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A tapered version of Kingspan Thermaroof® TR26, Kingspan Thermataper® TT46 board is designed for use beneath mechanically fixed single-ply non-bituminous roofing systems.

The Kingspan Thermataper® range has been specifically designed to prevent water ponding, the most common cause of failure of flat roofs.

U Value calculations for the Kingspan Thermataper® range incorporate BS EN ISO 6946: 1997- Annex C (Building Components and Building Elements). Annex C outlines the calculation procedure to determine the total thermal transmittance of tapered insulation - what is termed the 'Annex C U Value'.

Kingspan Thermataper® TT46 LPC/FM is CFC / HCFC free and is manufactured with a blowing agent that has zero Ozone Depletion Potential (ODP).

Kingspan Thermataper® TT46 LPC/FM is manufactured in accordance with BS EN ISO 14001 Environmental Management Systems, BS EN ISO 9001 Quality Management Systems and OHSAS 18001 Health and Safety Management System.

Kingspan Thermataper® TT46 LPC/FM is also manufactured in accordance with the Harmonised Standard BS EN 13165: 2001 (Thermal insulation products for buildings- Factory made rigid polyurethane foam (PUR) products- Specification).

Kingspan Thermataper TT46 LPC/FM achieves a BRE Green Guide rating of A+.

Standard product features

Board size:

  • Length- 1.2m
  • Width- 1.2m

Thermal conductivity:

All insulation thicknesses- 0.022 W/mK.


Faced both sides with a low emissivity composite foil autohesively bonded to the insulation core during manufacture.

Density of insulation:

32 kg/m³.

Fire Performance:

Kingspan Thermataper® TT46 LPC/FM has been successfully fire tested in accordance with the LPCB to LPS 1181-1:2003 and Factory Mutual Research, USA to Standard 4450 (1989) and 4470 (1986). Kingspan Thermataper® TT46 LPC/FM can also achieve an FAA fire rating when tested to BS 476-3: 1958 The fire rating of any roof containing Kingspan Thermataper® TT46 LPC/FM will depend on the final waterproofing layer and/or surface finish. Please consult the appropriate waterproofing manufacturer for details of external fire performance.

NBS Specification

NBS Create logo
This product is associated with the following NBS Create clause:
45-45-65/430 Polyisocyanurate (PIR) foam board

Product specification

An important note about specifying



Kingspan Insulation


+44 (0)1544 388601

Product reference

Thermataper® TT46 LPC/ FM

Insulation thickness

___ mm - Please refer to product literature, consult your local distributor or contact Kingspan Insulation Technical Services for a full range of available thicknesses.

Standard Falls

[1: 60]
[1: 80]

Manufacturer details

Kingspan Insulation Ltd,
Herefordshire, HR6 9LA
Tel +44 (0)1544 388601
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