Gas Pipework Materials in London: Copper, Steel, and CSST Explained
Gas pipework in London homes and commercial premises is subject to strict material and installation requirements under the Gas Safety Regulations and current industry standards. This guide explains the approved materials for domestic and commercial gas installations, the differences between them, and the situations in which each is used.
The Legal Framework for Gas Pipework in London
All gas pipework installation and modification in London properties must be carried out by a Gas Safe registered engineer. The Gas Safety (Installation and Use) Regulations 1998 are the primary legislative framework, and they are supplemented by industry technical standards published by the Institution of Gas Engineers and Managers, principally the Utilisation Procedures, which specify the materials, installation methods, and testing requirements for gas pipework. The choice of pipe material for a gas installation is not simply a matter of preference: each material has approved applications and installation requirements that must be followed to comply with the Gas Safety Regulations and the relevant IGEM standards.
The three principal materials used for domestic and commercial gas pipework in London are copper tube, steel pipe, and corrugated stainless steel tubing, commonly abbreviated as CSST. Each has different physical properties, cost profiles, and suitability for different installation environments. In addition, certain older London properties still have gas pipework in iron or mild steel pipe that was installed several decades ago under previous standards, which presents particular inspection and maintenance considerations.
Copper Gas Pipework: The Domestic Standard
Copper tube conforming to BS EN 1057 Table X is the standard material for domestic gas pipework in London homes. It is used for the gas supply pipework from the meter to the individual appliance connections throughout the property, including connections to boilers, gas hobs, gas fires, and gas tumble dryers. Copper gas pipe is jointed using silver solder, which requires a higher temperature than the soft solder used for water pipework and must be carried out by a Gas Safe registered engineer. Compression fittings approved for gas service are also used with copper gas pipe, particularly in locations where brazing is impractical or where the connection is to a meter or appliance component.
Copper is the preferred material for domestic gas installations because it is easy to work with, widely available in the sizes required for domestic gas flows, resistant to corrosion in normal domestic environments, and produces a reliable, permanent joint when correctly brazed. It is however not suitable for use in external underground locations where it is exposed to soil contact, which can cause accelerated corrosion, and it requires careful routing to avoid locations where mechanical damage is likely. Internal gas pipework in London homes that is run within walls or under floors must be sleeved through any masonry or concrete it passes through to allow free movement and to protect the pipe from chemical attack by building materials.
Steel Gas Pipework for Commercial and Industrial Applications
Steel pipe conforming to BS EN 10255 is commonly used for gas installations in commercial premises, industrial sites, and for larger-diameter gas supplies in London where the flow requirements exceed the practical range of copper tube. Steel pipe is jointed by welding or by screwed fittings using BSPT threads and approved jointing compounds. Steel gas pipework in commercial London installations requires cathodic protection or anti-corrosion coating where it is installed underground, and must be pressure-tested and purged in accordance with IGEM UP/1 before being put into service.
In domestic contexts, steel gas pipework is less commonly specified for new installations but is encountered in older London properties where the original gas installation was carried out in solid-drawn steel or wrought iron pipe. Where inspection reveals that steel gas pipework is in good condition with no significant corrosion, it can be left in service. Where corrosion is evident, particularly in external sections or in sections that have been subject to moisture, replacement in copper or CSST is the appropriate course of action.
CSST: Corrugated Stainless Steel Tubing
Corrugated stainless steel tubing, sold under brand names such as Gastite and TracPipe, is a flexible gas pipe system that has gained widespread adoption in London commercial and residential gas installations over the past decade. CSST consists of a corrugated stainless steel inner tube with a yellow polyethylene outer jacket, supplied in coil lengths that can be routed through buildings without the need for joints at changes of direction. The corrugated profile gives the pipe flexibility while maintaining the high pressure rating required for gas service.
The principal advantage of CSST in London installations is speed of installation. A CSST run from the gas meter to a boiler in a multi-storey London property can be routed in a fraction of the time required to install equivalent copper pipework, because the flexible pipe can be threaded through joists, behind stud walls, and around obstacles without the need for elbows and joints at each change of direction. CSST systems require specific approved fittings and must be installed by engineers trained and certificated by the system manufacturer in addition to being Gas Safe registered. CSST requires electrical bonding at all connection points to protect against lightning strike and electrostatic discharge, which is a specific installation requirement that must not be omitted. Prestige Engineers install all three gas pipework materials across London commercial and domestic properties in compliance with Gas Safety Regulations and current IGEM standards.