling, humidification, or
dehumidification systems.
403.2.7 Off Hour Controls.
403.2.7.1 Automatic Setback or Shutdown Controls. HVAC systems shall
be equipped with automatic controls capable of accomplishing a reduction
of energy use through control setback or equipment shutdown. Exceptions
are as follows:
(a) Systems serving areas expected to operate continuously or
(b) Equipment with full load demands not exceeding 2 kW controlled
by readily accessible, manual off-hour controls.
403.2.7.2 Shutoff Dampers. Outdoor air supply and exhaust systems
shall be provided with motorized or gravity dampers or other means of
automatic volume shutoff or reduction. Exceptions are as follows:
(a) Systems serving areas expected to operate continuously.
(b) Individual systems which have a design airflow rate or 3000 cfm
or less.
(c) Gravity and other non-electrical ventilation systems controlled
by readily accessible, manual damper controls.
(d) Where restricted by health and life safety codes.
403.2.7.3 Zone Isolation systems that serve zones that can be
expected to operate nonsimultaneously for more than 750 hours per year
shall include isolation devices and controls to shut off or set back the
supply of heating and cooling to each zone independently. Isolation is
not required for zones expected to operate continuously or expected to
be inoperative only when all other zones are inoperative. For buildings
where occupancy patterns are not known at the time of system design,
such as speculative buildings, the designer may predesignate isolation
areas. The grouping of zones on one floor into a single isolation area
shall
[[Page 387]]
be permitted when the total conditioned floor area does not exceed
25,000 ft2 per group.
403.2.8 Economizer Controls.
403.2.8.1 Each fan system shall be designed and capable of being
controlled to take advantage of favorable weather conditions to reduce
mechanical cooling requirements. The system shall include either: A
temperature or enthalpy air economizer system that is capable of
automatically modulating outside air and return air dampers to provide
up to 85% of the design supply air quantity as outside air, or a water
economizer system that is capable of cooling supply air by direct and/or
indirect evaporation and is capable of providing 100% of the expected
system cooling load at outside air temperatures of 50[deg]F dry-bulb/
45[deg]F wet-bulb and below. Exceptions are as follows:
(a) Individual fan-cooling units with a supply capacity of less than
3000 cfm or a total cooling capacity less than 90,000 Btu/h.
(b) Systems with air-cooled or evaporatively cooled condensers that
include extensive filtering equipment provided in order to meet the
requirements of RS-41 (incorporated by reference, see Sec. 434.701).
(c) Systems with air-cooled or evaporatively cooled condensers where
the design engineer certifies to the building official that use of
outdoor air cooling affects the operation of other systems, such as
humidification, dehumidification, and supermarket refrigeration systems,
so as to increase overall energy usage.
(d) Systems that serve envelope-dominated spaces whose sensible
cooling load at design conditions, excluding transmission and
infiltration loads, is less than or equal to transmission and
infiltration losses at an outdoor temperature of 60[deg]F.
(e) Systems serving residential spaces and hotel or motel rooms.
(f) Systems for which at least 75% of the annual energy used for
mechanical cooling is provided from a site-recovered or site-solar
energy source.
(g) The zone(s) served by the system each have operable openings
(windows, doors, etc.) with an openable area greater than 5% of the
conditioned floor area. This applies only to spaces open to and within
20 ft of the operable openings. Automatic controls shall be provided
that lock out system mechanical cooling to these zones when outdoor air
temperatures are less than 60[deg]F.
403.2.8.2 Economizer systems shall be capable of providing partial
cooling even when additional mechanical cooling is required to meet the
remainder of the cooling load. Exceptions are as follows:
(a) Direct-expansion systems may include controls to reduce the
quantity of outdoor air as required to prevent coil frosting at the
lowest step of compressor unloading. Individual direct-expansion units
that have a cooling capacity of 180,000 Btu/h or less may use economizer
controls that preclude economizer operation whenever mechanical cooling
is required simultaneously.
(b) Systems in climates with less than 750 average operating hours
per year between 8 a.m. and 4 p.m. when the ambient dry-bulb
temperatures are between 55 [deg]F and 69 [deg]F inclusive.
403.2.8.3 System design and economizer controls shall be such that
economizer operation does not increase the building heating energy use
during normal operation.
403.2.9 Distribution System Construction and Insulation.
403.2.9.1 Piping Insulation. All HVAC system piping shall be
thermally insulated in accordance with Table 403.2.9.1. Exceptions are
as follows:
(a) Factory-installed piping within HVAC equipment tested and rated
in accordance with subsection 403.1.
(b) Piping that conveys fluids that have a design operating
temperature range between 55[deg]F and 105[deg]F.
(c) Piping that conveys fluids that have not been heated or cooled
through the use of fossil fuels or electricity.
[[Page 388]]
Table 403.2.9.1--Minimum Pipe Insulation (in.) a
----------------------------------------------------------------------------------------------------------------
Insulation conductivity a Nominal pipe diameter (in.)
----------------------------------------------------------------------------------------------------------------
Conductivity
Fluid Design Operating Temp. Range (F) Range Btu in./ Mean <1.0 1.0 to 1.5 to 4.0 to 8.0
(h ft2 F) Temp. F 1.25 3.0 6.0
----------------------------------------------------------------------------------------------------------------
Heating systems (Steam, Steam Condensate, and Hot Water) b, c
----------------------------------------------------------------------------------------------------------------
350......................... 0.32-0.34 250 1.0 1.5 1.5 2.0 2.5
251-350................................ 0.29-0.32 200 1.0 1.0 1.5 2.0 2.0
201-250................................ 0.27-0.30 150 1.0 1.0 1.0 1.5 1.5
141-200................................ 0.25-0.29 125 1.0 1.0 1.0 1.5 1.5
105-140................................ 0.22-0.28 100 0.5 0.5 0.75 1.0 1.0
----------------------------------------
Domestic and Service Hot Water Systems
----------------------------------------------------------------------------------------------------------------
105 and Greater........................ 0.22-0.28 100 0.5 0.5 0.75 1.0 1.0
----------------------------------------
Cooling Systems (Chilled Water, Brine, and Refrigerant) d
----------------------------------------------------------------------------------------------------------------
40-55.................................. 0.22-0.28 100 0.5 0.5 0.5 0.5 0.5
Below 40............................... 0.22-0.28 100 0.5 0.5 0.5 0.5 0.5
----------------------------------------------------------------------------------------------------------------
a For insulation outside the stated conductivity range, the minimum thickness (T) shall be determined as
follows: T=r1+t/r)K/k-1{time}
Where T = minimum insulation thickness (in), r = actual outside radius of pipe (in), t = insulation thickness
listed in this table for applicable fluid temperature and pipe size, K = conductivity of alternate material at
mean rating temperature indicated for the applicable fluid temperature (Btu in/h ft2 F); and k = the upper
value of the conductivity range listed in this table for the applicable fluid temperature.
b These thicknesses are based on energy efficiency considerations only. Safety issues, such as insulation
surface temperatures, have not been considered.
c Piping insulation is not required between the control valve and coil on run-outs when the control valve is
located within four feet of the coil and the pipe diameter is 1 inch or less.
d Note that the required minimum thickness does not take water vapor transmission and possible surface
condensation into account.
Table 403.2.9.2--Minimum Duct Insulation R-value \a\
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Cooling supply ducts Heating supply ducts
---------------------------------------------------------------------------------------------------------------
Duct location 1,000< 1,500< 4,500< Return
CDD65 500< CDD65 CDD65 CDD65 =2,000 <=1,500 <=4,500 <=7,500 eq>=7,500
--------------------------------------------------------------------------------------------------------------------------------------------------------
Exterior of Building.......... R-3.3..... R-5.0..... R-6.5..... R-8.0.............. R-3.3..... R-5.0.... R-6.5.... R-8.0............. R-5.0
Ventilated Attic.............. R-3.3..... R-3.3..... R-3.3..... R-5.0.............. R-5.0..... R-5.0.... R-5.0.... R-5.0............. R-3.3
Unvented Attic................ R-5.0..... R-5.0..... R-5.0..... R-5.0.............. R-5.0..... R-5.0.... R-5.0.... R-5.0............. R-3.3
Other Conditioned Spaces b.... R-3.3..... R-3.3..... R-3.3..... R-3.3.............. R-3.3..... R-3.3.... R-3.3.... R-3.3............. R-3.3
Indirectly Conditioned Spaces none...... R-3.3..... R-3.3..... R-3.3.............. R-3.3..... R-3.3.... R-3.3.... R-3.3............. none
c.
Buried........................ none...... none...... none...... none............... R-5.0..... R-5.0.... R-5.0.... R-5.0............. R-3.3
--------------------------------------------------------------------------------------------------------------------------------------------------------
a Insulation R-values, measured in (h.ft 2.[deg]F)/Btu, are for the insulation as installed and do not include film resistance. The required minimum
thickness do not consider water vapor transmission and possible surface condensation. The required minimum thicknesses do not consider water vapor
transmission and condensation. For ducts that are designed to convey both heated and cooled air, duct insulation shall be as required by the most
restrictive condition. Where exterior walls are used as plenum walls, wall insulation shall be as required by the most restrictive condition of this
section or subsection 402. Insulation resistance measured on a horizontal plane in accordance with RS-6 (incorporated by reference, see Sec.
434.701) at a mean temperature of 75 [deg]F. RS-6 is in incorporated by reference at Sec. 434.701.
b Includes crawl spaces, both ventilated and non-ventilated.
c Includes return air plenums, with and without exposed roofs above.
403.2.9.2Duct and Plenum Insulation. All supply and return air ducts
and plenums installed as part of an HVAC air distribution system shall
be thermally insulated in accordance with Table 403.2.9.1. Exceptions
are as follows:
(a) Factory-installed plenums, casings, or ductwork furnished as a
part of the HVAC equipment tested and rated in accordance with
subsection 403.1
(b) Ducts within the conditioned space that they serve.
(incorporated by reference, see Sec. 434.701)ca a06oc0.186
403.2.9.3 Duct and Plenum Construction. All air-handling ductwork
and plenums shall be constructed and erected in accordance with RS-34,
RS-
[[Page 389]]
35, and RS-36 (incorporated by reference, see Sec. 434.701). Where
supply ductwork and plenums designed to operate at static pressures from
0.25 in. wc to 2 in. wc, inclusive, are located outside of the
conditioned space or in return plenums, joints shall be sealed in
accordance with Seal Class C as defined in RS-34 (incorporated by
reference, see Sec. 434.701). Pressure sensitive tape shall not be used
as the primary sealant where such ducts are designed to operate at
static pressures of 1 in. wc, or greater.
403.2.9.3.1 Ductwork designed to operate at static pressures in
excess of 3 in. wc shall be leak-tested in accordance with Section 5 of
RS-35, (incorporated by reference, see Sec. 434.701), or equivalent.
Test reports shall be provided in accordance with Section 6 of RS-35,
(incorporated by reference, see Sec. 434.701)m or equivalent. The
tested duct leakage class at a test pressure equal to the design duct
pressure class rating shall be equal to or less than leakage Class 6 as
defined in Section 4.1 of RS-35 (incorporated by reference, see Sec.
434.701). Representative sections totaling at least 25% of the total
installed duct area for the designated pressure class shall be tested.
403.2.10 Completion.
403.2.10.1 Manuals. Construction documents shall require an
operating and maintenance manual provided to the Federal Agency. The
manual shall include, at a minimum, the following:
(a) Submittal data stating equipment size and selected options for
each piece of equipment requiring maintenance, including assumptions
used in outdoor design calculations.
(b) Operating and maintenance manuals for each piece of equipment
requiring maintenance. Required maintenance activity shall be specified.
(c) Names and addresses of at least one qualified service agency to
perform the required periodic maintenance shall be provided.
(d) HVAC controls systems maintenance and calibration information,
including wiring diagrams, schematics, and control sequence
descriptions. Desired or field determined setpoints shall be permanently
recorded on control drawings, at control devices, or, for digital
control systems, in programming comments.
(e) A complete narrative, prepared by the designer, of how each
system is intended to operate shall be included with the construction
documents.
403.2.10.2 Drawings. Construction documents shall require that
within 30 days after the date of system acceptance, record drawings of
the actual installation be provided to the Federal agency. The drawings
shall include details of the air barrier installation in every envelope
component, demonstrating continuity of the air barrier at all joints and
penetrations.
403.2.10.3 Air System Balancing. Construction documents shall
require that all HVAC systems be balanced in accordance with the
industry accepted procedures (such as National Environmental Balancing
Bureau (NEBB) Procedural Standards, Associated Air Balance Council
(AABC) National Standards, or ANSI/ASHRAE Standard 111). Air and water
flow rates shall be measured and adjusted to deliver final flow rates
within 10% of design rates, except variable flow distribution systems
need not be balanced upstream of the controlling device (VAV box or
control valve).
403.2.10.3.1 Construction documents shall require a written balance
report be provided to the Federal agency for HVAC systems serving zones
with a total conditioned area exceeding 5,000 ft2.
403.2.10.3.2 Air systems shall be balanced in a manner to first
minimize throttling losses, then fan speed shall be adjusted to meet
design flow conditions or equivalent procedures. Exceptions are as
follows: Damper throttling may be used for air system balancing;
(a) With fan motors of 1 hp (0.746 kW) or less, or
(b) Of throttling results in no greater than \1/3\ hp (0.248 kW) fan
horsepower draw above that required if the fan speed were adjusted.
403.2.10.4 Hydronic System Balancing. Hydronic systems shall be
balanced in a manner to first minimize throttling losses; then the pump
impeller shall be trimmed or pump speed shall be adjusted to meet design
flow conditions. Exceptions are as follows:
[[Page 390]]
(a) Pumps with pump motors of 10 hp (7.46 kW) or less.
(b) If throttling results in no greater than 3 hp (2.23 kW) pump
horsepower draw above that required if the impeller were trimmed.
(c) To reserve additional pump pressure capability in open circuit
piping systems subject to fouling. Valve throttling pressure drop shall
not exceed that expected for future fouling.
403.2.10.5 Control System Testing. HVAC control systems shall be
tested to assure that control elements are calibrated, adjusted, and in
proper working condition. For projects larger than 50,000 ft2
conditioned area, detailed instructions for commissioning HVAC systems
shall be provided by the designer in plans and specifications.