Description
These are purpose-made protective guards for circular boiler flue terminals intended for use where people might come into contact with an exposed terminal. They don’t alter how the flue works; their job is purely safety and compliance — preventing accidental contact with a hot or sharp terminal and stopping items (or hands) reaching the flue outlet while allowing exhaust gases to escape freely.
Made by Tower (TFC Group), the CGDK family is a simple, installer-focused solution supplied in a variety of finishes and sizes to suit common domestic boiler terminals. The range includes compact, standard and deep/high-level versions so installers can match the guard to the flue’s position and any local plume-management arrangement.
Key specifications
- Typical diameter for CGDK3: 280 mm (11 in); depth ~165 mm (6.5 in).
- Available finishes: zinc & passivated plated, brown plastic-coated (BR), high-level brown plastic-coated with mesh infill (HLBRM), stainless steel (SS).
- Materials offered for non-condensing and condensing applications (see selection notes below).
- Typical pipe/terminal compatibility (from supplied record): 50 mm.
Materials and when to choose them
The CGDK guards are manufactured in different finishes to suit the installation environment and the type of appliance. Zinc-plated (no-suffix) guards are a cost-effective option for non-condensing boilers, but they are explicitly not recommended for condensing appliances because acidic condensate accelerates corrosion. For condensing boilers, plastic-coated (polyethylene) guards are the recommended standard; they give better corrosion resistance and are available in a brown coated finish that blends with many façades. Stainless steel variants are also offered where long-term durability and low maintenance are required — they’re suitable for condensing and non-condensing boilers and for installations exposed to weather or where maximum lifetime resistance to corrosion is needed.
Size, fit and compatibility
The range covers multiple sizes; the CGDK3 is a commonly stocked mid-size guard (around 280 mm diameter by 165 mm deep). Other sizes in the CGDK family cover smaller and larger circular terminals so you can pick a guard that maintains the required clearance around the terminal. The guard must be fitted so that no part of it sits closer than the minimum clearance required from the terminal (see installation rules below).
Regulation and installation cautions
These guards are intended to help meet the requirements of BS 5440-1 and the relevant sections of the UK Building Regulations for combustion appliances. In practice that usually means you must fit a guard where a terminal is less than 2.1 m above ground level, a balcony or a flat roof accessible to people; for plume-management arrangements the inlet height criteria differ slightly and the guard requirement may apply where the inlet is under 2.0 m. Once fitted, the guard should keep at least 50 mm clearance from every part of the terminal. These guards are an aid to compliance and safety; installers must still follow the appliance manufacturer’s installation instructions and the current statutory guidance when siting and securing a terminal guard.
Practical points for installers and landlords
Installation is straightforward for a competent engineer: the guard is positioned over the terminal and secured to the wall or brickwork so that the specified clearances are preserved. High-level versions with a mesh infill and cut-out are available where extra protection is required or where plume management requires a cut-out to accommodate an inlet or outlet. When specifying, confirm the guard material against the boiler type (condensing versus non-condensing) and consider stainless steel if the site is coastal, industrial, or otherwise aggressive.
Finally, the CGDK range is widely used in the UK heating trade and is offered in many supplier catalogues; however, stock and exact finish availability can vary between suppliers. If you need a lifetime, maintenance-free option, order stainless steel where the manufacturer lists it as available, and if you are fitting to a condensing boiler specify the plastic-coated or stainless option rather than zinc-plated.
