SpecSeal Flute Filler Plugs and Strips

SpecSeal® Flute Filler Plugs and Strips are pre‑formed mineral wool firestop components engineered to fit 1.5-inch, 2-inch, and 3-inch steel deck flutes with precision. Manufactured from UL‑Classified mineral wool batt insulation*, these plug‑and‑strip assemblies provide a reliable, code‑compliant firestopping solution for protecting concealed spaces within fluted steel floor and roof assemblies. When installed in conjunction with approved SpecSeal® firestop sealants and coatings, SpecSeal Flute Filler Plugs and Strips deliver fire‑resistance ratings of up to 4 hours, helping prevent the spread of fire, smoke, and hot gases through steel deck profiles. Their pre‑formed design ensures consistent fit, simplified installation, and dependable performance across commercial, industrial, and multi‑story applications. SpecSeal Flute Fillers offer a time‑efficient, high‑performance method of restoring the fire‑rated integrity of head of wall joints incorporating steel deck assemblies.

Test Standards ASTM E1966 (UL2079)

Third Party Approvals

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Features

Precut mineral wool plugs fit to standard size steel deck flutes
Reduces material waste
Improves productivity on job sites
Available in three common sizes
Provides a smooth surface to enhance coverage of applied sealants and coatings

Applications

Head-of-Wall

Properties

Joint Movement

Light Weight

Low VOC

No Expiration

Specifications

Property	Value
Appearance	Fibrous yellow insulation material
Dimensions - F11235	1-1/2” x 3.5” x 4.5” x 48” (38 mm x 89 mm x 114 mm x 122 cm)
Dimensions - F20045	2” x 4.5” x 5.5” x 48” (51 mm x 114 mm x 140 mm x 122 cm)
Dimensions - F3005	3” x 5” x 7” x 48” (76 mm x 127 mm x 178 mm x 122 cm)
Dimensions - FSTRIP	1” x 2” x 48” (25 mm x 51 mm x 122 cm)
Product Form	Mineral Wool, synthetic vitreous fiber
Shelf Life	No Limit

Ordering Information

Catalog Number	UPC Number	Description	(UOM) Qty.	Case Qty.	Weight (Each)
F11235	730573052358	Flute Filler 1.5" x 3.5" x 4.5" x 48"	1	24	1 lbs
F20045	730573052457	Flute Filler 2" x 4.5" x 5.5" x 48"	1	20	1.42 lbs
F3005	730573053058	Flute Filler 3" x 5" x 7" x 48"	1	12	2.3 lbs