[ Common Uses of Foam ] [ Polyurethane Foam Properties ] [ AMA Article on Toxicity ] [ Open Cell vs. Closed Cell ] [ Blowing Agent ] [ HFC Comparison ]
Polyurethane Foam Properties
The R-value of foam is higher per inch than other types of insulation
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The R-value of insulation materials is dependent on ambient temperature and wind conditions. Independent tests show that at 18 degrees F, with a 15 mph wind, the theoretical R-value of polyurethane foam drops
from 19 to 18, while batt insulation drops from 19 to 7.
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In retrofits with smaller existing framing sizes, this means that buildings can still be insulated to meet current code requirements.
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In new construction this means that smaller framing sizes (lower lumber costs and larger rooms) can still be insulated to today's energy efficient standards.
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Plumbing can be installed in outside walls without freezing because only a thin layer of foam is required between pipes and the outside sheathing.
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This is effective in bays with steel columns, which have a very small space available for insulation between the steel and the sheathing.
Foam is a good air sealant
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Air leakage is the number one cause of poor building performance. Foam insulated homes
out-perform conventionally insulated homes without
requiring complicated and labor-intensive air sealing details.
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Because foam is air tight, it performs better in windy conditions and resists R-value loss.
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Batt insulation has virtually no air sealing ability and has to rely on other components of a total thermal envelope to maintain performance levels.
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Air leakage at penetrations creates an environment for condensation. This
affects overall performance and can compromise indoor air quality (bugs, mold, and rot). Condensation can also lead to
premature structural failure in structural framing and sheathing materials.
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Independent testing shows that polyurethane insulated buildings can perform as much as ten times better than today’s energy standards.
Closed-cell foam has a very low permeance
or potential for water vapor to pass through it
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This provides protection against moisture transport into the insulation with its related potential for condensation. Vapor that remains on the inside (the warm side) will not come in contact with cold
surfaces where the dew point can be reached.
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Imperfections in vapor retarders are less critical with closed-cell foams.
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Indoor humidity levels are more easily maintained at healthy levels if vapor cannot escape during dry winter weather.
Closed-cell Polyurethane foam is not susceptible to damage from short term wet conditions
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PUF will not be damaged by roof leaks, foundation leaks, or condensation.
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PUF can be used below grade and in masonry construction
and not sustain damage from water penetration.
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PUF sealants can help to protect structures against wind-driven rain penetration.
Foam bonds to the structure
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Foam will not compress or settle.
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Foam adheres to steel decking on flat roof structures providing effective insulation where venting is impossible and there is no framing cavity to support other types of insulation.
Foam can have structural advantages
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Foam can help to resist wind shear.
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Foam can serve to reinforce exterior sheathing and windows.
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Polyurethane foams are used in structural panels and other composite structures.
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Foam can be walked on or nailed into without damaging its performance. It can also be washed without damage.
Foam systems perform well for some types of sound control
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Both open and closed-cell foams provide good sealing against air-borne sound transmission.
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Both open and closed-cell foams provide good STC ratings against air-borne sound transmission.
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No low-density insulation materials are effective against structure-borne sound. Double layer structural systems, resilient structural materials, or massive structures are the best defense against
structure-borne sound.
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