STI Series FP Intumescent Firestop Plugs

Stop Fire and Smoke From Traveling Through Conduits to Other Rooms

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What's special about this firestop seal?

  • 2 hour rating for cable penetrations and blank openings through concrete and gypsum board/stud assemblies
  • Made of Polyurethane foam, which expands 10X its normal size to seal out smoke and fire
  • Fast and Easy installation; no tools required, so you save time and money
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With a 2 hour safety rating, 10X expansion rate and easy installation, this Firestop Plug will help protect your business or home from fire and smoke that could pass through EMT conduit in the walls.


STI-FP200 Intumescent Firestop Plug 2" (51 mm) Red
STI-FP400 Intumescent Firestop Plug 4" (102 mm) Red
  • Red color for easy identification and inspection
  • This fire plug is intumescent, which means that it will swell when the temperature reaches 350° F (176° C), to expand and seal off the EMT conduit
  • Paintable to match any décor
  • Designed for permanent or temporary use
  • Tested to meet the exacting criteria of ASTM E814 (UL1479) and CAN/ULC S115


This product has starred in our Product Showcase Blog! Click here to check it out.


Color Red
Nominal Density 19 pcf (304 kg/m3)
Weight 2" - 0.20 lb (91 g)
4" - 0.50 lb (227 g)
Expansion Begins 350° F (176° C)
Volume Expansion 10 X
In-Service Temperature < 130° F (54° C)
Shelf Life N/A
VOC Content N/A

This product has starred in our Product Showcase Blog! Click here to check it out.








Intumescent SealantSTI SpecSeal® Triple S® Intumescent Sealant Tube
This sealant is ideal for construction gaps and blank openings in walls or floors. Tested and approved for use with metallic penetrants up to 30", SSS can be safely combined with other SpecSeal products.
Firestop Sleeve KitsSTI Split Firestop Sleeve Kits
Ready™ Split Sleeves are designed with a split pathway and come with wall plates which allow them to be implemented around existing cable bundles.
Firestop PillowsSTI SpecSeal® Firestop Pillow
Able to expand in all directions when exposed to extreme heat, these easy to use intumescent pillows block the spread of smoke and flame through wall penetrations and construction gaps.
SSP PuttySTI SpecSeal® SSP Putty
An excellent product for retrofit jobs and cabling that call for a firestopping sealant. It is easy to apply and meets the highest quality standards. This 36 cubic inch bar is all you need for metallic conduits, telephone, data or electrical power cable penetrations as well as a variety of sleeved and non-sleeved applications.

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