[Plumbing] PEX+Spray Foam
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Jinger Zeng
Oct 5, 2012, 9:09:50 AM10/5/12
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Uponor crosslinked polyethylene (PEX) tubing is an extremely durable product ideal for use in radiant floor heating and cooling, plumbing and fire sprinkler applications. As a result, contact with closed-cell spray foam insulation should not compromise the performance of the tubing or the brass fittings, nor will it void the warranty on Uponor AquaPEX® or Wirsbo hePEX™ tubing, provided the temperature during the chemical reaction process of installation does not exceed 250°F (121°C).
The majority of closed-cell spray foams on the market today are polyurethane based. Polyurethane, the harshest of all bases, is chemically compatible with both Uponor PEX tubing and brass fittings. The biggest issue concerning spray foams to date is primarily related to the fact that temperature outputs of the chemical reaction during spray foam application may exceed the maximum temperature limitations of Uponor PEX tubing. The following data shows the temperatures associated with a particular amount of lift or depth of foam and the associated board foot accumulated per set.
1" = 130°F (54°C) 2.4 lb/sf 3,800 bdft
2" = 200°F (93°C) 2.2 lb/sf 4,000 bdft
3" = 320°F (160°C) 2 lb/sf 4,500 bdft
The information shows that applying 1" of foam creates maximum temperatures of 130°F (54°C) and 3,800 bdft per set of material. As the installer applies the spray foam more generously, the reaction temperature increases as well as the output of the material per set. If insulation requirements necessitate more than a 2" lift, Uponor recommends the installer performs a two-lift application by applying 2" or less to the first layer, then applying the remaining layer after a 15-minute period (15 minutes is the time required for the heat from a 2" lift to dissipate).
Closed-cell insulation is recommended for use with Uponor PEX tubing and brass fittings; however, Uponor engineered plastic (EP) fittings require an overwrap of 4-6 mil poly or other suitable waterproof protection where contact is possible.
The majority of closed-cell spray foams on the market today are polyurethane based. Polyurethane, the harshest of all bases, is chemically compatible with both Uponor PEX tubing and brass fittings. The biggest issue concerning spray foams to date is primarily related to the fact that temperature outputs of the chemical reaction during spray foam application may exceed the maximum temperature limitations of Uponor PEX tubing. The following data shows the temperatures associated with a particular amount of lift or depth of foam and the associated board foot accumulated per set.
1" = 130°F (54°C) 2.4 lb/sf 3,800 bdft
2" = 200°F (93°C) 2.2 lb/sf 4,000 bdft
3" = 320°F (160°C) 2 lb/sf 4,500 bdft
The information shows that applying 1" of foam creates maximum temperatures of 130°F (54°C) and 3,800 bdft per set of material. As the installer applies the spray foam more generously, the reaction temperature increases as well as the output of the material per set. If insulation requirements necessitate more than a 2" lift, Uponor recommends the installer performs a two-lift application by applying 2" or less to the first layer, then applying the remaining layer after a 15-minute period (15 minutes is the time required for the heat from a 2" lift to dissipate).
Closed-cell insulation is recommended for use with Uponor PEX tubing and brass fittings; however, Uponor engineered plastic (EP) fittings require an overwrap of 4-6 mil poly or other suitable waterproof protection where contact is possible.
Eric Weber
Oct 7, 2012, 8:51:06 PM10/7/12
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This is great info, Jinger. This information should be incorporated into the uponor spec, to ensure we don't have any issues.
Thanks!
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