Therma TT46 LPC/FM

Therma T26

Tapered Insulation To Enhance Water Drainage From Flat Roofs

Kingspan Therma TT46 LPC/FM is a tapered high performance, fibre-free rigid thermoset insulation, faced on both sides with a low emissivity composite foil  autohesively bonded to the insulation core during manufacture.

  • FM approved for Class 1 steel deck roof assemblies
  • Insulation and drainage in one
  • LPCB approved to LPS 1181: Part 1
  • Easy to handle and install

Product Information

Product Data Table
Specification Guide
Testing and Data Table
Product Dimensions 1200 mm x 1200 mm (1.44 m²)
Product thickness Systems with a 1:30 & 1:40 fall: 50 mm minimum
Systems with a 1:60 & 1:80 fall: 25 mm minimum
Systems with a 1:120 fall: 30 mm minimum*
All systems: Unlimited maximum*
Taper Gradients Falls of 1:30, 1:40, 1:60 and 1:80**

*Packer boards will be required above a specific thickness.
**For information regarding tapered roof designs incorporating
Kingspan Therma TT46 LPC/FM in a wider range of falls please contact the Kingspan Insulation Technical Service team at

Assumption and Key

The effective thermal conductivity and thermal resistance of the insulation in a tapered roofing system is specific to the individual roof design. The Kingspan Insulation Tapered Roofing Department performs calculations to determine these values in accordance with Annex C of BS EN ISO 6946: 2007 (Building components and Building elements – Thermal resistance and thermal transmittance – Calculation method) as part of the scheme design process. 
The roof insulation shall be Kingspan Therma TT46 LPC/FM ____ mm thick, comprising a CFC/HCFC-free and zero Ozone Depletion Potential (ODP) rigid thermoset insulation core with composite foil facings on both sides, manufactured under a management system certified to BS / I.S. EN ISO 9001:2008, BS / I.S. EN ISO 14001:2004 and BS / I.S. OHSAS 18001:2007 by Kingspan Insulation Limited and shall be installed in accordance with the instructions issued by them.

A Project Specific Warranty provided by Kinspan Insulation must be submitted.

Specify with:NatSpec logo

Management Standards

Standard Management System
BS / I.S. EN ISO 9001:2008 Quality Management
BS / I.S. EN ISO 14001:2004 Environmental Management
BS / I.S. OHSAS 18001:2007 Health and Safety Management

Kingspan Therma TT46 LPC/FM is also manufactured to the highest standards in accordance with the requirements of:
Requirement Rigid polyisocyanurate (PIR) and polyurethane(PUR) products for building end–use applications
BS 4841-4 Specification for laminated boards (roofboards) with auto–adhesively or separately bonded facings for use as roofboard thermal insulation under single−ply roofing membranes

Spanning On Metal Decks

Trough Opening (mm) Minimum Insulant Thickness (mm)
≤75 25
76 - 100 30
101 - 125 35
126 - 150 40
151 - 175 45
176 - 200 50
201 - 225 55
226 - 250 60

Product Testing

Characteristic Standard Result
 Compressive Strength AS 2498.3 Typically exceeds 150 kPa at 10% compression
Water Vapour Resistance AS 2498.5 > 100 MN·s/g·m

Fire Performance

Kingspan Therma TT46 LPC/FM, when subjected to the British and Austrlian Standard fire tests specified in the table below, will achieve the result shown, when waterproofed with a single–ply waterproofing membrane.
Test Result
BS 476-3: 2004
(external fire exposure roof test)
Dependent on single-ply membrane adopted
AS 1530.3
(Ignitability. Flame Spread, Heat Release, Smoke Release)
Spread of Flame Index: 0
Smoke Development Index: 1
AS 2122.1
(Flame Propagation AS 1366)

Further details on the fire performance of Kingspan Insulation products may be obtained from the Kingspan Insulation Technical Service.

FM Certification

Kingspan Therma TT46 LPC/FM is certified as achieving Class 1 Insulated Steel Deck Pass to Factory Mutual Research Standards 4450 (Approval Standard for Class 1 Insulated Steel Deck Pass) and 4470 (Approval Standard for Single–Ply, Polymer–Modified Bitumen Sheet, Built–Up Roof (BUR) and Liquid Applied Roof Assemblies for use in Class 1 Non-combustible Roof Deck Construction), subject to the conditions of approval as a roof insulation product for use in Class 1 roof constructions as described in the current edition of the Factory Mutual Research Approval Guide.

LPCB Certification

Metal deck roofing constructions incorporating Kingspan Therma TT46 LPC/FM, produced at Kingspan Insulation’s Pembridge and Castleblayney manufacturing facilities, have been successfully tested to LPS 1181: Part 1 (Requirements and Tests for Built–up Cladding and Sandwich Panel Systems for use as the External Envelope of Buildings). 

Do you need help and advice on your project?

Our teams are dedicated to helping you make process as easy as possible and ensure you get the right materials for your needs.

Contact Us

Contact Us

Kingspan Insulation Australia

Kingspan Insulation operates Australia wide. Contact us to find your local State Representative. For any enquiries, call 1300 247 235 or send an email to

Head Office

266 Beringarra Avenue, Malaga

Western Australia


Call: 1300 247 235

Fax: 1300 247 329

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