Sponge Features

NFPA Class A, UBC Class 1
Fire resistance, heat shielding
Does not ignite at temperatures below 1120ºF
Excellent heat insulation properties; no flaming drip
Excellent sound control characteristics in a wide range of frequencies

Material Specifications

ASTM E-84, Steiner Tunnel Test: Flame Spread: 5, Smoke Density: 50
UL 1715, Corner Burn Test: Passes
NFPA 101


Interior Partition Closure
Metal Deck Flute Closure Plug
Clean Room Ceiling Tile Seal
When fire classified foam is required

Contact us

P: 800.521.9594 or


Williams Everlastic® Fire Classified Closures 1715

This product is a compressible, lightweight, open cell melamine sponge.

Typical Physical Properties
Property Test Method Typical Values
Density ASTM D – 1667 0.7 pounds / cubic foot
Tensile Strength ASTM D3574 8 psi
Tear Strength ASTM F3574 0.3 pounds / inch
Elongation ASTM D – 3574 8%
Indentation load deflection:
Stress strain with 40% compression
Single deflection
Repetitive deflection
ASTM D3574 130.5 lbs
65.25 lbs
Heat Conductivity
K Factor
R value
ASTM C177 .24 at 50ºF
Temperature Stability 0 to 302ºF
Chemical Resistance Organic solvents and various diluted acids and alkali
Sound Absorption
Finish Thickness Coefficients per ASTM C423-90A
125hz 250hz 500hz 1kHz 2kHz 4kHz NRC Mounting Type
Natural 1-1/2″ 0.08 0.29 0.73 0.94 0.97 0.89 0.75 B
(White & Light Gray) 2″ 0.05 0.31 0.81 1.01 0.99 0.95 0.8 A