Ohio’s Proposed 2018 IRC Includes Five Compliance Paths

CodeWatcher Ohio 2018 IRC

Ohio debates stronger compliance paths while offering builders a gaping back door to build to a lower standard.

The Ohio Board of Building Standards (BBS) held a public hearing on November 9 as they continue to gather feedback on the state’s proposed 2018 IRC. It has been published in the state Register, and it includes five compliance paths: The three standard approaches found in the IECC, amended by the BBS; something called “The Ohio Home Builder’s Association (OHBA) Alternative Energy Code Option”; and the unamended IECC.

This is quite a document. Usually, a state energy code has two or three paths. The prescriptive and performance are always there. The ERI path, while not really new anymore, hasn’t been adopted everywhere, but it has caught on in certain corners of the United States. It’s the other two proposed paths that are questionable.

We’ll start with the unamended IECC. If a jurisdiction makes amendments to the model code, it’s typically a weakening amendment. Case in point: The state amended the requirements for basement wall and crawl space minimum R-values in their Insulation and Fenestration Table. For basement and crawl space walls, they weakened it from 15/19 (in the 2018 IECC model code) to 10/13 (in the state code) for climate zones 5 and marine 4. Therefore, if you built a home to the unamended 2018 IECC, you would be building an above-code home and it would obviously be in compliance.

The OHBA path (Section 1112; page 38) goes in the opposite direction. Meaning, instead of going in the more stringent direction, it provides even weaker options than the state’s amended code. The first thing one might notice about their version of the Insulation and Fenestration Table is that it doesn’t delineate by climate zone. Instead, it gives a builder two compliance paths, which appear to be independent of geography. Here’s a breakdown of each path:

Compliance Path #1

• Skylight U-factor weakens from 0.55 to 0.60
• Glazed fenestration solar heat gain coefficient (SGHC) weakens (in climate zone 4 except marine
only) from 0.40 to not required
• Wood frame wall R-value is weakened from (20 or 13+5) to (15 or 13+3)
• Mass wall value improves (in climate zone 4 except marine only) from 8/13 to 13/17
• Floor R-value improves (in climate zone 4 except marine only) from 19 to 30

Compliance Path #2

• Fenestration U-factor weakens (in climate zone 5 and marine 4) from 0.30 to 0.32
• Skylight U-factor weakens from 0.55 to 0.60
• Glazed fenestration solar heat gain coefficient (SGHC) weakens (in climate zone 4 except marine
only) from 0.40 to not required
• Wood frame wall R-value is weakened from (20 or 13+5) to 13
• Mass wall value improves (in climate zone 4 except marine only) from 8/13 to 13/17
• Floor R-value improves (in climate zone 4 except marine only) from 19 to 30

There are no provisions for mechanical system or hot water pipe insulation. They also introduced a sampling protocol into the air leakage testing section. The duct leakage testing section has the aforementioned compliance paths 1 and 2. Here’s how the two OHBA compliance paths compare to the amended state energy code for rough-in duct tightness testing:

OHBA Compliance Path #1

Total Leakage – with air handler installed ≤ 6 cfm
Total Leakage – without air handler installed≤ 4 cfm

OHBA Compliance Path #2

Total Leakage – with air handler installed ≤ 4 cfm
Total Leakage – without air handler installed≤ 3 cfm

OH Amended Prescriptive Path

Total Leakage – with air handler installed ≤ 4 cfm
Total Leakage – without air handler installed≤ 3 cfm

Post-Construction Duct Tightness Testing
(Total Leakage per 100 s.f. of cfa)

OHBA Compliance Path #1 ≤ 9 cfm
OHBA Compliance Path #2 ≤ 6 cfm
OH Amended Prescriptive Path ≤ 4 cfm

It’s not clear why the BBS would recommend an energy code that has three varying levels of compliance. This isn’t a suggestion that the state should choose the weakest compliance option on the table. If a builder chooses to build above code, then that builder is inherently complying with the code. You don’t need to waste the time debating or developing a stronger compliance path if you’re going to allow the equivalent of a gaping back door. States should be moving towards, not away, from zero-net energy homes. This code gives builders the choice to walk backwards on the path of progress.