• Envirograf Intumescent Fire Stop Blocks

Envirograf Intumescent Fire Stop Blocks

Product 2

Unfortunately, we no longer stock this product; please contact our technical team on 0113 2455450 (option 2) or send a message to [email protected] where we will be happy to offer you up to 10% off a suitable alternative product for your project.



Block Sizes

Reference Size in mm Length Fire Rating
IB1 50mm thick x 150mm wide 1200mm Up to 1 hour
IB1/A 50mm thick x 100mm wide 1200mm Up to 1 hour
IB1/B 50mm thick x 50mm wide 1200mm Up to 1 hour
IB2 100mm thick x 150mm wide 1200mm Up to 2 hours
IB2/A 100mm thick x 100mm wide 1200mm Up to 2 hours
IB2/B 100mm thick x 50mm wide 1200mm Up to 2 hours

Special sizes can be made to order - contact our technical team on 0113 245 5450 for more information.

Envirograf Intumescent Fire Stop Blocks are easy to cut and shape using a sharp knife or hacksaw, filling gaps around pipes and services to form a fire break barrier against smoke and fire.

The blocks are foil clad and have intumescent strips that expand in opposite directions when exposed to high temperatures, sealing an area against smoke. The edges have double-sided tape so you can adhere blocks together for a tight seal.

Made from a compressible and non-flammable rock-fibre composition that is clean fixing and dust-free, fire stop blocks are easy to install and remove for refurbishment and maintenance.

Advantages of Envirograf Intumescent Fire Stop Blocks

  • Clean fixing
  • Dust free
  • Simple to install
  • Can be removed to install other services
  • Cut with a sharp knife
  • Can be shaped around services openings


The Intumescent Blocks can be cut with a sharp knife or hacksaw blade, fitting into the opening to form a fire seal. Can be cut and pushed around services and pipes.

Where plastic pipes are 75mm or over then use Envirograf Wrap or Pipe Sleeve fixing into the blocks.

Where blocks are going over cable trays, leave a small gap and use Envirograf Product 29 Cable Tray Pillows.

The blocks have double-sided tape around the edges so they can be adhered to each other to form a smoke seal. Where there are any open joints use Envirograf Product 63 Intumescent Cement Filler.

Envirograf Intumescent Blocks can be used between screen walling and concrete floors as a firebreak.

Material Specification

Rock-Fibre composition, Inert vitreous silicate mineral wool bonded with a thermosetting phenolic resin which has been urea extended up to 0.3% of mineral oil products for special application will have up to 0.5% silicone oil, or silicon emulsion.

Multigraf Intumescent material chemical constitution

  • Mineral Wool Fibre 20-70% by weight
  • Exfoliating Graphite 20-60% by weight
  • Organic Binder (including adhesive coating) 5.0-30% by weight

Test Details

Test Integrity Insulation
Fulmer Yarsley - J 84201/4 84 Minutes 13 Minutes
Fulmer Yarsley - J 84201/14 138 Minutes 55 Minutes (Vertical) 100 Minutes (Horizontal)

IMPORTANT FIRE PRODUCTS NOTICE: The information displayed on this website should be used as a guide ONLY and our Technical Department should be contactedto obtain a tailored specification and any advice necessary before you place an order for fire protection products. Fire protection products are non-returnable except in accordance with Condition 8 of the Terms and ConditionsWe will not be held liable for any resulting damage to property, human life or monetary costs incurred due to the incorrect specification you have prepared or use of fire protection products caused by your negligence, including your failure to have contacted us to obtain the relevant advice/specification.

Any Envirograf products to be used in or for Harrods department store should be authorised with our Technical Team prior to purchase.

Product Details
Product 2

Customer agrees that before placing an Order, Customer has read and understood the most up to date Product Data Sheet for the Product. Where we have access to the Product Data Sheet from the manufacturer, we will either provide a copy on request, or include a link to the Product Data Sheet available on the manufacturer’s website. Customer further agrees that we have no liability for any errors or omissions contained within the Product Data Sheets. For more information, please see our Terms & Conditions of Sale.

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