Expanding Foam: Fire Rated Or Not? - 08/09/2017

What is B2 Fire Rating? Frankly, it’s not worth much. B2 Fire Rated foam does not mean that it can be used for fire-stopping or fire-proofing. B2 rating is not acceptable as a fire stopping material; B1 grade is needed.

To sell something as ‘B2’ Fire Rated is very misleading, whilst factually correct. Many think that the classification B2 indicates a 2 hour fire rating, and consequently buy/sell the B2 foam as a fire-stopping material.

Further information below on B2 & B1 foams shows a list of the suggested uses; several uses are recommended, but there are no comments on any fire properties for the B2.

B2 Foam – 417981


  • Excellent stability (no shrinkage or post-expansion)
  • High filling capacity
  • Good adhesion on all surfaces (except PE, PP and PTFE)
  • High insulation value, thermal and acoustic
  • Very good bonding properties
  • Very precise to dose


  • Installing of window and door frames
  • Filling of cavities
  • Sealing of all openings in roof constructions
  • Apply of an acoustic baffle
  • Apply of a sound absorbing layer
  • Improving thermal isolation in cooling systems


B1 Firestop Foam – 418011


  • Fire retardant up to 240 minutes (tested according to EN1366-4).
  • Efficient seal against smoke and gas
  • Excellent adhesions on most substrates (exempt Teflon, PE and PP)
  • High thermal and acoustical insulation
  • High bonding strength
  • Very good filling characteristics
  • Excellent stability: no shrink or post-expansion
  • Can be after full cure
  • Fitted with the Click&Fix system for ultimate ease in application

Application examples

  • Fire retardant installation of window and door frames
  • Fire and smoke retardant sealing of connections between partition walls, ceilings and floors
  • Filling of cavities
  • All applications where fire retardant characteristics are required such as:
  • Sealing of all openings in roof constructions
  • Sealing of cable and pipe penetrations
  • Creation of a sound proof screen
  • Bonding of insulation materials
  • Application of sound-deadening layers
  • Improving thermal insulation in cold store areas

As the industry is now more conscious than ever of the importance of fire protection, be sure to double check which product you require. The difference in price between the B1 and other foams is a small price to pay to protect a building and, potentially, lives. To summarise, B1 foam is the only fire retardant option. B2 and higher grades are not fire retardant.

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