What type of chimney construction is generally required for oil burning appliances?

In the context of oil burning appliances, double wall construction is generally required because it provides enhanced safety and efficiency. This type of chimney is designed with two layers: an inner layer that contains the flue gases and an outer layer that reduces the risk of heat transfer to surrounding structures. Double wall chimneys are insulated, which helps to maintain the temperature of flue gases and improves the draft, reducing the likelihood of condensation that could lead to corrosion or other issues.

The design of double wall chimneys also helps to minimize the risk of fire hazards by keeping heat away from combustible materials. Given the potential for high temperatures during the operation of oil burning appliances, this construction method is crucial for ensuring both safe operation and compliance with building codes and regulations.

Single wall construction is typically less effective in terms of insulation and may not adequately protect adjacent materials from heat. Flexible materials may not provide the strength required for supporting the weight and pressure of flue gases. Metal-only construction without proper insulation may result in excessive heat loss and safety risks. Therefore, double wall construction stands out as the most suitable choice for these specific appliances.