Pipe Insulation by Pipe Size

Browse our full range of pipe insulation by pipe size, from 15mm domestic copper pipe through to 273mm large-bore industrial pipework. We stock Armaflex elastomeric foam, Rockwool mineral wool, Kingspan Kooltherm phenolic and Tubolit polyethylene foam in all standard bore sizes, with a range of wall thicknesses to suit domestic, commercial and industrial applications.

How to Choose the Correct Pipe Size

Selecting the correct bore size for pipe insulation is straightforward once you know how pipe sizing works:

Copper pipe is measured by outside diameter (OD) — a 15mm copper pipe has a 15mm outside diameter. Pipe insulation bore must match the OD of the pipe, not the internal bore.
Steel pipe sizing differs — steel pipe is measured by nominal bore (NB), which does not correspond directly to the actual outside diameter. Always check the actual OD before selecting insulation.
Plastic pipe (CPVC, PEX, PB) — plastic pipe sizes vary by manufacturer and system. Check the actual OD and select insulation to match.
When in doubt, measure the OD — wrap a tape measure around the pipe and divide by π (3.14) to get the OD, then select the nearest standard insulation bore size.

For a full explanation of copper pipe sizing and how it relates to insulation selection, see our Copper Pipe Sizes Guide.

Shop Pipe Insulation by Size

15mm Pipe Insulation — the most common domestic pipe size for hot and cold water services
22mm Pipe Insulation — standard domestic hot water and central heating pipework
28mm Pipe Insulation — larger domestic and light commercial hot water pipework
35mm Pipe Insulation — commercial heating and hot water distribution
42mm Pipe Insulation — commercial HVAC and heating pipework
54mm Pipe Insulation — commercial hot water and chilled water services
67mm Pipe Insulation — medium commercial pipework
76mm Pipe Insulation — commercial and industrial pipework
89mm Pipe Insulation — large commercial and industrial pipework
108mm Pipe Insulation — large-bore commercial pipework
114mm Pipe Insulation — steel pipe and large commercial services
133mm Pipe Insulation — large-bore steel and industrial pipework
219mm Pipe Insulation — large industrial and district heating pipework
273mm Pipe Insulation — large-bore industrial and district heating applications

Common Applications by Pipe Size

Pipe Size Range	Typical Application	Common Products
15mm – 28mm	Domestic hot & cold water, central heating	Armaflex EVO, Tubolit, K-Flex ST
35mm – 54mm	Commercial heating, hot water distribution	Armaflex Class O, Rockwool Rocklap
67mm – 114mm	Commercial HVAC, chilled water, refrigeration	Armaflex, Kooltherm, Rockwool
133mm – 273mm	Industrial process, district heating, steam	Rockwool Rocklap, Kooltherm

Wall Thickness Guide

Once you've identified the correct bore size, you'll need to select the appropriate wall thickness. This depends on the pipe temperature, application and compliance requirement (Part L, BS 5422 or CIBSE Guide C). As a general guide:

Domestic hot water (Part L) — typically 25mm wall for 15mm–28mm pipework
Chilled water and refrigeration — typically 19mm–32mm depending on pipe size and ambient conditions
High-temperature pipework — refer to BS 5422 or manufacturer data for mineral wool and phenolic products

See our Pipe Insulation Wall Thickness Guide for full guidance, or call our technical team on 0161 775 1190 (Mon–Fri 8am–4pm).

Knowledge Hub — Pipe Size Guides

Copper Pipe Sizes Explained — OD, nominal bore and how to select the correct insulation size
Pipe Insulation Wall Thickness Guide — Choosing the right wall thickness for your application
BS 5422 Pipe Insulation Standards Guide — Compliance and thickness specification
The Ultimate Guide to Pipe Lagging — Comprehensive pipe insulation reference
Pipe Insulation — Full range by material and brand
Foam Pipe Insulation — Elastomeric and polyethylene foam
Armaflex Pipe Insulation — Full Armaflex range by size
Rockwool Pipe Insulation — Mineral wool for high-temperature applications