6-Inch Twin Wall Flue Pipes

Frequently Asked Questions

When installing a twin wall flue pipe, there are specific regulations and guidelines that must be followed to ensure safety and compliance with building codes. Key rules include maintaining a safe distance between the flue pipe and any combustible materials, which is typically at least 50mm, although this may vary based on local regulations and the manufacturer’s specifications. The flue must also extend to a certain height above the roofline to ensure proper draft and prevent downdrafts; typically, this is 600mm above the highest point of the roof within a 2.3-meter radius. Additionally, the flue system must be securely supported and should not rely on the appliance for support. Always consult a qualified installer to ensure compliance with all relevant regulations.

A twin wall flue pipe is used primarily for its insulation properties, which help maintain the temperature of the exhaust gases as they travel through the flue. This is especially important when the flue passes through unheated areas, such as lofts or outside walls, where the temperature drop could cause condensation or reduce the efficiency of the draft. The twin wall construction, with an insulating layer between the inner and outer pipes, ensures that the flue gases stay hot, improving the performance of your stove or fireplace and reducing the risk of condensation or tar build-up within the flue. Additionally, twin wall flue pipes are safe to use where there is a risk of the flue coming into contact with combustible materials, as the outer layer remains cooler than a single wall pipe.

Cutting down a twin wall flue pipe is not recommended, as it can compromise the integrity and safety of the flue system. Each section of a twin wall flue pipe is precisely manufactured to ensure proper insulation and secure connections. Cutting the pipe will damage the insulating layer and make it almost impossible to achieve a proper seal when reassembling the sections. If you need a specific length of flue pipe, it’s best to purchase an adjustable length or pre-manufactured section that meets your requirements.

The width of a twin wall flue pipe is determined by the diameter of the inner pipe, with the outer pipe being larger due to the insulation layer. For a 6-inch twin wall flue pipe, the inner diameter is 6 inches (150mm), and the outer diameter is typically around 8 inches (200mm). This additional width is necessary to accommodate the insulating layer between the inner and outer pipes, which ensures the safe and efficient operation of the flue system. Always ensure that your installation allows sufficient space for the outer diameter of the twin wall flue pipe.

Twin wall flue pipes are typically constructed from high-grade stainless steel for both the inner and outer layers, which provides durability and resistance to corrosion. The inner pipe is usually made from 316-grade stainless steel, known for its high resistance to heat and acidic condensation, making it ideal for withstanding the harsh conditions inside the flue. The outer pipe is often made from 304-grade stainless steel, which is durable and resistant to weathering. Between the two layers, an insulating material, often mineral wool or ceramic fibre, is used to maintain the temperature of the flue gases and ensure safe operation. This combination of materials makes twin wall flue pipes reliable and long-lasting in various installations.

Our HETAS and CE-approved 6-inch twin wall flue kits are simple, clean and easy to install, however we recommend a competent person to fit this product. Shop now for free UK delivery when you spend over £100.