Nelson FSP™ Firestop Putty

Moldable, Reusable, and Instant Firestopping

We Guarantee to Have the Best Price

What's special about moldable firestop?

  • Constructed of a blend of organic and inorganic intumescent materials that expand with extreme heat to seal voids from exposure to fire and smoke
  • Pre-mixed material is ready to use right out of the box, so it requires no additional blending, and saves time on the jobsite
  • Hand moldable, so it requires no specialty tools for installation or adhesion
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Nelson FSP™ is an excellent way to create an instant fire seal. This easy to use mixture can be pressed in place by hand, and requires no special equipment or processes, so installation and cleanup are a breeze. FPS™ is the perfect solution for retrofit applications, and situations in which frequent cabling changes take place.


NFS-AA458 Nelson FSP Moldable Putty Pad 6" x 7" x 1/8" 1 0.625 lb
  • Reusability is ideal for making changes to your cabling throughway, and convenient for retrofit installations
  • Putty stays pliable at all times and doesn't set, so it can be easily removed and reapplied
  • Requires no curing or drying time
  • Weather resistant for added durability and corrosion resistance
  • Acoustically tested to reduce the transmission of noise and vibration
  • For faster installation, no cable derating is needed
  • 3-hour rating complies with ASTM E119 and UL263 for building construction materials
  • Available as an easy to carry and store putty bar, or as putty pads


Ideal for filling voids on or around:



  Physical Properties
Color Tan
Density 0.049 lbs / in3
Consistency 7.00mm (Penetrometer)
Activation Temperature 500° F (260° C) Max.
Application Temperature 40° F (4° C) to 110° F (43° C)
Dielectric Strength >356 v/mil
STC Rating 54
  Test Compliance
  Flame Spread - 5
  Smoke Developed - 10
ASTM E814 and UL 1479
ANSI / UL 263
Underwriters Laboratories, Inc "Fill, Void, or Cavity Material (XHHW)", FM, ABS, and USCG City of New York, New York, Department of Buildings
MEA 135-00-M
MEA 196-84-M Vol 3
  Storage & Handling
Nelson FSP™ should be stored indoors. Long term storage temperature: 140° F (60° C) maximum. There is no indication of shelf-life limitations. Partially used bars should be re-wrapped in their original packaging before being stored.






firestop putty, SP100STI 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.

Fire Protection 3M? Fire Barrier Pillow

3M™ Fire Barrier Pillow
During a fire, 3M™ Fire Barrier Pillow intumesces (expands) and locks itself into place, completely surrounding the penetrant(s) stopping smoke, fire and toxic gases from spreading to the next room or next floor for the rated time period. They are easy to install and great for retrofit projects. Just remove and replace pillows as needed.


firestop sleeveSTI 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. These sleeves weigh half of what competing threaded products do, and have fewer parts, which make them the product you need when you are working on ladders or in cramped spaces in rated and non-rated construction zones.

Fire Caulk 3M? Fire Barrier 2000 Silicone Sealant3M™ Fire Barrier 2000 Silicone Sealant
Ideal for sealing simple penetrations such as around metallic or glass pipes and conduits to control the spread of fire. Helps limit the spread of noxious gas, smoke and water. Maintains the integrity of fire-rated construction.


Nelson Firestop CPS SheetsNelson Firestop CPS™ Composite Sheet
Perfect for protecting vital network equipment, this easy-to-install, 2-hour flame rated composite sheet blocks the spread of smoke and flame in through-wall cable penetrations.

firestop bricks, AA834Nelson Firestop Bricks
Price per 6 pack
Firestop Brick is ideal for applications where there might be a need to re-penetrate an area, and is easy to re-position. When the brick comes into contact with fire, the brick material expands within the opening, forming a solid char that prevents through-penetration of the fire for up to 2 hours.

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