Customer Bulletin 03-10 March 2010

CUSTOMER BULLETIN 0310

A Comparison of ISO-C1 Polyisocyanurate Insulation

to Extruded Polystyrene (XPS)

PURPOSE

This Customer Bulletin is another in a series of white papers aimed at providing our clients,

engineers, contractors, fabricators, and friends with objective information on competitive

products. Marketing literature on the internet and in printed media address the physical and

performance characteristics of polyisocyanurate rigid foam (ISO) and extruded polystyrene

insulation (XPS). As is often the case, some literature can be misleading and/or in some cases

there may not be sufficient information to credibly compare products. This Customer Bulletin

provides factual, clarifying information which should allow for an objective comparison of

Dyplast’s ISO-C1® with the competing XPS Billet product.

SUMMARY OF RESULTS

When it comes to selecting the best overall insulation product for pipe insulation for low

temperature systems, polyiso is the product of choice over extruded polystyrene (XPS). In fact,

no other foam insulation has the combination of features so important for long term performance.

For example, polyiso insulation:

Delivers the highest R-value per inch of thickness

o Aged R-value of ISO-C1 is 5.7 versus 3.861 for XPS

Is moisture resistant, water repellent, and will not wick moisture

o ISO-C1 has water vapor permeance of 1.65 perm-inch per ASTM E96, and when

properly installed with zero-perm vapor barrier the insulation system has superior

properties

Possesses excellent dimensional stability, particularly at lower temperatures

o ISO-C1 has <0.1% change in volume or length at -40F

Demonstrate excellent performance in fire tests

o ISO-C1 ASTM E-84 tests demonstrate 25 flame spread and 130 smoke

developed2 up to 4 inches in thickness

Has low Global Warming Potential

1 ITW Insulation System’s Product Information sheet on XPS pipe insulation billets (XPS TDS, Form No. 10010-

0709) 2 Per Factory Mutual ASTM E-84 tunnel tests

Customer Bulletin 03-10 March 2010

o ISO-C1 utilizes hydrocarbon blowing agents with GWP ratings of approximately

10; XPS pipe insulation billets still continue to be sold with HCFCs3 which can

have GWP ratings of over 2000.

THIRD PARTY INDEPENDENT TESTING

Dyplast Products utilizes independent testing facilities to evaluate the physical properties of its

polyisocyanurate products. When comparing competitive foam insulations, buyers and specifiers

should request third party verification information in order to ensure their comparisons are

credible.

THERMAL PERFORMANCE

Polyiso insulation delivers more R-value per inch of thickness than extruded polystyrene

products. For example, ISO-C1’s aged R-value of 5.7 provides a benefit of 45% over extruded

polystyrene with an R of 3.86. This benefit produces considerable savings in energy

consumption as well as process efficiencies.

FIRE TEST PERFORMANCE

Not all foam plastic insulations perform equally in fire tests, including the ASTM E-84 “tunnel

test”. Polystyrene insulations are thermoplastic materials, which soften at 165°F and melt

between 200°F to 210°F. Because of the high temperatures reached in the E-84 test, polystyrene

melts and drips to the bottom of the tunnel as it burns and smokes.

Although many polystyrene insulations claim a Flame Spread of 5, PIMA4 notes that “ignition of

molten residue on the furnace floor results in flame travel equivalent to calculated flame spread

classification of 45 and smoke developed classification of 350 for 1 inch thickness - - -, and

90/500 for 4 inches”. On the other hand ISO-C1, a thermoset material, stays intact during the fire

exposure and successfully performs by forming a protective char layer and remaining in place

during the tunnel test. Factory Mutual (FM) has certified ISO-C1 to have a 25/130 rating, and

Underwriters Laboratory (UL) rates ISO-C1 as 25/195 for up to 4 inches in thickness.

3 ITW Insulation System’s Product Information sheet on XPS pipe insulation billets (XPS TDS,

Form No. 10010-0709) notes billets with HCFC’s continue to be marketed.

4 Polyisocyanurate Insulation Manufacturer’s Association

Customer Bulletin 03-10 March 2010

BILLET/BUN SIZE

ISO-C1 is produced as continuous bunstock that can be produced in variable sizes; for instance 2

lb/ft3 foam can have widths up to 4 feet and lengths up to 24 feet. Variable bunstock sizing and

subsequent cutting into precisely sized “chunks” can lead to efficiencies in shipping

(optimization of truck volumes) and during fabrication into pipe shapes (less waste). ISO-C1 can

also be produced in multiple densities, including 2.5, 4, 6, and 10 lb/ft3; higher densities provide

significant flexibility for various applications, including pipe hangars. XPS is commonly

produced only in 1.8 lb/ft3 billets, with limited size alternatives, the largest of which is typically

10” x 20” x 9’.

GLOBAL WARMING POTENTIAL (GWP)

Polyisocyanurate insulation manufacturers have been required to discontinue use of CFCs and

HCFCs, and thus now utilize hydrocarbon blowing agents such as pentane which has a GWP of

approximately 10. XPS pipe insulation billets still continue to be sold with HCFCs which can

have GWP ratings of over 2000.

RESISTANCE TO CONSTRUCTION MATERIALS

Extruded polystyrene can be attacked by many petroleum based solvents in adhesives, paints,

stains, water repellent and preservative coatings, and in bituminous waterproofing. As many

contractors have discovered, the application of these common construction materials causes the

extruded polystyrene to dissolve. This problem is solved by using ISO-C1 polyiso insulation,

which is not affected by these materials.