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Intumescent Liner for Letter Box

Product 50


Intumescent liners for improving the fire rating of existing letter box apertures.

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Intumescent Liner for Letter Box

An intumescent liner for letter box. This product comprises of two adhesive L-shaped sections with self-adhesive backing for fixing. For mail apertures in fire doors where letter flaps already exist. Aperture sizes up to the limit for each type (LBL1 and LBL2) adjust the liners by cutting with a sharp knife as required. Seal any bare wood apertures with paint or wood sealer before fixing the liner, this will ensure optimum efficiency. Suitable for fitting to doors from 38mm to 70mm thick. See the order references tab for all standard sizes that are available. Sizes to suit other openings are available to order. If you are looking for a letter box unit in addition to the letter box liner, take a look at the Intumescent Letter Box Unit Range online here.

These products were included in a  fire test employing the general procedures and criteria of BS476 Part 22 (1987) built into a composite door, maintaining the integrity of the door for 61 minutes. Also tested to European Standard EN1634-1 (2000), achieving 68 minutes.

Our products upgrade doors to Fire Door rating, in compliance with Building Control. Browse our full range of Fire Door products and Fire Door Accessories online


– Provides up to 68 minutes protection- Can be custom made to suit a range of aperture sizes
– Suitable for fitting to doors from 38mm to 70mm thick
– Liner can be easily cut to size to fit the opening

Application Instructions

2 L-shaped sections supplied with double sided tape on the back. Place long section on top of
the side section and cut both angles to length. Peel off double sided tape and adhere to the
inside of the opening. It is advisable to put panel pins into both side pieces. A bare wood aperture must be sealed with paint or wood sealer before fixing the liner.

Order References / Sizes

LBL1    (85 x 340mm)

LBL2   (65 x 290mm)

LBL3   (39 x 254mm)