Envirograf Flexible Fire Bag

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Envirograf Intumescent Fire Bag

Envirograf’s Flexible Fire Bags are to be installed around mail slots. There is also a metal box equivalent for if preferred. Please see the Envirograf Metal Boxes. They are both appropriate for using in internal areas which are vulnerable to arson and vandalism.

The intumescent material in the bags extinguishes fire, to protect the property. This can easily be renewed.

Use the bag when doors need to be opened wide and there is a tight gap between the door and the wall.

Fire Testing:

These products have been tested to BS476 Part 22 (1987).

This means that the fireboxes and bags self extinguish flames and fire, therefore will not allow anything to burn.

Application Instructions:

Attach the letter box opening over existing internal openings or flaps.

Use the Fire Proof Silicone (which comes with the product) either over the external plate or around the internal side of the door, around the letter box opening.

Turn the clips and separate the Velcro tape to open the lid.

Screw the metal plate to the door using the screws provided, through the holes at the end of the metal plate.

Order REFA (Wall/Door height)B (Outside Height)C (Depth)D (Width)
Flexible bags with horizontal letter opening:-
FLEX1 – suitable for a 315 x 70mm aperture335mm335mm130mm420mm
FLEX2 – suitable for UPVC doors with a 290mm x 55mm aperture. Single layer of cloth.335mm335mm130mm420mm
FLEX3 – suitable for UPVC doors with a 290mm x 55mm aperture260mm260mm95mm400mm
FLEX3/A – suitable for UPVC doors with a 315mm x 70mm aperture260mm260mm95mm400mm
Flexible bags with vertical letter opening:-
FLEX4V – suitable for a 315mm x 70mm aperture560mm560mm130mm360mm
FLEX5V – suitable for a 290mm x 55mm aperture530mm530mm100mm300mm

Use an Envirograf letter box liner with any letter box on the front of the door. Please contact us if a bespoke size is needed.


For all technical enquiries, call us on 01752 690997.


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