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.