Masonry chimneys must have a lining system when each appliance has a minimum less than ______ Btu/h.

Masonry chimneys must have a lining system when each appliance has a minimum less than ______ Btu/h.

• A. 500,000 Btu/h
• B. 300,000 Btu/h
• C. 400,000 Btu/h
• D. 200,000 Btu/h

Answer: (C)

The key idea is that masonry chimneys need a flue lining to protect the masonry and ensure safe venting when the connected heating appliance produces a lot of heat. The code sets a threshold at 400,000 Btu/h: if an appliance has a heat input rating at or above this level, a lining is required. The lining helps resist high temperatures, protects the brick or mortar from deterioration, and reduces risks associated with creosote and improper draft. If the appliance’s input is below that level, a lining is not required by this rule, though you should still follow any local code or manufacturer instructions.

The key idea is that masonry chimneys need a flue lining to protect the masonry and ensure safe venting when the connected heating appliance produces a lot of heat. The code sets a threshold at 400,000 Btu/h: if an appliance has a heat input rating at or above this level, a lining is required. The lining helps resist high temperatures, protects the brick or mortar from deterioration, and reduces risks associated with creosote and improper draft. If the appliance’s input is below that level, a lining is not required by this rule, though you should still follow any local code or manufacturer instructions.