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Everlastic® Fire Classified Closures 1715

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Compressible Open Cell Sponge

Sponge Features

Class 1 Fire Classified

Does not ignite at temperatures below 1120°F

Excellent heat insulation properties; no flaming drip

Very low density, lightweight and highly flexible

Excellent sound control characteristics in a wide range of frequencies

Material Specifications


UL 1715

NEPA Class A

UBC Class 1


Interior Partition Closure

Metal Deck Flute Closure Plug

Clean Room Ceiling Tile Seal

Typical Physical Properties

Property Test Method Typical Values
Density ASTM D - 1667 0.7 pounds / cubic foot
Tensile Strength ASTM D3574-77 8 psi
Tear Strength ASTM F3574-77 0.3 pounds / inch
Elongation ASTM D-3574-77 8%
Indentation load deflection:

Stress strain with 40% Compression

Single Deflection

Repetitive Deflection


ASTM D 412-92

130.5 lbs.

65.25 lbs.

Heat Conductivity

K Factor

R Value

ASTM C177 0.24 at 50°F


Temperature Stability   0 to 302°F
Chemical Resistance


Organic Solvents and various diluted acids and alkali


Installation for interior partition closures
When ordering, oversize the Everlastic Fire Classified Closures 15% in thickness (distance from end of partition to the glass or mullion).  Apply a bead (approximately 1/4") of silicone sealant or urethane to the end of the partition wall that abuts the glass or mullion.  Place the bead 1/2" in from the side of the wall you are working from.  Compress the closure plug and slide into place.
For metal deck flute plug;  Place bead of silicone or urethane (approximately 1/4") 1/2" back from flute opening.  Place bead on all four sides of flute.  Compress closure plug and slide into place.


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Rubber, Neoprene, Foam, Gasket, Seal, Construction. To the best of our knowledge this published information is accurate, however, to determine suitability of material/product for a specific application is the user's responsibility.  Williams Products, Inc. shall not be liable for any loss or damage resulting from inappropriate usage.
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