Low Perm™, Isoseal™, SuperIsoseal™, Superseal™, Spectroseal® low-permeability sealing foams for dust-, light-, vapor- and watertight gaskets

Country: USA · Model: Low Perm / Isoseal / SuperIsoseal / Superseal / Spectroseal

A family of sealing polyurethane foams with low air and vapor permeability for low-pressure gaskets. The Superseal™ grade holds 4 inches of water for 24 h at 50 % compression, and Low Perm™ has a density of 1.5–2.8 pcf. The foams are placed in air duct dampers, vehicle bodies, household appliances and electronics housings.

Material: flexible polyether-based polyurethane foam (Superseal — also polyester-based) with low air and vapor permeability
Low Perm™ LP150 / LP180 / LP250: density 1.65 / 1.95 / 2.4 pcf (26 / 31 / 38 kg/m³); pores 30 / 30 / 35 ppi; tensile 110 / 103 / 97 kPa; compression set 15 / 8 / 8 %
Low Perm™ density range: 1.5–2.8 pcf (≈24–45 kg/m³); 'Paint Pot' leak test
Isoseal™: 1.6 pcf (26 kg/m³), 103 kPa, compression set 4 %; holds a water column of 1 inch (25 mm) for 24 h at 50 % compression

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Technical specifications

Material	flexible polyether-based polyurethane foam (Superseal — also polyester-based) with low air and vapor permeability
Low Perm™ LP150 / LP180 / LP250	density 1.65 / 1.95 / 2.4 pcf (26 / 31 / 38 kg/m³); pores 30 / 30 / 35 ppi; tensile 110 / 103 / 97 kPa; compression set 15 / 8 / 8 %
Low Perm™ density range	1.5–2.8 pcf (≈24–45 kg/m³); 'Paint Pot' leak test
Isoseal™	1.6 pcf (26 kg/m³), 103 kPa, compression set 4 %; holds a water column of 1 inch (25 mm) for 24 h at 50 % compression
SuperIsoseal™	1.65 pcf (26 kg/m³), 117 kPa; holds 3 inches (76 mm) of water for 24 h
Superseal™	2.2–3.3 pcf (35–53 kg/m³), 90 ppi, open cell with low compression set (4–6 %); holds 4 inches (≈100 mm) of water for 24 h at 50 % compression
Spectroseal®	sealing foam with increased compression force, replacement for rubber gaskets
Compressive stress 25 %	2.8–12.4 kPa (0.4–1.8 psi)
Flammability	MVSS 302 for all grades; LP250 — also UL 94 HF-1
Supply form	blocks, rolls, sheets 0.125–2 inches (3.2–51 mm) thick; with biocide; lamination of Low Perm/Isoseal onto backings
OEM approvals	Ford (ESA-M4D200-B, WSS-99P2222-A1 and others), GM (GM251M T1, GMW14196 T3), Chrysler (MS-AY-326A and others), Toyota TSK6712G…, Mercedes-Benz DBL 5450.10, Delphi SD2-209, Denso DDS 8072-010, Visteon

Specifications are taken from the manufacturer’s technical documentation. Updated 11/10/2026.

Description

Low Perm™ is an open-cell polyether foam that nevertheless blocks air and is designed for the automotive 'Paint Pot' leak test. Grades LP150, LP180 and LP250 have densities of 1.65, 1.95 and 2.4 pcf (26, 31 and 38 kg/m³), pores of 30–35 ppi, tensile of about 100 kPa, compressive stress of 2.8 kPa at 25 % deformation and compression set of 8–15 %. Isoseal™ at a density of 1.6 pcf and compression set of 4 % holds 1 inch of water for at least 24 h, and SuperIsoseal™ holds 3 inches. Superseal™ has a density of 35–53 kg/m³, pores of 90 ppi and remains open-cell. Spectroseal® gives much more compression force and replaces bulky rubber seals. In the test a sample 10 mm thick is compressed by 50 % between acrylic plates, water is poured to 100 mm and it is checked whether the level has dropped within 24 h. All grades are tested to MVSS 302, LP250 also to UL 94 HF-1. Sheets and rolls are supplied 0.125–2 inches thick.

How to choose

For dust, light and air take Low Perm™, for water pressure up to 1 inch Isoseal™ is enough. If the water column is higher, switch to SuperIsoseal™ or Superseal™, the latter withstands 4 inches. Spectroseal® is chosen when a rubber gasket needs to be replaced with a foam that is lighter in weight.

Request a price and lead time

Low Perm™, Isoseal™, SuperIsoseal™, Superseal™, Spectroseal® low-permeability sealing foams for dust-, light-, vapor- and watertight gaskets. We reply within one business day.

Or email office@usk.ua or call +38 (044) 339-50-20.

FAQ

Which foam grade holds the highest water column?

The best water seal is given by Superseal™, which holds 4 inches of water for 24 h at 50 % compression. Isoseal™ holds 1 inch, SuperIsoseal™ holds 3 inches.

What is the density of the Low Perm LP150, LP180 and LP250 grades?

1.65, 1.95 and 2.4 pcf respectively, that is 26, 31 and 38 kg/m³. The whole density range of the Low Perm™ family is 1.5–2.8 pcf.

How is the watertightness of Isoseal and Superseal tested?

A sample 10 mm thick is compressed by 50 % between acrylic plates and water is poured to 100 mm. The test is passed if the level has not dropped within 24 h.

Do these foams pass flammability tests?

All grades are tested to MVSS 302, and LP250 also to UL 94 HF-1.

What thickness is the sealing foam supplied in?

In blocks, rolls and sheets from 0.125 to 2 inches (3.2–51 mm) thick. Low Perm™ and Isoseal™ can be laminated onto backings, including adhesive ones.