FAQs and Technical Questions

These are “actual” responses from the Illinois Office of Energy & Recycling, Department of Commerce and Economic Opportunity (DCEO), regarding provisions of the Illinois Energy Efficient Building Act [“the Act” 20 ILCS 3125], and categorized by Code Section for the utility of code users. The Technical Opinions offered with respect to the Act, including ACCA Technical Reference Notes, are not exclusive, but offered willingly and openly to provide technical support and clarification of the International Energy Conservation Code® (IECC) with Illinois Amendments, as it applies to the State of Illinois for jurisdictions, home builders, design professionals and members of the Illinois construction community.

The opinions are based solely on information provided by the inquirer. The Illinois Office of Energy & Recycling has made no independent effort to verify the accuracy of the submitted information, nor have we conducted a review beyond the scope of the questions involved.

While the Technical Opinions provided here are approved by the Illinois Office of Energy & Recycling and represent the official position of the Department of Commerce, please note that only the code official has the authority to administer and enforce the code and that the opinions of the Illinois Office of Energy & Recycling are advisory.

Energy Code Interpretations of the 2015 Energy Conservation Code – Email your questions or call 1-708-770-0554 for technical interpretations of the 2015 International Energy Conservation Code (IECC), with amendments, as it applies to the State of Illinois.

Illinois Energy Conservation Code Training and Support Program 2015
IECC – Frequently Asked Questions- 2015 IECC

1. The Act and ENFORCEMENT

Q: Our legal department has determined that since we have adopted by reference the 2006 IECC before May, 15 2009 our jurisdiction is not required to enforce the 2015 IECC for residential construction.

A: On issues pertaining to the provisions of the Illinois Energy Efficient Building Act [20 ILCS 3125] specific to Home rule communities, please note the following language as excerpted from the Act [20 ILCS 3125/45(b)], addressing Home rule units, “… the following entities may regulate energy efficient building standards for residential buildings in a manner that is more stringent than the provisions contained in this Act.” [Underline for emphasis].

Therefore, jurisdictions adopting by reference the 2006 IECC before May, 15 2009, may only elect to enforce the current Illinois Energy Conservation Code with Illinois Amendments, or amend and enforce such amendments to the code in a manner that is more stringent than the residential provisions of the 2015 IECC. Regardless, the provisions of the 2015 IECC for residential buildings, with Illinois Amendments, are to be enforced at a minimum, in accordance with the Act.

2. The Act and USGBC LEED

Q: I was recently in a meeting with an architect in which they asserted that their project would be LEED Certified and that jurisdictions accept that as being compliant with the IECC. Can you confirm for me that a LEED Certified building, by design, is considered compliant with the IECC?

A: No. LEED certification does not guarantee compliance with the Illinois Energy Efficient Building Act (i.e., 2015 IECC or ASHRAE 90.1-2013, referenced therein). While there is language in the IECC addressing “Above code programs,” one must be particularly familiar with the edition/version of the U.S. Green Building Council’s voluntary, non-consensus-developed Leadership in Energy and Environmental Design (LEED) building certification program(s) before equating the level of energy efficiency therein to that obtained through compliance with the 2015 IECC

C102.1.1 Above code programs. The code official or other authority having jurisdiction shall be permitted to deem a national, state or local energy efficiency program to exceed the energy efficiency required by this code. Buildings approved in writing by such an energy efficiency program shall be considered in compliance with this code. The requirements identified as “mandatory” in Chapters 4 and 5 of this code, as applicable, shall be met.

For additional reading on the issue, please note that in October 2010, Henry Gifford, a public critic of LEED, filed a class action law suit against the USGBC and its founders personally on behalf of “consumers, taxpayers, building design and construction professionals.” The allegations were essentially fraud and false advertising, an anti-trust claim and a RICO claim. His theory was that the USGBC had falsely claimed that its rating systems make buildings save energy, and that building owners have spent more money to have their buildings certified, that professionals have gotten worthless professional credentials, and people in general have been duped into thinking LEED, alone, saves more energy than model energy codes. The Complaint can be downloaded here.

“You had to know this was coming.” Mr. Gifford’s Lanham Act and Consumer Fraud Act claims against the USGBC were ultimately dismissed with prejudice in August of 2011. A copy of the Order is available here.

This order may not be the end of the Gifford v. USGBC story. Gifford may appeal, and he retains the opportunity to file his state claims in New York state court. Moreover, since the Judge did not resolve the merits of the claims, the debate over whether LEED buildings save more energy than model energy codes is likely to rage on.

3. The Act and REM/rate

Q: I was recently in a meeting with an architect in which they asserted that their project would be evaluated using the REM/Rate software tool. Can you confirm for me that a REM/Rate report is considered compliant with the IECC?

A: Our attention was drawn to homes being constructed in your jurisdiction recently by way of comments shared by the folks coordinating the REMrate submittals for these projects. They mentioned some form of “miscommunication” relative to the acceptance of this procedure.

There is nothing unusual with this request, there remain pockets of misconception regarding the development/review/acceptance of the REM/rate tool. In fact, as of our State-sponsored spring 2016 trainings, the three lone ERI/HERS software developers either had not yet developed or delayed the release of their 2015 IECC and 2015 Illinois-specific compliant versions as follows: a) NORESCO released a 2015 IECC ERI/HERS-compliant version 7/1/2016, b) the Florida Solar Energy Center released a 2015 IECC ERI/HERS-compliant version 3/31/2016, and Ekotrope plans to release a 2015 IECC ERI/HERS-compliant module in the fall of 2016.

By this message, the State Office of Energy & Recycling intends to clarify that the folks developing REMrate have made corrections/improvements and adjustments that that affect the opinions conveyed this past spring.

In rather lengthy opinion we issued in June of this year the Illinois Office of Energy & Recycling does not prohibit the use or REMrate v14.6.3, but rather encourages Illinois AHJ’s to obtain additional, comprehensive reports to support their energy compliance decisions. Accordingly, the Illinois Office of Energy & Recycling supports Illinois Authorities Having Jurisdiction (AHJ’s) embracing the continued use of REM/Rate v.14.6.3 (2015 IECC reports w/ Illinois Amendments) in accordance with Section R102, Alternative Materials & Methods. A consensus has been reached on the construction documents needed for permit applicants to submit in order to substantiate a REM/Rate v.14.6.3 submittal as follows:

  1. Architectural Construction Plans and Specifications
  2. Manual J, S, D Calculations
  3. REM v14.6.3, 2015 Illinois IECC Building File Report (a.k.a., Building Summary Report)
  4. REM v14.6.3, 2015 Illinois IECC Building Energy Cost Compliance Report
  5. REM v14.6.3, 2015 IECC “.blg” file
  6. REM v14.6.3, 2015 IECC Inspection Checklist

Moreover, the State would be pleased to visit with your plan reviewers/inspectors to assist in preparing staff to review these documents.

4. The Act, FARM RESIDENCES and AGRICULTURAL LAND USES

Q: May a county require building permits, building inspections, and impose fees with respect thereto, for farm residences built on land which is zoned for agricultural uses; and 2) under what circumstances are dwellings located on land zoned for agricultural uses considered “buildings or structures used or to be used for agricultural purposes” or “farm residences”?

A: The Energy Code applies to “any commercial or residential building or structure in this State for which a building permit application is received by a municipality or county.” 71 Ill Admin Code 600.110(c)(2). Therefore, the Code does NOT apply if no permit application is received, and since buildings declared for “agricultural use” do not require permits, the Code does not apply to such buildings.

Thomas Klein, General Counsel & Ethics Officer for the Illinois Capital Development Board writes, “For the reasons hereinafter stated, it is my opinion that, as a general principle, counties may not require the issuance of building permits or the performance of building inspections, or impose fees related thereto, for construction of farm residences which are built on land which is zoned for agricultural uses. If, however, a dwelling is situated on land which is zoned for agricultural purposes and the dwelling is used solely for residential purposes by persons who are not engaged in agriculture, then the dwelling may not, in my opinion, be considered a farm residence.”

5. The Act and ISBE PUBLIC SCHOOLS

Q: Does Illinois’ adoption of the 2015 IECC exempt public school facilities?

A: Yes. Please note, however, that the Illinois State Board of Education (ISBE) is tasked with adopting codes for public schools and therefore those facilities are not required to comply with the Illinois Energy Conservation Code (2015 IECC w/ Illinois amendments).

So then, since public K-12 facilities are covered by the Illinois School Code (viewed at http://www.ilga.gov/legislation/ilcs/ilcs4.asp?DocName=010500050HArt%2E+2&ActID=1005& ChapterID=17&SeqStart=14200000&SeqEnd=34150000), and in accordance with (105 ILCS 5/2- 3.12(c)) of the Illinois Administrative Code (ILCS); The document applicable to buildings and structures constructed and renovated by ISBE “… shall be known as the “Health/Life Safety Code for Public Schools” and shall be the governing code for all facilities that house public school students or are otherwise used for public school purposes, whether such facilities are permanent or temporary and whether they are owned, leased, rented, or otherwise used by the district.”

The codes that are required for public schools are further defined in the Illinois Administrative Code Title 23, Part 180.60:

Section 180.60 Applicability

a) Except as provided in subsection (b), every facility other than a vehicular facility shall conform to the standards identified in this subsection (a) and published by the International Code Council, Inc., 4051 W. Flossmoor Road, Country Club Hills IL 60478-5795, unless a variance or waiver is obtained pursuant to Section 180.70 or use of a temporary facility is authorized pursuant to Section 180.230. No later amendments to or editions of these standards are incorporated. The legal occupancy of any facility that existed on or before June 30, 2016 shall be permitted to continue without change; however, any repairs, alterations, occupancy changes, relocation and/or additions to these existing facilities are subject to the 2015 International Existing Building Code (also see Appendix A of this Part). With respect to any project for which the design contract is executed on or after July 1, 2016, the applicable standards shall be the 2015 International Building Code and its subcodes, as follows:

  1. the 2015 International Energy Conservation Code (IECC);
  2. the 2015 International Existing Building Code (IEBC);
  3. the 2015 International Fire Code (IFC), excluding Chapter 4;
  4. the 2015 International Fuel Gas Code (IFGC);
  5. the 2015 International Mechanical Code (IMC); and
  6. the 2015 International Property Maintenance Code (IPMC).

b) The applicability of the codes listed in subsection (a) shall be limited as set forth in this subsection (b).

1. Emergency and Crisis Response. Instead of Chapter 4 of the International Fire Code, the provisions of 29 Ill. Adm. Code 1500 (Joint Rules of the Office of the State Fire Marshal and the Illinois State Board of Education: School Emergency and Crisis Response Plans) shall apply.

2. Administrative Provisions

  • A) Instead of the Plumbing Code listed in Section 101.4.3 and referenced elsewhere in the International Building Code, Section 180.60(b)(5) of this Part shall apply
  • B) Instead of Sections 102.6 and 102.6.2 of the International Building Code and Section 101.4.2 of the International Existing Building Code, Section 180.60(a) of this Part shall apply.
  • C) Instead of Sections 103 through 106, 109, and 111 through 115 of the International Building Code, the requirements of Sections 180.40 through 180.70, 180.200 through 180.230 and 180.300 through 180.420 of this Part shall apply.

3. Storm Shelters. Instead of the provisions contained in Section 423 of the International Building Code, the ICC/NSSA Standard for the Design and Construction of Storm Shelters (ICC 500-2014), published jointly by the International Code Council and the National Storm Shelter Association, shall apply. No later amendments to or editions of these standards are incorporated.

  • A) The standards of this subsection (b)(3) shall apply to any new school building construction project for which the design contract was executed on or after January 1, 2015. (See Section 2-3.12(e-5) of the School Code.)
  • B) As used in this subsection (b)(3), “new school building construction” means:
  • i) any new, stand-alone school building with an aggregate Group E occupant load of 50 or more, as defined in Section 305 of the International Building Code; or
  • ii) one or more additions to an existing school building completed within a period of 24 months that increases the total square footage of the remaining existing building by 50% or more. The storm shelter, which may be placed in the new addition or the existing building, must have sufficient capacity to serve both the addition or additions and the existing building.

4. Accessibility. International Building Code, the Illinois Accessibility Code (71 Ill. Adm. Code 400) shall apply (except as provided in Section 10-20.51 of the School Code [105 ILCS 5/10- 20.51] regarding press boxes).

5. Plumbing. Instead of the plumbing provisions set forth in Section 101.3.2 of Chapter 1 and incorporated in Chapter 35 of the International Building Code, the requirements set forth in the Illinois Plumbing Code (77 Ill. Adm. Code 890) and Section 405.3.1 of the 2015 International Plumbing Code shall apply.

6. Boiler and Pressure Vessel Safety.  Instead of the provisions set forth in Chapter 20 of the International Mechanical Code, the requirements set forth in the Illinois State Fire Marshal’s rules titled Boiler and Pressure Vessel Safety (41 Ill. Adm. Code 120) shall apply.

7. Elevators. Instead of the elevator provisions in the International Building Code, the requirements set forth in the Illinois State Fire Marshal’s rules titled Illinois Elevator Safety Rules (41 Ill. Adm. Code 1000) shall apply.

8. Sprinkler Systems. In conjunction with the sprinkler requirements set forth in Section 22-23 of the School Code, the International Building Code, and the International Fire Code, the requirements set forth in 41 Ill. Adm. Code 109.110 (Compliance Standards) shall apply.

(Source: Amended at 40 Ill. Reg. 3059, effective January 27, 2016)

Illinois Energy Conservation Code Training and Support Program 2015
IECC – Frequently Asked Questions- 2015 IECC

1. C401.2 APPLICATION IECC vs. ASHRAE 90.1

Q: For commercial buildings, do 2015 IECC Sections C401.1, Scope, and 401.2, Application, allow the permit applicant to mix-and-match provisions of IECC Chapter CE 4 and ASHRAE Standard 90.1-2013 on a single permit application for compliance assessment?

A: No, designers are not permitted to “cherry-pick” a customized path to compliance by combining provisions of both Standard 90.1 and the IECC. In fact, Section C401.2 now requires the designer to demonstrate compliance with either the provisions of IECC Chapter CE 4 (in its entirety) or the provisions of Standard 90.1 (in its entirety); no combination thereof is permitted. (C401.2)

2. C401.2 APPLICATION – MEMBRANE-COVERED STRUCTURES

Q: An 8,500 s.f. membrane-covered frame structure is proposed for receptions and similar uses during early fall, inclement winter and late spring weather. The Jurisdiction has received a request that the structure only be erected for a maximum of 180 days so that they can fall into a temporary structure status. The design team proposes that this structure go up in the winter and down in the summer each year. They are proposing to condition the structure with eight, 6-ton air-conditioning units, and a permanently connected, natural-gas-fed HVAC unit. These units will be metered and supplied with permanently connected 800 Amp electrical service. Does this type of structure need to comply with any of the requirements of the IECC? If so, is there anything that can be done to get this exempt?

A: From the inquiries the State has received over the years, membrane-covered tent and dome structures, such as this one, are very difficult to meet code and typically, if enforced, an annual total building energy simulation must be done to demonstrate compliance which could result in hiring a consultant who specializes in whole building analyses. The State conducted a blind “straw-poll” of several jurisdictions in the suburban Chicago-land area for their candid opinions. These are experienced men and women in code enforcement and leadership positions with whom we have consulted in the past on issues of interest to the State Office of Energy & Recycling. Their unattributed responses follow:

1) “Given the permanent nature of this temporary structure, I find it hard, in good conscience, to give them a pass from the requirements of the IECC by the very nature of what it is supposed to be doing. However, the 90-day temporary plus one, 90-day extension is the limit. It may be that the political will of the jurisdiction (economic development, Mayor, and/or trustees) would need to be brought to bear in order consider other circumstances when granting the building department, the authority to go beyond 180 days.”

2) “We do not permit Membrane structures. It does allow tents on a temporary basis 90 days with the possibility of one 90-day extension. We would not impose the requirements of the IECC for a temporary tent.”

3) “By definition, the tent is a building. The IECC covers all buildings but gives no guidance on “temporary” use. ICC please wake up here. No matter what you call it, the tent will not be able to meet the straight requirements of the IECC. Think of the R-value for the membrane walls and roof along with single pane plastic windows. What I have done in the past is just make sure that the mechanical units themselves meet the code. Nothing you can do with the rest in my opinion.”

4) “It is the position of this jurisdiction is that:

  • a. It would have to be approved by the Planning & Zoning Commission and the Village Board as a special use (temporary uses are only allowed for 30 days twice a year by zoning);
  • b. It would have to be protected by an automatic sprinkler system (local municipal code amendment);
  • c. The permanent installation of HVAC and electrical service to this structure renders the temporary nature of the structure void in our opinion;
  • d. If the above doesn’t kill it, 2012 IECC C101.3 does not list an exemption for temporary structures or uses. It states “…over the useful life of each building.”

We hope this assists you in arriving at a decision.

3. SECTION C402.1.1 – LOW-ENERGY BUILDINGS

Q: How might the Illinois Energy Conservation Code (2015 IECC) apply to a car-wash facility as a separate building?

A: In short, this type of project need not comply with the building thermal envelope provisions of the Illinois Energy Conservation Code (2015 IECC w/ Illinois amendments). Bottom-line, only buildings or portions thereof considered conditioned space “primarily for human comfort” are required to meet the provisions of Illinois Energy Conservation Code.

More specifically, Section C402.1.1, Item 2, allows us to exempt this type of facility as it does not contain conditioned space.

Much of the interest in this and similar occupancy types, dates to when the scope and intent of the IECC had been greatly reduced and inadvertently simplified as a result of changes proposed by the U.S. Department of Energy during 2006 and 2009 code development cycles. Drawing your attention to the language found in section 101.2 of the 2003 IECC as it reads, “… as well as those portions of factory and industrial occupancies designed primarily for human occupancy.” It is this phrase that had been (inadvertently) omitted from the 2009 IECC code language and subsequent editions. Note, however, that the Illinois Energy Office still supports and upholds this intent of the code for car wash facilities, as we have with similar situations, such as with greenhouses (now specifically exempt C402.1.1(3), municipal booster pumping stations, and wastewater treatment plants.

Note, it is within the discretion of the Authority Having Jurisdiction to evaluate the specific circumstances, and whether the heating is, indeed, “primarily (66.7%)” for the comfort of workers/human traffic, or rather to maintain the temperature of the “commercial commodity” being sold or the “integrity of the industrial process,” to avoid “spoilage” or a “process malfunction,” respectively.

IMPORTANT: Regardless, commercial buildings provided with service water heating (e.g., lavatories) and electric lighting systems shall meet the applicable provisions of the IECC.

4. TABLE C402.1.3 – METAL BUILDINGS

Q: A metal building roof is proposed using batten insulation lapping over purlins and girts. The insulation is compressed at all girts and purlins so R-values will be significantly less at these locations. Are the values specified for “Metal Building Roofs” intended to be maximums, minimums or averages?

A: Often referred to in the industry as “through-fastened” or “screw-down” metal roofing, a complying prescriptive option no longer exists in the 2015 IECC where the batten insulation is simply draped over purlins and then compressed as the metal purlins (spanning members) are attached. The 2015 IECC now addresses this matter by requiring all metal building roof systems to be provided with “thermal spacer blocks” to limit conduction and a Liner System (LS) to limit air leakage. (Table C402.1.3, Footnote ‘b’) Simply put, a metal building roof complies with the 2015 IECC where the battens are installed along with R-3.5 “thermal spacer blocks.” No area-weighted averaging, effective averaging, or averaging of any kind is permitted. While somewhat dated, the NAIMA Compliance Guide for Metal Buildings (MB304) provides additional detail for typical metal building construction assemblies, and may be found at the following URL: http://insulationinstitute.org/wp-content/uploads/2015/12/MB304.pdf. (Table C402.1.3)

5. C402.2.2 ROOF ASSEMBLY – TAPERED INSULATION

Q: Could you explain the “tapered insulation” provisions of the 2015 IECC?

A: The minimum R-30ci [Table C402.1.3] applies to the area-weighted average U-factor (U- 0.032) from Table C402.1.4 for the tapered insulation assembly. However, at no point (i.e., at roof drains) is the thickness of insulation to vary more than 1-inch (25 mm) from the required minimum R-30ci. For instance, if the density of the proposed insulation were R-5/in., and the code-required minimum R-value is R-30ci, then the minimum thickness of insulation permissible at roof drains (i.e., where the taper begins) would be 5-inches (i.e., 6-in. x R-5/in. = R-30ci; 5-in. x R-5/in. = R-25ci).

Put another way, Exception 2 to Section C402.2.2 is such that a deficit of no more than 1-inch of insulation is allowed at any point within the roof field [i.e., provided the field is thickened elsewhere to compensate for areas where insulation levels are less than the minimum R-value (thickness in inches) required], such that the overall, area-weighted average insulation U-factor for the entire roof field achieves the minimum U-factor equivalent to the R-value specified in Table C402.1.3. We see the exception allowing a degree of latitude, while requiring a minimum level of insulation over the entire roof field so as to minimize issues of condensation and energy performance for roofs.

6. R402.4 AIR LEAKAGE (Mandatory)

Q: If you install some form of permanent heating (radiant, warm-air forced-air, or heat-pump) in a garage does the garage have to meet the thermal envelope requirements of the IECC?

A: Not exactly. Illinois amendments to Section R402.4.1.2, now afford an Exception for newly constructed and existing garages (attached and detached) where heating is proposed. In most cases, once the input capacity of the heater (or unit heater) exceeds 3.4 Btu/h • ft2 (1.0 W/ ft2) of floor area, the space, in this case the garage, is considered “conditioned” space. Therefore, the surrounding walls, windows, doors, overhead doors, roof, and slab-edge become the boundary of the building thermal envelope and must be insulated. However, utilizing the newly developed/amended Section R402.4.1.2, Exception 2, as long as the heated (or newly heated) Garage is “thermally isolated” from other habitable, conditioned areas of the home, the airleakage testing provisions of the code (R402.4.1.2) do not apply to new construction. Furthermore (and for both New! and alterations to existing homes), the exterior walls, roof/ceilings, windows and doors are to meet the applicable “Thermal Isolation” provisions of Sections R402.2.13 and R402.3.5, as well as the envelope tightness and insulation installation items in Table R402.4.1.1, applicable to the method of construction. (R101.4, R402.2.13, R402.3.5, R402.4.1.2)

7. R402.5.7 VESTIBULES – AIR-CURTAIN

Q: Is the installation of an air curtain a suitable alternative to the vestibule requirements of IECC Section C402.5.7?

A: Yes. The newly added Exception 7 to this section provides the technical specifications and performance standard needed for adding an effective alternative to vestibule construction, saving valuable floor space.

8. C402.4.1.1, C402.4.1.2, C405.2.3 INCREASED GLAZING/SKYLIGHT AREA W/ DAYLIGHT-RESPONSIVE CONTROLS 2012 IECC (An Illinois legacy code)

 Q: Is daylight harvesting and thereby, daylight zone control required by the 2012 IECC?

A: Yes, but recall, that users of the IECC may choose their own path to compliance based on the circumstances and the owner’s project requirements: either Compliance with IECC Chapter C4 (in its entirety), or Compliance with ASHRAE Standard 90.1-2010 (in its entirety).

The 2012 IECC requires daylight harvesting where the design professional seeks window-to-wall ratios greater than 30 percent (up to and including 40 percent) and/or skylight areas greater than 3 percent (up to and including 5 percent). Accordingly, the lamps for general lighting in the daylight zone areas shall be manually controlled by at least one multilevel photo-control (including continuous dimming devices).

Daylight harvesting is also required for certain spaces >10,000 ft2, with ceiling heights >15 feet, and located directly under a roof. No less than half of the floor area shall be located in a daylight zone for spaces meeting the aforementioned criteria and used as an office, lobby, atrium, concourse, corridor, storage, gymnasium/exercise center, convention center, automotive service, manufacturing, non-refrigerated warehouse, retail store, distribution or sorting areas, transportation or workshop. Specific exceptions apply. (2012 IECC C402.3.2)

The ASHRAE 90.1 Standard, 2010 Edition, also requires daylight harvesting where the combined primary side-lighted area in any enclosed space equals or exceeds 250 ft2. Accordingly, the lamps for general lighting in the primary side-lighted area shall be separately, but automatically, controlled by at least one multilevel photo-control or continuous dimming device.

Automatic daylighting controls for top-lighting are required by ASHRAE 90.1 where the total daylight area under skylights plus the total daylight area under rooftop monitors in an enclosed space exceeds 900 ft2. Accordingly, the lamps for general lighting located partially or entirely within the daylight area shall be separately, but automatically, controlled by at least one multilevel photo-control or continuous dimming device.

Daylight harvesting is also required by ASHRAE 90.1 for certain spaces >5,000 ft2, with ceiling heights >15 feet, and located directly under a roof. No less than half of the floor area shall be located in a daylight zone for spaces meeting the aforementioned criteria and used as an office, lobby, atrium, concourse, corridor, storage, gymnasium/exercise center, convention center, automotive service, manufacturing, non-refrigerated warehouse, retail store, distribution/sorting area, transportation or workshop. Specific exceptions apply. (2012 IECC C402.3.2)

 

 Q2: Under the 2012 IECC, are manual daylighting controls permitted when the increase from 30 percent to 40 percent fenestration area is used?

A2: No, a manually-actuated daylighting control strategy is not permitted by the 2012 IECC.

Section C405.2.2.3.1 requires manual daylighting controls to be installed unless automatic daylighting controls are installed in accordance with C405.2.2.3.2.

Section C402.3 required automatic daylighting controls specified in Section C402.3 to comply with Section C405.2.2.3.2.

Section C402.3.1.1, Item #2, clearly states that automatic daylighting controls are required to be installed when the increase from 30 to 40 percent vertical fenestration area is desired.

So, automatic daylighting controls complying with Section C405.2.2.3.2 are required and manually-actuated daylighting controls are not permitted.

 

 Q3: Under the 2012 IECC, are manual daylighting controls permitted when the increase from 3 percent to 5 percent fenestration area is used?

A3: No, a manually-actuated daylighting control strategy is not permitted by the 2012 IECC.

Section C405.2.2.3.1 requires manual daylighting controls to be installed unless automatic daylighting controls are installed in accordance with C405.2.2.3.2.

Section C402.3 required automatic daylighting controls specified in Section C402.3 to comply with Section C405.2.2.3.2.

Section C402.3.1.2 clearly states that automatic daylighting controls are required to be installed when the increase from 3 to 5 percent skylight area is desired.

So, automatic daylighting controls complying with Section C405.2.2.3.2 are required and manually-actuated daylighting controls are not permitted.

 

 Q4: Under the 2012 IECC, are manual daylighting controls permitted in daylight zones under skylights when the minimum skylight fenestration area is used for an enclosed space greater than 10,000 ft2 directly under a roof with a ceiling height greater than 15 feet?

A4: No, a manually-actuated daylighting control strategy is not permitted by the 2012 IECC.

Section C402.3.2.1 requires all lighting in the daylight zone to be controlled by multi-level lighting controls that comply with Section C405.2.2.3.3.

Section C405.2.2.3.3 describes two methods of multi-level light controls. Both methods are actually “automatic daylighting control” methodologies.

Method #1: The general lighting in the daylight zone is separately controlled by at least one multi-level lighting control that “reduces the lighting power in response to daylight” available in the space.

Method #2: Where the daylit illuminance in the space is greater than the rated illuminance of the general lighting of daylight zones, the general lighting shall be automatically controlled so that its power draw is not greater than 35 percent of rated power.

So, multi-level light controls (automatic daylighting controls) complying with Section C405.2.2.3.3 are required and manually-actuated daylighting controls are not permitted.

9. C403.2.4.7 ECONOMIZER FAULT DETECTION AND DIAGNOSTICS (FDD)

I am Applications Engineer with an OEM and we have been doing a lot of research for our customers lately that are trying to interpret the 2015 IECC correctly. We have come across NEW! provisions for Economizer Fault Detection and Diagnostic controls and have a few questions: 

Q1: Must one or all seven FDD measures be met by the OEM’s FDD system?

A1: The answer is that indeed an OEM’s FDD system must comply with ALL of the terms outlined in Items (1-7) for compliance with Section C403.2.4.7.

 

Q2: Regarding Section C403.2.4.7, Item 6: In a light commercial situation (i.e., HVAC equipment between 3 and 60 tons cooling capacity) can we use a thermostat that only indicates there has been an economizer fault of some kind?

  • 6. The unit shall be capable of reporting faults to a fault management application accessible by day-to-day operating or service personnel, or annunciated locally on zone thermostats.

A2: We believe so, Yes. Two items in both the code and the literature review give us cause to support this determination:

1. The code language requires fault reporting and detection to be, “…accessible by day-today operating or service personnel, or annunciated locally on zone thermostats.”

  • a. Locating the FDD reporting/detection/annunciation device inside the equipment enclosure is “not accessible” to day-to-day operating personnel unless there is some form remote monitoring or communication to a central service location.
  • b. Locating the FDD reporting/detection/annunciation device on the outside of/on the equipment enclosure is “not accessible” to day-to-day operating or service personnel as this presumes the building owner, operator or service personnel are visiting these “roof-top” locations with regularity, day-to-day.
  • c. Locating the FDD reporting/detection/annunciation device on/at the zone thermostat is “accessible” to day-to-day operating or service personnel.

2. The Western Cooling Efficiency Center (WCEC) report by Heinemeier, under “Definition of FDD Approaches” (p.15) reads, “The objective of an FDD system is to detect faults early, diagnose their causes, and enable correction of the faults before additional damage to the system or loss of service occurs. This is accomplished by continuously monitoring the operating conditions and comparing them to a model of expected performance. When actual measured operation does not match expectations determined with use of a model, a fault is detected. Ultimately, the objective is to ensure that the building owner or operator will respond in an appropriate manner, remedying the problem.”

 

Q3: Do we have to provide a device that indicates all faults?

A3: Yes. The OEM or FDD manufacturer shall provide an FDD system that complies with ALL of the terms outlined in Items (1-7) for compliance with Section C403.2.4.7. Put another way, the FDD system (or Thermostat) must be “configured” to annunciate under all of the fault conditions/terms identified in Section C403.2.4.7

 

Q4: We have looked for FDD devices and have not found anything on the market other than a networked product.

A4: While dated to 2011, a review of the CASE Study, particularly Figure 5, Third Party FDD System Faults Detected (p.17), cites that a number of third party systems, in addition to HVAC OEMs offer fault detection on some of their currently available (2011) models.

Upon a cursory analysis of thermostat products, we found three “off the shelf” thermostats meet all of the control requirements and can display the fault alert from the economizer controller.

  • Honeywell Prestige IAQ with EIM accessory board
  • Honeywell VisionPro with EIM accessory board
  • Venstar Voyager T4900

10. C403.4.1.1 FAN AIRFLOW CONTROL – APPLICABLE TO DX UNITS

I am an Applications Engineer with an OEM and we have been doing a lot of research for our customers lately that are trying to interpret the 2015 IECC correctly. We have come across a code “loophole” that some of our competitors appear to be using and we were hoping to get some clarification on it.

Attached is the code excerpt indicating the Fan Airflow Control only required for “Multiple Zone” systems, yet the language refers to Direct expansion (DX), single-zone units. This obviously has a huge impact on what type of unitary packaged units might be acceptable, since other portions of the code seem to indicate constant volume units need not comply.

C403.4.1.1 Fan airflow control. Each cooling system listed in Table C403.4.1.1 shall be designed to vary the indoor fan airflow as a function of load and shall comply with the following requirements:

  • 1. Direct expansion (DX) and chilled water cooling units that control the capacity of the mechanical cooling directly based on space temperature shall have not fewer than two stages of fan control. Low or minimum speed shall not be greater than 66 percent of full speed. At low or minimum speed, the fan system shall draw not more than 40 percent of the fan power at full fan speed. Low or minimum speed shall be used during periods of low cooling load and ventilation-only operation.
  • 2. Other units including DX cooling units and chilled water units that control the space temperature by modulating the airflow to the space shall have modulating fan control. Minimum speed shall be not greater than 50 percent of full speed. At minimum speed the fan system shall draw not more than 30 percent of the power at full fan speed. Low or minimum speed shall be used during periods of low cooling load and ventilation only operation.
  • 3. Units that include an airside economizer in accordance with Section C403.3 shall have not fewer than two speeds of fan control during economizer operation.

Q1: Does Illinois accept constant volume (single fan speed) packaged RTUs with economizer on single zone applications?

A1: No. Such systems are not permitted. Perhaps we should direct you to similar language found in Section C403.3.1 (excerpted below). In this case, DX systems equipped with and air economizer must meet Section C403.3.1, Line items 1 and 2 or Line Items 1 and 3. The fan airflow control provisions of Section C403.3.1 apply to single zone DX systems equipped with air economizers as they do in Standard 90.1-2013.

C403.3.1 Integrated economizer control. Economizer systems shall be integrated with the mechanical cooling system and be capable of providing 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 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 C403.3.1.

 

Q2: Do the multiple compressor staging requirements of Section C403.4.1.1 only apply to VAV controlled units?

A2: The requirements for multistage compressors in Section C403.3.1 apply to constant volume systems as well as those in Section C403.4.1.1 applying to VAV systems. Multistage compressors work to maintain the correct supply air temperature in VAV systems. When the system is in full cooling the fan is at full speed and the compressors are all running at maximum. As the fan speed is modulated lower, the stages of compression are reduced to maintain the desired supply air temperature.

11. C405.2 LIGHTING CONTROLS (Mandatory)

Q1: Does the code require at least one manual lighting control (e.g., a switch, dial, sceneselector or pull-chain) for each area enclosed by floor-to-ceiling height partitions?

A1: Not exactly. However, “Manual-OFF” functionality is most often required. Recall that users of the IECC may choose their own path to compliance based on the circumstances and the owner’s project requirements: either Compliance with 2015 IECC Chapter 4 (in its entirety), or Compliance with ASHRAE Standard 90.1-2013 (in its entirety). Specific to lighting controls:

  •  The IECC requires specific spaces identified in Section C405.2.1 to be equipped with occupant sensor controls (either vacancy-based or occupancy-based). Manual-OFF functionality must be incorporated into these controls.
  • Standard 90.1-2013 requires certain spaces to have at least one automatic-FULL-off control (vacancy-sensing, 9.4.1.1(h)) or automatic-PARTIAL-off on (vacancy-sensing, partial-off, 9.4.1.1(g)) with the first step at 50 percent power. In addition to all off and full on, Standard 90.1 buildings shall afford a control step between 30-70 percent power in all spaces (9.4.1.1(a)), with limited exceptions. (9.4.1.1, Table 9.6.1)

Occupancy sensors with either vacancy-sensing or occupant-sensing capability are now required in:

  • Both IECC and 90.1: Classrooms/lecture/training rooms, Conference/ meeting/ multipurpose rooms, Copy/ print rooms, Lounges, Employee lunch and break rooms, Restrooms, Janitorial closets, Locker rooms, Warehouses;
  • 2015 IECC Only: Private offices, Storage rooms of any size, Warehouses of any size, and “Other spaces” ≤ 300 ft2 with floor-to-ceiling height partitions;
  • Standard 90.1 Only: Private offices ≤ 250 ft2, Storage rooms 50 ft2 ≥ x ≤ 1,000 ft2, and Dressing rooms.

12. C407 TOTAL BUILDING PERFORMANCE & ASHRAE 90.1–Appendix ‘G’

Q: Most of our projects are energy modeled and most are also LEED buildings. Our project teams typically use ASHRAE 90.1-2010, Normative Appendix G to prove both code and LEED compliance. As the State pointed out in their seminar, the newly appropriated Informative Appendix G is not intended (and thereby, excluded) as a compliance path in the latest ASHRAE 90.1-2013 Standard. We will now be forced to use 90.1-2013 Chapter 11 (Energy Cost Budget – ECB) methodology to prove code compliance and 90.1-2010 Normative ‘G’ for LEED v.4 compliance.

We are currently comparing various installation combinations between ASHRAE 90.1-2010, Normative ‘G’ and Chapter 11 ECB. We are hoping you have some insight:

  • As to why ASHRAE did not intend Appendix ‘G’, Normative or Informative, to be considered a compliance path?
  • Is one modeling method (Ch. 11 ECB vs Normative ‘G’) “more conservative” (strict) than the other?
  • Why ASHRAE is favoring the more rigid energy modeling method (Ch. 11 ECB) over the method that promotes a methodology for modeling/incorporating advanced energy conservation measures into the design (Normative ‘G’)

There are a variety of ways that the relationships among can be interpreted, please explain?

A: Compliance with LEED EA1 via ASHRAE 90.1-2010, Informative* Appendix ‘G’ is not considered an ASHRAE 90.1 or IECC code-equivalent compliance path. Rather, it is only recognized within the voluntary, non-consensus-developed LEED building certification program for credit therein.

At this point (and note particular emphasis), Illinois is not convinced that LEED certification alone (i.e., Compliance with EA1 and a reliance upon the ASHRAE 90.1-2010, Informative* Appendix ‘G’) guarantees compliance with the 2015 IECC (Illinois Energy Efficient Building Act) or the equivalent energy efficiency provisions of ASHRAE 90.1-2013, referenced therein. Particularly due to the inconsistencies in the 90.1-2013, Chapter 11 – Energy Cost Budget (ECB) approach vs. the non-consensus, Informative Appendix ‘G’ located in 90.1-2010 as is required by LEED v.4. * “Informative” Appendices are not code-enforceable extensions of the ASHRAE 90.1 Standard.

The response of the Office of Energy & Recycling to Illinois stakeholders remains as follows with regard to LEED Credit EA1:

  • LEED certification (i.e., Compliance with LEED v.4 Credit EA1 and a reliance upon ASHRAE 90.1-2010, Informative Appendix ‘G’) does not guarantee compliance with the Illinois Energy Efficient Building Act (2015 IECC, or ASHRAE 90.1-2013 referenced therein). ASHRAE 90.1 Informative Appendix ‘G’ is not a code-enforceable extension of the ASHRAE 90.1-2013 Standard. While there is language in the IECC addressing “Above code programs” (see Section C102.1.1), the requirements identified as ‘mandatory’ must still be met. Even the most experienced design professionals must be particularly familiar with the coordination and relationship of edition and version of USGBC’s voluntary, non-consensus-developed, LEED building certification program— particularly the referenced standards within—before equating a level of energy efficiency sought by LEED to that obtained by means of complying with either the 2015 IECC or the ASHRAE 90.1-2013 Standard.”

13. C503 LIGHTING ALTERATIONS

Q: With respect to Lighting Alterations, Section C101.4.3, Exception 7 has been deleted by the Illinois Energy Code Advisory Council (see Illinois Amendments). However, Section C506.3 allows alterations that replace less than 10 percent of the luminaires in a space, provided that such alterations do not increase the installed interior lighting power. There are a variety of ways that this exception can be interpreted, please explain?

A: If the scope of the work includes lighting and other IECC regulated systems, and less than 10% of the luminaires are replaced, the lighting alterations (alone) are exempt, provided that the lighting alterations (alone) do not increase interior connected lighting power beyond the former level of connected lighting power for the altered/affected spaces. Note the following:

  1.  Firstly, the code uses the term “SPACE,” which is otherwise not defined by the IECC, but for which ASHRAE Standard 90.1 provides a definition which the Illinois Office of Energy & Recycling embraces. A SPACE being defined as an area (single area) defined by floor to-ceiling-type partitions. Hence, we respond with this definition in mind.
  2. Secondly, please bear in mind that alterations typically involve the relocation or reconfiguration of existing tenant space partitions/walls. This is important in the sense that the permit applicant will need to determine the pre-alteration connected lighting power condition in order for affected spaces to establish the upper-bound of existing connected lighting power for the “floor-level” or “building-space(s)” being-altered to which the newly proposed connected lighting power load shall be compared.
  3. Thirdly, controls installed as direct replacements for existing controls are subject to the provisions of Section C405.2.

Lastly, the approach and suitable documentation shall be depicted on the construction documents and approved by the Authority Having Jurisdiction.

14. C503 ROOF ALTERATIONS

Q: Please explain RE-ROOFING as addressed in the 2015 IECC with Illinois Amendments?

A: The Office of Energy & Recycling has responded to the Chicago DoB, the Illinois State Board of Education, CRCA, NRCA, GAF and Johns Manville this year (2016), consistently. In responding to your question (and theirs), we offer solutions to each of the roofing terms defined in the IECC and the IBC below.

1) On issues pertaining to reroofing, roof recover, and roof replacement defined by the International Building Code (IBC) and the Illinois Energy Conservation Code (IECC), only items altered or affected by alterations, renovations or repairs to an existing building are required to conform to the provisions of the code as they relate to new construction. These definitions are integral to our interpretation:

REROOFING. The process of recovering or replacing an existing roof covering. See “Roof recover” and “Roof replacement.” This definition is the primary term from which “RECOVER” and “REPLACEMENT” are derived.

  • a) ROOF RECOVER. The process of installing an additional roof covering over a prepared existing roof covering without removing the existing roof covering. Section C503.1, Exception 5 addresses the issue. The new work must result in a roof assembly insulation level that is not less than the pre-existing Rvalue.
  • b) ROOF REPAIR. Reconstruction or renewal of any part of an existing roof for the purposes of its maintenance. Section C504.1, Exception 2 addresses the issue. The new work must result in a roof assembly insulation level that is not less than the pre-existing R-value.

2) ROOF REPLACEMENT. The process of removing the existing roof covering, repairing any damaged substrate and installing a new roof covering. Must comply with flat roof insulation requirement of R-30ci, unless the AHJ determines that the installation of insulation above the structural roof deck, and necessary to achieve a code-required R- 30ci (U-0.032), is deemed “technically infeasible” to accommodate the added thickness (i.e., HVAC or skylight curbs, flashing heights, VTR, drainage patterns, or parapets).

3) ROOF PEAL (not defined in the IECC or I-Codes). Such work does not meet any of the aforementioned definitions. Hence, the work must comply with flat roof insulation requirement of R-30ci, unless the AHJ determines that the installation of insulation above the structural roof deck, and necessary to achieve a code-required R-30ci (U- 0.032), is deemed “technically infeasible” to accommodate the added thickness (i.e., HVAC or skylight curbs, flashing heights, VTR, drainage patterns, or parapets).

15. C503 ALTERATIONS – LIGHTING ALTERATIONS

Q1: With respect to Lighting Alterations, Section C506.3 allows alterations that replace less than 10 percent of the luminaires in a space, provided that such alterations do not increase the installed interior lighting power. There are a variety of ways that this exception can be interpreted, please explain?

A1: If the scope of the work includes lighting and other IECC regulated systems, and less than

  • 1. Firstly, please note the code uses the term “SPACE,” which is otherwise not defined by the IECC, but for which ASHRAE Standard 90.1 provides a definition which the Illinois Office of Energy & Recycling embraces. A SPACE being defined as an area (single area) defined by floor-to-ceiling-type partitions. Hence, we respond to each of your questions below, in Blue, with this definition in mind.
  • 2. Secondly, please bear in mind that “renovations (a.k.a., alterations)” typically involve the relocation or reconfiguration of existing partitions/walls. This is important in the sense that the designer will need to determine the pre-alteration connected lighting power condition in order to establish the upper-bound of existing connected lighting power for “floor-level” or “building-area(s)” being-altered to which the newly proposed connected lighting power load shall be compared.
  • 3. Thirdly, controls installed as direct replacements for existing controls are subject to the provisions of Section C405.2.
  • 4. Lastly, the approach and suitable documentation shall be clearly depicted on the construction documents and approved by the Authority Having Jurisdiction.

 

Q2: If we relocate 7% of the fixtures and replace 2% of the luminaires, without increasing loads, are we within allowable limits of C506.3?

A2: The question you pose proposes the replacement of 2% of the luminaires which is less than the replacement threshold of 10% of the luminaires, so Yes. Subject to Items 1 – 4 in our response, above.

 

Q3: If we relocate 7% of the fixture and replace 9% of the luminaires, without increasing loads, are we within allowable limits of C506.3?

A3: The question you pose proposes the replacement of 9% of the luminaires which is less than the replacement threshold of 10% of the luminaires, so Yes. Subject to Items 1 – 4 in our response, above.

 

Q4: If we delete 3% of the luminaires, move 4% of the luminaires and add 3% of the luminaires, without increasing loads, are we within allowable limits of C101.4.3, Exception 7?

A4: The question you pose proposes the replacement of 3% of the luminaires which is less than the replacement threshold of 10% of the luminaires, so Yes. Subject to Items 1 – 4 in our response, above.

Illinois Energy Conservation Code Training and Support Program 2015
IECC – Frequently Asked Questions- 2015 IECC

1. R402.1.1 VAPOR RETARDER

Q: Where did provisions for moisture control go? Our community requires the use of a vapor retarder in framed-walls. Acceptable retarders include polyethylene, foil-backed drywall or kraft-paper-facing. Please clarify the moisture control requirements of the 2015 IECC?

A: Neither the 2012 nor the 2015 IECC editions contain provisions for moisture control. Final action to Code Change EC28-06/07 (AM) resulted in identifying and defining vapor retarder materials by Class. Consequently, both the 2009 and 2012 editions of the International Residential Code® (IRC®) now recognize that wall assemblies can be designed and constructed to dry inwards and outwards under particular conditions. The moisture control provisions have been relocated to Section R1405.3 of the 2015 International Building Code® (IBC®) for commercial buildings and Section R702.7 of the IRC for residential buildings. Based on these revised and improved provisions, it is not likely homes constructed in Illinois will require kraftpaper-facing, foil-facing, or even polyethylene vapor retarders any more. Please consult the provisions of IRC R702.7 directly for additional detail.

Where kraft-paper- and foil-facing (Class I) vapor retarders, or polyethylene (Class II) vapor retarders are proposed in lieu of latex or enamel paint (Class III), the installation of these vapor retarders shall be continuous over the wall field. Therefore, in order to maintain continuity of the vapor retarder, it would mean the kraft-paper-facings would need to be face-stapled to meet the requirements of R702.7. In addition to restricting water vapor diffusion, the installation of a vapor retarder impedes airflow, provided that it is continuous. Where openings are left in the vapor retarder during installation, either intentionally or by accident, they nullify the control of airflow, and therefore, the flow of moisture.

2. R402.2.2 CEILINGS WITHOUT ATTIC SPACES

Q1. You describe a low-rise (3-stories or less) multi-family building with a low slopped (flat) roof. We intend to install continuous “tapered” rigid-foam insulation. What is the minimum continuous insulation level required (above the deck) … R-49, R-38, or potentially R-30?

A1. The roof you describe must comply with flat roof RESIDENTIAL building insulation provisions of Table R402.1.2, or Table R402.1.4 equivalent to an R-49 (U-0.026), respectively, unless the AHJ determines that the installation of insulation above the structural roof deck, and necessary to achieve a code-required R-49 (U-0.026) framed-roof R-value/U-factor, is deemed “technically infeasible” to accommodate the added thickness (i.e., HVAC or skylight curbs, flashing heights, VTR, drainage patterns, or parapets).

IMPORTANT NOTE: The continuous insulation (ci) R-Value that is equivalent to a RESIDENTIAL R-49 (U-0.026) framed-roof R-value/U-factor is … R-38 ci (U-0.026). Recall that continuous insulation is defined by the code as “uninterrupted by framing components.”

 

Q2. Since this to be a “tapered” ISO insulation, may I calculate requirement based on an “area-weighted” average R-value?

A2. Yes, you may.

3. R402.2.7 WALLS WITH PARTIAL STRUCTURAL SHEATHING

Q. Could you please clarify the intent of the code regarding the reduction of R-5 continuous insulating sheathing where walls are partially-covered with structural sheathing?

A: Since you ask for feedback relative to the intent of Section R402.2.7, it was very clearly intended that a wall with full structural sheathing still requires the full R-5 continuous insulating sheathing, not R-2, as allowed by Section R402.2.7 and it relates to the the R-13+5ci requirement for Illinois Climate Zones 4 and 5.

The original intent was to make it easy to comply with what was becoming a popular approach to wall construction at the time (and still is)—using structural sheathing only at the corners and R-2 insulating sheathing everywhere else—to maintain a consistent total sheathing thickness and a uniform nailing or attachment surface. The 2015 IECC intends to resolve the interpretive inconsistency of the 2009 IECC by clearly limiting the R-value reduction from R-5 to R-2 ONLY to the sheathed portions of walls where the structure is provided with less than 40 percent structural sheathing. Where the structure is provided with 40 percent or more structural sheathing (up to 100%), R-5 continuous insulating sheathing must be applied over the entire building thermal envelope.

4. R402.4 AIR LEAKAGE (Mandatory)

Q: If you install some form of permanent heating (radiant, warm-air forced-air, or heat-pump) in a garage does the garage have to meet the thermal envelope requirements of the IECC?

A: Not exactly. Illinois amendments to Section R402.4.1.2, now afford an Exception for newly constructed and existing garages (attached and detached) where heating is proposed. In most cases, once the input capacity of the heater (or unit heater) exceeds 3.4 Btu/h • ft2 (1.0 W/ ft2) of floor area, the space, in this case the garage, is considered “conditioned” space. Therefore, the surrounding walls, windows, doors, overhead doors, roof, and slab-edge become the boundary of the building thermal envelope and must be insulated. However, utilizing the newly developed/amended Section R402.4.1.2, Exception 2, as long as the heated (or newly heated) Garage is “thermally isolated” from other habitable, conditioned areas of the home, the airleakage testing provisions of the code (R402.4.1.2) do not apply to new construction. Furthermore (and for both New! and alterations to existing homes), the exterior walls, roof/ceilings, windows and doors are to meet the applicable “Thermal Isolation” provisions of Sections R402.2.13 and R402.3.5, as well as the envelope tightness and insulation installation items in Table R402.4.1.1, applicable to the method of construction. (R101.4, R402.2.13, R402.3.5, R402.4.1.2)

5. R402.4.1.2 TESTING

Q1: Am I required to utilize diagnostic testing for assessing compliance with the 2012 IECC?

A1: Yes, while available originally in the 2009 IECC, there are no longer two options for assessing compliance with the home air leakage requirements of the 2015 IECC. The visual inspection option of the 2009 IECC has been removed. Under the 2012 and 2015 IECC Editions, all new residential one- and two-family dwellings and townhouses and low-rise multi-family buildings shall be tested and verified as having an air leakage rate not exceeding 5 air changes per hour (ACH) when tested at a pressure of 0.2 inches w.g. (50 Pascal), 5ACH50.

The common tool used for measuring air tightness is the blower door, which measures air pressure difference and flow rate. The blower door, as its name implies, is affixed to the front door of the home and using a variable speed fan and manometer to measure the building or dwelling unit air leakage rate. A house air leakage rate can be quantified by inducing a pressure difference across the apparatus and between the interior and exterior of the house, measuring the airflow necessary to maintain this constant pressure difference. A home-performance contractor or field-inspector then locates air leakage sites requiring additional sealing. For compliance assessment, blower door measurements, reported at 50 Pascal of pressure (representing a 20 mph wind), can be combined with a factor representing the dimensions of the home to yield the comparable air tightness value expressed in cfm/ft2 @ 50Pa (CFM50).

 

Q2: I noticed that Section R402.4.1.2, Testing, says “Where required by the code official, [blower door] testing shall be conducted by an approved third party.” Does that mean that it’s up to the code official to require that the blower door test be conducted or not?

A2: No. The language “…where required by the code official…” excerpted from 2015 IECC with Illinois Amendments (below), refers only to whether an approved third party is required to conduct the test.

  • R402.4.1.2 Testing. The building or dwelling unit shall be tested and verified as having an air leakage rate of not exceeding five air changes per hour (ACH) in Climate Zones 1 and 2, and three air changes per hour in Climate Zones 3 through 8. 4 and 5. The building or dwelling unit shall be provided with a whole – house mechanical ventilation system as designed in accordance with Section R403.6. Testing shall be conducted in accordance with ASTM E779 or ASTM E1827 and reported at a pressure of 0.2 inches w.g. (50 Pascals). Where required by the code official, testing shall be conducted by an approved third party. A written report of the results of the test, indicating the ACH, shall be signed by the party conducting the test and provided to the code official. Testing shall be performed at any time after creation of all penetrations of the building thermal envelope have been sealed.

 

Q3: Does the blower door test have to be done by a third party, or can the builder perform the test?

A3: Yes. The 2009, 2012 and 2015 IECC editions require blower door testing be conducted by an approved third party or an approved inspection agency. A review of Code Change EC13- 09/10, Part I, to the 2012 IECC, which was Approved as Modified by Public Comments (AMPC) 5, 19, and 20 reveals the following:

  • The supporting statement to EC13-09/10, Part 1–PC19 shows that the public comment was submitted and approved to prevent an installing contractor from performing the blower door test on their own work. Specific reference to the test being performed by an approved third party is now referenced in the 2015 IECC with respect to these matters; along with citing third party inspection programs as a common practice that has worked well for design professionals, and required to employ approved special inspectors to conduct special inspections on the work. The supporting statement continues, “Nothing in the proposed language would deny the code official’s prerogative to do the blower door testing himself or using his own personnel, should any building department choose to develop this capability.”
  • The Illinois Office of Energy and Recycling has identified a means for approval of third parties which they believe will be of assistance to “Authorities Having Jurisdiction” in their pursuit of IECC compliance. Currently, certifications recognized by the Illinois Office of Energy and Recycling, but still requiring approval by the local code official are:
  • 1. BPI-BA/EP Certified,
  • 2. RESNET – HERS Certified, or
  • 3. Equivalent as verified by established training results.
  • Looking for a duct pressure testing contractor or energy analyst? Either the Illinois Home Performance web-site or the Illinois Code Diagnostics web-site can match you with a contractor qualified to perform the work. We suggest that you get multiple bids.
  • For additional detail on how these programs will be integrating into Illinois’ compliance assessment programs, contact Bruce Selway, Program Manager for Energy Efficiency Education and Codes.

Bruce Selway
Energy Efficiency Education / Codes
IL Dept. of Commerce & Economic Opportunity
Illinois Energy Office
217.785.2023 Phone
Bruce.Selway@Illinois.gov
www.illinoisenergy.org

6. R402.4.2 FIREPLACES

Q: Citing 2012 IECC, Section R402.4.2 the language of the 2009 IECC was revised to replace the aforementioned requirement for gasketed doors with a requirement for “tight-fitting flue dampers.” However, the language for “gasketed doors” had been retained in new text added to the “Fireplace” entry of Table R402.4.1.1, reading, “Fireplaces shall have gasketed doors.” Citing the 2015 IECC, it appears we have finally received clarity with regard to fireplace air leakage control in Section R402.4.2. What is meant by this provision?

A: To be clear, we interpret the effect of revisions to Section R402.4.2 to require either “tight-fitting flue dampers,” or “fire-place doors” (NO GASKET) for “masonry fireplaces” constructed in accordance with IRC R1001 (NOT UL 127 “factory-built” fireplaces). Note also that the 2015 IECC, R402.4.2, and 2015 IRC, R1006, require factory-built and masonry fireplaces to be equipped with a direct supply of outdoor combustion air.

7. R503 ALTERATIONS – WINDOW REPLACEMENT

Q: Work proposed to a home consists of replacing existing window units in their entirety. Currently we do not require permits for window replacements. How do others interpret or enforce window replacements?

A: The 2015 IECC considers window replacements alterations to the building. We recognize that for some time, some Illinois municipalities have considered the replacement window issue a matter of jurisdictional choice by way of a jurisdiction’s unique adopting ordinance; most often reading, “If it fits into the same opening, then you do not need to obtain a building permit. However, where the new window size is different than the size of the opening, a permit application is required.”

As of the onset of energy efficiency requirements for residential buildings effective January 29, 2010, all window replacements, as with alterations, require a permit in accordance with the IECC. Jurisdictions subject to the Illinois Energy Efficient Building Act use the 2015 IECC to perform compliance assessment, and thereby inspect and verify fenestration thermal performance (U-factor, Solar Heat Gain Coefficient and Air leakage) for homeowners in their communities. Documentation shall be provided with the permit application indicating that the replacement window products afford a fenestration U-factor and SHGC no greater than required by the IECC.

Section 600.110, Part c) 2) of the Act, Privately Funded Commercial Facilities and Residential Buildings, reads:

  • “The Code as [2015 IECC] described in Subparts C [Privately Funded Commercial Facilities] and D [Residential Buildings] of this Part applies to any new building or structure in this State for which a building permit application is received by a municipality or county. [20 ILCS 3125/20]
  • A) Additions, alterations, renovations or repairs to an existing building, building system or portion thereof shall conform to the provisions of the Code [2015 IECC] as they relate to new construction without requiring the unaltered portion of the existing building or building system to comply with the Code [2015 IECC]. [20 ILCS 3125/20(c)]
  • B) All exceptions listed in the Code [2015 IECC] related to additions, alterations, renovations or repairs to an existing building are acceptable provided the energy use of the building is not increased.

[Underline for emphasis] (C503.1 or R503.1)

8. R503 ALTERATIONS – WALL ASSEMBLY

Q: If a wood-framed wall of an existing residential building is being re-insulated, what is the minimum required R-value based on our Climate Zone 4A or 5A? This is not for the whole wall assembly; the scope of work simply consists of interior alterations which require removing and replacing wall cavity insulation and then applying new interior drywall finish.

A: The work constitutes an “alteration” as outlined in Section R503.1.1, Exception 2, requiring replacement with insulation having a density of at least R-3/inch. Note that many of the exceptions outlined in the Subsections to R503 are derivations, in whole or in part, from language appearing in ASHRAE Standard 90.1. In particular, note Section 5.1.3, Exception 3 of the Standard. (R503.1.1, 90.1-2013 5.1.3)

Computing Manual J Infiltration Loads Based Upon a
Target Envelope Leakage Requirement

Overview

This bulletin defines proper use of ANSI/ACCA 2 Manual J – 2016 (Ver 2.50) procedure (A.K.A. Manual J) when the infiltration load for a dwelling that is proposed for construction (i.e., not yet built) is based on a maximum air change per hour (ACH) value established by code (e.g., International Energy Conservation Code, IECC), a standard (e.g., PHIUS+2015 Passive House Building Standard), or a performance-based “above-code” or “utility-based” incentive program (e.g., ENERGY STAR®, Home Energy Rating System (HERS) Index).

For example, a code or standard may state that the envelope ACH value shall not exceed 3.0 when a 50 pascal blower door test is used to measure envelope leakage.

  • Since the ACH value is for a 50 pascal pressure difference, it is an ACH50 value.
  • The ACH50 value is based on the leakage CFM for a 50 pascal test (CFM50 value).
  • The CFM50 value equals the blower door CFM value for the 50 pascal test.
  • While the measurements of pressure difference (at 50Pa) and airflow (in CFM50 or ACH50) can be used to determine airtightness and other leakage characteristics of the envelope, they do not “directly” reflect the “as-built” condition caused by natural infiltration (ELA at 4 Pa).
  • In accordance with prevailing codes and standards, natural infiltration is related to the leakage that is caused by a 4 pascal pressure difference (see Section 2.0).

This bulletin shows how to convert a maximum allowable leakage limit (ACH50) to a Manual J infiltration CFM value (ICFM), and then to the infiltration loads (Btuh) for sensible heating, sensible cooling, and latent cooling. It also discusses the use of blower data for two or more test points. 1.0

1.0 Summary of Procedure

These steps convert an allowable leakage threshold (in ACH50) to natural infiltration loads for winter and summer design conditions.

  • When engineered ventilation causes a positive or negative space pressure, the infiltration CFM values, in accordance with this procedure, shall be adjusted for the space pressure effect, when using Manual J Worksheet H and Worksheet E procedures.

Step 1: Determine the appropriate above and below grade volume for the specific home. See Section 6 for details.

  • Volume = Floor Area x Ceiling Height (for the conditioned spaces)

 

Step 2: Convert the target ACH50 value to a CFM50 value using the volume from Step 1. See Section 6 for details.

  • CFM50 = (ACH50 x Volume) / 60. See Section 6 for details

 

Step 3: Determine the natural condition equivalent leakage area (ELA4). See Section 5.3 for details, and for Figure 2.

  • ELA4 = Figure 2 Factor x CFM50

 

Step 4: Determine the natural condition infiltration CFM (ICFM4) values to be used in the load calculations. See Section 4 for details.

  • ICFM4 = ELA4 x (Cs x Indoor-Outdoor Temp Difference + Cw x Wind velocity2) 0.5
  • Use the Cs and Cw values from Manual J Table 5D or 5E (see page 4)

 

Step 5: Calculate the Manual J Infiltration Loads using the ICFM4 values. See Section 7 for details.

  • Sensible heating load (Btuh) = 1.1 x altitude adjustment factor x ICFM4heat x (Indoor-Outdoor temperature difference)
  • Sensible cooling load (Btuh) = 1.1 x altitude adjustment factor x ICFM4cool x (Indoor-Outdoor temperature difference)
  • Latent cooling load (Btuh) = 0.68 x altitude adjustment factor x ICFM4cool x (Indoor-Outdoor humidity ratio difference)

 

A single family home has one level that is totally above grade, rooms that are partially blow grade, rooms that are mostly below grade, and a closed crawlspace below the first floor bedrooms and bath rooms. (Attachment 1 provides sketches of the structure.)

layout-1

layout-2

layout-3

1.1 Test Volume

  • Upper Level Volume = 56 x 32 x 8 = 14,336 CF
  • Volume of lower level rooms = 33 x 32 x 10 = 10,560 CF
  • Crawlspace volume = Not applicable:
  • Total test volume = 24,896 CF

 

1.2 CFM50

The Maximum ACH value, per the AHJ, is 3.0 ACH.

  • CFM50 = 3.0 x 24,896 / 60 = 1,244.8

 

1.3 ELA4

The local altitude is 955 feet (1,000 feet). Figure 2 (next page) provides the CFM50 to ELA4 conversion factor for various altitudes

  • ELA4 = 0.054 x 1,244.8 = 67.2 sq In

coversion-factors-ela4
1.4 Infiltration CFM (ICFM)

Manual J, Table 5D provides ICFM values for heating and for cooling (see page 4). Make the calculation for two stories. Use Wind Shielding Class 4 (Manual J default) if site plan circumstances are unknown. Use the default values for winter wind (15.0 MPH), and summer wind (7.5 MPH) if the 20-year record of local NOAA weather data shows that the average winter wind velocity and summer wind velocity values do not exceed the default values. For this example, the Manual J Worksheet A values for HTD, CTD, and grains are 76F, 15F, and 38 grains.

  • ICFM for heating = 67.2 x (0.0299 x 76 + 0.0051 x 152) 0.5
  • ICFM for heating = 124.3
  • ICFM for cooling = 67.2 x (0.0299 x 15 + 0.0051 x 7.52) 0.5
  • ICFM for cooling = 57.8

 

1.5 Infiltration Loads

The local altitude is 955 feet (1,000 feet). Figure 2 provides the CFM50 to ELA4 conversion factor for various altitudes

  • ACF per Manual J Table 10A = 0.97
  • Heating Btuh = 1.1 x 0.97 x 124.3 x 76 = 10,080 Btuh
  • Sensible Cooling Btuh = 1.1 x 0.97 x 15 x 57.8 = 925 Btuh
  • Latent Cooling Btuh = 0.68 x 0.97 x 38 x 57.8 = 1,449 Btuh

coversion-factors-ela4

2.0 Leakage vs. Pressure Difference Curve

Structural leakage CFM depends on blower door pressure difference, per a curve that can be produced by blower door software. Tests at two or more pressure difference values are required. Figure 1 (next page) provides an example of a multipoint curve.

  •  The values for the constant C and the exponent n can determined by a two-point blower door test (see ASTM E1827, Section 9.4).
  • Blower door software can produce C and n values per a multipoint test. See Manual J 2.50, Section 21-5.
  • For a single point test, n is assumed to equal 0.65, and C is determined by this equation: C
  • C = Test CFM / PD 0.65
  • For a 50 pascal test, C is determined by this equation:
  • C = CFM50 / 50 0.65 = 0.079 x CFM50

multipoint-blower-door-test

3.0 Leakage for a 4 Pascal Test

Per industry research, the pressure difference value for natural infiltration circumstances is about 4 pascal, so the envelope leakage test should be a CFM4 test. However, the 4 pascal pressure difference produced by the blower door apparatus is not the only pressure acting on the envelope.

  • The pressure difference value for the momentary wind effect can be similar to the 4 pascal blower door value.
  • The pressure difference value for the momentary stack effect can be similar to the 4 pascal blower door value.
  • A 4 pascal test that has interference from two other, uncontrolled, pressure difference effects, which may be some combination of positive and negative pressures acting on the various structural surfaces, may not be very accurate.
  • A 50 pascal test overwhelms the effect of the pressure differences cause by the momentary wind and stack effects. So a test that uses a large pressure difference is a more accurate way to measure envelope leakage.

4.0 Infiltration CFM for Load Calculations

This equation, plus values from Manual J Table 1A or Table 1B (project design conditions), and from Table 5D or Table 5E (see next page), determines the infiltration CFM (ICFM) values for heating and cooling.

  • ICFM = ELA4 x (Cs x TD + Cw x V2) 0.5

Where:

Section 5.0 (below) provides the ELA4 value. Cs depends on the number of stories. Shielding Class 4 is the default shielding class for Cw. TD for heating is the Manual J Worksheet A HTD value. TD for cooling is the Manual J Worksheet A CTD value. The default wind velocity for heating is 15 MPH. The default wind velocity for cooling is 7.5 MPH.

See also: Manual J, Section 21.

table-10a

table-5d-5e-effective-leakage-equation

5.0 Effective Leakage Area (ELA4)

This equation determines the ELA4 value (sq in) for locations at altitude:

  • Altitude ELA4 = 2.929 x C x (PD) n – 0.5 x (d / 2) 0.5
  • Where: PD = 4 pascal; and d = air density (lb/cf)

This equation determines the ELA4 value (sq in) for sea level air:

  • Sea level ELA4 = 0.2835 x C x (PD) n
  • Where: PD = 4 pascal.

5.1 ELA4 for a Single Point, 50 Pascal Test

The Section 5.0 equations require a two point, or multipoint, test to produce a C value and an n value. The last equation in the following string of equations determines the ELA4 value for a single point, 50 pascal test, conducted at sea level.

  • Sea level ELA4 = 0.2835 x C x (4) 0.65
  • Per Section 2.0, C = 0.079 x CFM50
  • So:
  • Sea level ELA4 = 0.2835 x 0.079 x CFM50 x (4) 0.65
  • Or:
  • Sea level ELA4 = 0.2835 x 0.079 x CFM50 x 2.46
  • Therefore:
  • Sea level ELA4 = 0.055 x CFM50

5.2 ELA4 for other Test Pressures – Sea Level

Figure 2 shows conversion factors for other test pressures. For example, if the test pressure is 30 pascal, the conversion factor is 0.077.

  • Sea level ELA4 = 0.077 x CFM50

5.3 ELA4 vs. Test Pressure and Altitude

The conversion factor for converting a test CFM value to an ELA4 value depends on the test pressure and the altitude. Figure 2 provides conversion factors for various test pressure and altitudes. For example, if the test pressure is 50 pascal and the site altitude is 5,000 feet, the conversion factor is 0.050.

  • Altitude ELA4 = 0.050 x CFM50

coversion-factors-ela4

6.0 Test Volume for Load Calculations

A blower door leakage test cannot be performed on a building under construction until all penetrations in the building thermal envelope have been sealed. Accordingly, either the maximum ACH50 allowed by the AHJ, or the target ACH50 specified by a code or performance-based program is used to determine the maximum acceptable CFM50 value for a blower door test that will be performed in accordance with this equation:

  • Maximum CFM50 = (ACH50 x Test Volume) / 60
  • Where: The ACH50 value is specified by the code, standard or performance-based criteria established by the AHJ.
  • The test volume in cubic feet (CF) is the volume enclosed by the building thermal envelope and pressure boundary that will be tested for leakage (see Section 6.1).
  • 60 minutes = 1 hour.

6.1 Test Volume

The test volume is the volume enclosed by the building thermal envelope and pressure boundary of the dwelling unit, or alternatively as determined by the AHJ. ACCA requirements for Manual J load calculations are cited here:

6.1.1 Test Volume for Load Calculations

For Manual J load calculations, and subsequent Manual S equipment sizing, the test volume shall include the rooms and spaces served by the HVAC equipment.

  • For the heating load, the test volume shall include all rooms and spaces that are heated.
  • For the cooling load, the test volume shall include all rooms and spaces that are air conditioned.

 

7.0 Infiltration Loads

These equations calculate the Manual J infiltration loads:

  • Sensible heating Btuh = 1.1 x ACF x ICFMheat x HTD
  • Sensible cooling Btuh = 1.1 x ACF x ICFMcool x CTD
  • Latent cooling Btuh = 0.68 x ACF x ICFMcool x grains
  • Where:
  • ACF = Altitude Correction Factor,
  • see Table 10A;
  • or, ACF = 1.0 – 0.0000308 x Feet.
  • Manual J Worksheet A provides the HTD value.
  • Manual J Worksheet A provides the CTD value.
  • Manual J Worksheet A provides the grains value.

table-10a

 

7.1 Leakage Test vs. ACH4 Values

While the measurements of pressure difference (at 50 Pascal) and airflow (in CFM50 or ACH50) can be used to determine airtightness and other leakage characteristics of the envelope, they do not “directly” reflect the “as-built” condition caused by natural infiltration (ELA at 4 Pascal).

 

8.0 Summary

As explained above, the ICFM values for calculating infiltration loads are derived from a set of equations that make these conversions:

  • ACH50 to CFM50 to ELA4 to ICFM

  • For a home proposed for construction in a jurisdiction with a maximum air leakage rate not exceeding a 5ACH50 threshold, 5ACH50 is converted to a CFM50 value utilizing the volume of the conditioned space enclosed by the building thermal envelope and pressure boundary.
  • The CFM50 value is then converted to an ELA4 value in accordance with Manual J Section 21-5.
  • The ELA4 value is, in turn, converted to a set of ICFM (CFMinf) values (one for heating, and another for cooling), in accordance with Manual J Section 21 5.
  • The ICFM values are then used in the psychrometric equations for calculating the heating load (Btuh), sensible cooling load (Btuh), and latent cooling load (Btuh), in accordance with Manual J Section 21-6. 2

* ACCA develops the industry standards for heating, ventilation, air conditioning and building performance that raise the bar for contracting.

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