COLUMN BUILDING SCIENCES ASHRAE Journal, January 2020). Pretty straightforward up to now, but there are a few 800 lb gorillas hanging around. Fire is one of those gorillas. Some spray polyurethane foams burn and some do not. Yup, there are some spray polyurethane foams around that do not burn. You read that correctly. But, most do and, therefore, require some form of fire protection. You have been warned. Blowing agent ozone depletion potential and greenhouse gas global warming potential characteristics are two other gorillas. Some spray polyurethane foams have very low ozone depletion potential and greenhouse gas global warming potential characteristics; some do not. You have been informed. As for embodied carbon and carbon accounting-a couple of more gorillas-my view is that if we used the same approaches to calculate our taxes the IRS would make sure we ended up in prison; you can pretty much get any answer you want. For the time being I am focusing on energy efficiency, something I can reasonably measure. Hard to get all the gorillas to behave and dance at the circus. FIGURE 15 Conditioned crawlspaces should be constructed as "mini" basements and completely connected to the house. Cladding Acrylic Latex Paint Gypsum Board Air Gap Wood-Based Sheathing (Plywood or OSB) Water Control Layer Spray Polyurethane Foam (SPF) Sealant Capillary Break High-Density Closed-Cell Spray Polyurethane Foam Continuous Polyurethane Sealed to Perimeter Crawl Space Wall Capillary Break Over Footing Damp Proofing O Handle high pressure and temperature applications with the MetraPak packed expansion joint from OO 215 SUPPLYING SPECIALTY PIPING SOLUTIONS SINCE 1958 CHICAGO, IL 60612 * 1-800-621-4347 WWW.METRAFLEX.COM/METRAPAK FEBRUARY 2020 ashrae.org ASHRAE JOURNAL 67http://WWW.METRAFLEX.COM/METRAPAK https://www.ashrae.org/