Proper Chimney Height

NFPA v. OSHA

• The National Fire Protection Association (NFPA) is a trade association whose members include experts in the house development and house safety industries. The Occupational Safety and Hazard Association (OSHA) is a government subdivision under the U.S. Department of Labor. The two organizations offer different recommendations for house safety standards, including chimney heights. However, OSHA recognizes NFPA's fire prevention standards as comparable to their own and allows building owners to use NFPA's standards if they wish.

Minimum Height

• NFPA provides a standard for chimney stacks attached to a house. For fire safety, the minimum height of chimneys must be greater than three feet above the point where the stack emerges from the roofline. Not all local municipalities adhere the NFPA's recommendations, and may have their own chimney height standards.

Air Intake

• A chimney's minimum height changes if a house has an air intake on its roof. Air intakes are filters that allow outdoor air to enter the house; intakes prevent debris from entering the house. According to OSHA, chimney stacks must be at least 10 feet taller than an air intake system or roof line within 50 feet of the chimney. The chimney's top must be 10 feet taller than whatever object, roof line or air intake has a higher elevation.

Problems

• If a chimney is too short, homeowners may experience some challenges from their chimney's faulty design. For instance, short chimneys do not vent as efficiently as properly built chimneys and are possible fire hazards. Also, faulty venting results in filling up your room with smoke and long-term damage to the chimney's flue stack and chimney cap.