Talk on cell foams; Additional requirement on EIFS codes

Talk on cell foams

John,
Regarding the article "The Chemistry of High Performance Buildings," by Tom Harris ( Walls & Ceilings, May 2006), he states that: "Both types are fully adhered and monolithic but open-cell foams have far greater air and vapor transmission capabilities. As such, these products do not qualify as air barriers as defined in ASTM International E 2178, Standard Test Method for Air Permeance of Building Materials."

The Icynene Insulation System is an open cell expanding foam insulation material that does qualify as an air barrier material. We have conducted testing as per the requirements of ASTM E283 and ASTM E2178. In both cases, the test results have confirmed an air permeability less than 0.02 L/s*m2@ 75 Pa, which is the requirement for qualification as an air barrier material.

We hope thatW&Cwill endeavor to provide its readers with accurate information regarding the air barrier characteristics of expanding open cell foam insulation.

Ed Reeves,
Engineering Manager,
Icynene Inc.

Additional requirement on EIFS codes

Robert Thomas,
I read the Finish Line column entitled "Special Inspection of EIFS," (Walls and Ceilings, March 2006). While I commend you for trying to explain the requirements imposed by the International Building Code, I would like to point out an additional requirement.

Section 1704.12 of the IBC specifies the requirements and exceptions for special inspections as you referenced in your column. However, an additional requirement for special inspections is specified in Paragraph 5.3.3 of AC212 (ICC-ES Acceptance Criteria for Water-Resistive Coatings used as Water-Resistive Barriers over Exterior Sheathing-dated March 1, 2005).

Most EIFS manufacturers supply coatings that have been qualified for use by AC212 and are mainly used as the water-resistive barrier as a component of an EIF system with drainage. Therefore, drainage systems evaluated to the IBC that utilize a water-resistive barrier coating are also subjected to special inspections. I bring this to your attention since evaluation reports for EIFS with drainage include this requirement.

In summary, special inspections are required for:
  • Application of all face-sealed EIFS over a sheathing substrate, and;
  • Application of a water-resistive barrier coating over exterior sheathing.

William M. Preston,
Senior Engineer/Code Specialist,
Dryvit


Columnist Robert Thomas responds:
Bill is correct. There are additional inspection requirements that relate to the building code, in a roundabout way. The requirement for inspection of water-resistive barriers is not in the code per se but in a related document used by the code authorities as the basis for recognizing EIF systems. This document is often called the "acceptance criteria."

Normally, the evaluation report issued by ICC's technical arm (evaluation services) to a given EIF system producer, for a specific product, is the basis upon which the EIF system can be used. Hence, the extra requirement for WRB inspection is applicable to all EIF systems in which WRB's are used (such as EIF systems with drainage).

Sometimes, this requirement is not apparent, as it exists in an acceptance criteria document that is not part of the code itself but nonetheless is effectively part of the code. The moral: Take a look at the evaluation report for the specific EIF system you're using to see what is required.