INVESTIGATION RECAP - Spray Polyurethane Foam Alliance (SPFA) conversation
BRS conversation recap with Rick Duncan -SPFA head technical director (4-18-2018)
Two Types of Post Applied Spray Foam:
1.) Open cell (like foam in upholstery –can absorb moisture)
-Open cell not appropriate for metal panel applications- absorbs moisture
2.) Closed cell (like a portable foam cooler- hard exterior no moisture absorption)
-Closed cell appropriate for metal panel applications-no moisture absorption
CLOSED CELL DISCUSSION ONLY -POST ERECTION WET APPLIED APPLICATIONS
Investigative discussion items:
Item 1.) Any structures over 100’-0” wide requires expansion joints.
Item 2.) Recommends multi-pass due to heat development during curing process.
Item 3.) Metal structures require 0-1/2” initial pass to assist in cutting down “Oil Canning” or metal panel distortion due to the foam curing process.
Item 4.) All metal structures require multi-passes to build up spray foam thicknesses.
- a.) Single pass 2” (maximum recommended) and generates in the interior core between 300-350 degrees while curing whiles inducing metal deformation.
- b.) The foam cures to the touch within 1-2 minutes with an average exterior temperature of 120 degrees but it takes 24 hours or less to be fully cured except for the ongoing core process.
- c.) Single pass 4” is not recommended may cause actual scorching due to the intense core curing heat temperature and may warp metal.
- d.) Single pass 6” is highly discouraged due to the possibility of spontaneous combustion or fire due to the extreme center core curing temperatures.
- e.) All foam must have fire retardant products as part of their ingredients.
- f.) All foam exterior shell is flash cured to 99% in the first 1-2 minutes, however, the chemical properties of the spray polyurethane foam will always be curing-never fully cured.
Item 5.) All spray foam (closed cell or open cell) is tested to ASTM E84 standards for smoke and flame spread development. CLOSED CELL ONLY Flame spread < 75 and Smoke development <450
Item 6.) Spray foam develops a lot more smoke which is also toxic (10-20% more than wood) including hydrogen cyanide, carbon monoxide and other toxic gases are released.
Item 7.) According to IBC -Spray foam CANNOT be used in Type I non-combustible structures (such as hospitals, etc.) Type II through IV structures must have a 15-minute separator sheet/membrane and is usually a 0-1/2” gypsum board.
Item 8.) All installers must follow strict building codes and practices.
Item 9.) All spray foam DOES EXERT some pressure during flash curing process and is capable of relocating weaker fixtures or appliances. Pound foot per torque is not available since it varies from project application thickness and installer as well as maker of spray foam.
Item 10.) Typical 0-1/2”multi-pass applications produce a core temperature produce 120-degree centers during the flash curing process.
Item 11.) Typically there are no insurance rate increases from spray foam over fiberglass blanket if sufficient fire retardant chemicals are added into the process –no penalty assessed even though the smoke development is so much greater.
Item 12.) Destructive remedial metal roof or wall repairs cannot be conducted since the underside of the panels cannot be successfully separated for removal without total destruction of the materials.
Item 13.) All surfaces must be cleaned, especially metal panels regardless of age of installation.
Item 14.) All applicators are trained to use the products and are expected to clean the surfaces for proper adhesion: such as power washing the underside of metal surfaces. All surfaces must be dry before the application process can begin.
Item 15.) Closed cell post applied wet foam applications provides rigid/hard surfaces once cured that create fixity of the movable clips and apparatuses of standing seam roofing system. The application of post spray foam to standing seam roof panels will “lock” the clips in place thereby restricting the thermal cycle ability negatively impacting the roof system performance.
Item 16.) The application of post spray foam closed insulation once cured will not allow any remedial repairs (if required).
Item 17.) Non-adhesion of the spray foam to the bottom side of the metal may allow the creation/ holding of trapped moisture between the foam and the metal surface resulting in an aggressive wet environment causing the accelerated rusting /degradation of the metal panel from the inside out. -Unknown until failure or rupture of topside panel surface.
Item 18.) Application of post applied spray foam may invalidate third-party pass-through substrate and /or paint warranties. -Check with coil and paint supplier warranties before applying.
Building Research Systems, Inc (BRS) DOES NOT RECOMMEND the use of post-applied spray foam to our standing seam roofing systems. The application of closed cell spray foam will fix the thermal cycle capabilities and negatively impact the in-place performance design of the roof system.