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Session 402

October 31, 1:30 - 2:30 p.m.

Rhode Island Room (Lobby Level)

Click here for session handout.

Remediating B-side Residue In/On Substrates After Off-Ratio Foam Has Been Removed

Henri C. Fennell, CSI/CDT

Building Enclosure Consultant

H.C. Fennell Consulting, Inc. - North Thetford, VT

Session Description 

This program introduces a method for neutralizing SPF B-side unreacted chemicals in and on substrate materials. Spray foam manufacturers typically provide this information for A-side chemicals in the “accidental release” section of their SDSs; however, this information is not provided in the B-side SDSs. It is the unreacted B-side components that can produce odors and/or long-term health problems related to off-ratio SPF. If the A side is the surplus component, it will generally not produce odors/health hazards because isocyanates react with moisture and become inert in a relatively short period of time (hours or days). For these reasons, I consider A-side exposure primarily an installer risk, with PPE and engineering controls to be the appropriate worker protection required while the isocyanate is aerosolized into the air during and immediately after the spray application.

If the B side is the surplus component, it will frequently produce odors or health hazards because the B-side compounds do not become inert unless they are in the fully reacted foam product. Surplus B side does not react with air or water vapor and remains on the surface of misapplied spray foam and in/on the substrate. Unfortunately, removing off-ratio B-rich foam does not necessarily eliminate all odor and health problem risks because unreacted polyol will soak into wood framing and sheathing.

A search for neutralizers for residue in/on substrates often found in my misapplied foam projects has led to a new method for remediating an off-ratio B-rich foam installation. This presentation introduces the results of tests performed on spruce containing residue of three mainstream SPF products.

Learning Objectives:
1. Participants will be able to identify A-rich and B-rich foam installations.
2. Participants will be able to neutralize A-rich and B-rich foam installations.
3. Participants will be able to test other SPF products not included in this study.


Presentation Categories:  Occupant Health/Medical Issues; Investigations, Testing & Research; Cleaning & Remediation​

Presentation Level: Basic, Intermediate

About Henri Fennell:

Henri Fennell is a building envelope specialist and architect with forty-five years of experience in energy conservation design, manufactured products, and services. His work with polyurethane foam began during the energy crisis of the 1970s. 
His experience has included being a practicing architect, managing a contracting business, a building envelope consultant, and a remediation and commissioning consultant. Major projects include the Guggenheim Museum and Grande Hotel condominium complex ice dam remediation projects in the northeast. He has designed several new micro-load buildings, including a cutting-edge net-zero energy research structure in Antarctica, and performed large contracts including the largest frozen-earth retaining installation for the Big Dig.
He has four energy-related U.S. patents, and has contributed to ASTM standards, ASHRAE Journal, trade organizations, and is often cited in articles related to energy conservation and building performance.

Carnegie Mellon University
Pittsburgh, PA 
Bachelor of Architecture