Nelson Firestop LBS3™ Latex Sealant

Ideally Suited for Non-Combustible PVC, PEX, CPVC, & ABS in Floors and Walls

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What's special about this fire sealant?

  • Elastomeric, one-part, water-based, intumescent, firestopping sealant designed for use in penetrations and construction joints where firestop is needed to keep fire, smoke, gasses and water out
  • Dries to the touch quickly; skin develops within 2 hours and is tack-free within approximately 10-15 minutes which means it is ready to be painted, although it is best to wait 72 hours
  • Rated up to 3 hours for fire protection
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Nelson Firestop Sealant (LBS3™) is ideally suited for for firestopping through-penetrationsof non-combustible pipe, insulated pipe and combustible pipe (such as PVC, PEX, CPVC and ABS) in floors or walls. It can applied using a standard caulk gun, bulk loader, or trowel. If you are working with a large area, it can be pumped directly from the pail.


NFS-AA892 Nelson Firestop LBS3™ Latex Sealant 10.3 oz Tube 18.5 in3 (304 ml)
NFS-AA893 Nelson Firestop LBS3™ Latex Sealant 20.2 oz Foil Pack 36.45 in3 (597 ml)
NFS-AA895 Nelson Firestop LBS3™ Latex Sealant 5 Gallon Bucket 1155 in3 (19.0 L)

To apply, begin on the edge of the opening and ensure that the sealant makes complete contact with the inside surface of the opening, as well as the surface of the penetrating item(s).

  • No-sag (thixotropic), halogen-free formula won’t drip even when applied overhead, and is safe to work with
  • Because it is water based, it is easy to clean and there are no special handling or disposal requirements
  • Endothermic quality allows the sealant to absorb heat and release chemically-bound water
  • Able to withstand extremely cold temperatures and thaw without expanding or contracting
  • Acoustically tested to reduce noise transmission
  • One year manufacturer warranty


Use to seal construction openings, blank openings and penetrating items against the passage of flame, noxious gas, smoke and water. Restores fire rated construction to its original integrity.

Chemical Name / Class Polyvinyl Acetate and Acrylic Latex Based Emulsion
Product Use Elastomeric Intumescent Firestop Sealant
Color Red
Odor Mild Latex Odor
Cure Time Approx 2 hour
Full Cure 3 to 4 weeks
Asbestos Filler None
Solvents None
Density 10.0 lbs / gallon
VOC Content 10.86 g/l
Application Temperature 40° to 90° F (4° to 32° C)
Activation Temperature Exp. begins @ 250°
STC Rating 52
Test Compliance
Standards ASTM E84 and UL 723
Flame Spread 0
Smoke Developed 5
Test Methods ASTM E90; ASTM E814 & UL 1479; ASTM E1966 & UL 2079; ASTM C719
Storage between 40° to 90° F (4° to 32° C); protect from freezing
Shelf Life 1 year from date of shipment
Relative Vapor Density (air = 1) >1
Evaporation Rate (n-BuAc = 1) 1
Specific Gravity (water = 1) Not available
Viscosity Unknown
Solubility in Water Appreciable
Boiling Point >100° C (212° F)
Vapor Pressure, mm Hg @ 20° C Unknown
pH n/a
Bulk Density (lbs / Cubic Foot) n/a
% Volatiles (gr/L) (70° F / 21° C) 10.86 g/l 10
Stability Stable
Decomposition Products Carbon dioxide, Carbon monoxide, Low molecular weight hydrocarbons, Aldehydes
Hazardous Polymerization Will not occur
Conditions to Avoid Strong oxidizers, strong acids


Composition & Information on Ingredients

Ingredient CAS # Percent (Max)
2-Porpenoic acid, polymer 052640-81-0 10-20
Dipentaerythritol 00126-58-9 1-5
Graphite 007782-42-5 1-5
Melamine 00108-78-1 1-5
Methenamine 000100-97-0 < 1
Phenol, isopropylated, phosphate (3:1) 068937-41-7 5-10
Phenol-formaldehyde polymer 009003-35-4 1-5
Polyvinyl Acetate Emulsion NJ801415075P 10-20
Pseudocumene 000095-63-6 < 1
Silicic acid, sodium salt 001344-09-8 5-10
Talc 014807-96-6 1-5
Triphenyl phosphate 000115-86-6 1-5
Zinc borate 001332-07-6 1-5






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