ADOPTS WITH AMENDMENTS:

International Residential Code 2015 (IRC 2015)

Part I — Administrative

Part II — Definitions

Part III — Building Planning and Construction

Part IV — Energy Conservation

Part V — Mechanical

Part VI — Fuel Gas

Part VII — Plumbing

Part VIII — Electrical

Part IX — Referenced Standards

E-1

Heads up: There are no amended sections in this chapter.

Appendix E (E-1 Through E-4) Residential Requirements for Energy Conservation

AMENDMENT
This section has been amended at the state or city level.
(The provisions contained in this appendix are adopted as part of this code.)

Appendix E-1

AMENDMENT
This section has been amended at the state or city level.
Energy Efficiency Certificate (Section N1101.14)

ENERGY EFFICIENCY CERTIFICATE (N1101.14)
Builder, Permit Holder or Registered Design Professional
Print Name:
Signature:
Property Address:
Date:
Insulation Rating — List the value covering largest area to all that apply R-Value
Ceiling/roof: R-
Wall: R-
Floor: R-
Closed crawl space wall: R-
Closed crawl space floor: R-
Slab: R-
Basement wall: R-
Fenestration:
U-Factor
Solar Heat Gain Coefficient (SHGC)
Building Air Leakage
□ Visually inspected according to N1102.4.2.1 OR
□ Building air leakage test results
(Sec. N1102.4.2.2)
ACH50 [Target: 5.0] or
CFM50/SFSA [Target: 0.30]
Name of Tester/Company:
Date:                                                                                                                       Phone:
Ducts:
Insulation R-
Total duct leakage test result (Sect. N1103.3.3)
Circle one:
Total duct leakage test
(CFM25 Total/100SF) [Target: 5] or
Duct leakage to the outside test
(CFM25 Total/100SF) [Target: 4]
Name of Tester or Company:
Date:                                                                                                                     Phone:
Certificate to be displayed permanently

Appendix E-2 Insulation and Air Sealing Details

AMENDMENT
This section has been amended at the state or city level.

Appendix E-2.1

AMENDMENT
This section has been amended at the state or city level.
N1102.2.1 Ceilings with attic spaces: Exception for fully enclosed attic floor systems

Appendix E-2.2

AMENDMENT
This section has been amended at the state or city level.
N1102.2.11 Closed crawl space walls. Insulation illustrations

Appendix E-2.3

AMENDMENT
This section has been amended at the state or city level.
N1102.2.14 Framed cavity walls. Insulation enclosure—1. Tubs



N1102.2.14 Framed cavity walls. Insulation enclosure—2. Showers



N1102.2.14 Framed cavity walls. Insulation enclosure—3. Stairs



N1102.2.14 Framed cavity walls. Insulation enclosure—3. Stairs



N1102.2.14 Framed cavity wall. Insulation enclosure—4. Direct vent gas fireplace



N1102.2.15 Framed cavity walls. Insulation enclosure—5. Walls that adjoin attic spaces



N1102.2.15 Framed cavity walls. Insulation enclosure—5. Walls that adjoin attic spaces

Appendix E-2.4

AMENDMENT
This section has been amended at the state or city level.
N1102.4.1 Building thermal envelope.—1. Block and seal floor/ceiling systems



N1102.4.1 Building thermal envelope.—1. Block and seal floor/ceiling systems



N1102.4.1 Building thermal envelope. —1. Block and seal floor/ceiling systems



N1102.4.1 Building thermal envelope—2. Cap and seal shafts and chases




N1102.4.1 Building thermal envelope. —3. Cap and seal soffit or dropped ceiling



N1102.4.1 Building thermal envelope.—4. Seal HVAC boot penetration—floor



N1102.4.1 Building thermal envelope.—4. Seal HVAC boot penetration—ceiling



N1102.4.1 Building thermal envelope.—5. Sealed exterior air barrier with housewrap

Follow manufacturer's instructions for sealing air barrierrated housewrap, including choice of materials, to provide an exterior air barrier at the following locations:



N1102.4.1 Building thermal envelope.—5. Sealed exterior air barrier with sheathing



N1102.4.2.1 Visual inspection option.Table N1102.4.2 Seal ceiling mechanical box penetrations



N1102.4.2.1 Visual inspection option.Table N1102.4.2 Seal ceiling electrical box penetrations

Appendix E-3 Sample Worksheets for Residential Air and Duct Leakage Testing

AMENDMENT
This section has been amended at the state or city level.

Appendix E-3A Air Sealing: Visual Inspection Option (Section N1102.4.2.1) Sample Worksheet

AMENDMENT
This section has been amended at the state or city level.
N1102.4.2 Air sealing. Building envelope air tightness shall be demonstrated by Section N1102.4.2.1 or N1102.4.2.2.

TABLE N1102.4.2
AIR BARRIER INSPECTION
COMPONENT CRITERIA
Ceiling/attic Sealants or gaskets provide a continuous air barrier system joining the top plate of framed walls with either the ceiling drywall or the top edge of wall drywall to prevent air leakage. Top plate penetrations are sealed.

For ceiling finishes that are not air barrier systems such as tongue-and-groove planks, air barrier systems (for example, taped house wrap), shall be used above the finish.

Note: It is acceptable that sealants or gaskets applied as part of the application of the drywall will not be observable by the code official.
Walls Sill plate is gasketed or sealed to subfloor or slab.
Windows and doors Space between window and exterior door jambs and framing is sealed.
Floors (including above-garage and cantilevered floors) Air barrier system is installed at any exposed edge of insulation.
Penetrations Utility penetrations through the building thermal envelope, including those for plumbing, electrical wiring, ductwork, security and fire alarm wiring, and control wiring, shall be sealed.
Garage separation Air sealing is provided between the garage and conditioned spaces. An air barrier system shall be installed between the ceiling system above the garage and the ceiling system of interior spaces.
Ceiling penetrations Ceiling electrical box penetrations and ceiling mechanical box penetrations shall be caulked, gasketed, or sealed at the penetration of the ceiling finish. See
Appendix E-2.4
.
Exception: Ceiling electrical boxes and ceiling mechanical boxes not penetrating the building thermal envelope
Recessed lighting Recessed light fixtures are air tight, IC rated, and sealed to drywall.

Exception: Fixtures in conditioned space.


Property Address
________________________________________________________
N1102.4.2.1 Visual Inspection Option. The inspection information including tester name, date, and contact shall be included on the certificate described in Section N1101.14.
________________________________     _____________________
Signature                                                     Date
N1102.4.2.1 Visual inspection option. Building envelope tightness shall be considered acceptable when items providing insulation enclosure in Section N1102.2.14 and enclosure and air sealing in Section N1102.2.15 and air sealing in Section N1102.4.1 are addressed and when the items listed in Table N1102.4.2, applicable to the method of construction, are certified by the builder, permit holder or registered design professional via the certificate in Appendix E-1.

Appendix E-3B Air Sealing: Testing Option (Section N1102.4.2.2) Sample Worksheet

AMENDMENT
This section has been amended at the state or city level.
N1102.4.2 Air sealing. Building envelope air tightness shall be demonstrated by Section N1102.4.2.1 or N1102.4.2.2:

N1102.4.2.2 Testing option. Building envelope tightness shall be considered acceptable when items providing insulation enclosure in Section N1102.2.14 and enclosure and air sealing in Section N1102.2.15 and air sealing in Section N1102.4.1 are addressed and when tested air leakage is less than or equal to one of the two following performance measurements:
  1. 0.30 CFM50/Square Foot of Surface Area (SFSA) or
  2. Five (5) air changes per hour (ACH50)
     When tested with a blower door fan assembly, at a pressure of 33.5 psf (50 Pa). A single point depressurization, not temperature corrected, test is sufficient to comply with this provision, provided that the blower door fan assembly has been certified by the manufacturer to be capable of conducting tests in accordance with ASTM E779—03. Testing shall occur after rough in and after installation of penetrations of the building envelope, including penetrations for utilities, plumbing, electrical, ventilation and combustion appliances. Testing shall be reported by the permit holder, a North Carolina licensed general contractor, a North Carolina licensed HVAC contractor, a North Carolina licensed Home Inspector, a registered design professional, a certified BPI Envelope Professional or a certified HERS rater.

During testing:
  1. Exterior windows and doors, fireplace and stove doors shall be closed, but not sealed;
  2. Dampers shall be closed, but not sealed, including exhaust, backdraft, and flue dampers;
  3. Interior doors shall be open;
  4. Exterior openings for continuous ventilation systems, air intake ducted to the return side of the conditioning system, and energy or heat recovery ventilators shall be closed and sealed;
  5. Heating and cooling system(s) shall be turned off; and
  6. Supply and return registers shall not be sealed.
     The air leakage information, including building air leakage result, tester name, date, and contact information, shall be included on the certificate described in Section N1101.14.

For Test Criteria 1 in this section, the report shall be produced in the following manner: Perform the blower door test and record the CFM50 ___________. Calculate the total square feet of surface area for the building thermal envelope, all floors, ceilings, and walls (this includes windows and doors) and record the area______________. Divide CFM50 by the total square feet and record the result below. If the result is less than or equal to [0.30 CFM50/SFSA] the envelope tightness is acceptable; or

For Test Criteria 2, the report shall be produced in the following manner: Perform a blower door test and record the CFM50 ___________. Multiply the CFM50 by 60 minutes to create CFHour50 and record ______________. Then calculate the total conditioned volume of the home and record_________________. Divide the CFH50 by the total volume and record the result below. If the result is less than or equal to [5 ACH50] the envelope tightness is acceptable.

Property Address______________________________________________________
Fan attachment location_________________Company Name__________________
Contact Information____________________________________________________
____________________________________________________________________
Signature of Tester______________________Date___________________________

Permit Holder, NC Licensed General Contractor, NC Licensed HVAC Contractor,
NC Licensed Home Inspector, Registered Design Professional,
Certified BPI Envelope Professional, or Certified HERS Rater
(circle one).
N1103.3.2 Sealing (Mandatory Requirements). Ducts, air handlers, filter boxes, and building cavities used as ducts shall be sealed. Joints and seams shall comply with either the International Mechanical Code or International Residential Code, as applicable.

N1103.3.3 Duct leakage (Prescriptive) and duct testing (Mandatory). Duct testing and duct leakage shall be verified by compliance with either Section N1103.3.3.1 or N1103.3.3.2. Duct testing shall be verified using one of the two following methods:

N1103.3.3.1 Total duct leakage. Total duct leakage shall be less than or equal to 5 CFM (12 L/min) per 100 ft2 (9.29 m2) of conditioned floor area served by that system when tested at a pressure differential of 0.1 inches w.g. (25 Pa) across the entire system, including the manufacturer's air handler enclosure.

During testing:
  1. Block, if present, ventilation air duct(s) connected to the conditioning system.
  2. The duct air leakage testing equipment shall be attached to the largest return in the system or to the air handler.
  3. The filter shall be removed and the air handler power shall be turned off.
  4. Supply boots or registers and return boxes or grilles shall be taped, plugged, or otherwise sealed air tight.
  5. The hose for measuring the 25 Pascals of pressure differential shall be inserted into the boot of the supply that is nominally closest to the air handler.
  6. Specific instructions from the duct testing equipment manufacturer shall be followed to reach duct test pressure and measure duct air leakage.
N1103.3.3.2 Duct leakage to the outside. Conduct the test using fan pressurization of distribution system and building at a fixed reference pressure for combined supply and return leaks. Duct leakage to the outside shall be less than or equal to 4 CFM (12 L/min) per 100 ft2 (9.29 m2) of conditioned floor area served by that system when tested at a pressure differential of 0.1 inches w.g. (25 Pa) across the entire system, relative to the outside, including the manufacturer's air handler enclosure.

During testing:
  1. Block, if present, the ventilation air duct(s) connected to the conditioning system.
  2. The duct air leakage testing equipment shall be attached to the largest return in the system or to the air handler.
  3. The filter shall be removed and the air handler power shall be turned off.
  4. Supply boots or registers and return boxes or grilles shall be taped, plugged, or otherwise sealed air tight or as tight as possible.
  5. The hose for measuring the 25 Pascals of pressure differential shall be inserted into the boot of the supply that is nominally closest to the air handler.
  6. Open all interconnecting doors in the building, close dampers for fireplaces and other operable dampers.
  7. Set up an envelope air moving/flow-regulating/flow measurement assembly, such as a blower door, following the manufacturer's prescribed procedure.
  8. Specific instructions from the duct testing equipment manufacturer shall be followed to reach duct test pressure and measure duct air leakage used in combination with a blower door. Typical steps are as follows:
    1. Depressurize the ductwork system to 25 Pa using the measurement hose in Step 5 above.
    2. Depressurize the house to 25 Pa using an envelope air moving/flow-regulating/flow measurement assembly, such as a blower door.
    3. Correct the duct pressure to measure 0 Pa of pressure differential between the house and the ductwork system.
    4. Read the CFM of duct leakage using the procedures for the specific equipment being used. (Note that most automatically calculating pressure gauges cannot compute the CFM25 automatically with a duct-to-house difference in pressure of 0 Pa, so the gauge setting should be set to read CFM instead of CFM25).
     Testing shall be performed and reported by the permit holder, a North Carolina licensed general contractor, a North Carolina licensed HVAC contractor, a North Carolina licensed Home Inspector, a registered design professional, a certified BPI Envelope Professional or a certified HERS rater. A single point depressurization, not temperature corrected, test is sufficient to comply with this provision, provided that the duct testing fan assembly(s) has been certified by the manufacturer to be capable of conducting tests in accordance with ASTM E1554-07.

     The duct leakage information, including duct leakage test selected and result, tester name, date, and contact information, shall be included on the certificate described in Section N1101.14.

     For the Test Criteria, the report shall be produced in the following manner: perform the HVAC system air leakage test and record the CFM25. Calculate the total square feet of Conditioned Floor Area (CFA) served by that system. Multiply CFM25 by 100, divide the result by the CFA and record the result. If the result is less than or equal to 5 CFM25/100SF for the "Total duct leakage test" or less than or equal to 4 CFM25/100SF for the "Duct leakage to the outside" test, then the HVAC system air tightness is acceptable.

Complete one duct leakage report for each HVAC system serving the home:

Property Address_________________________________________________________________
Test Performed: Total duct leakage or Duct leakage to the outside (circle one)
HVAC System Number:____________Describeaea of home served:_________________________
CFM25 Total___________. Conditioned Floor Area(CFA) served by system:_________s.f.
CFM25 x 100 divided by CFM = _____ CFM25/100SF (e.g. 100 CFM25 x 100/2,000 CFA = 5 CFM25/100SF)
Fan attachment location____________________________________________________________
Company Name___________________________________________________________________
Contact Information:________________________________________________________________
________________________________________________________________________________
__________________________                                                ______________________________
Signature of Tester                                                                      Date

Permit Holder, NC Licensed General Contractor, NC Licensed HVAC Contractor,
NC Licensed Home Inspector, Registered Design Professional,
Certified BPI Envelope Professional, or Certified HERS Rater
(circle one)
  1. Introduction. The increased energy efficiency measures identified in this appendix are strictly voluntary at the option of the permit holder and have been evaluated to be the most cost effective measures for achieving an additional 10 to 15-percent energy efficiency beyond the code minimums.
  2. Requirements. Follow all sections of Chapter 11 of the North Carolina Residential Code, Chapter 11, except the following.
    1. Instead of using Table N1102.1.2 in Section N1102.1.2, use Table E-4A shown below.
    2. Instead of using Table N1102.1.4 in Section N1102.1.4, use Table E-4B to find the maximum Ufactors for building components.
    3. For compliance with Section N1102.4 Air leakage control (Mandatory Requirements), Sections N1102.4.1 (Building thermal envelope) and N1102.4.2.2 (Testing option) must be followed, with the maximum leakage rate shown below. Section N1102.4.2.1 (Visual inspection option) cannot be used to show compliance.
      1. 0.24 CFM50/Square Foot of Surface Area (SFSA) or
      2. Four (4) air changes per hour (ACH50)
    4. Instead of using the duct leakage value for maximum leakage shown in Section N1103.3.3 use the following:
      1. N1103.3.3.1 Total duct leakage. Total duct leakage shall be less than or equal to 4 CFM (113 L/min) per 100 ft2 (9.29 m2) of conditioned floor area served by that system when tested at a pressure differential of 0.1 inches w.g. (25 Pa) across the entire system, including the manufacturer's air handler enclosure.
      2. N1103.3.3.2 Duct leakage to the outside. Conduct the test using fan pressurization of distribution system and building at a fixed reference pressure for combined supply and return leak. Duct leakage to the outside shall be less than or equal to 3 CFM (85 L/min) per 100 ft2 (9.29 m2) of conditioned floor area served by that system when tested at a pressure differential of 0.1 inches w.g. (25 Pa) across the entire system, relative to the outside, including the manufacturer's air handler enclosure.
    5. For compliance with Section N1104.1 (Lighting equipment), the home must comply with the following:

      Not less than 90 percent of the lamps in permanently installed lighting fixtures shall be high-efficacy lamps or not less than 90 percent of the permanently installed lighting fixtures shall contain only high-efficacy lamps.
TABLE E-4A
INSULATION AND FENESTRATION REQUIREMENTS BY COMPONENTa
CLIMATE
ZONE
FENESTRATION
U-FACTORb, j
SKYLIGHTb
U-FACTOR
GLAZED
FENESTRATION
SHGCb, k
CEILING
R-VALUEm
WOOD
FRAME
WALL
R-VALUE
MASS
WALL
R-VALUEi
FLOOR
R-VALUE
BASEMENTc, o
WALL
R-VALUE
SLABd
R-VALUE
CRAWL
SPACEc
WALL
R-VALUE
3 0.32 0.55 0.25 38 or 30 cil 19n, 13 +
5, or 15 +
3h
5/13 or
5/10ci
19 5/13f 5 5/13
4 0.32 0.55 0.25 38 or 30 cil 19n, 13 +
5, or 15 +
3h
5/13 or
5/10ci
19 10/15 10 10/15
5 0.32 0.55 (NR) 38 or 30 cil 19n, 13 +
5, or 15 +
3h
13/17 or
13/12.5ci
30g 10/15 10 10/19
For SI: 1 foot = 304.8 mm.
  1. R-values are minimums. U-factors and SHGC are maximums. When insulation is installed in a cavity that is less than the label or design thickness of the insulation, the installed R-value of the insulation shall not be less than the R-value specified in the table.
  2. The fenestration U-factor column excludes skylights. The SHGC column applies to all glazed fenestration.
  3. "10/15" means R-10 continuous insulated sheathing on the interior or exterior of the home or R-15 cavity insulation at the interior of the basement wall or crawl space wall.
  4. For monolithic slabs, insulation shall be applied from the inspection gap downward to the bottom of the footing or a maximum of 24 inches below grade, whichever is less. For floating slabs, insulation shall extend to the bottom of the foundation wall or 24 inches, whichever is less. (See Appendix O) R-5 shall be added to the required slab edge R-values for heated slabs.
  5. Deleted.
  6. Basement wall insulation is not required in warm-humid locations as defined by Figure N1101.7 and Table N1101.7.
  7. Or insulation sufficient to fill the framing cavity, R-19 minimum.
  8. The first value is cavity insulation, the second value is continuous insulation, so "13 + 5" means R-13 cavity insulation plus R-5 continuous insulation. If structural sheathing covers 25 percent or less of the exterior, insulating sheathing is not required where structural sheathing is used. If structural sheathing covers more than 25 percent of exterior, structural sheathing shall be supplemented with insulated sheathing of at least R-2.
  9. The second R-value applies when more than half the insulation is on the interior of the mass wall.
  10. In addition to the exemption in Section N1102.3.3, a maximum of two glazed fenestration product assemblies having a U-factor no greater than 0.55 shall be permitted to be substituted for minimum code compliant fenestration product assemblies without penalty.
  11. In addition to the exemption in Section N1102.3.3, a maximum of two glazed fenestration product assemblies having a SHGC no greater than 0.70 shall be permitted to be substituted for minimum code compliant fenestration product assemblies without penalty.
  12. R-30 shall be deemed to satisfy the ceiling insulation requirement wherever the full height of uncompressed R-30 insulation extends over the wall top plate at the eaves. Otherwise R-38 insulation is required where adequate clearance exists or insulation must extend to either the insulation baffle or within 1 inch of the attic roof deck.
  13. Table value required except for roof edge where the space is limited by the pitch of the roof, there the insulation must fill the space up to the air baffle.
  14. R-19 fiberglass batts compressed and installed in a nominal 2 × 6 framing cavity is deemed to comply. Fiberglass batts rated R-19 or higher compressed and installed in a 2 × 4 wall is not deemed to comply.
  15. Basement wall meeting the minimum mass wall specific heat content requirement may use the mass wall R-value as the minimum requirement.
TABLE E-4B
EQUIVALENT U-FACTORSa
CLIMATE
ZONE
FENESTRATION
U-FACTORd
SKYLIGHT
U-FACTOR
CEILING
U-FACTOR
FRAME
WALL
U-FACTOR
MASS
WALL
U-FACTORb
FLOOR
U-FACTOR
BASEMENT
WALL
U-FACTORc
CRAWL SPACE
WALL
U-FACTOR
3 0.32 0.55 0.030 0.061 0.141 0.047 0.091 0.136
4 0.32 0.55 0.030 0.061 0.141 0.047 0.059 0.065
5 0.32 0.55 0.030 0.061 0.082 0.033 0.059 0.065
  1. Nonfenestration U-factors shall be obtained from measurement, calculation or an approved source.
  2. When more than half the insulation is on the interior, the mass wall U-factors shall be a maximum of 0.07 in Climate Zone 3, 0.07 in Climate Zone 4, and 0.054 in Climate Zone 5.
  3. Basement wall U-factor of 0.360 in warm-humid locations as defined by Figure N1101.10 (R301.1) and Table N1101.10 (R301.1).
  4. A maximum of two glazed fenestration product assemblies having a U-factor no greater than 0.55 and a SHGC no greater than 0.70 shall be permitted to be substituted for minimum code compliant fenestration product assemblies without penalty.
Table E-4C:
Sample Confirmation Form for ADDITIONAL VOLUNTARY CRITERIA FOR INCREASING ENERGY EFFICIENCY (High Efficiency Residential Option)
North Carolina Energy Conservation Code:
HIGH EFFICIENCY RESIDENTIAL OPTION INSULATION AND FENESTRATION VALUES
(Notes correlate to Table N1102.1.2)
PROPOSED
PROJECT
VALUES
Climate Zone 3 4 5
Fenestration U-Factorb, j 0.32 0.32 0.32  
Skylight U-Factorb 0.55 0.55 0.55  
Glazed fenestration SHGCb, k 0.25 0.25 (NR)  
Ceiling R-valuem 38 or 30 cil 38 or 30 cil 38 or 30 cil  
Wood frame wall R-valueh 19n, 13 + 5,
or 15 + 3
19n, 13 + 5,
or 15 + 3
19n, 13 + 5,
or 15 + 3
 
Mass wall R-valuei 5/13 or 5/10
ci
5/13 or 5/10
ci
13/17 or
13/12.5 ci
 
Floor R-value 19 19 30g  
Basement wall R-valuec, o 5/13f 10/15 10/15  
Slab R-value and depthd 5 10 10  
Crawl space wall R-valuec 5/13 10/15 10/19  
  * Note: ci = continuous insulation  
High Efficacy Lighting  
% of lighting that is high efficacy according to N1104.1. (90% required)  
Building Air Leakage  
Building Air Leakage Test according to N1102.4.2.2 (check box). Show test value:  
ACH50 [Target: 4.0], or  
CFM50/SFSA [Target: 0.24]  
Name of Tester / Company:
Date:                                                                         Phone:
Duct Insulation and Sealing  
Insulation value R-
Duct Leakage Test Result (Sect. N1103.3.3)       □Total duct leakage or             □ Duct leakage to the exterior
(CFM25 Total/100SF) [Target: 4 Total/ 3 To exterior]  
Name of Tester or Company:  
Date:                                                                         Phone:


E-4D:
SAMPLE WORKSHEETS FOR RESIDENTIAL AIR AND DUCT LEAKAGE TESTING

E-4D.1
AIR SEALING: TESTING
(Section N1102.4.2.2)

Sample Worksheet for Alternative Residential
Energy Code for Higher Efficiency

Air sealing. Building envelope air tightness shall be demonstrated by Section N1102.4.2.2:

Air sealing: Testing option (Section N1102.4.2.2)
Sample Worksheet for Alternative Residential
Energy Code for Higher Efficiency

N1102.4.2.2 Testing. Building envelope tightness shall be considered acceptable when items providing insulation enclosure in Section N1102.2.14 and enclosure air sealing in Section N1102.2.15 and air sealing in Section N1102.4.1 are addressed and when tested air leakage is less than or equal to one of the two following performance measurements:
  1. 0.24 CFM50 (6.8 L/min)/square foot of surface area (SFSA) or
  2. Four (4) air changes per hour (ACH50)
     When tested with a blower door fan assembly, at a pressure of 0.2 inches water gauge (50 Pa), a single point depressurization, not temperature corrected, test is sufficient to comply with this provision, provided that the blower door fan assembly has been certified by the manufacturer to be capable of conducting tests in accordance with ASTM E779—03. Testing shall occur after rough in and after installation of penetrations of the building envelope, including penetrations for utilities, plumbing, electrical, ventilation and combustion appliances. Testing shall be reported by the permit holder, a North Carolina licensed general contractor, a North Carolina licensed HVAC contractor, a North Carolina licensed Home Inspector, a registered design professional, a certified BPI Envelope Professional or a certified HERS rater.

During testing:
  1. Exterior windows and doors, fireplace and stove doors shall be closed, but not sealed;
  2. Dampers shall be closed, but not sealed, including exhaust, backdraft, and flue dampers;
  3. Interior doors shall be open;
  4. Exterior openings for continuous ventilation systems, air intake ducted to the return side of the conditioning system, and energy or heat recovery ventilators shall be closed and sealed;
  5. Heating and cooling system(s) shall be turned off; and
  6. Supply and return registers shall not be sealed.
     The air leakage information, including building air leakage result, tester name, date, and contact information, shall be included on the certificate described in Section N1101.14.

For Test Criteria 1 in this section, the report shall be produced in the following manner: Perform the blower door test and record the CFM50___________. Calculate the total square feet of surface area for the building thermal envelope, all floors, ceilings, and walls (this includes windows and doors) and record the area______________. Divide CFM50 by the total square feet and record the result below. If the result is less than or equal to [0.24 CFM50/SFSA] the envelope tightness is acceptable; or

For Test Criteria 2, the report shall be produced in the following manner: Perform a blower door test and record the CFM50 = ___________. Multiply the CFM50 by 60 minutes to create CF/Hour50 and record = ______________. Then calculate the total conditioned volume of the home and record = _________________cubic feet. Divide the CF/Hour50 by the total volume and record the result = _____________________ ACH50. If the result is less than or equal to [4 ACH50] the envelope tightness is acceptable.

  Property Address:___________________________________________________
Fan attachment location______________Company Name__________________
Contact Information:_________________________________________________
___________________________________________________________________
____________________________________       ________________________
Signature of Tester                                               Date


Permit Holder, NC Licensed General Contractor, NC Licensed HVAC Contractor,
NC Licensed Home Inspector, Registered Design Professional,
Certified BPI Envelope Professional, or Certified HERS Rater
(circle one)

E-4D.2
DUCT SEALING. Duct air leakage test
(Section N1103.3.3)
Sample Worksheet for Alternative Residential
Energy Code for Higher Efficiency

N1103.3.3 Duct leakage (Prescriptive) and duct testing (Mandatory). Duct testing and duct leakage shall be verified by compliance with either Section N1103.3.3.1 or N1103.3.3.2. Duct testing shall be performed and reported by the permit holder, a NC licensed general contractor, a NC licensed HVAC contractor, a NC licensed Home Inspector, a registered design professional, a certified BPI Envelope Professional or a certified HERS rater. A single point depressurization, not temperature corrected, test is sufficient to comply with this provision, provided that the duct testing fan assembly(s) has been certified by the manufacturer to be capable of conducting tests in accordance with ASTM E1554—07.

     The duct leakage information, including duct leakage test selected and result, tester name, date, and contact information, shall be included on the certificate described in Section N1101.3.

     For the Test Criteria, the report shall be produced in the following manner: perform the HVAC system air leakage test and record the CFM25. Calculate the total square feet of Conditioned Floor Area (CFA) served by that system. Multiply CFM25 by 100, divide the result by the CFA and record the result. If the result is less than or equal to 4 CFM25/100SF for the "Total duct leakage test or less than or equal to 3 CFM25/100SF for the Duct leakage to the outside" test, then the HVAC system air tightness is acceptable.

Exceptions to testing requirements:
  1. Duct systems or portions thereof inside the building thermal envelope shall not be required to be leak tested.
  2. Installation of a partial system as part of replacement, renovation or addition does not require a duct leakage test.
1103.3.3.1 Total duct leakage. Total duct leakage less than or equal to 4 CFM (113 L/min) per 100 ft2 (9.29 m2) of conditioned floor area served by that system when tested at a pressure differential of 0.1 inches w.g. (25 Pa) across the entire system, including the manufacturer's air handler enclosure. During testing:
  1. Block, if present, ventilation air duct(s) connected to the conditioning system.
  2. The duct air leakage testing equipment shall be attached to the largest return in the system or to the air handler.
  3. The filter shall be removed and the air handler power shall be turned off.
  4. Supply boots or registers and return boxes or grilles shall be taped, plugged, or otherwise sealed air tight.
  5. The hose for measuring the 25 Pascals of pressure differential shall be inserted into the boot of the supply that is nominally closest to the air handler.
  6. Specific instructions from the duct testing equipment manufacturer shall be followed to reach duct test pressure and measure duct air leakage.
1103.3.3.2 Duct leakage to the outside. Conduct the test using fan pressurization of distribution system and building at a fixed reference pressure for combined supply and return leak. Duct leakage to the outside shall be less than or equal to 3 CFM (85 L/min) per 100 ft2 (9.29 m2) of conditioned floor area served by that system when tested at a pressure differential of 0.1 inches w.g. (25 Pa) across the entire system, relative to the outside, including the manufacturer's air handler enclosure.

During testing:
  1. Block, if present, the ventilation air duct(s) connected to the conditioning system.
  2. The duct air leakage testing equipment shall be attached to the largest return in the system or to the air handler.
  3. The filter shall be removed and the air handler power shall be turned off.
  4. Supply boots or registers and return boxes or grilles shall be taped, plugged, or otherwise sealed air tight or as tight as possible.
  5. The hose for measuring the 25 Pascals of pressure differential shall be inserted into the boot of the supply that is nominally closest to the air handler.
  6. Open all interconnecting doors in the building, close dampers for fireplaces and other operable dampers.
  7. Set up an envelope air moving/flow-regulating/flow measurement assembly, such as a blower door, following the manufacturer's prescribed procedure.
  8. Specific instructions from the duct testing equipment manufacturer shall be followed to reach duct test pressure and measure duct air leakage used in combination with a blower door. Typical steps are as follows:
    1. Depressurize the ductwork system to 25 Pa using the measurement hose in Step 5 above.
    2. Depressurize the house to 25 Pa using an envelope air moving/flow-regulating/flow measurement assembly, such as a blower door.
    3. Correct the duct pressure to measure 0 Pa of pressure differential between the house and the ductwork system.
    4. Read the CFM of duct leakage using the procedures for the specific equipment being used. (Note that most automatically calculating pressure gauges cannot compute the CFM25 automatically with a duct-to-house difference in pressure of 0 Pa, so the gauge setting should be set to read CFM instead of CFM25).

Complete one duct leakage report for each HVAC system serving the home:

  Property Address:___________________________________________________
HVAC System Number:____________Describeaea of home served:__________
CFM25 Total________. Conditioned Floor Area(CFA) served by system:_____s.f.
CFM25 x 100 divided by CFM = _____ CFM25/100SF
(e.g. 50 CFM25 x 100/2,000 CFA = 2.5 CFM25/100SF)
Fan attachment location______________
Company Name_____________________________________________________
Contact Information:_________________________________________________
___________________________________________________________________
____________________________________          ________________________
Signature of Tester                                                  Date

Permit Holder, NC Licensed General Contractor, NC Licensed HVAC Contractor,
NC Licensed Home Inspector, Registered Design Professional,
Certified BPI Envelope Professional, or Certified HERS Rater
(circle one)
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