Home
Information
downloads
Print page
Enquire Online
Directions
 

Therm-A-Plate

Letterbox Liner

Intumescent letterbox liner

THERM-A-PLATE (INTUMESCENT LETTERBOX LINER)

A cost effective method of fire proofing letter apertures in doors


  
Download datasheet

INTRODUCTION

It is increasingly common to find that entrance doors to flats and apartments in tower blocks and houses in multiple occupation, are fire resisting to 30 or 60 minutes rating. As these doors are effectively external doors, many have apertures cut in them to serve as letter boxes, but this unfortunately compromises the doorleaves integrity.

THERM-A-PLATE offers a simple
solution to the problem by providing a lining kit for the cut aperture for both 30 and 60 minute constructions.

DESCRIPTION

A THERM-A-PLATE kit comprises of three pieces of THERM-A-FLEX graphite based intumescent material. This material is renowned for its longevity and resistance to degradation by atmospheric influences. The intumescent strips are pre-cut to the correct width for 45mm and 54mm thick doorleaves. The intumescent materials are backed with a high bond strength

 

 

self-adhesive tape for ease of
installation. For small letter plate
apertures up to 50mm high the
thickness of the intumescent material is 4mm and for 85mm or 120mm apertures the thickness is 6mm. For the largest aperture 4no. steel pins, 30mm long and 1.5mm diameter are required to fix the top and bottom intumescent strips 50mm from the ends of the aperture and 10mm from the face of the door.

PERFORMANCE

The performance of the THERM-A-PLATE kits has been proven in fire tests carried out to BS476 Part 22 (1987).

Dr\Ap 50x250 85x250 120x300
45mm 67 - 39
54mm - 70 66

TEST RESULTS

Test results (time to failure in minutes) are shown for 45mm and 54mm doors with different aperture sizes. Test reports DFR 9807141, DFR 9804271,
DFR 9810292 and DFR 9809151 are available on request.

ISO 9001

  

AVAILABILITY

THERM-A-PLATE intumescent letter plate kits are produced in five standard aperture sizes to suit both 30 and 60 minute fire doors.

Type FD30 FD60
50 x 250 LPTA45 LPTA54
85 x 250 LPTC45 LPTB54
120 x 300 LPTC45 LPTC54

Other sizes are available on request.

INSTALLATION

The kit is supplied in pieces backed with self adhesive tape and these are bonded to the inside sides of the aperture.

The faces of the aperture must be clean, dry and dust free for optimum adhesion.

Kits may be trimmed to suit the aperture size as required. It is recommended that metal letter plates are used to comply with the recommendations in BS8214 (1990) and the largest aperture requires a metal tidy but does not have end pieces of intumescent.