Heads up: There are no amended sections in this chapter.
The provisions in this chapter are applicable to commercial buildings and their building sites.

Commercial buildings shall comply with one of the following compliance paths:

  1. ASHRAE Compliance Path: The requirements of ASHRAE 90.1-2016 (as amended), as set forth in Appendix CA.
  2. Prescriptive Compliance Path: The requirements of Sections C402 through C405 and C408. In addition, commercial buildings shall comply with Section C406 and tenant spaces shall comply with Section C406.1.1.
  3. Performance Compliance Path: The requirements of Section C407.

Where Group R-3 buildings must comply with Section C401.2, the requirements of Sections R401.3, R402.4.1.2, and R403.6.2 shall also be met.

Building thermal envelope assemblies for buildings that are intended to comply with the code on a prescriptive basis in accordance with the compliance path described in Item 2 of Section C401.2, shall comply with the following:

  1. The opaque portions of the building thermal envelope shall comply with the specific insulation requirements of Section C402.2 and the thermal requirements of either the R-value-based method of Section C402.1.3; the U-, C- and F-factor-based method of Section C402.1.4; or the component performance alternative of Section C402.1.5. When the total area of the penetrations from the through-the-wall mechanical equipment or equipment listed in Table C403.3.2(3) exceeds 1 percent of the opaque above-grade wall area, the building thermal envelope shall comply with the U-, C- and F-factor-based method of Section C402.1.4.
  2. Roof solar reflectance and thermal emittance shall comply with Section C402.3.
  3. Fenestration in building envelope assemblies shall comply with Section C402.4.

Alternatively, where buildings have a vertical fenestration area or skylight area exceeding that allowed in Section C402.4, the building and building thermal envelope shall comply with Section C401.2, Item 1 or Section C401.2, Item 3.

Walk-in coolers, walk-in freezers, refrigerated warehouse coolers and refrigerated warehouse freezers shall comply with Section C403.10.1 or C403.10.2.

The following low-energy buildings, or portions thereof separated from the remainder of the building by building thermal envelope assemblies complying with this section, shall be exempt from the building thermal envelope provisions of Section C402.

  1. Those with a peak design rate of energy usage less than 3.4 Btu/h • ft2 (10.7 W/m2) or 1.0 watt per square foot (10.7 W/m2) of floor area for space conditioning purposes.
  2. Those that do not contain conditioned space.
  3. Greenhouses.

Buildings that comply with the following shall be exempt from the building thermal envelope provisions of this code:

  1. Are separate buildings with floor area not more than 500 square feet (50 m2).
  2. Are intended to house electronic equipment with installed equipment power totaling not less than 7 watts per square foot (75 W/m2) and not intended for human occupancy.
  3. Have a heating system capacity not greater than (17,000 Btu/h) (5 kW) and a heating thermostat setpoint that is restricted to not more than 50°F (10°C).
  4. Have an average wall and roof U-factor less than 0.200 in Climate Zones 1 through 5 and less than 0.120 in Climate Zones 6 through 8.
  5. Comply with the roof solar reflectance and thermal emittance provisions for Climate Zone 1.

Building thermal envelope opaque assemblies shall comply with the requirements of Sections C402.2 and C402.4 based on the climate zone specified in Chapter C3. For opaque portions of the building thermal envelope intended to comply on an insulation component R-value basis, the R-values for insulation shall be not less than that specified in Table C402.1.3. Commercial buildings or portions of commercial buildings enclosing Group R occupancies shall use the R-values from the "Group R" column of Table C402.1.3. Commercial buildings or portions of commercial buildings enclosing occupancies other than Group R shall use the R-values from the "All other" column of Table C402.1.3.

TABLE C402.1.3

OPAQUE THERMAL ENVELOPE INSULATION COMPONENT MINIMUM REQUIREMENTS, R-VALUE METHODa, h

CLIMATE ZONE 4 EXCEPT MARINE 5 AND MARINE 4 6
All other Group R All other Group R All other Group R
Roofs
Insulation entirely
above roof deck
R-33ci R-33ci R-30ci R-30ci R-30ci R-30ci
Metal buildingsb R-19 +
R-11 LS
R-19 +
R-11 LS
R-19 +
R-11 LS
R-19 +
R-11 LS
R-25 +
R-11 LS
R-25 +
R-11 LS
Attic and other R-53 R-53 R-38 R-49 R-49 R-49
Walls, above grade
Massf R-11.2ci R-13.25ci R-11.4ci R-13.3ci R-13.3ci R-15.2ci
Metal building R-13 +
R-14.9ci
R-13 +
R-14.9ci
R-13 +
R-13ci
R-13 +
R-13ci
R-13 +
R-13ci
R-13 +
R-13ci
Metal framed R-13 +
R-8.5ci
R-13 +
R-8.5ci
R-13 +
R-7.5ci
R-13 +
R-7.5ci
R-13 +
R-7.5ci
R-13 +
R-7.5ci
Wood framed and
other
R-13 +
R-4.5ci or
R-19 +
R-1.5ci
R-13 +
R-4.5ci or
R-19 +
R-1.5ci
R-13 +
R-3.8ci
or R-20
R-13 +
R-7.5ci
or R-20
+ R-3.8ci
R-13 +
R-7.5ci
or R-20
+ R-3.8ci
R-13 +
R-7.5ci
or R-20
+ R-3.8ci
Walls, below grade
Below-grade wallc R-7.5ci R-10ci R-7.5ci R-7.5ci R-7.5ci R-7.5ci
Floors
Massd R-14.6ci R-16.7ci R-10ci R-12.5ci R-12.5ci R-12.5ci
Joist/framinge R-30 R-30 R-30 R-30 R-30 R-30
Slab-on-grade floors
Unheated slabs R-15 for 24"
below
R-15 for 24"
below
R-10 for 24"
below
R-10 for 24"
below
R-10 for 24"
below
R-15 for 24"
below
Heated slabsg R-20 for 48"
below
+ R-5
full slab
R-20 for 48"
below
+ R-5
full slab
R-15 for 36"
below
+ R-5
full slab
R-15 for 36"
below
+ R-5
full slab
R-15 for 36"
below
+ R-5
full slab
R-20 for 48"
below
+ R-5
full slab
Opaque doors
Nonswinging R-4.75 R-4.75 R-4.75 R-4.75 R-4.75 R-4.75

For SI: 1 inch = 25.4 mm, 1 pound per square foot = 4.88 kg/m2, 1 pound per cubic foot = 16 kg/m3.

ci = Continuous insulation, NR = No Requirement, LS = Liner System.

  1. Assembly descriptions can be found in ANSI/ASHRAE/IESNA Appendix A.
  2. Where using R-value compliance method, a thermal spacer block shall be provided, otherwise use the U-factor compliance method in Table C402.1.4.


  3. Where heated slabs are below grade, below-grade walls shall comply with the exterior insulation requirements for above grade mass walls.
  4. "Mass floors" shall be in accordance with Section C402.2.3.
  5. Steel floor joist systems shall be insulated to R-38.
  6. "Mass walls" shall be in accordance with Section C402.2.2.
  7. The first value is for perimeter insulation and the second value is for slab insulation. Perimeter insulation is not required to extend below the bottom of the slab.
  8. Not applicable to garage doors. See Table C402.1.4.

Building thermal envelope opaque assemblies shall meet the requirements of Sections C402.2 and C402.4 based on the climate zone specified in Chapter C3. Building thermal envelope opaque assemblies intended to comply on an assembly U-, C- or F-factor basis shall have a U-, C- or F-factor not greater than that specified in Table C402.1.4. Commercial buildings or portions of commercial buildings enclosing Group R occupancies shall use the U-, C- or F-factor from the "Group R" column of Table C402.1.4. Commercial buildings or portions of commercial buildings enclosing occupancies other than Group R shall use the U-, C- or F-factor from the "All other" column of Table C402.1.4.

TABLE C402.1.4

OPAQUE THERMAL ENVELOPE ASSEMBLY MAXIMUM REQUIREMENTS, U-FACTOR METHODa, b

CLIMATE ZONE 4
EXCEPT MARINE
5
AND MARINE 4
6
All other Group R All other Group R All other Group R
Roofs
Insulation entirely above
roof deck
U-0.030 U-0.030 U-0.032 U-0.032 U-0.032 U-0.032
Metal buildings U-0.035 U-0.035 U-0.035 U-0.035 U-0.031 U-0.031
Attic and other U-0.020 U-0.020 U-0.027 U-0.021 U-0.021 U-0.021
Walls, above grade
Massf U-0.099 U-0.086 U-0.090 U-0.080 U-0.080 U-0.071
Metal building U-0.048 U-0.048 U-0.052 U-0.052 U-0.052 U-0.052
Metal framed U-0.061 U-0.061 U-0.064 U-0.064 U-0.064 U-0.064
Wood framed and otherc U-0.061 U-0.061 U-0.064 U-0.064 U-0.051 U-0.051
Walls, below grade
Below-grade wallc C-0.119 C-0.092 C-0.119 C-0.119 C-0.119 C-0.119
Floors
Massd U-0.057 U-0.051 U-0.074 U-0.064 U-0.064 U-0.064
Joist/framing U-0.033 U-0.033 U-0.033 U-0.033 U-0.033 U-0.033
Slab-on-grade floors
Unheated slabs F-0.52 F-0.52 F-0.54 F-0.54 F-0.54 F-0.52
Heated slabse F-0.63
0.64
F-0.63
0.64
F-0.79
0.64
F-0.79
0.64
F-0.79
0.55
F-0.69
0.55
Opaque doors
Swinging door U-0.50 U-0.50 U-0.37 U-0.37 U-0.37 U-0.37
Garage door <14%
glazing
U-0.31 U-0.31 U-0.31 U-0.31 U-0.31 U-0.31

For SI: 1 pound per square foot = 4.88 kg/m2, 1 pound per cubic foot = 16 kg/m3.

ci = Continuous insulation, NR = No Requirement, LS = Liner System.

  1. Where assembly U-factors, C-factors, and F-factors are established in ANSI/ASHRAE/IESNA 90.1 Appendix A, such opaque assemblies shall be a compliance alternative where those values meet the criteria of this table, and provided that the construction, excluding the cladding system on walls, complies with the appropriate construction details from ANSI/ASHRAE/ISNEA 90.1 Appendix A.
  2. Where U-factors have been established by testing in accordance with ASTM C1363, such opaque assemblies shall be a compliance alternative where those values meet the criteria of this table. The R-value of continuous insulation shall be permitted to be added to or subtracted from the original tested design.
  3. Where heated slabs are below grade, below-grade walls shall comply with the U-factor requirements for above-grade mass walls.
  4. "Mass floors" shall be in accordance with Section C402.2.3.


  5. The first value is for perimeter insulation and the second value is for full slab insulation.
  6. "Mass walls" shall be in accordance with Section C402.2.2.

U-factors of walls with cold-formed steel studs shall be permitted to be determined in accordance with Equation 4-1:


(Equation 4-1)

where:

Rs = The cumulative R-value of the wall components along the path of heat transfer, excluding the cavity insulation and steel studs.

ER = The effective R-value of the cavity insulation with steel studs as specified in Table C402.1.4.1.

TABLE C402.1.4.1

EFFECTIVE R-VALUES FOR STEEL STUD WALL ASSEMBLIES

NOMINAL STUD DEPTH
(inches)
SPACING OF FRAMING
(inches)
CAVITY R-VALUE
(insulation)
CORRECTION FACTOR
(Fc)
EFFECTIVE R-VALUE (ER)
(Cavity R-Value × Fc)
31/2 16 13 0.46 5.98
15 0.43 6.45
31/2 24 13 0.55 7.15
15 0.52 7.80
6 16 19 0.37 7.03
21 0.35 7.35
6 24 19 0.45 8.55
21 0.43 9.03
8 16 25 0.31 7.75
24 25 0.38 9.50

U-factors of opaque assemblies within fenestration framing systems shall be determined in accordance with Table C402.1.4.2.

TABLE C402.1.4.2

EFFECTIVE U-FACTORS FOR SPANDREL PANELSa

FRAME TYPE SPANDREL PANEL RATED R-VALUE OF INSULATION BETWEEN FRAMING MEMBERS
R-4 R-7 R-10 R-15 R-20 R-25 R-30
Aluminum without Thermal
Breakb
Single glass pane, stone, or
metal panel
0.242 0.222 0.212 0.203 0.198 0.195 0.193
Double glass with no low-e
coatings
0.233 0.218 0.209 0.202 0.197 0.194 0.192
Triple or low-e glass 0.226 0.214 0.207 0.200 0.196 0.194 0.192
Aluminum with Thermal
Breakc
Single glass pane, stone, or
metal panel
0.211 0.186 0.173 0.162 0.155 0.151 0.149
Double glass with no low-e
coatings
0.200 0.180 0.170 0.160 0.154 0.151 0.148
Triple or low-e glass 0.191 0.176 0.167 0.159 0.153 0.150 0.148
Structural Glazingd Single glass pane, stone, or
metal panel
0.195 0.163 0.147 0.132 0.123 0.118 0.114
Double glass with no low-e
coatings
0.180 0.156 0.142 0.129 0.122 0.117 0.114
Triple or low-e glass 0.169 0.150 0.138 0.127 0.121 0.116 0.113
No framing or Insulation is
Continuouse
Single glass pane, stone, or
metal panel
0.148 0.102 0.078 0.056 0.044 0.036 0.031
Double glass with no low-e
coatings
0.136 0.097 0.075 0.054 0.043 0.035 0.030
Triple or low-e glass 0.129 0.093 0.073 0.053 0.042 0.035 0.030
  1. Opaque assembly U-factors based on designs tested in accordance with ASTM C1363 or NFRC 100 shall be permitted. Interpolation outside of the table shall not be permitted. Spandrel panel assemblies in the table do not include metal backpans.
  2. Aluminum frame without a thermal break shall be used for systems where the mullion provides a thermal bridge through the insulation.
  3. Aluminum frame with a thermal break shall be used for systems where a urethane or other nonmetallic element separates the metal exposed to the exterior from the metal that is exposed to the interior condition.
  4. Structural glazing frame type shall be used for systems that have no exposed mullion on the interior.
  5. No framing or insulation that is continuous shall be used for systems where there is no framing or the insulation is continuous and uninterrupted between framing.

When the total area of penetrations from through-the-wall mechanical equipment or equipment listed in Table C403.3.2(3) exceeds 1 percent of the opaque above-grade wall area, the mechanical equipment penetration area shall be calculated as a separate wall assembly with a default U-factor of 0.5.

Exception: Where mechanical equipment has been tested in accordance with testing standards approved by the department, the mechanical equipment penetration area may be calculated as a separate wall assembly with the U-factor as determined by such test.

Building envelope values and fenestration areas determined in accordance with Equation 4-2 shall be an alternative to compliance with the U-, F- and C-factors in Tables C402.1.4 and C402.4 and the maximum allowable fenestration areas in Section C402.4.1. Fenestration shall meet the applicable SHGC requirements of Section C402.4.3.


(Equation 4-2)

where:

A = Sum of the (UA Dif) values for each distinct assembly type of the building thermal envelope, other than slabs on grade and below-grade walls.

UA Dif = UA Proposed - UA Table.

UA Proposed = Proposed U-value × Area.

UA Table = (U-factor from Table C402.1.3, C402.1.4 or C402.4 × Area.

B = Sum of the (FL Dif) values for each distinct slab-on-grade perimeter condition of the building thermal envelope.

FL Dif = FL Proposed - FL Table.

FL Proposed = Proposed F-value × Perimeter length.

FL Table = (F-factor specified in Table C402.1.4) × Perimeter length.

C = Sum of the (CA Dif) values for each distinct below-grade wall assembly type of the building thermal envelope.

CA Dif = CA Proposed - CA Table.

CA Proposed = Proposed C-value × Area.

CA Table = (Maximum allowable C-factor specified in Table C402.1.4) × Area.

Where the proposed vertical glazing area is less than or equal to the maximum vertical glazing area allowed by Section C402.4.1, the value of D (Excess Vertical Glazing Value) shall be zero. Otherwise:

D = (DA × UV) - (DA × U Wall), but not less than zero.

DA = (Proposed Vertical Glazing Area) - (Vertical Glazing Area allowed by Section C402.4.1).

UA Wall = Sum of the (UA Proposed) values for each opaque assembly of the exterior wall.

U Wall = Area-weighted average U-value of all above-grade wall assemblies.

UAV = Sum of the (UA Proposed) values for each vertical glazing assembly.

UV = UAV/total vertical glazing area.

Where the proposed skylight area is less than or equal to the skylight area allowed by Section C402.4.1, the value of E (Excess Skylight Value) shall be zero. Otherwise:

E = (EA × US) - (EA × U Roof), but not less than zero.

EA = (Proposed Skylight Area) - (Allowable Skylight Area as specified in Section C402.4.1).

U Roof = Area-weighted average U-value of all roof assemblies.

UAS = Sum of the (UA Proposed) values for each skylight assembly.

US = UAS/total skylight area.

The minimum thermal resistance (R-value) of the insulating material installed either between the roof framing or continuously on the roof assembly shall be as specified in Table C402.1.3, based on construction materials used in the roof assembly. Insulation installed on a suspended ceiling having removable ceiling tiles shall not be considered as part of the minimum thermal resistance of the roof insulation. Continuous insulation board shall be installed in not less than 2 layers and the edge joints between each layer of insulation shall be staggered.

Exceptions:

  1. Continuously insulated roof assemblies where the thickness of insulation varies 1 inch (25 mm) or less and where the area-weighted U-factor is equivalent to the same assembly with the R-value specified in Table C402.1.3.
  2. Where tapered insulation is used with insulation entirely above deck, the R-value where the insulation thickness varies 1 inch (25 mm) or less from the minimum thickness of tapered insulation shall comply with the R-value specified in Table C402.1.3.
  3. Two layers of insulation are not required where insulation tapers to the roof deck, such as at roof drains.
  4. The insulation thickness variation is not limited to 1 inch (25 mm) or less where an alternative compliance method is chosen by roof assembly U-Factor (Section C402.1.4) or component performance alternative (C402.1.5).

Skylight curbs shall be insulated to the level of roofs with insulation entirely above the deck or R-5, whichever is less.

Exception: Unit skylight curbs included as a component of a skylight listed and labeled in accordance with NFRC 100 shall not be required to be insulated.

The minimum thermal resistance (R-value) of materials installed in the wall cavity between framing members and continuously on the walls shall be as specified in Table C402.1.3, based on framing type and construction materials used in the wall assembly. The R-value of integral insulation installed in concrete masonry units shall not be used in determining compliance with Table C402.1.3 except as otherwise noted in the table. In determining compliance with Table C402.1.4, the use of the U-factor of concrete masonry units with integral insulation shall be permitted.

"Mass walls" where used as a component in the thermal envelope of a building shall comply with one of the following:

  1. Weigh not less than 35 pounds per square foot (171 kg/m2) of wall surface area.
  2. Weigh not less than 25 pounds per square foot (122 kg/m2) of wall surface area where the material weight is not more than 120 pcf (1900 kg/m3).
  3. Have a heat capacity exceeding 7 Btu/ft2 • °F (144 kJ/m2 • K).
  4. Have a heat capacity exceeding 5 Btu/ft2 • °F (103 kJ/m2 • K), where the material weight is not more than 120 pcf (1900 kg/m3).

The thermal properties (component R-values or assembly U-, C- or F-factors) of floor assemblies over outdoor air or unconditioned space shall be as specified in Table C402.1.3 or C402.1.4 based on the construction materials used in the floor assembly. Floor framing cavity insulation or structural slab insulation shall be installed to maintain permanent contact with the underside of the subfloor decking or structural slabs.

"Mass floors" where used as a component of the thermal envelope of a building shall provide one of the following weights:

  1. 35 pounds per square foot (171 kg/m2) of floor surface area.
  2. 25 pounds per square foot (122 kg/m2) of floor surface area where the material weight is not more than 120 pounds per cubic foot (1923 kg/m3).

Exceptions:

  1. The floor framing cavity insulation or structural slab insulation shall be permitted to be in contact with the top side of sheathing or continuous insulation installed on the bottom side of floor assemblies where combined with insulation that meets or exceeds the minimum R-value in Table C402.1.3 for "Metal framed" or "Wood framed and other" values for "Walls, Above Grade" and extends from the bottom to the top of all perimeter floor framing or floor assembly members.
  2. Insulation applied to the underside of concrete floor slabs shall be permitted an airspace of not more than 1 inch (25 mm) where it turns up and is in contact with the underside of the floor under walls associated with the building thermal envelope.

Where the slab on grade is in contact with the ground, the minimum thermal resistance (R-value) of the insulation around the perimeter of unheated or heated slab-on-grade floors designed in accordance with the R-value method of Section C402.1.3 shall be as specified in Table C402.1.3. The perimeter insulation shall be placed on the outside of the foundation or on the inside of the foundation wall. The perimeter insulation shall extend downward from the top of the slab for the minimum distance shown in the table or to the top of the footing, whichever is less, or downward to not less than the bottom of the slab and then horizontally to the interior or exterior for the total distance shown in the table. Insulation extending away from the building shall be protected by pavement or by not less than of 10 inches (254 mm) of soil.

Exception: Where the slab-on-grade floor is greater than 24 inches (61 mm) below the finished exterior grade, perimeter insulation is not required.

The C-factor for the below-grade exterior walls shall be in accordance with Table C402.1.4. The R-value of the insulating material installed continuously within or on the below-grade exterior walls of the building envelope shall be in accordance with Table C402.1.3. The C-factor or R-value required shall extend to a depth of not less than 10 feet (3048 mm) below the outside finished ground level, or to the level of the lowest floor of the conditioned space enclosed by the below-grade wall, whichever is less.

Radiant heating system panels, and their associated components that are installed in interior or exterior assemblies shall be insulated to an R-value of not less than R-3.5 on all surfaces not facing the space being heated. Radiant heating system panels that are installed in the building thermal envelope shall be separated from the exterior of the building or unconditioned or exempt spaces by not less than the R-value of insulation installed in the opaque assembly in which they are installed or the assembly shall comply with Section C402.1.4.

Exception: Heated slabs on grade insulated in accordance with Section C402.2.4.

Where the thermal properties of airspaces are used to comply with this code in accordance with Section C401.2, such airspaces shall be enclosed in an unventilated cavity constructed to minimize airflow into and out of the enclosed airspace. Airflow shall be deemed minimized where the enclosed airspace is located on the interior side of the continuous air barrier and is bounded on all sides by building components.

Exception: The thermal resistance of airspaces located on the exterior side of the continuous air barrier and adjacent to and behind the exterior wall-covering material shall be determined in accordance with ASTM C1363 modified with an airflow entering the bottom and exiting the top of the airspace at an air movement rate of not less than 70 mm/second.

New wood-burning fireplaces shall have tight-fitting flue dampers or doors, and outdoor combustion air as required by the fireplace construction provisions of the New York City Construction Codes, as applicable. Where using tight-fitting doors on factory-built fireplaces listed and labeled in accordance with UL 127, the doors shall be tested and listed for the fireplace.

In new construction, balconies and parapets that interrupt the building thermal envelope shall comply with one of the following:

  1. Shall be insulated with continuous insulation having a minimum thermal resistance equivalent to the continuous insulation component required in the adjacent wall assembly as listed in Table C402.1.3. Where more than one wall assembly is interrupted by an adjacent balcony, the higher thermal resistance shall be followed.
  2. Shall incorporate a minimum R-3 thermal break where the structural element penetrates the building thermal envelope.

Low-sloped roofs directly above cooled conditioned spaces in Climate Zones 1, 2 and 3 shall comply with one or more of the options in Table C402.3.

Exceptions: The following roofs and portions of roofs are exempt from the requirements of Table C402.3:

  1. Portions of the roof that include or are covered by the following:

    1. 1.1. Photovoltaic systems or components.
    2. 1.2. Solar air or water-heating systems or components.
    3. 1.3. Roof gardens or landscaped roofs.
    4. 1.4. Above-roof decks or walkways.
    5. 1.5. Skylights.
    6. 1.6. HVAC systems and components, and other opaque objects mounted above the roof.
  2. Portions of the roof shaded during the peak sun angle on the summer solstice by permanent features of the building or by permanent features of adjacent buildings.
  3. Portions of roofs that are ballasted with a minimum stone ballast of 17 pounds per square foot [74 kg/m2] or 23 psf [117 kg/m2] pavers.
  4. Roofs where not less than 75 percent of the roof area complies with one or more of the exceptions to this section.

TABLE C402.3

MINIMUM ROOF REFLECTANCE AND EMITTANCE OPTIONSa

Three-year-aged solar reflectance indexb of 55 and 3-year aged thermal emittancec of 0.75
Three-year-aged solar reflectance indexd of 64
  1. The use of area-weighted averages to comply with these requirements shall be permitted. Materials lacking 3-year-aged tested values for either solar reflectance or thermal emittance shall be assigned both a 3-year-aged solar reflectance in accordance with Section C402.3.1 and a 3-year-aged thermal emittance of 0.90.
  2. Aged solar reflectance tested in accordance with ASTM C1549, ASTM E903 or ASTM E1918 or CRRC-S100.
  3. Aged thermal emittance tested in accordance with ASTM C1371 or ASTM E408 or CRRC-S100.
  4. Solar reflectance index (SRI) shall be determined in accordance with ASTM E1980 using a convection coefficient of 2.1 Btu/h • ft2 •°F (12W/m2 • K). Calculation of aged SRI shall be based on aged tested values of solar reflectance and thermal emittance.

Where an aged solar reflectance required by Section C402.3 is not available, it shall be determined in accordance with Equation 4-3.


(Equation 4-3)

where:

Raged = The aged solar reflectance.

Rinitial = The initial solar reflectance determined in accordance with CRRC-S100.

Fenestration shall comply with Sections C402.4.1 through C402.4.5 and Table C402.4. Daylight responsive controls shall comply with this section and Section C405.2.3.1.

TABLE C402.4

BUILDING ENVELOPE FENESTRATION MAXIMUM U-FACTOR AND SHGC REQUIREMENTS

CLIMATE ZONE 4 EXCEPT MARINE
Vertical fenestration
Below 95'b 95' and aboveb
U-factora
Nonmetal framing (all) 0.28 0.28
Metal framing fixed 0.30 0.36
Metal framing operable 0.40 0.42
Curtainwall fixed 0.36 0.36
Entrance doors 0.77
SHGCC
PF < 0.2 0.36
0.2 ≤ PF < 0.5 0.43
PF ≥ 0.5 0.58
Skylights
U-factora 0.48
SHGCc 0.38

PF = Projection Factor.

  1. U-factor shall be rated in accordance with NFRC 100.
  2. Where any portion of the fenestration frame is installed at or above 95 feet (28 950 mm) above grade, the unit may meet the requirements for 95 feet (28 950 mm) and above.
  3. SHGC shall be rated in accordance with NFRC 200.
The vertical fenestration area, not including opaque doors and opaque spandrel panels, shall be not greater than 30 percent of the gross above-grade wall area. The skylight area shall be not greater than 3 percent of the gross roof area.

In Climate Zones 1 through 6, not more than 40 percent of the gross above-grade wall area shall be vertical fenestration, provided that all of the following requirements are met:

  1. In buildings not greater than two stories above grade, not less than 50 percent of the net floor area is within a daylight zone.
  2. In buildings three or more stories above grade, not less than 25 percent of the net floor area is within a daylight zone.
  3. Daylight responsive controls complying with Section C405.2.3.1 are installed in daylight zones.
  4. Visible transmittance (VT) of vertical fenestration is not less than 1.1 times solar heat gain coefficient (SHGC).

    Exception: Fenestration that is outside the scope of NFRC 200 is not required to comply with Item 4.

The skylight area shall be not more than 6 percent of the roof area provided that daylight responsive controls complying with Section C405.2.3.1 are installed in toplit zones.

In an enclosed space greater than 2,500 square feet (232 m2) in floor area, directly under a roof with not less than 75 percent of the ceiling area with a ceiling height greater than 15 feet (4572 mm), and used as an office, lobby, atrium, concourse, corridor, storage space, gymnasium/exercise center, convention center, automotive service area, space where manufacturing occurs, nonrefrigerated warehouse, retail store, distribution/sorting area, transportation depot or workshop, the total toplit daylight zone shall be not less than half the floor area and shall provide one of the following:

  1. A minimum skylight area to toplit daylight zone of not less than 3 percent where all skylights have a VT of not less than 0.40 as determined in accordance with Section C303.1.3.
  2. A minimum skylight effective aperture of not less than 1 percent, determined in accordance with Equation 4-4.


    (Equation 4-4)

    where:

    Skylight area = Total fenestration area of skylights.

    Skylight VT = Area weighted average visible transmittance of skylights.

    WF = Area weighted average well factor, where well factor is 0.9 if light well depth is less than 2 feet (610 mm), or 0.7 if light well depth is 2 feet (610 mm) or greater.

    Light well depth = Measure vertically from the underside of the lowest point of the skylight glazing to the ceiling plane under the skylight.

Exception: Skylights above daylight zones of enclosed spaces are not required in:

  1. Buildings in Climate Zones 6 through 8.
  2. Spaces where the designed general lighting power densities are less than 0.5 W/ft2 (5.4 W/m2).
  3. Areas where it is documented that existing structures or natural objects block direct beam sunlight on not less than half of the roof over the enclosed area for more than 1,500 daytime hours per year between 8 a.m. and 4 p.m.
  4. Spaces where the daylight zone under rooftop monitors is greater than 50 percent of the enclosed space floor area.
  5. Spaces where the total area minus the area of sidelight daylight zones is less than 2,500 square feet (232 m2), and where the lighting is controlled in accordance with Section C405.2.3.
Daylight responsive controls complying with Section C405.2.3.1 shall be provided to control all electric lights within toplit zones.

Skylights in office, storage, automotive service, manufacturing, nonrefrigerated warehouse, retail store and distribution/sorting area spaces shall have a glazing material or diffuser with a haze factor greater than 90 percent when tested in accordance with ASTM D1003.

Exception: Skylights designed and installed to exclude direct sunlight entering the occupied space by the use of fixed or automated baffles or the geometry of skylight and light well.

The maximum U-factor and solar heat gain coefficient (SHGC) for fenestration shall be as specified in Table C402.4.

The window projection factor shall be determined in accordance with Equation 4-5.


(Equation 4-5)

where:

PF= Projection factor (decimal).

A = Distance measured horizontally from the farthest continuous extremity of any overhang, eave or permanently attached shading device to the vertical surface of the glazing.

B = Distance measured vertically from the bottom of the glazing to the underside of the overhang, eave or permanently attached shading device.

Where different windows or glass doors have different PF values, they shall each be evaluated separately.

In Climate Zones 1 through 6, skylights shall be permitted a maximum SHGC of 0.60 where located above daylight zones provided with daylight responsive controls.
Where skylights are installed above daylight zones provided with daylight responsive controls, a maximum U-factor of 0.9 shall be permitted in Climate Zones 1 through 3 and a maximum U-factor of 0.75 shall be permitted in Climate Zones 4 through 8.

Where dynamic glazing is intended to satisfy the SHGC and VT requirements of Table C402.4, the ratio of the higher to lower labeled SHGC shall be greater than or equal to 2.4, and the dynamic glazing shall be automatically controlled to modulate the amount of solar gain into the space in multiple steps. Dynamic glazing shall be considered separately from other fenestration, and area-weighted averaging with other fenestration that is not dynamic glazing shall not be permitted.

Exception: Dynamic glazing is not required to comply with this section where both the lower and higher labeled SHGC already comply with the requirements of Table C402.4.

An area-weighted average shall be permitted to satisfy the U-factor requirements for each fenestration product category listed in Table C402.4. Individual fenestration products from different fenestration product categories listed in Table C402.4 shall not be combined in calculating area-weighted average U-factor.
Daylight zones referenced in Sections C402.4.1.1 through C402.4.3.2 shall comply with Sections C405.2.3.2 and C405.2.3.3, as applicable. Daylight zones shall include toplit zones and sidelit zones.
Opaque swinging doors shall comply with Table C402.1.4. Opaque nonswinging doors shall comply with Table C402.1.3. Opaque doors shall be considered as part of the gross area of above-grade walls that are part of the building thermal envelope. Other doors shall comply with the provisions of Section C402.4.3 for vertical fenestration.
The thermal envelope of buildings shall comply with Sections C402.5.1 through C402.5.8, or the building thermal envelope shall be tested in accordance with ASTM E 779 at a pressure differential of 0.3 inch water gauge (75 Pa) or an equivalent method approved by the building official and deemed to comply with the provisions of this section when the tested air leakage rate of the building thermal envelope is not greater than 0.40 cfm/ft2 (2.0 L/s • m2). Where compliance is based on such testing, the building shall also comply with Sections C402.5.5, C402.5.6 and C402.5.7.

A continuous air barrier shall be provided throughout the building thermal envelope. The air barriers shall be permitted to be located on the inside or outside of the building envelope, located within the assemblies composing the envelope, or any combination thereof. The air barrier shall comply with Sections C402.5.1.1 and C402.5.1.2.

Exception: Air barriers are not required in buildings located in Climate Zone 2B.

The continuous air barrier shall be constructed to comply with the following:

  1. The air barrier shall be continuous for all assemblies that are the thermal envelope of the building and across the joints and assemblies.
  2. Air barrier joints and seams shall be sealed, including sealing transitions in places and changes in materials. The joints and seals shall be securely installed in or on the joint for its entire length so as not to dislodge, loosen or otherwise impair its ability to resist positive and negative pressure from wind, stack effect and mechanical ventilation.
  3. Penetrations of the air barrier shall be caulked, gasketed or otherwise sealed in a manner compatible with the construction materials and location. Sealing shall allow for expansion, contraction and mechanical vibration. Joints and seams associated with penetrations shall be sealed in the same manner or taped. Sealing materials shall be securely installed around the penetration so as not to dislodge, loosen or otherwise impair the penetrations' ability to resist positive and negative pressure from wind, stack effect and mechanical ventilation. Sealing of concealed fire sprinklers, where required, shall be in a manner that is recommended by the manufacturer. Caulking or other adhesive sealants shall not be used to fill voids between fire sprinkler cover plates and walls or ceilings.
  4. Recessed lighting fixtures shall comply with Section C402.5.8. Where similar objects are installed that penetrate the air barrier, provisions shall be made to maintain the integrity of the air barrier.

Materials with an air permeability not greater than 0.004 cfm/ft2 (0.02 L/s • m2) under a pressure differential of 0.3 inch water gauge (75 Pa) when tested in accordance with ASTM E2178 shall comply with this section. Materials in Items 1 through 16 shall be deemed to comply with this section, provided that joints are sealed and materials are installed as air barriers in accordance with the manufacturer's instructions.

  1. Plywood with a thickness of not less than 3/8 inch (10 mm).
  2. Oriented strand board having a thickness of not less than 3/8 inch (10 mm).
  3. Extruded polystyrene insulation board having a thickness of not less than 1/2 inch (12.7 mm).
  4. Foil-back polyisocyanurate insulation board having a thickness of not less than 1/2 inch (12.7 mm).
  5. Closed-cell spray foam having a minimum density of 1.5 pcf (2.4 kg/m3) and having a thickness of not less than 11/2 inches (38 mm).
  6. Open-cell spray foam with a density between 0.4 and 1.5 pcf (0.6 and 2.4 kg/m3) and having a thickness of not less than 4.5 inches (113 mm).
  7. Exterior or interior gypsum board having a thickness of not less than 1/2 inch (12.7 mm).
  8. Cement board having a thickness of not less than 1/2 inch (12.7 mm).
  9. Built-up roofing membrane.
  10. Modified bituminous roof membrane.
  11. Fully adhered single-ply roof membrane.
  12. A Portland cement/sand parge, or gypsum plaster having a thickness of not less than 5/8 inch (15.9 mm).
  13. Cast-in-place and precast concrete.
  14. Fully grouted concrete block masonry.
  15. Sheet steel or aluminum.

Assemblies of materials and components with an average air leakage not greater than 0.04 cfm/ft2 (0.2 L/s • m2) under a pressure differential of 0.3 inch of water gauge (w.g.)(75 Pa) when tested in accordance with ASTM E2357, ASTM E1677 or ASTM E283 shall comply with this section. Assemblies listed in Items 1 through 3 shall be deemed to comply, provided that joints are sealed and the requirements of Section C402.5.1.1 are met.

  1. Concrete masonry walls coated with either one application of block filler or two applications of a paint or sealer coating.
  2. Masonry walls constructed of clay or shale masonry units with a nominal width of 4 inches (102 mm) or more.
  3. A Portland cement/sand parge, stucco or plaster not less than 1/2 inch (12.7 mm) in thickness.

New buildings and additions of a certain size must comply with the following requirements and the rules of the department:

  1. New buildings and additions 10,000 square feet (929 m2) and greater, but less than 50,000 square feet (4 645.2 m2), and less than or equal to 75 feet (22.86 m) in height must show compliance through testing in accordance with ASTM E779 or other approved standards. R-2 buildings may alternatively show compliance through testing in accordance with Section R402.4.1.3 of this code.
  2. New buildings and additions 10,000 square feet (929 m2) and greater, but less than 50,000 square feet (4 645.2 m2), and greater than 75 feet (22.86 m) in height, shall test or inspect each type of unique air barrier joint or seam in the building envelope for continuity and defects, as per an Air Barrier Continuity Plan developed by a registered design professional. Alternatively, such buildings and additions may show compliance through testing in accordance with Item 1 of this section.
  3. New buildings and additions 50,000 square feet (4 645.2) and greater shall test or inspect each type of unique air barrier joint or seam in the building envelope for continuity and defects, as per an Air Barrier Continuity Plan developed by a registered design professional. Alternatively, such buildings and additions may show compliance through testing in accordance with Item 1 of this section.

The air leakage of fenestration assemblies shall meet the provisions of Table C402.5.2. Testing shall be in accordance with the applicable reference test standard in Table C402.5.2 by an accredited, independent testing laboratory and labeled by the manufacturer.

Exceptions:

  1. Field-fabricated fenestration assemblies that are sealed in accordance with Section C402.5.1.
  2. Fenestration in buildings that comply with the testing alternative of Section C402.5 are not required to meet the air leakage requirements in Table C402.5.2.

TABLE C402.5.2

MAXIMUM AIR LEAKAGE RATE FOR FENESTRATION ASSEMBLIES

FENESTRATION ASSEMBLY MAXIMUM
RATE (CFM/FT2)
TEST PROCEDURE
Windows 0.20 a AAMA/WDMA/CSA101/I.S.2/A440
or
NFRC 400
Sliding doors 0.20 a
Swinging doors 0.20 a
Skylights — with condensation
weepage openings
0.30
Skylights — all other 0.20 a
Curtain walls 0.06 NFRC 400
or
ASTM E283 at 1.57 psf
(75 Pa)
Storefront glazing 0.06
Commercial glazed 1.00
Power-operated sliding
doors and power
operated folding doors
1.00
Revolving doors 1.00
Garage doors 0.40 ANSI/DASMA 105,
NFRC 400, or
ASTM E283 at 1.57 psf
(75 Pa)
Rolling doors 1.00
High-speed doors 1.30

For SI: 1 cubic foot per minute = 0.47 L/s, 1 square foot = 0.093 m2.

  1. The maximum rate for windows, sliding and swinging doors, and skylights is permitted to be 0.3 cfm per square foot of fenestration or door area when tested in accordance with AAMA/WDMA/CSA101/I.S.2/A440 at 6.24 psf (300 Pa).

In Climate Zones 3 through 8, where combustion air is supplied through openings in an exterior wall to a room or space containing a space-conditioning fuel-burning appliance, one of the following shall apply:

  1. The room or space containing the appliance shall be located outside of the building thermal envelope.
  2. The room or space containing the appliance shall be enclosed and isolated from conditioned spaces inside the building thermal envelope. Such rooms shall comply with all of the following:

    1. 2.1. The walls, floors and ceilings that separate the enclosed room or space from conditioned spaces shall be insulated to be not less than equivalent to the insulation requirement of below-grade walls as specified in Table C402.1.3 or C402.1.4.
    2. 2.2. The walls, floors and ceilings that separate the enclosed room or space from conditioned spaces shall be sealed in accordance with Section C402.5.1.1.
    3. 2.3. The doors into the enclosed room or space shall be fully gasketed.
    4. 2.4. Water lines and ducts in the enclosed room or space shall be insulated in accordance with Section C403.
    5. 2.5. Where an air duct supplying combustion air to the enclosed room or space passes through conditioned space, the duct shall be insulated to an R-value of not less than R-8.

Exception: Fireplaces and stoves complying with the New York City Mechanical Code, and the fireplace fire-blocking requirements of the New York City Building Code.

Doors and access openings from conditioned space to shafts, chutes stairways and elevator lobbies not within the scope of the fenestration assemblies covered by Section C402.5.2 shall be gasketed, weatherstripped or sealed.

Exceptions:

  1. Door openings required to comply with the duct and air transfer opening requirements of the New York City Building Code.
  2. Doors and door openings required to comply with UL 1784 by the New York City Building Code.
Stairway enclosures, elevator shaft vents and other outdoor air intakes and exhaust openings integral to the building envelope shall be provided with dampers in accordance with Section C403.7.7.
Cargo door openings and loading door openings shall be equipped with weatherseals that restrict infiltration and provide direct contact along the top and sides of vehicles that are parked in the doorway.

Building entrances shall be protected with an enclosed vestibule, with all doors opening into and out of the vestibule equipped with self-closing devices. Vestibules shall be designed so that in passing through the vestibule it is not necessary for the interior and exterior doors to open at the same time. The installation of one or more revolving doors in the building entrance shall not eliminate the requirement that a vestibule be provided on any doors adjacent to revolving doors.

Exceptions: Vestibules are not required for the following:

  1. Buildings in Climate Zones 1 and 2.
  2. Doors not intended to be used by the public, such as doors to mechanical or electrical equipment rooms, or intended solely for employee use.
  3. Doors opening directly from a sleeping unit or dwelling unit.
  4. Doors that open directly from a space less than 3,000 square feet (298 m2) in area, in buildings less than 75 feet (22.86 m) in height, and doors that open directly from a space less than 1,000 square feet (92.9 m2) in area, in buildings 75 feet (22.86 m) and greater in height.
  5. Revolving doors.
  6. Doors used primarily to facilitate vehicular movement or material handling and adjacent personnel doors.

Recessed luminaires installed in the building thermal envelope shall be all of the following:

  1. IC-rated.
  2. Labeled as having an air leakage rate of not more 2.0 cfm (0.944 L/s) when tested in accordance with ASTM E283 at a 1.57 psf (75 Pa) pressure differential.
  3. Sealed with a gasket or caulk between the housing and interior wall or ceiling covering.

Applications for construction document approval shall include the following documentation of thermal bridges:

TABLE C402.6

AVERAGE THERMAL TRANSMITTANCE FOR UNMITIGATED LINEAR THERMAL BRIDGES

TYPE OF THERMAL BRIDGE Ψ-VALUEa
[Btu/hr • ft • °F]
Balcony 0.50
Floor Slab 0.44
Fenestration Perimeter Transitionb 0.32
Parapet 0.42
Shelf Angle 0.41
  1. Psi-values are derived from the BC Hydro Building Envelope Thermal Bridging Guide Version. 1.2—September 2018, and are based on poor performing details.
  2. Fenestration Perimeter Transition is the thermal bridge between any fenestration frame and the typical wall, roof or floor assembly it abuts or is mounted within.
Where otherwise not included in pre-calculated assembly U-factors, C-factors, or F-factors outlined in Appendix A of ASHRAE 90.1-2016 (as amended), as set forth in Appendix CA of this code, clear field thermal bridges in a wall, roof, or floor assembly shall be noted as such in the drawings.
Point thermal bridges greater than or equal in area to 12 in2 (7744 mm2) and not associated with HVAC or electrical systems shall be noted as thermal bridges in the drawings.

Construction documents shall include the following documentation in tabular format for linear thermal bridges listed in Table C402.6:

  1. Linear thermal bridge type.
  2. Aggregate length of each type of linear thermal bridge.
  3. Relevant detail in the construction documents showing a cross-section through the thermal bridge.
  4. Ψ-value for each thermal bridge from Table C402.6.

Exception: Where linear thermal bridges have been tested or modeled using methods approved by the department, alternate values may be used.

Mechanical systems and equipment serving the building heating, cooling, ventilating or refrigerating needs shall comply with this section.
Design loads associated with heating, ventilating and air conditioning of the building shall be determined in accordance with ANSI/ASHRAE/ACCA Standard 183 or by an approved equivalent computational procedure using the design parameters specified in Chapter C3. Heating and cooling loads shall be adjusted to account for load reductions that are achieved where energy recovery systems are utilized in the HVAC system in accordance with the ASHRAE HVAC Systems and Equipment Handbook by an approved equivalent computational procedure.
Mechanical systems shall be designed to comply with Sections C403.2.1 and C403.2.2. Where elements of a building's mechanical systems are addressed in Sections C403.3 through C403.12, such elements shall comply with the applicable provisions of those sections.

HVAC systems serving zones that are over 25,000 square feet (2323 m2) in floor area or that span more than one floor and are designed to operate or be occupied nonsimultaneously shall be divided into isolation areas. Each isolation area shall be equipped with isolation devices and controls configured to automatically shut off the supply of conditioned air and outdoor air to and exhaust air from the isolation area. Each isolation area shall be controlled independently by a device meeting the requirements of Section C403.4.2.2. Central systems and plants shall be provided with controls and devices that will allow system and equipment operation for any length of time while serving only the smallest isolation area served by the system or plant.

Exceptions:

  1. Exhaust air and outdoor air connections to isolation areas where the fan system to which they connect is not greater than 5,000 cfm (2360 L/s).
  2. Exhaust airflow from a single isolation area of less than 10 percent of the design airflow of the exhaust system to which it connects.
  3. Isolation areas intended to operate continuously or intended to be inoperative only when all other isolation areas in a zone are inoperative.
Ventilation, either natural or mechanical, shall be provided in accordance with Chapter 4 of the New York City Mechanical Code. Where mechanical ventilation is provided, the system shall provide the capability to reduce the outdoor air supply to the minimum required by Chapter 4 of the New York city Mechanical Code.
Heating and cooling equipment installed in mechanical systems shall be sized in accordance with Section C403.3.1 and shall be not less efficient in the use of energy than as specified in Section C403.3.2.

The output capacity of heating and cooling equipment shall be not greater than that of the smallest available equipment size that exceeds the loads calculated in accordance with Section C403.1.1. A single piece of equipment providing both heating and cooling shall satisfy this provision for one function with the capacity for the other function as small as possible, within available equipment options.

Exceptions:

  1. Required standby equipment and systems provided with controls and devices that allow such systems or equipment to operate automatically only when the primary equipment is not operating.
  2. Multiple units of the same equipment type with combined capacities exceeding the design load and provided with controls that are configured to sequence the operation of each unit based on load.

Equipment shall meet the minimum efficiency requirements of Tables C403.3.2(1) through C403.3.2(8) and Tables C403.3.2(10) through C403.3.2(14) when tested and rated in accordance with the applicable test procedure. Plate-type liquid-to-liquid heat exchangers shall meet the minimum requirements of Table C403.3.2(9). The efficiency shall be verified through certification under an approved certification program or, where a certification program does not exist, the equipment efficiency ratings shall be supported by data furnished by the manufacturer. Where multiple rating conditions or performance requirements are provided, the equipment shall satisfy all stated requirements. Where components, such as indoor or outdoor coils, from different manufacturers are used, calculations and supporting data shall be furnished by the designer that demonstrates that the combined efficiency of the specified components meets the requirements herein.

TABLE C403.3.2(1)

MINIMUM EFFICIENCY REQUIREMENTS: ELECTRICALLY OPERATED UNITARY AIR CONDITIONERS AND CONDENSING UNITS

EQUIPMENT TYPE SIZE CATEGORY HEATING
SECTION TYPE
SUBCATEGORY OR
RATING CONDITION
MINIMUM TEST
PROCEDUREa
Air conditioners, air cooled < 65,000 Btu/hb All Split System,
three phase
13.0 SEER AHRI 210/240
Single Package,
three phase
14.0 SEER
Through-the-wall (air cooled) ≤ 30,000 Btu/hb All Split system,
three phase
12.0 SEER
Single Package,
three phase
12.0 SEER
Small-duct high-velocity
(air cooled)
< 65,000 Btu/hb All Split System,
three phase
11.0 SEER
Air conditioners, air cooled ≥ 65,000 Btu/h and
< 135,000 Btu/h
Electric Resistance
(or None)
Split System and
Single Package
11.2 EER
12.9 IEER
AHRI 340/360
All other Split System and
Single Package
11.0 EER
12.7 IEER
≥ 135,000 Btu/h and
< 240,000 Btu/h
Electric Resistance
(or None)
Split System and
Single Package
11.0 EER
12.4 IEER
All other Split System and
Single Package
10.8 EER
12.2 IEER
≥ 240,000 Btu/h and
< 760,000 Btu/h
Electric Resistance
(or None)
Split System and
Single Package
10.0 EER
11.6 IEER
All other Split System and
Single Package
9.8 EER
11.4 IEER
≥ 760,000 Btu/h Electric Resistance
(or None)
Split System and
Single Package
9.7 EER
11.2 IEER
All other Split System and
Single Package
9.5 EER
11.0 IEER
Air conditioners, water cooled < 65,000 Btu/hb All Split System and
Single Package
12.1 EER
12.3 IEER
AHRI 210/240
≥ 65,000 Btu/h and
< 135,000 Btu/h
Electric Resistance
(or None)
Split System and
Single Package
12.1 EER
13.9 IEER
AHRI 340/360
All other Split System and
Single Package
11.9 EER
13.7 IEER
≥ 135,000 Btu/h and
< 240,000 Btu/h
Electric Resistance
(or None)
Split System and
Single Package
12.5 EER
13.9 IEER
All other Split System and
Single Package
12.3 EER
13.7 IEER
≥ 240,000 Btu/h and
< 760,000 Btu/h
Electric Resistance
(or None)
Split System and
Single Package
12.4 EER
13.6 IEER
All other Split System and
Single Package
12.2 EER
13.4 IEER
≥ 760,000 Btu/h Electric Resistance
(or None)
Split System and
Single Package
12.2 EER
13.5 IEER
All other Split System and
Single Package
12.0 EER
13.3 IEER
Air conditioners,
evaporatively cooled
< 65,000 Btu/hb All Split System and
Single Package
12.1 EER
12.3 IEER
AHRI 210/240
≥ 65,000 Btu/h and
< 135,000 Btu/h
Electric Resistance
(or None)
Split System and
Single Package
12.1 EER
12.3 IEER
AHRI 340/360
All other Split System and
Single Package
11.9 EER
12.1 IEER
≥ 135,000 Btu/h and
< 240,000 Btu/h
Electric Resistance
(or None)
Split System and
Single Package
12.0 EER
12.2 IEER
All other Split System and
Single Package
11.8 EER
12.0 IEER
≥ 240,000 Btu/h and
< 760,000 Btu/h
Electric Resistance
(or None)
Split System and
Single Package
11.9 EER
12.1 IEER
All other Split System and
Single Package
11.7 EER
11.9 IEER
≥ 760,000 Btu/h Electric Resistance
(or None)
Split System and
Single Package
11.7 EER
11.9 IEER
All other Split System and
Single Package
11.5 EER
11.7 IEER
Condensing units, air cooled ≥ 135,000 Btu/h 10.5 EER
11.8 IEER
AHRI 365
Condensing units, water cooled ≥ 135,000 Btu/h 13.5 EER
14.0 IEER
Condensing units,
evaporatively cooled
≥ 135,000 Btu/h 13.5 EER
14.0 IEER

For SI: 1 British thermal unit per hour = 0.2931 W.

  1. Chapter C6 contains a complete specification of the referenced test procedure, including the reference year version of the test procedure.
  2. Single-phase, air-cooled air conditioners less than 65,000 Btu/h are regulated by the U.S. Department of Energy Code of Federal Regulations 10 CFR 430. SEER values for single-phase products are set by the U.S. Department of Energy.
  3. See ASHRAE 90.1—2016 Informative Appendix F for the U.S. Department of Energy minimum efficiency requirements of single-phase air conditioner

TABLE C403.3.2(2)

MINIMUM EFFICIENCY REQUIREMENTS: ELECTRICALLY OPERATED UNITARY AND APPLIED HEAT PUMPS

EQUIPMENT TYPE SIZE CATEGORY HEATING
SECTION TYPE
SUBCATEGORY OR
RATING CONDITION
MINIMUM TEST
PROCEDUREa
Air cooled (cooling mode) < 65,000 Btu/hb All Split System,
three phase
14.0 SEER AHRI 210/240
Single Package,
three phase
14.0 SEER
Through-the-wall, air cooled
(cooling mode)
≤ 30,000 Btu/hb All Split System,
three phase
12.0 SEER
Single Package,
three phase
12.0 SEER
Single-duct, high-velocity, air cooled < 65,000 Btu/hb All Split System,
three phase
11.0 SEER
Air cooled (cooling mode) ≥ 65,000 Btu/h and
< 135,000 Btu/h
Electric Resistance
(or None)
Split System and
Single Package
11.0 EER
12.2 IEER
AHRI 340/360
All other Split System and
Single Package
10.8 EER
12.0 IEER
≥ 135,000 Btu/h and
< 240,000 Btu/h
Electric Resistance
(or None)
Split System and
Single Package
10.6 EER
11.6 IEER
All other Split System and
Single Package
10.4 EER
11.4 IEER
≥ 240,000 Btu/h Electric Resistance
(or None)
Split System and
Single Package
9.5 EER
10.6 IEER
All other Split System and
Single Package
9.3 EER
10.4 IEER
Water to Air, Water Loop
(cooling mode)
< 17,000 Btu/h All 86°F entering water 12.2 EER ISO 13256-1
≥ 17,000 Btu/h and
< 65,000 Btu/h
All 86°F entering water 13.0 EER
≥ 65,000 Btu/h and
< 135,000 Btu/h
All 86°F entering water 13.0 EER
Water to Air, Ground Water
(cooling mode)
< 135,000 Btu/h All 59°F entering water 18.0 EER ISO 13256-1
Brine to Air, Ground Loop
(cooling mode)
< 135,000 Btu/h All 77°F entering fluid 14.1 EER ISO 13256-1
Water to Water, Water Loop
(cooling mode)
< 135,000 Btu/h All 86°F entering water 10.6 EER ISO 13256-2
Water to Water, Ground Water
(cooling mode)
< 135,000 Btu/h All 59°F entering water 16.3 EER
Brine to Water: Ground Loop
(cooling mode)
< 135,000 Btu/h All 77°F entering fluid 12.1 EER
Air cooled (heating mode) < 65,000 Btu/hb
(cooling capacity)
Split System,
three phase
8.2 HSPF AHRI 210/240
Single Package,
three phase
8.0 HSPF
Through-the-wall, air cooled,
(heating mode)
≤ 30,000 Btu/hb (cooling capacity) Split System,
three phase
7.4 HSPF
Single Package,
three phase
7.4 HSPF
Small-duct, high velocity,
air cooled, (heating mode)
< 65,000 Btu/hb Split System,
three phase
6.8 HSPF
Air cooled (heating mode) ≥ 65,000 Btu/h and
< 135,000 Btu/h
(cooling capacity)
47°F db/43°F wb 3.3 COPH AHRI 340/360
17°Fdb/15°F wb 2.25 COPH
≥ 135,000 Btu/h
(cooling capacity)
47°F db/43°F wb 3.2 COPH
17°Fdb/15°F wb 2.05 COPH
Water to Air, Water Loop
(heating mode)
< 135,000 Btu/h
(cooling capacity)
68°F entering water 4.3 COPH ISO 13256-1
Water to Air, Ground Water
(heating mode)
< 135,000 Btu/h
(cooling capacity)
50°F entering water 3.7 COPH
Brine to Air, Ground Loop
(heating mode)
< 135,000 Btu/h
(cooling capacity)
32°F entering fluid 3.2 COPH
Water to Water, Water Loop
(heating mode)
< 135,000 Btu/h
(cooling capacity)
68°F entering water 3.7 COPH ISO 13256-2
Water to Water, Ground Water
(heating mode)
< 135,000 Btu/h
(cooling capacity)
50°F entering water 3.1 COPH
Brine to Water, Ground Loop
(heating mode)
< 135,000 Btu/h
(cooling capacity)
32°F entering fluid 2.5 COPH

For SI: 1 British thermal unit per hour = 0.2931 W, °C = [(°F) - 32]/1.8.

  1. Chapter C6 contains a complete specification of the referenced test procedure, including the reference year version of the test procedure.
  2. Single-phase, air-cooled heat pumps less than 65,000 Btu/h are regulated by the U.S. Department of Energy Code of Federal Regulations 10 CFR 430. SEER and HSPF values for single-phase products are set by the U.S. Department of Energy.
  3. See ASHRAE 90.1—2016 Informative Appendix F for the U.S. Department of Energy minimum efficiency requirements of single-phase air conditioners.

TABLE C403.3.2(3)

MINIMUM EFFICIENCY REQUIREMENTS: ELECTRICALLY OPERATED PACKAGED TERMINAL AIR CONDITIONERS, PACKAGED TERMINAL HEAT PUMPS, SINGLE-PACKAGE VERTICAL AIR CONDITIONERS, SINGLE-PACKAGE VERTICAL HEAT PUMPS, ROOM AIR CONDITIONERS AND ROOM AIR-CONDITIONER HEAT PUMPS

EQUIPMENT TYPE SIZE CATEGORY (INPUT) SUBCATEGORY OR
RATING CONDITION
MINIMUM EFFICIENCY TEST
PROCEDUREa
PTAC (cooling mode)
standard size
All Capacities 95°F db outdoor air 14.0 — (0.300 × Cap/1000)c EER AHRI 310/380
PTAC (cooling mode)
nonstandard sizeb
All Capacities 95°F db outdoor air 10.9 - (0.213 × Cap/1000)c EER
PTHP (cooling mode)
standard size
All Capacities 95°F db outdoor air 14.0 - (0.300 × Cap/1000)c EER
PTHP (cooling mode)
nonstandard sizeb
All Capacities 95°F db outdoor air 10.8 - (0.213 × Cap/1000)c EER
PTHP (heating mode)
standard size
All Capacities 3.7 - (0.052 × Cap/1000)c COPH
PTHP (heating mode)
nonstandard sizeb
All Capacities 2.9 - (0.026 × Cap/1000)c COPH
SPVAC (cooling mode) < 65,000 Btu/h 95°F db/ 75°F wb outdoor air 11.0 EER AHRI 390
≥ 65,000 Btu/h and
< 135,000 Btu/h
95°F db/ 75°F wb outdoor air 10.0 EER
≥ 135,000 Btu/h and
< 240,000 Btu/h
95°F db/ 75°F wb outdoor air 10.0 EER
SPVHP (cooling mode) < 65,000 Btu/h 95°F db/ 75°F wb outdoor air 11.0 EER
≥ 65,000 Btu/h and
< 135,000 Btu/h
95°F db/ 75°F wb outdoor air 10.0 EER
≥ 135,000 Btu/h and
< 240,000 Btu/h
95°F db/ 75°F wb outdoor air 10.0 EER
SPVHP (heating mode) < 65,000 Btu/h 47°F db/ 43°F wb outdoor air 3.3 COPH AHRI 390
≥ 65,000 Btu/h and
< 135,000 Btu/h
47°F db/ 43°F wb outdoor air 3.0 COPH
≥ 135,000 Btu/h and
< 240,000 Btu/h
47°F db/ 43°F wb outdoor air 3.0 COPH
SPVAC (cooling mode),
nonweatherized space
constrained
≤ 30,000 Btu/h 95°F db/ 75°F wb outdoor air 9.2 EER AHRI 390
> 30,000 Btu/h and
≤ 36,000 Btu/h
9.0 EER
SPVHP (cooling mode),
nonweatherized space
constrained
≤ 30,000 Btu/h 95°F db/ 75°F wb outdoor air 9.2 EER
> 30,000 Btu/h and
≤ 36,000 Btu/
9.0 EER
SPVHP (heating mode),
nonweatherized space
constrained
≤ 30,000 Btu/h 47°F db/ 43°F wb outdoor air 3.0 COPH
> 30,000 Btu/h and
≤ 36,000 Btu/h
3.0 COPH
Room air conditioners,
without reverse cycle,
with louvered sides
< 6,000 Btu/h 11.0 CEER 109 CFR Part 430, Subpart B, Appendix F
≥ 6,000 Btu/h and
< 8,000 Btu/h
11.0 CEER
≥ 8,000 Btu/h and
< 14,000 Btu/h
10.9 CEER
≥ 14,000 Btu/h and
< 20,000 Btu/h
10.7 CEER
≥ 20,000 Btu/h and
≤ 28,000 Btu/h
9.4 CEER
> 28,000 Btu/h 9.0 CEER
Room air conditioners,
without reverse cycle,
without louvered sides
< 6,000 Btu/h 10.0 CEER 10 CFR Part 430, Subpart B, Appendix F
≥ 6,000 Btu/h and
< 8,000 Btu/h
10.0 CEER
≥ 8,000 Btu/h and
< 11,000 Btu/h
9.6 CEER
≥ 11,000 Btu/h and
< 14,000 Btu/h
9.5 CEER
≥ 14,000 Btu/h and
< 20,000 Btu/h
9.3 CEER
≥ 20,000 Btu/h 9.4 CEER
Room air-conditioners,
with reverse cycle,
with louvered sides
< 20,000 Btu/h 9.8 CEER
≥ 20,000 Btu/h 9.3 CEER
Room air-conditioners,
with reverse cycle,
without louvered sides
< 14,000 Btu/h 9.3 CEER
≥ 14,000 Btu/h 8.7 CEER
Room air conditioner, casement only All capacities 9.5 CEER 10 CFR Part 430, Subpart B, Appendix F
Room air conditioner, casement-slider All capacities 10.4 CEER

For SI: 1 British thermal unit per hour = 0.2931 W, °C = [(°F) - 32]/1.8, wb = wet bulb, db = dry bulb.

  1. Chapter C6 contains a complete specification of the referenced test procedure, including the referenced year version of the test procedure.
  2. Nonstandard size units must be factory labeled as follows: "MANUFACTURED FOR NONSTANDARD SIZE APPLICATIONS ONLY: NOT TO BE INSTALLED IN NEW STANDARD PROJECTS." Nonstandard size efficiencies apply only to units being installed in existing sleeves having an external wall opening of less than 16 inches (406 mm) high or less than 42 inches (1067 mm) wide and having a cross-sectional area less than 670 in2.
  3. "Cap" means the rated cooling 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 calculations.

TABLE C403.3.2(4)

WARM-AIR FURNACES AND COMBINATION WARM-AIR FURNACES/AIR-CONDITIONING UNITS, WARM-AIR DUCT FURNACES AND UNIT HEATERS, MINIMUM EFFICIENCY REQUIREMENTS

EQUIPMENT TYPE SIZE CATEGORY
(INPUT)
SUBCATEGORY OR
RATING CONDITION
MINIMUM TEST PROCEDUREa
Warm-air furnaces,
gas fired
< 225,000 Btu/h Maximum capacityc 80% AFUE or
80%Etb, d
DOE 10 CFR Part 430 or
Section 2.39
Thermal Efficiency,
ANSI Z21.47
≥ 225,000 Btu/h 80%Etd Section 2.39,
Thermal Efficiency,
ANSI Z21.47
Warm-air furnaces,
oil fired
< 225,000 Btu/h Maximum capacityc 83% AFUE or
80%Etb, d
DOE 10 CFR Part 430 or
Section 42, Combustion,
UL 727
≥ 225,000 Btu/h 81%Etd Section 42, Combustion,
UL 727
Warm-air duct furnaces,
gas fired
All capacities Maximum capacityc 80%Ece Section 2.10, Efficiency,
ANSI Z83.8
Warm-air unit heaters,
gas fired
All capacities Maximum capacityc 80%Ece, f Section 2.10, Efficiency,
ANSI Z83.8
Warm-air unit heaters,
oil fired
All capacities Maximum capacityc 80%Ece, f Section 40, Combustion,
UL 731

For SI: 1 British thermal unit per hour = 0.2931 W.

  1. Chapter C6 contains a complete specification of the referenced test procedure, including the referenced year version of the test procedure.
  2. Combination units not covered by the U.S. Department of Energy Code of Federal Regulations 10 CFR 430 (three-phase power or cooling capacity greater than or equal to 65,000 Btu/h) may comply with either rating.
  3. Compliance of multiple firing rate units shall be at the maximum firing rate.
  4. Et = thermal efficiency. Units must also include an interrupted or intermittent ignition device (IID), have jacket losses not exceeding 0.75 percent of the input rating, and have either power venting or a flue damper. A vent damper is an acceptable alternative to a flue damper for those furnaces where combustion air is drawn from the conditioned space.
  5. Ec = combustion efficiency (100 percent less flue losses). See test procedure for detailed discussion.
  6. As of August 8, 2008, according to the Energy Policy Act of 2005, units must also include an interrupted or intermittent ignition device (IID) and have either power venting or an automatic flue damper.

TABLE C403.3.2(5)

MINIMUM EFFICIENCY REQUIREMENTS: GAS- AND OIL-FIRED BOILERS

EQUIPMENT TYPEa SUBCATEGORY OR
RATING CONDITION
SIZE CATEGORY (INPUT) MINIMUM EFFICIENCYb, c TEST PROCEDURE
Boilers, hot water Gas-fired < 300,000 Btu/hf, g 82% AFUE 10 CFR Part 430
≥ 300,000 Btu/h and
≤ 2,500,000 Btu/hd
80% Et 10 CFR Part 431
> 2,500,000 Btu/ha 82% Ec
Oil-firede < 300,000 Btu/hg 84% AFUE 10 CFR Part 430
≥ 300,000 Btu/h and
≤ 2,500,000 Btu/hd
82% Et 10 CFR Part 431
> 2,500,000 Btu/ha 84% Ec
Boilers, steam Gas-fired < 300,000 Btu/hf 80% AFUE 10 CFR Part 430
Gas-fired- all, except natural draft ≥ 300,000 Btu/h and
≤ 2,500,000 Btu/hd
79% Et 10 CFR Part 431
> 2,500,000 Btu/ha 79% Et
Gas-fired-natural draft ≥ 300,000 Btu/h and
≤ 2,500,000 Btu/hd
77% Et
79% Et
(as of 3/2/2020)
> 2,500,000 Btu/ha 77% Et
79% Et
(as of 3/2/2020)
Oil-firede < 300,000 Btu/h 82% AFUE 10 CFR Part 430
≥ 300,000 Btu/h and
≤ 2,500,000 Btu/hd
81% Et 10 CFR Part 431
> 2,500,000 Btu/ha 81% Et

For SI: 1 British thermal unit per hour = 0.2931 W.

  1. These requirements apply to boilers with rated input of 8,000,000 Btu/h or less that are not packaged boilers and to all packaged boilers. Minimum efficiency requirements for boilers cover all capacities of packaged boilers.
  2. Ec = combustion efficiency (100 percent less flue losses). See reference document for detailed information.
  3. Et = thermal efficiency. See reference document for detailed information.
  4. Maximum capacity-minimum and maximum ratings as provided for and allowed by the unit's controls.
  5. Includes oil-fired (residual).
  6. Boilers shall not be equipped with a constant burning pilot light.
  7. A boiler not equipped with a tankless domestic water-heating coil shall be equipped with an automatic means for adjusting the temperature of the water such that an incremental change in inferred heat load produces a corresponding incremental change in the temperature of the water supplied.


TABLE C403.3.2(6)

WATER CHILLING PACKAGES — EFFICIENCY REQUIREMENTSa, b, d

EQUIPMENT TYPE SIZE CATEGORY UNITS PATH A PATH B TEST
PROCEDUREc
Air-cooled chillers < 150 Tons EER
(Btu/W)
≥ 10.100 FL ≥ 9.700 FL AHRI 550/590
≥ 13.700 IPLV ≥ 15.800 IPLV
≥ 150 Tons ≥ 10.100 FL ≥ 9.700 FL
≥ 14.000 IPLV ≥ 16.100 IPLV
Air cooled without
condenser,
electrically operated
All capacities EER
(Btu/W)
Air-cooled chillers without condenser shall be rated with
matching condensers and complying with air-cooled chiller
efficiency requirements.
Water cooled,
electrically operated
positive displacement
< 75 Tons kW/ton ≤ 0.750 FL ≤ 0.780 FL
≤ 0.600 IPLV ≤ 0.500 IPLV
≥ 75 tons and < 150 tons ≤ 0.720 FL ≤ 0.750 FL
≤ 0.560 IPLV ≤ 0.490 IPLV
≥ 150 tons and < 300 tons ≥ 0.660 FL ≥ 0.680 FL
≥ 0.540 IPLV ≥ 0.440 IPLV
≥ 300 tons and < 600 tons ≤ 0.610 FL ≤ 0.625 FL
≤ 0.520 IPLV ≤ 0.410 IPLV
≥ 600 tons ≤ 0.560 FL ≤ 0.585 FL
≤ 0.500 IPLV ≤ 0.380 IPLV
Water cooled,
electrically operated
centrifugal
< 150 Tons kW/ton ≤ 0.610 FL ≤ 0.695 FL
≤ 0.550 IPLV ≤ 0.440 IPLV
≥ 150 tons and < 300 tons ≤ 0.610 FL ≤ 0.635 FL
≤ 0.550 IPLV ≤ 0.400 IPLV
≥ 300 tons and < 400 tons ≤ 0.560 FL ≤ 0.595 FL
≤ 0.520 IPLV ≤ 0.390 IPLV
≥ 400 tons and < 600 tons ≤ 0.560 FL ≤ 0.585 FL
≤ 0.500 IPLV ≤ 0.380 IPLV
≥ 600 Tons ≤ 0.560 FL ≤ 0.585 FL
≤ 0.500 IPLV ≤ 0.380 IPLV
Air cooled, absorption,
single effect
All capacities COP ≥ 0.600 FL NAc AHRI 560
Water cooled
absorption, single
effect
All capacities COP ≥ 0.700 FL NAc
Absorption, double
effect, indirect fired
All capacities COP ≥ 1.000 FL NAc
≥ 1.050 IPLV
Absorption double effect
direct fired
All capacities COP ≥ 1.000 FL NAc
≥ 1.050 IPLV
  1. The requirements for centrifugal chiller shall be adjusted for nonstandard rating conditions in accordance with Section C403.3.2.1 and are only applicable for the range of conditions listed in Section C403.3.2.1. The requirements for air-cooled, water-cooled positive displacement and absorption chillers are at standard rating conditions defined in the reference test procedure.
  2. Both the full-load and IPLV requirements shall be met or exceeded to comply with this standard. Where there is a Path B, compliance can be with either Path A or Path B for any application.
  3. NA means the requirements are not applicable for Path B and only Path A can be used for compliance.
  4. FL represents the full-load performance requirements and IPLV the part-load performance requirements.

TABLE C403.3.2(7)

MINIMUM EFFICIENCY REQUIREMENTS: HEAT REJECTION EQUIPMENT

EQUIPMENT TYPE TOTAL SYSTEM HEAT
REJECTION
CAPACITY AT RATED
CONDITIONS
SUBCATEGORY OR RATING CONDITIONi PERFORMANCE
REQUIREDa, b, c, d, g, h
TEST PROCEDUREe, f
Propeller or axial fan
open-circuit cooling
towers
All 95°F entering water
85°F leaving water
75°F entering wb
≥ 40.2 gpm/hp CTI ATC-105 and
CTI STD-201 RS
Centrifugal fan
open-circuit cooling
towers
All 95°F entering water
85°F leaving water
75°F entering wb
≥ 20.0 gpm/hp CTI ATC-105 and
CTI STD-201 RS
Propeller or axial fan
closed-circuit cooling
towers
All 102°F entering water
90°F leaving water
75°F entering wb
≥ 16.1 gpm/hp CTI ATC-105S and
CTI STD-201 RS
Centrifugal fan
closed- circuit cooling
towers
All 102°F entering water
90°F leaving water
75°F entering wb
≥ 7.0 gpm/hp CTI ATC-105S and
CTI STD-201 RS
Propeller or axial fan
evaporative condensers
All Ammonia Test Fluid
140°F entering gas temperature
96.3°F condensing temperature
75°F entering wb
≥ 134,000 Btu/h × hp CTI ATC-106
Centrifugal fan
evaporative condensers
All Ammonia Test Fluid
140°F entering gas temperature
96.3°F condensing temperature
75°F entering wb
≥110,000 Btu/h × hp CTI ATC-106
Propeller or axial fan
evaporative condensers
All R-507A Test Fluid
165°F entering gas temperature
105°F condensing temperature
75°F entering wb
≥ 157,000 Btu/h × hp CTI ATC-106
Centrifugal fan
evaporative condensers
All R-507A Test Fluid
165°F entering gas temperature
105°F condensing temperature
75°F entering wb
≥ 135,000 Btu/h × hp CTI ATC-106
Air-cooled condensers All 125°F Condensing Temperature
190°F Entering Gas Temperature
15°F subcooling
95°F entering db
≥ 176,000 Btu/h × hp AHRI 460

For SI: °C = [(°F) - 32]/1.8, L/s • kW = (gpm/hp)/(11.83), COP = (Btu/h • hp)/(2550.7),

db = dry bulb temperature, °F, wb = wet bulb temperature, °F.

  1. The efficiencies and test procedures for both open- and closed-circuit cooling towers are not applicable to hybrid cooling towers that contain a combination of wet and dry heat exchange sections.
  2. For purposes of this table, open circuit cooling tower performance is defined as the water flow rating of the tower at the thermal rating condition, divided by the fan nameplate-rated motor power.
  3. For purposes of this table, closed-circuit cooling tower performance is defined as the process water flow rating of the tower at the thermal rating condition, divided by the sum of the fan motor nameplate power and the integral spray pump motor nameplate power.
  4. For purposes of this table, air-cooled condenser performance is defined as the heat rejected from the refrigerant divided by the fan motor nameplate power.
  5. Chapter C6 contains a complete specification of the referenced test procedure, including the referenced year version of the test procedure. The certification requirements do not apply to field-erected cooling towers.
  6. Where a certification program exists for a covered product and it includes provisions for verification and challenge of equipment efficiency ratings, then the product shall be listed in the certification program; or, where a certification program exists for a covered product, and it includes provisions for verification and challenge of equipment efficiency ratings, but the product is not listed in the existing certification program, the ratings shall be verified by an independent laboratory test report.
  7. Cooling towers shall comply with the minimum efficiency listed in the table for that specific type of tower with the capacity effect of any project-specific accessories and/or options included in the capacity of the cooling tower.
  8. For purposes of this table, evaporative condenser performance is defined as the heat rejected at the specified rating condition in the table divided by the sum of the fan motor nameplate power and the integral spray pump nameplate power.
  9. Requirements for evaporative condensers are listed with ammonia (R-717) and R-507A as test fluids in the table. Evaporative condensers intended for use with halocarbon refrigerants other than R-507A shall meet the minimum efficiency requirements listed in this table with R-507A as the test fluid.

TABLE C403.3.2(8)

MINIMUM EFFICIENCY AIR CONDITIONERS AND CONDENSING UNITS SERVING COMPUTER ROOMS

EQUIPMENT TYPE NET SENSIBLE COOLING CAPACITYa MINIMUM SCOP-127b EFFICIENCY
DOWNFLOW UNITS / UPFLOW UNITS
TEST PROCEDURE
Air conditioners, air cooled < 65,000 Btu/h 2.20 / 2.09 ANSI/ASHRAE 127
≥ 65,000 Btu/h and < 240,000 Btu/h 2.10 / 1.99
≥ 240,000 Btu/h 1.90 / 1.79
Air conditioners, water cooled < 65,000 Btu/h 2.60 / 2.49
≥ 65,000 Btu/h and < 240,000 Btu/h 2.50 / 2.39
≥ 240,000 Btu/h 2.40 / 2.29
Air conditioners, water cooled with < 65,000 Btu/h 2.55 / 2.44
≥ 65,000 Btu/h and < 240,000 Btu/h 2.45 / 2.34
≥ 240,000 Btu/h 2.35 / 2.24
Air conditioners, glycol cooled
(rated at 40% propylene glycol)
< 65,000 Btu/h 2.50 / 2.39
≥ 65,000 Btu/h and < 240,000 Btu/h 2.15 / 2.04
≥ 240,000 Btu/h 2.10 / 1.99
Air conditioners, glycol cooled
(rated at 40% propylene glycol)
with fluid economizer
< 65,000 Btu/h 2.45 / 2.34
≥ 65,000 Btu/h and < 240,000 Btu/h 2.10 / 1.99
≥ 240,000 Btu/h 2.05 / 1.94

For SI: 1 British thermal unit per hour = 0.2931 W.

  1. Net sensible cooling capacity: the total gross cooling capacity less the latent cooling less the energy to the air movement system. (Total Gross — latent — Fan Power).
  2. Sensible coefficient of performance (SCOP-127): a ratio calculated by dividing the net sensible cooling capacity in watts by the total power input in watts (excluding reheaters and humidifiers) at conditions defined in ASHRAE Standard 127. The net sensible cooling capacity is the gross sensible capacity minus the energy dissipated into the cooled space by the fan system.

TABLE C403.3.2(9)

HEAT TRANSFER EQUIPMENT

EQUIPMENT TYPE SUBCATEGORY MINIMUM EFFICIENCY TEST PROCEDUREa
Liquid-to-liquid heat exchangers Plate type NR AHRI 400

NR = No Requirement.

  1. Chapter C6 contains a complete specification of the referenced test procedure, including the referenced year version of the test procedure.

TABLE C403.3.2(10)

MINIMUM EFFICIENCY REQUIREMENTS: ELECTRICALLY OPERATED VARIABLE-REFRIGERANT-FLOW AIR CONDITIONERS

EQUIPMENT TYPE SIZE CATEGORY HEATING
SECTION TYPE
SUBCATEGORY OR
RATING CONDITION
MINIMUM EFFICIENCY TEST PROCEDURE
VRF air conditioners,
air cooled
< 65,000 Btu/h All VRF multisplit 13.0 SEER AHRI 1230
≥ 65,000 Btu/h and
< 135,000 Btu/h
Electric resistance
(or none)
VRF multisplit 11.2 SEER
15.5 IEER
≥ 135,000 Btu/h and
< 240,000 Btu/h
Electric resistance
(or none)
VRF multisplit 11.0 EER
14.9 IEER
≥ 240,000 Btu/h Electric resistance
(or none)
VRF multisplit 10.0 EER
13.9 IEER

TABLE C403.3.2(11)

MINIMUM EFFICIENCY REQUIREMENTS: ELECTRICALLY OPERATED VARIABLE-REFRIGERANT-FLOW AIR-TO-AIR AND APPLIED HEAT PUMPS

EQUIPMENT TYPE SIZE CATEGORY HEATING
SECTION TYPE
SUBCATEGORY OR
RATING CONDITION
MINIMUM EFFICIENCY TEST PROCEDURE
VRF air cooled
(cooling mode)
< 65,000 Btu/h All VRF multisplit system 13.0 SEER AHRI 1230
≥ 65,000 Btu/h and
< 135,000 Btu/h
Electric resistance
(or none)
VRF multisplit system 11.0 EER
14.6 IEER
≥ 65,000 Btu/h and
< 135,000 Btu/h
Electric resistance
(or none)
VRF multisplit system
with heat recovery
10.8 EER
14.4 IEER
≥ 135,000 Btu/h and
< 240,000 Btu/h
Electric resistance
(or none)
VRF multisplit system 10.6 EER
13.9 IEER
≥ 135,000 Btu/h and
< 240,000 Btu/h
Electric resistance
(or none)
VRF multisplit system
with heat recovery
10.4 EER
13.7 IEER
≥ 240,000 Btu/h Electric resistance
(or none)
VRF multisplit system 9.5 EER
12.7 IEER
≥ 240,000 Btu/h Electric resistance
(or none)
VRF multisplit system
with heat recovery
9.3 EER
12.5 IEER
VRF water source
(cooling mode)
< 65,000 Btu/h All VRF multisplit systems
86°F entering water
12.0 EER
16 IEER
AHRI 1230
< 65,000 Btu/h All VRF multisplit systems
with heat recovery
86°F entering water
11.8 EER
15.8 IEER
≥ 65,000 Btu/h and
< 135,000
All VRF multisplit systems
86°F entering water
12.0 EER
16.0 IEER
≥ 65,000 Btu/h and
< 135,000
All VRF multisplit systems
with heat recovery
86°F entering water
11.8 EER
15.8 IEER
≥ 135,000 Btu/h and
< 240,000 Btu/h
All VRF multisplit systems
86°F entering water
10.0 EER
14.0 IEER
≥ 135,000 Btu/h and
< 240,000 Btu/h
All VRF multisplit systems
with heat recovery
86°F entering water
9.8 EER
13.8 IEER
≥ 240,000 Btu/h All VRF multisplit systems
86°F entering water
10.0 EER
12.0 IEER
≥ 240,000 Btu/h All VRF multisplit systems
with heat recovery
86°F entering water
9.8 EER
11.8 IEER
VRF ground source
(cooling mode)
< 135,000 Btu/h All VRF multisplit system
59°F entering water
16.2 EER AHRI 1230
< 135,000 Btu/h All VRF multisplit system
with heat recovery
59°F entering water
16.0 EER
≥ 135,000 Btu/h All VRF multisplit system
59°F entering water
13.8 EER
≥ 135,000 Btu/h All VRF multisplit system
with heat recovery
59°F entering water
13.6 EER
< 135,000 Btu/h All VRF multisplit system
77°F entering water
13.4 EER
< 135,000 Btu/h All VRF multisplit system
with heat recovery
77°F entering water
13.2 EER
≥ 135,000 Btu/h All VRF multisplit system
77°F entering water
11.0 EER
≥ 135,000 Btu/h All VRF multisplit system
with heat recovery
77°F entering water
10.8 EER
VRF air cooled
(heating mode
< 65,000 Btu/h
(cooling capacity)
VRF multisplit system 7.7 HSPF AHRI 1230
≥ 65,000 Btu/h and
< 135,000 Btu/h
(cooling capacity)
VRF multisplit system
47°F db/43°F wb
outdoor air
3.3 COPH
17°F db/15°F wb 2.25 COPH
≥ 135,000 Btu/h
(cooling capacity)
VRF multisplit system
47°F db/43°F wb
outdoor air
3.2 COPH
17°F db/15°F wb 2.05 COPH
VRF water source
(heating mode)
< 65,000 Btu/h
(cooling capacity)
VRF multisplit system
68°F entering water
4.3 COPH AHRI 1230
≥ 65,000 Btu/h and
< 135,000 Btu/h
(cooling capacity)
VRF multisplit system
68°F entering water
4.3 COPH
≥ 135,000 Btu/h and
< 240,000 Btu/h
(cooling capacity)
VRF multisplit system
68°F entering water
4.0 COPH
≥ 240,000 Btu/h
(cooling capacity)
VRF multisplit system
68°F entering water
3.9 COPH
VRF groundwater
source (heating
mode)
< 135,000 Btu/h
(cooling capacity)
VRF multisplit system
50°F entering water
3.6 COPH AHRI 1230
≥ 135,000 Btu/h
(cooling capacity)
VRF multisplit system
50°F entering water
3.3 COPH
VRF ground source
(heating mode)
< 135,000 Btu/h
(cooling capacity)
VRF multisplit system
32°F entering water
3.1 COPH AHRI 1230
VRF ground source
(heating mode)
≥ 135,000 Btu/h
(cooling capacity)
VRF multisplit system
32°F entering water
2.8 COPH AHRI 1230

TABLE C403.3.2(12)

VAPOR COMPRESSION BASED INDOOR POOL DEHUMIDIFIERS—MINIMUM EFFICIENCY REQUIREMENTS

EQUIPMENT TYPE SUBCATEGORY
OR RATING CONDITION
MINIMUM EFFICIENCY TEST PROCEDURE
Single package indoora
(with or without economizer)
Rating Conditions: A, B, or C 3.5 MRE AHRI 910
Single package indoor water-cooled
(with or without economizer)
3.5 MRE
Single package indoor air-cooled
(with or without economizer)
3.5 MRE
Split system indoor air-cooled
(with or without economizer)
3.5 MRE
  1. Units without air-cooled condenser.

TABLE C403.3.2(13)

ELECTRICALLY OPERATED DX-DOAS UNITS, SINGLE-PACKAGE AND REMOTE CONDENSER, WITHOUT ENERGY RECOVERY—MINIMUM EFFICIENCY REQUIREMENTS

EQUIPMENT TYPE SUBCATEGORY
OR RATING CONDITION
MINIMUM EFFICIENCY TEST PROCEDURE
Air cooled
(dehumidification mode)
4.0 ISMRE AHRI 920
Air source heat pumps
(dehumidification mode)
4.0 ISMRE AHRI 920
Water cooled
(dehumidification mode)
Cooling tower condenser water 4.9 ISMRE AHRI 920
Chilled Water 6.0 ISMRE
Air source heat pump
(heating mode)
2.7 ISCOP AHRI 920
Water source heat pump
(dehumidification mode)
Ground source, closed loop 4.8 ISMRE AHRI 920
Ground-water source 5.0 ISMRE
Water source 4.0 ISMRE
Water source heat pump
(heating mode)
Ground source, closed loop 2.0 ISCOP AHRI 920
Ground-water source 3.2 ISCOP
Water source 3.5 ISCOP

TABLE C403.3.2(14)

ELECTRICALLY OPERATED DX-DOAS UNITS, SINGLE-PACKAGE AND REMOTE CONDENSER, WITH ENERGY RECOVERY— MINIMUM EFFICIENCY REQUIREMENTS

EQUIPMENT TYPE SUBCATEGORY
OR RATING CONDITION
MINIMUM EFFICIENCY TEST PROCEDURE
Air cooled
(dehumidification mode)
5.2 ISMRE AHRI 920
Air source heat pumps
(dehumidification mode)
5.2 ISMRE AHRI 920
Water cooled
(dehumidification mode)
Cooling tower condenser water 5.3 ISMRE AHRI 920
Chilled Water 6.6 ISMRE
Air source heat pump
(heating mode)
3.3 ISCOP AHRI 920
Water source heat pump
(dehumidification mode)
Ground source, closed loop 5.2 ISMRE AHRI 920
Ground-water source 5.8 ISMRE
Water source 4.8 ISMRE
Water source heat pump
(heating mode)
Ground source, closed loop 3.8 ISCOP AHRI 920
Ground-water source 4.0 ISCOP
Water source 4.8 ISCOP

Equipment not designed for operation at AHRI Standard 550/590 test conditions of 44°F (7°C) leaving chilled-water temperature and 2.4 gpm/ton evaporator fluid flow and 85°F (29°C) entering condenser water temperature with 3 gpm/ton (0.054 I/s • kW) condenser water flow shall have maximum full-load kW/ton (FL) and part-load ratings requirements adjusted using Equations 4-6 and 4-7.


(Equation 4-6)

(Equation 4-7)

where:

Kadj = A × B

FL = Full-load kW/ton value as specified in Table C403.3.2(6).

FLadj = Maximum full-load kW/ton rating, adjusted for nonstandard conditions.

IPLV = Value as specified in Table C403.3.2(6).

PLVadj = Maximum NPLV rating, adjusted for nonstandard conditions.

A = 0.00000014592 × (LIFT)4 — 0.0000346496 × (LIFT)3 + 0.00314196 × (LIFT)2 — 0.147199 × (LIFT) + 3.9302

B = 0.0015 × LvgEvap + 0.934

LIFT = LvgCondLvgEvap

LvgCond = Full-load condenser leaving fluid temperature (°F).

LvgEvap = Full-load evaporator leaving temperature (°F).

The FLadj and PLVadj values are only applicable for centrifugal chillers meeting all of the following full-load design ranges:

  1. Minimum evaporator leaving temperature: 36°F.
  2. Maximum condenser leaving temperature: 115°F.
  3. 20°F ≤ LIFT ≤ 80°F.
Equipment with a leaving fluid temperature higher than 32°F (0°C) and water-cooled positive displacement chilling packages with a condenser leaving fluid temperature below 115°F (46°C) shall meet the requirements of Table C403.3.2(6) when tested or certified with water at standard rating conditions, in accordance with the referenced test procedure.

Cooling systems shall not use hot gas bypass or other evaporator pressure control systems unless the system is designed with multiple steps of unloading or continuous capacity modulation. The capacity of the hot gas bypass shall be limited as indicated in Table C403.3.3, as limited by Section C403.5.1.

TABLE C403.3.3

MAXIMUM HOT GAS BYPASS CAPACITY

RATED CAPACITY MAXIMUM HOT GAS BYPASS CAPACITY
(% of total capacity)
≤ 240,000 Btu/h 50
> 240,000 Btu/h 25

For SI: 1 British thermal unit per hour = 0.2931 W.

Boiler systems with design input of greater than 1,000,000 Btu/h (293 kW) shall comply with the turndown ratio specified in Table C403.3.4.

The system turndown requirement shall be met through the use of multiple single-input boilers, one or more modulating boilers or a combination of single-input and modulating boilers.

TABLE C403.3.4

BOILER TURNDOWN

BOILER SYSTEM DESIGN INPUT (Btu/h) MINIMUM
TURNDOWN
RATIO
≥ 1,000,000 and less than or equal to 5,000,000 3 to 1
> 5,000,000 and less than or equal to 10,000,000 4 to 1
> 10,000,000 5 to 1

For SI: 1 British thermal unit per hour = 0.2931 W.

New buildings where space heating is served by one or more gas hot water boilers with a minimum thermal efficiency (Et) of 90 percent when rated in accordance with the test procedures in Table C403.3.2(5) shall comply with this section, unless otherwise approved by the authority having jurisdiction. The hot water distribution system shall be designed so that the coils and other heat exchangers are selected such that at outdoor design conditions, the hot water return temperature entering the boilers is 120°F (49°C) or less when the boiler is firing.
Each heating and cooling system shall be provided with controls in accordance with Sections C403.4.1 through C403.4.5.

The supply of heating and cooling energy to each zone shall be controlled by individual thermostatic controls capable of responding to temperature within the zone. Where humidification or dehumidification or both is provided, not fewer than one humidity control device shall be provided for each humidity control system.

Exception: Independent perimeter systems that are designed to offset only building envelope heat losses, gains or both serving one or more perimeter zones also served by an interior system provided that both of the following conditions are met:

  1. The perimeter system includes not fewer than one thermostatic control zone for each building exposure having exterior walls facing only one orientation (within ± 45 degrees) (0.8 rad) for more than 50 contiguous feet (15 240 mm).
  2. The perimeter system heating and cooling supply is controlled by thermostats located within the zones served by the system.
Heat pumps having supplementary electric resistance heat shall have controls that, except during defrost, prevent supplementary heat operation where the heat pump can provide the heating load.

Where used to control both heating and cooling, zone thermostatic controls shall be configured to provide a temperature range or deadband of not less than 5°F (2.8°C) within which the supply of heating and cooling energy to the zone is shut off or reduced to a minimum.

Exceptions:

  1. Thermostats requiring manual changeover between heating and cooling modes.
  2. Occupancies or applications requiring precision in indoor temperature control as approved by the building official.
Where a zone has a separate heating and a separate cooling thermostatic control located within the zone, a limit switch, mechanical stop or direct digital control system with software programming shall be configured to prevent the heating setpoint from exceeding the cooling setpoint and to maintain a deadband in accordance with Section C403.4.1.2.

The heating system for heated vestibules and air curtains with integral heating shall be provided with controls configured to shut off the source of heating when the outdoor air temperature is greater than 45°F (7°C). Vestibule heating and cooling systems shall be controlled by a thermostat located in the vestibule configured to limit heating to a temperature not greater than 60°F (16°C) and cooling to a temperature not less than 85°F (29°C).

Exception: Control of heating or cooling provided by site-recovered energy or transfer air that would otherwise be exhausted.

Hot water boilers that supply heat to the building through one- or two-pipe heating systems shall have an outdoor setback control that lowers the boiler water temperature based on the outdoor temperature.

Each zone shall be provided with thermostatic setback controls that are controlled by either an automatic time clock or programmable control system.

Exceptions:

  1. Zones that will be operated continuously.
  2. Zones with a full HVAC load demand not exceeding 6,800 Btu/h (2 kW) and having a manual shutoff switch located with ready access.
Thermostatic setback controls shall be configured to set back or temporarily operate the system to maintain zone temperatures down to 55°F (13°C) or up to 85°F (29°C).
Automatic time clock or programmable controls shall be capable of starting and stopping the system for seven different daily schedules per week and retaining their programming and time setting during a loss of power for not fewer than 10 hours. Additionally, the controls shall have a manual override that allows temporary operation of the system for up to 2 hours; a manually operated timer configured to operate the system for up to 2 hours; or an occupancy sensor.
Automatic start controls shall be provided for each HVAC system. The controls shall be configured to automatically adjust the daily start time of the HVAC system in order to bring each space to the desired occupied temperature immediately prior to scheduled occupancy.
The heating of fluids that have been previously mechanically cooled and the cooling of fluids that have been previously mechanically heated shall be limited in accordance with Sections C403.4.3.1 through C403.4.3.3. Hydronic heating systems comprised of multiple-packaged boilers and designed to deliver conditioned water or steam into a common distribution system shall include automatic controls configured to sequence operation of the boilers. Hydronic heating systems composed of a single boiler and greater than 500,000 Btu/h (146.5 kW) input design capacity shall include either a multistaged or modulating burner.
Hydronic systems that use a common return system for both hot water and chilled water are prohibited.
Systems that use a common distribution system to supply both heated and chilled water shall be designed to allow a deadband between changeover from one mode to the other of not less than 15°F (8.3°C) outside air temperatures; be designed to and provided with controls that will allow operation in one mode for not less than 4 hours before changing over to the other mode; and be provided with controls that allow heating and cooling supply temperatures at the changeover point to be not more than 30°F (16.7°C) apart.
Hydronic heat pump systems shall comply with Sections C403.4.3.3.1 through C403.4.3.3.3.

Hydronic heat pumps connected to a common heat pump water loop with central devices for heat rejection and heat addition shall have controls that are configured to provide a heat pump water supply temperature deadband of not less than 20°F (11°C) between initiation of heat rejection and heat addition by the central devices.

Exception: Where a system loop temperature optimization controller is installed and can determine the most efficient operating temperature based on real-time conditions of demand and capacity, deadbands of less than 20°F (11°C) shall be permitted.

The following shall apply to hydronic water loop heat pump systems in Climate Zones 3 through 8:

  1. Where a closed-circuit cooling tower is used directly in the heat pump loop, either an automatic valve shall be installed to bypass the flow of water around the closed-circuit cooling tower, except for any flow necessary for freeze protection, or low-leakage positive-closure dampers shall be provided.
  2. Where an open-circuit cooling tower is used directly in the heat pump loop, an automatic valve shall be installed to bypass all heat pump water flow around the open-circuit cooling tower.
  3. Where an open-circuit cooling tower is used in conjunction with a separate heat exchanger to isolate the open-circuit cooling tower from the heat pump loop, heat loss shall be controlled by shutting down the circulation pump on the cooling tower loop.

Exception: Where it can be demonstrated that a heat pump system will be required to reject heat throughout the year.

Each hydronic heat pump on the hydronic system having a total pump system power exceeding 10 hp (7.5 kW) shall have a two-position valve.

Hydronic systems greater than or equal to 300,000 Btu/h (87.9 kW) in design output capacity supplying heated or chilled water to comfort conditioning systems shall include controls that are configured to do all of the following:

  1. Automatically reset the supply-water temperatures in response to varying building heating and cooling demand using coil valve position, zone-return water temperature, building-return water temperature or outside air temperature. The temperature shall be reset by not less than 25 percent of the design supply-to-return water temperature difference.
  2. Automatically vary fluid flow for hydronic systems with a combined pump motor capacity of 2 hp (1.5 kW) or larger with three or more control valves or other devices by reducing the system design flow rate by not less than 50 percent or the maximum reduction allowed by the equipment manufacturer for proper operation of equipment by valves that modulate or step open and close, or pumps that modulate or turn on and off as a function of load.
  3. Automatically vary pump flow on heating-water systems, chilled-water systems and heat rejection loops serving water-cooled unitary air conditioners as follows:

    1. 3.1. Where pumps operate continuously or operate based on a time schedule, pumps with nominal output motor power of 2 hp or more shall have a variable speed drive.
    2. 3.2. Where pumps have automatic direct digital control configured to operate pumps only when zone heating or cooling is required, a variable speed drive shall be provided for pumps with motors having the same or greater nominal output power indicated in Table C403.4.4 based on the climate zone and system served.
  4. Where a variable speed drive is required by Item 3 of this Section, pump motor power input shall be not more than 30 percent of design wattage at 50 percent of the design water flow. Pump flow shall be controlled to maintain one control valve nearly wide open or to satisfy the minimum differential pressure.

Exceptions:

  1. Supply-water temperature reset is not required for chilled-water systems supplied by off-site district chilled water or chilled water from ice storage systems.
  2. Variable pump flow is not required on dedicated coil circulation pumps where needed for freeze protection.
  3. Variable pump flow is not required on dedicated equipment circulation pumps where configured in primary/secondary design to provide the minimum flow requirements of the equipment manufacturer for proper operation of equipment.
  4. Variable speed drives are not required on heating water pumps where more than 50 percent of annual heat is generated by an electric boiler.

TABLE C403.4.4

VARIABLE SPEED DRIVE (VSD) REQUIREMENTS FOR DEMAND-CONTROLLED PUMPS

CHILLED WATER AND HEAT REJECTION LOOP
PUMPS IN THESE CLIMATE ZONES
HEATING WATER PUMPS
IN THESE CLIMATE ZONES
VSD REQUIRED FOR MOTORS WITH
RATED OUTPUT OF:
4A ≥ 5 hp
5A, 6A 5A, 6A ≥ 7.5 hp
4A ≥ 10 hp

Chilled water plants including more than one chiller shall be capable of and configured to reduce flow automatically through the chiller plant when a chiller is shut down. Chillers piped in series for the purpose of increased temperature differential shall be considered as one chiller.

Boiler systems including more than one boiler shall be capable of and configured to reduce flow automatically through the boiler system when a boiler is shut down.

Economizers shall comply with Sections C403.5.1 through C403.5.5.

An air or water economizer shall be provided for the following cooling systems:

  1. Chilled water systems with a total cooling capacity, less cooling capacity provided with air economizers, as specified in Table C403.5(1).
  2. Individual fan systems with cooling capacity greater than or equal to 54,000 Btu/h (15.8 kW) serving other than Group R occupancies.

    The total supply capacity of all fan cooling units serving other than Group R occupancies not provided with economizers shall not exceed 20 percent of the total supply capacity of all fan cooling units serving other than Group R occupancies or 300,000 Btu/h (88 kW), whichever is greater.

  3. Individual fan systems with cooling capacity greater than or equal to 270,000 Btu/h (79.1 kW) serving Group R occupancies.

    The total supply capacity of all fan cooling units serving Group R occupancies not provided with economizers shall not exceed 20 percent of the total supply capacity of all fan cooling units serving Group R occupancies or 1,500,000 Btu/h (440 kW), whichever is greater.

Exceptions: Economizers are not required for the following systems.

  1. Individual fan systems not served by chilled water for buildings located in Climate Zones 1A and 1B.
  2. Where more than 25 percent of the air designed to be supplied by the system is to spaces that are designed to be humidified above 35°F (1.7°C) dew-point temperature to satisfy process needs.
  3. Systems expected to operate less than 20 hours per week.
  4. Systems serving supermarket areas with open refrigerated casework.
  5. Where the cooling efficiency is greater than or equal to the efficiency requirements in Table C403.5(2).
  6. Systems that include a heat recovery system in accordance with Section C403.9.5.

TABLE C403.5(1)

MINIMUM CHILLED-WATER SYSTEM COOLING CAPACITY FOR DETERMINING ECONOMIZER COOLING REQUIREMENTS

CLIMATE ZONES
(COOLING)
TOTAL CHILLED-WATER SYSTEM CAPACITY LESS CAPACITY OF COOLING UNITS WITH AIR ECONOMIZERS
Local Water-cooled Chilled-water Systems Air-cooled Chilled-water Systems or District Chilled-Water Systems
4A 720,000 Btu/h 940,000 Btu/h
5A, 6A 1,320,000 Btu/h 1,720,000 Btu/h

For SI: 1 British thermal unit per hour = 0.2931 W.

TABLE C403.5(2)

EQUIPMENT EFFICIENCY PERFORMANCE EXCEPTION FOR ECONOMIZERS

CLIMATE COOLING EQUIPMENT PERFORMANCE
IMPROVEMENT (EER OR IPLV)
4A 20% efficiency improvement

Economizer systems shall be integrated with the mechanical cooling system and be configured to provide partial cooling even where additional mechanical cooling is required to provide the remainder of the cooling load. Controls shall not be capable of creating a false load in the mechanical cooling systems by limiting or disabling the economizer or any other means, such as hot gas bypass, except at the lowest stage of mechanical cooling.

Units that include an air economizer shall comply with the following:

  1. Unit controls shall have the mechanical cooling capacity control interlocked with the air economizer controls such that the outdoor air damper is at the 100-percent open position when mechanical cooling is on and the outdoor air damper does not begin to close to prevent coil freezing due to minimum compressor run time until the leaving air temperature is less than 45°F (7°C).
  2. Direct expansion (DX) units that control 75,000 Btu/h (22 kW) or greater of rated capacity of the mechanical cooling directly based on occupied space temperature shall have not fewer than two stages of mechanical cooling capacity.
  3. Other DX units, including those that control space temperature by modulating the airflow to the space, shall be in accordance with Table C403.5.1.

TABLE C403.5.1

DX COOLING STAGE REQUIREMENTS FOR MODULATING AIRFLOW UNITS

RATING CAPACITY MINIMUM NUMBER MINIMUM
COMPRESSOR DISPLACEMENTa
≥ 65,000 Btu/h and < 240,000 Btu/h 3 stages ≤ 35% of full load
≥ 240,000 Btu/h 4 stages ≤ 25% full load

For SI: 1 British thermal unit per hour = 0.2931 W.

  1. For mechanical cooling stage control that does not use variable compressor displacement, the percent displacement shall be equivalent to the mechanical cooling capacity reduction evaluated at the full load rating conditions for the compressor.

HVAC system design and economizer controls shall be such that economizer operation does not increase building heating energy use during normal operation.

Exception: Economizers on variable air volume (VAV) systems that cause zone level heating to increase because of a reduction in supply air temperature.

Where economizers are required by Section C403.5, air economizers shall comply with Sections C403.5.3.1 through C403.5.3.5.
Air economizer systems shall be configured to modulate outdoor air and return air dampers to provide up to 100 percent of the design supply air quantity as outdoor air for cooling.

Economizer controls and dampers shall be configured to sequence the dampers with the mechanical cooling equipment and shall not be controlled by only mixed-air temperature.

Exception: The use of mixed-air temperature limit control shall be permitted for systems controlled from space temperature (such as single-zone systems).

Air economizers shall be configured to automatically reduce outdoor air intake to the design minimum outdoor air quantity when outdoor air intake will not reduce cooling energy usage. High-limit shutoff control types for specific climates shall be chosen from Table C403.5.3.3. High-limit shutoff control settings for these control types shall be those specified in Table C403.5.3.3.

TABLE C403.5.3.3

HIGH-LIMIT SHUTOFF CONTROL SETTING FOR AIR ECONOMIZERSb

DEVICE TYPE CLIMATE ZONE REQUIRED HIGH LIMIT
(ECONOMIZER OFF WHEN):
Equation Description
Fixed dry bulb 5A, 6A TOA > 70°F Outdoor air temperature exceeds 70°F
4A TOA > 65°F Outdoor air temperature exceeds 65°F
Differential dry bulb 5A, 6A TOA > TRA Outdoor air temperature exceeds
return air temperature
Fixed enthalpy with fixed
dry-bulb temperatures
All hOA > 28 Btu/lba or
TOA > 75°F
Outdoor air enthalpy exceeds
28 Btu/lb of dry aira or
Outdoor air temperature exceeds 75°F
Differential enthalpy with
fixed dry-bulb
temperature
All hOA > hRA or
TOA > 75°F
Outdoor air enthalpy exceeds
return air enthalpy or
Outdoor air temperature exceeds 75°F

For SI: 1 foot = 305 mm, °C = (°F - 32)/1.8, 1 Btu/lb = 2.33 kJ/kg.

  1. At altitudes substantially different than sea level, the fixed enthalpy limit shall be set to the enthalpy value at 75°F and 50-percent relative humidity. As an example, at approximately 6,000 feet elevation, the fixed enthalpy limit is approximately 30.7 Btu/lb.
  2. Devices with selectable setpoints shall be capable of being set to within 2°F and 2 Btu/lb of the setpoint listed.
Systems shall be capable of relieving excess outdoor air during air economizer operation to prevent overpressurizing the building. The relief air outlet shall be located to avoid recirculation into the building.
Return, exhaust/relief and outdoor air dampers used in economizers shall comply with Section C403.7.7.
Where economizers are required by Section C403.5, water-side economizers shall comply with Sections C403.5.4.1 and C403.5.4.2.

Water economizer systems shall be configured to cool supply air by indirect evaporation and providing up to 100 percent of the expected system cooling load at outdoor air temperatures of not greater than 50°F (10°C) dry bulb/45°F (7°C) wet bulb.

Exceptions:

  1. Systems primarily serving computer rooms in which 100 percent of the expected system cooling load at 40°F (4°C) dry bulb/35°F (1.7°C) wet bulb is met with evaporative water economizers.
  2. Systems primarily serving computer rooms with dry cooler water economizers that satisfy 100 percent of the expected system cooling load at 35°F (1.7°C) dry bulb.
  3. Systems where dehumidification requirements cannot be met using outdoor air temperatures of 50°F (10°C) dry bulb/45°F (7°C) wet bulb and where 100 percent of the expected system cooling load at 45°F (7°C) dry bulb/40°F (4°C) wet bulb is met with evaporative water economizers.
Precooling coils and water-to-water heat exchangers used as part of a water economizer system shall either have a water-side pressure drop of less than 15 feet (45 kPa) of water or a secondary loop shall be created so that the coil or heat exchanger pressure drop is not seen by the circulating pumps when the system is in the normal cooling (noneconomizer) mode.

Air-cooled unitary direct-expansion units listed in Tables C403.3.2(1) through C403.3.2(3) and variable refrigerant flow (VRF) units listed in Tables C403.3.2(10) and C403.3.2(11) that are equipped with an economizer in accordance with Sections C403.5 through C403.5.4 shall include a fault detection and diagnostics system complying with the following:

  1. The following temperature sensors shall be permanently installed to monitor system operation:

    1. 1.1. Outside air.
    2. 1.2. Supply air.
    3. 1.3. Return air.
  2. Temperature sensors shall have an accuracy of ±2°F (1.1°C) over the range of 40°F to 80°F (4°C to 26.7°C).
  3. Refrigerant pressure sensors, where used, shall have an accuracy of ±3 percent of full scale.
  4. The unit controller shall be configured to provide system status by indicating the following:

    1. 4.1. Free cooling available.
    2. 4.2. Economizer enabled.
    3. 4.3. Compressor enabled.
    4. 4.4. Heating enabled.
    5. 4.5. Mixed air low limit cycle active.
    6. 4.6. The current value of each sensor.
  5. The unit controller shall be capable of manually initiating each operating mode so that the operation of compressors, economizers, fans and the heating system can be independently tested and verified.
  6. The unit shall be configured to report faults to a fault management application available for access by day-to-day operating or service personnel, or annunciated locally on zone thermostats.
  7. The fault detection and diagnostics system shall be configured to detect the following faults:

    1. 7.1. Air temperature sensor failure/fault.
    2. 7.2. Not economizing when the unit should be economizing.
    3. 7.3. Economizing when the unit should not be economizing.
    4. 7.4. Damper not modulating.
    5. 7.5. Excess outdoor air.
Sections C403.6.1 through C403.6.9 shall apply to mechanical systems serving multiple zones.

Supply air systems serving multiple zones shall be variable air volume (VAV) systems that have zone controls configured to reduce the volume of air that is reheated, recooled or mixed in each zone to one of the following:

  1. Twenty percent of the zone design peak supply for systems with DDC and 30 percent for other systems.
  2. Systems with DDC where all of the following apply:

    1. 2.1. The airflow rate in the deadband between heating and cooling does not exceed 20 percent of the zone design peak supply rate or higher allowed rates under Items 3, 4 and 5 of this section.
    2. 2.2. The first stage of heating modulates the zone supply air temperature setpoint up to a maximum setpoint while the airflow is maintained at the deadband flow rate.
    3. 2.3. The second stage of heating modulates the airflow rate from the deadband flow rate up to the heating maximum flow rate that is less than 50 percent of the zone design peak supply rate.
  3. The outdoor airflow rate required to meet the minimum ventilation requirements of Chapter 4 of the New York City Mechanical Code.
  4. Any higher rate that can be demonstrated to reduce overall system annual energy use by offsetting reheat/recool energy losses through a reduction in outdoor air intake for the system as approved by the building official.
  5. The airflow rate required to comply with applicable codes or accreditation standards such as pressure relationships or minimum air change rates.

Exception: The following individual zones or entire air distribution systems are exempted from the requirement for VAV control:

  1. Zones or supply air systems where not less than 75 percent of the energy for reheating or for providing warm air in mixing systems is provided from a site-recovered, including condenser heat, or site-solar energy source.
  2. Systems that prevent reheating, recooling, mixing or simultaneous supply of air that has been previously cooled, either mechanically or through the use of economizer systems, and air that has been previously mechanically heated.
Single-duct VAV systems shall use terminal devices capable of and configured to reduce the supply of primary supply air before reheating or recooling takes place.
Systems that have one warm air duct and one cool air duct shall use terminal devices that are configured to reduce the flow from one duct to a minimum before mixing of air from the other duct takes place.
Individual dual-duct or mixing heating and cooling systems with a single fan and with total capacities greater than 90,000 Btu/h [(26.4 kW) 7.5 tons] shall not be equipped with air economizers.

Multiple-zone HVAC systems shall include controls that automatically reset the supply-air temperature in response to representative building loads, or to outdoor air temperature. The controls shall be configured to reset the supply air temperature not less than 25 percent of the difference between the design supply-air temperature and the design room air temperature.

Exceptions:

  1. Systems that prevent reheating, recooling or mixing of heated and cooled supply air.
  2. Seventy-five percent of the energy for reheating is from site-recovered or site-solar energy sources.
  3. Zones with peak supply air quantities of 300 cfm (142 L/s) or less.

Multiple-zone VAV systems with direct digital control of individual zone boxes reporting to a central control panel shall have automatic controls configured to reduce outdoor air intake flow below design rates in response to changes in system ventilation efficiency (Ev) as defined by the New York City Mechanical Code.

Exceptions:

  1. VAV systems with zonal transfer fans that recirculate air from other zones without directly mixing it with outdoor air, dual-duct dual-fan VAV systems, and VAV systems with fan-powered terminal units.
  2. Systems where total design exhaust airflow is more than 70 percent of total design outdoor air intake flow requirements.

Parallel-flow fan-powered VAV air terminals shall have automatic controls configured to:

  1. Turn off the terminal fan except when space heating is required or where required for ventilation.
  2. Turn on the terminal fan as the first stage of heating before the heating coil is activated.
  3. During heating for warmup or setback temperature control, either:

    1. 3.1. Operate the terminal fan and heating coil without primary air.
    2. 3.2. Reverse the terminal damper logic and provide heating from the central air handler by primary air.

For systems with direct digital control of individual zones reporting to the central control panel, the static pressure setpoint shall be reset based on the zone requiring the most pressure. In such case, the setpoint is reset lower until one zone damper is nearly wide open. The direct digital controls shall be capable of monitoring zone damper positions or shall have an alternative method of indicating the need for static pressure that is configured to provide all of the following:

  1. Automatic detection of any zone that excessively drives the reset logic.
  2. Generation of an alarm to the system operational location.
  3. Allowance for an operator to readily remove one or more zones from the reset algorithm.
Static pressure sensors used to control VAV fans shall be located such that the controller setpoint is not greater than 1.2 inches w.c. (299 Pa). Where this results in one or more sensors being located downstream of major duct splits, not less than one sensor shall be located on each major branch to ensure that static pressure can be maintained in each branch.
In addition to other requirements of Section C403 applicable to the provision of ventilation air or the exhaust of air, ventilation and exhaust systems shall be in accordance with Sections C403.7.1 through C403.7.7.

Demand control ventilation (DCV) shall be provided for spaces larger than 500 square feet (46.5 m2) and with an average occupant load of 25 people or greater per 1,000 square feet (93 m2) of floor area, as established in the New York City Mechanical Code, and served by systems with one or more of the following:

  1. An air-side economizer.
  2. Automatic modulating control of the outdoor air damper.
  3. A design outdoor airflow greater than 3,000 cfm (1416 L/s).

Exceptions:

  1. Systems with energy recovery complying with Section C403.7.4.
  2. Multiple-zone systems without direct digital control of individual zones communicating with a central control panel.
  3. Systems with a design outdoor airflow less than 1,200 cfm (566 L/s).
  4. Spaces where the supply airflow rate minus any makeup or outgoing transfer air requirement is less than 1,200 cfm (566 L/s).
  5. Ventilation provided only for process loads.

Enclosed parking garages used for storing or handling automobiles operating under their own power shall employ contamination-sensing devices and automatic controls configured to stage fans or modulate fan average airflow rates to 50 percent or less of design capacity, or intermittently operate fans less than 20 percent of the occupied time or as required to maintain acceptable contaminant levels in accordance with New York City Mechanical Code provisions. Failure of contamination-sensing devices shall cause the exhaust fans to operate continuously at design airflow.

Exceptions:

  1. Garages with a total exhaust capacity less than 5,000 cfm (2 360 L/s) with ventilation systems that do not utilize heating or mechanical cooling.
  2. Garages that have a garage area to ventilation system motor nameplate power ratio that exceeds 1125 cfm/hp (710 L/s/kW) and do not utilize heating or mechanical cooling.
Units that provide ventilation air to multiple zones and operate in conjunction with zone heating and cooling systems shall not use heating or heat recovery to warm supply air to a temperature greater than 60°F (16°C) when representative building loads or outdoor air temperatures indicate that the majority of zones require cooling.

Where the supply airflow rate of a fan system exceeds the values specified in Tables C403.7.4(1) and C403.7.4(2), the system shall include an energy recovery system. The energy recovery system shall be configured to provide a change in the enthalpy of the outdoor air supply of not less than 50 percent of the difference between the outdoor air and return air enthalpies, at design conditions. Where an air economizer is required, the energy recovery system shall include a bypass or controls that permit operation of the economizer as required by Section C403.5.

Exception: An energy recovery ventilation system shall not be required in any of the following conditions:

  1. Where energy recovery systems are prohibited by the New York City Mechanical Code.
  2. Laboratory fume hood systems that include not fewer than one of the following features:

    1. 2.1. Variable-air-volume hood exhaust and room supply systems configured to reduce exhaust and makeup air volume to 50 percent or less of design values.
    2. 2.2. Direct makeup (auxiliary) air supply equal to or greater than 75 percent of the exhaust rate, heated not warmer than 2°F (1.1°C) above room setpoint, cooled to not cooler than 3°F (1.7°C) below room setpoint, with no humidification added, and no simultaneous heating and cooling used for dehumidification control.
  3. Systems serving spaces that are heated to less than 60°F (15.5°C) and that are not cooled.
  4. Where more than 60 percent of the outdoor heating energy is provided from site-recovered or site-solar energy.
  5. Heating energy recovery in Climate Zones 1 and 2.
  6. Cooling energy recovery in Climate Zones 3C, 4C, 5B, 5C, 6B, 7 and 8.
  7. Systems requiring dehumidification that employ energy recovery in series with the cooling coil.
  8. Where the sum of the airflow rates exhausted and relieved within 30 feet of each other is less than 75 percent of the design ventilation outdoor air flow rate, excluding exhaust air that is any of the following:

    1. Used for another energy recovery system,
    2. Not allowed by ASHRAE Standard 170 for use in energy recovery systems with leakage potential,
    3. Prohibited by the New York City Mechanical Code, or
    4. Of Class 4 as defined in ASHRAE 62.1.
  9. Systems expected to operate less than 20 hours per week at the outdoor air percentage covered by Table C403.7.4(1).
  10. Systems exhausting toxic, flammable, paint or corrosive fumes or dust.
  11. Commercial kitchen hoods used for collecting and removing grease vapors and smoke.

TABLE C403.7.4(1)

ENERGY RECOVERY REQUIREMENT (Ventilation systems operating less than 8,000 hours per year)

CLIMATE ZONE PERCENT (%) OUTDOOR AIR AT FULL DESIGN AIRFLOW RATE
≥ 10% and < 20% ≥ 20% and < 30% ≥ 30% and < 40% ≥ 40% and <
50%
≥ 50% and <
60%
≥ 60% and <
70%
≥ 70% and <
80%
≥ 80%
DESIGN SUPPLY FAN AIRFLOW RATE (cfm)
4A, 5A, 6A ≥ 26,000 ≥ 16,000 ≥ 5,500 ≥ 4,500 ≥ 3,500 ≥ 2,000 ≥ 1,000 > 120

For SI: 1 cfm = 0.4719 L/s.

NR = Not Required.

TABLE C403.7.4(2)

ENERGY RECOVERY REQUIREMENT (Ventilation systems operating not less than 8,000 hours per year)

CLIMATE ZONE PERCENT (%) OUTDOOR AIR AT FULL DESIGN AIRFLOW RATE
≥ 10% and
< 20%
≥ 20% and
< 30%
≥ 30% and
< 40%
≥ 40% and
< 50%
≥ 50% and
< 60%
≥ 60% and
< 70%
≥ 70% and
< 80%
≥ 80%
Design Supply Fan Airflow Rate (cfm)
4A, 5A, 6A ≥ 200 ≥ 130 ≥ 100 ≥ 80 ≥ 70 ≥ 60 ≥ 50 ≥ 40

For SI: 1 cfm = 0.4719 L/s.

NR = Not Required.

Replacement air introduced directly into the exhaust hood cavity shall not be greater than 10 percent of the hood exhaust airflow rate. Conditioned supply air delivered to any space shall not exceed the greater of the following: