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Polyurethane
is a relatively new product, roughly around 35 years. EPS has been with us
for around 50 years. Polyurethane was produced to replace the shortfalls
of expanded polystyrene. Below you will see a detailed difference between
polyurethane, and expanded polystyrene.
R- Value - Polyurethane is the highest rated insulation in the
world. You will find it in most all of your refrigerators, freezers, and
even in your personal carry about coolers. Per inch of insulation it has
no equal. The walk in coolers and freezers for use thought the country are
made of polyurethane. EPS has a value of R-2 to R-5 per inch. Polyurethane has an R-Value OF R-7 to R-8 per inch.
MANUFACTURING - Probably the biggest difference between
Polyurethane and EPS is in the manufacturing of these panels. Both
products use OSB for covering both sides of their foam, but here is where
the similarity ends. In the bonding of the foam the actual polyurethane is
used as bonding agent to the OSB itself. Polyurethane is one of the best
glues used in the industry today. Some manufactures of OSB and plywood use
polyurethane to bond their products together. When it comes to adhering,
the use of polyurethane gives us both an excellent R- value and the
strongest bond in the industry. EPS panels use glue spread on both sides
of the OSB, and then the OSB is matched together with the EPS, and
mechanically held in place and under pressure until the glue is dried.
Moisture Resistance - With all the problems of mold and mildew,
moisture resistance is today a very important factor. Polyurethane has one
of the lowest moisture Permeability ratings of any product manufactured
for the building industry today. The permeance rating on
polyurethane is 1.2. The permeance rating on EPS is 2.0 to 5.0
This difference in a high humidity area would warrant another moisture
barrier for EPS panels. In calculating R-values, some EPS manufactures use
these additional moisture barriers in there calculations.
Fire Resistance - The polyurethane is a UL Class 1 rated foam. This
means that polyurethane is not a source for fire. On it's own,
polyurethane will not burn. When left on it's own, it will extinguish it
self. A Class 1 rating is the highest rating a building product can
obtain. Also, polyurethane is a thermal-set plastic. This means, that it
will not melt. Polyurethane is not affected until temperatures reach 1000
degrees and at that time it will only char. EPS on the other hand is not a
thermal-set plastic and will begin to soften at temperatures of 180
degrees, and melt at temperatures of 240 degrees. Polyurethane has a
distinct advantage.
DENSITY - The density of a product will determine the strength of
it. EPS has a density of 1 lb. The polyurethane has a density of
2.2lb.
CHEMICAL RESTANCE - Polyurethane is resistant to most counter
chemicals. EPS react violently to petroleum based products. PL 400 and
liquid nail will literally burn thru EPS.
From our experience, we feel that the investment made equals the quality
of product made. We believe that there is no comparison between
Polyurethane panels and those of EPS for these key reasons:
| Polyurethane
(PUR) |
Polystyrene
(EPS) |
| R-Value |
| 4.5"
Polyurethane Panel= R-25 |
4.5"
EPS Panel= R-17 |
| 6.5"
Polyurethane Panel= R-40 |
6.5"
EPS Panel= R-27 |
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| Fire
rating |
| resists
and helps to quench a fire and will char (not ignite) at 1,000 degrees |
melts
and fuels a fire at 280 degrees |
| Wind load |
| 180-200 MPH |
140-160
MPH |
| Note:
Category 5 storms are winds greater than 155 miles per hour. |
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