Merger in Progress

The potential impact of the ASHRAE 189.1/IgCC merger on residential products
Julie Ruth
May 9, 2016
COLUMN : Code Arena | Codes & Standards

At the present time, a merger of International Code Council International Green Construction Code and American Society of Heating, Refrigerating and Air-Conditioning Engineers 189.1, Design of High Performance Buildings, except Low-Rise Residential Buildings, is occurring. The resulting document will be referred to as the 2018 edition of ASHRAE 189/IgCC. Although the intent of both are somewhat similar, at this point, it can be very difficult to predict the final outcome.

There are significant differences between the two documents, including the processes used to develop them and the scope of each. The ICC follows a rigid schedule to update the I-codes, while ASHRAE maintains its documents through a continuous process that permits proposed changes to be submitted at any time. Every few years, all the approved changes are rolled into the previous edition and a new edition of the document is issued.

ICC requires that all proposed changes, public comments and supporting data for the I-codes be made available for viewing by any interested party within the ICC. ASHRAE restricts access to proposals being considered to only those members of the applicable ASHRAE committee or work group. Both organizations, however, permit the language being considered to be viewed by anyone at the time it is being discussed.

Voting on all I-codes is limited to ICC governmental member representatives (state, county and municipal government). Voting on ASHRAE documents is limited to those appointed by ASHRAE.

Given the similarities and differences between the two processes, it is difficult to imagine just how they might “mesh” into one document. However, a merger of the two processes appears to be unfolding.

A Difference in Scope

At this time, various groups that are active within the ICC and/or ASHRAE have submitted or are in the process of submitting certain provisions of the IgCC to the ASHRAE 189 committee. Those provisions are then sent to the various ASHRAE 189 committee work groups for consideration.

Still to be addressed as this merged process unfolds is the difference in scope of the two existing documents. ASHRAE 189.1 is not intended to be used for single-family homes, multi-family structures of three stories or fewer above grade, or mobile or modular homes. Although the IgCC is also primarily targeted to commercial buildings, it includes provisions that allow the local adopting jurisdiction to use ICC 700 National Green Building Standard for such residential buildings.

Whether or not ICC 700 will be referenced in the 2018 edition of ASHRAE 189/IgCC is unclear.

The technical content of ASHRAE 189/IgCC-18 will be determined by the ASHRAE 189 main committee. Since ASHRAE 189 does not address low-rise residential construction, it seems unlikely that they will develop technical content for it.

The administrative provisions of the resultant document, however, will be based upon the current administrative provisions of the 2015 IgCC. That document references ICC 700 as an option for those jurisdictions that wish to include low-rise residential buildings within the scope of their own regulations for sustainable construction. This would seem to indicate that reference to ICC 700 will be included in ASHRAE 189/IgCC-18.

Both documents are intended to be adoptable as law by a jurisdiction, thereby becoming enforceable. But, when a jurisdiction adopts any model code, it has the option to determine if it will adopt all the provisions of that document or not. Therefore, even if ASHRAE 189.1/IgCC-18 references ICC 700 for low-rise residential construction, an adopting jurisdiction may choose not to recognize it.

At this point, all that can be predicted with any degree of certainty with regard to sustainable residential construction is that it is unlikely any new provisions will emerge from the merged process. If any provisions for low-rise residential construction are included, they will likely be limited to referencing the ICC 700. The National Association of Home Builders offers a program for certification to this standard.

Code Arena is brought to you by the America Architectural Manufacturers Association. Julie Ruth may be reached through AAMA at 847/303-5664 or via e-mail at