BS 5422 Resource Centre

The complete UK reference for pipe insulation thickness, compliance and specification under BS 5422:2009

Used by heating engineers, M&E contractors, HVAC consultants and facilities managers throughout the UK

BS 5422:2009 (amended 2014) is the British Standard specifying minimum thermal insulation thicknesses for pipework, ductwork and equipment in building services installations. It is referenced by Part L of the Building Regulations and is the primary compliance standard for pipe insulation in the UK.

The standard covers heating systems, chilled water systems, cold water systems and steam applications, providing thickness tables based on pipe outside diameter, operating temperature and insulation material thermal conductivity (lambda value).

Featured Guides

BS 5422 Explained — The Complete Guide

The definitive reference for minimum insulation thicknesses

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What Thickness Pipe Insulation Do I Need?

Step-by-step thickness selection for every application

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Part L Compliance for Pipe Insulation

How BS 5422 satisfies Part L of the Building Regulations

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Technical Downloads

Armaflex EVO Technical Data Sheet PDF
Armaflex EVO Declaration of Performance PDF
Kingspan Kooltherm Technical Data Sheet PDF
Rockwool Rocklap Technical Data Sheet PDF
K-Flex ST Technical Data Sheet PDF

Frequently Asked Questions

BS 5422:2009 (amended 2014) is the British Standard specifying minimum thermal insulation thicknesses for pipework, ductwork and equipment in building services installations.
BS 5422 is referenced by Part L of the Building Regulations — compliance is required for notifiable building work in England and Wales.
BS 5422 covers pipe outside diameters from 10mm to over 100mm across heating, chilled water, cold water and steam applications.
Yes — BS 5422 applies to domestic heating and hot water pipework where the work is notifiable under Part L.
BS 5422 is published by BSI and available from the BSI Shop.
Use the BS 5422 tables for your pipe OD, operating temperature and insulation material lambda value — or contact our technical team on 0161 775 1190.

Need help with BS 5422 compliance?

Our technical team can advise on the correct insulation material, wall thickness and accessories for your project — from a single domestic pipe to a full commercial specification.