Gas services design

Gas services design covers the route from the meter to the appliance: incoming supply and meter capacity, pipe sizing and materials, ventilation and flueing of the plant room, and the safety provisions — isolation, detection, purge — that the installation is required to have.

The design work is governed by the IGEM technical standards rather than by a single British Standard, and by the Gas Safety (Installation and Use) Regulations 1998. Installation and commissioning must be carried out by a Gas Safe registered engineer; design sets what that engineer installs.

Where a building has a gas-fired appliance of any size — boilers, direct-fired heaters, commercial catering, laboratory or process gas — and on any project where the existing supply or meter may not have the capacity for a changed load.

Also on the way out: Scotland's New Build Heat Standard prohibits direct emissions heating in new buildings applying for a warrant from 1 April 2024, so on a new build in Scotland the honest answer is often that gas is not available for heating, and the design work becomes the electrification route instead.

Load first, then the supply. The connected load and the diversity applied to it determine whether the existing meter and service will do, and a capacity application to the gas transporter has a lead time that needs to start early rather than at tender.

Plant room ventilation and flue routing are resolved with the architect at coordination stage, because both need builder's work and both are difficult to add later.