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Question
I am wondering how you would go about calculating the flue size for a 3 sided wood fireplace.

Right now the actual box or pit that the wood would sit in is 4'x 1'9". From the fireplace opening is 3'7" and the rest of the chimney run is 22' - 7 3/4".

How does one go about calculating the required size of flue? Do we need more than one?

I am really stumped as to how to go about this.

Answer
Hi Andrew,

Add up ALL the opening sides to determine the number of square inches of fireplace opening.

You need 1/10th or 10% of the square inches of the entire fireplace opening to vent with square or rectangular tiles.  In other words, if you have 1000 square inches of opening, you need a minimum of 100 square inches of flue cross-sectional area to vent it.

You need 1/12th or 8% of the square inches of the entire fireplace opening to vent with round.In other words, if you have 1000 square inches of opening, you need a minimum of 100 square inches of flue cross-sectional area to vent it.  In other words, if you have 1000 square inches of opening, you need a minimum of 80 square inches of flue cross-sectional area to vent it.

Thanks for using AllExperts.Com and good luck with your project.

Sincerely,
A. Bart Ogden, President
Home Safe Hearth & Chimney, Inc.
Wichita, KS
Voice 316-265-9828
www.HomeSafeKS.com

CSIA Certified Chimney Sweep #2653
CSIA Certified Dryer Exhaust Technician #10
NFI Certified Wood Specialist
NFI Certified Gas Specialist
NFI Certified Pellet Specialist
NFI Master Hearth Professional
NFI Instructor
NCSG Technical Advisory Council Member
2011 White House Chimney Sweeping Team Member

Advice given is general in nature. Local laws and ordinances may govern and/or supersede the information and recommendations provided. Final determinations are the responsibility of a local professional with first-hand knowledge of the situation, and the AHJ.

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Bart Ogden

Expertise

I can answer questions related to chimney and fireplace cleaning, construction and repair as well as questions related to the performance of chimneys and fireplaces. I can also answer questions related to clothes dryer vent cleaning and repair. Additionally, I can field questions related to masonry repair.

Experience


Experience in the area:
28 years experience in the chimney service/installation/repair field
President, Home Safe Hearth & Chimney, Inc. Wichita, Kansas

Professional Organizations:
Member, National Chimney Sweep Guild (NCSG)
Member, Hearth, Patio & Barbecue Association (HPBA)
Member, Kansas Guild of Professional Chimney Sweeps (KGPCS)
Member, Midwest Chimney Safety Council (MCSC)
Member, Kansas Association of Real Estate Inspectors (KAREI)
Past At-Large Director of the National Chimney Sweep Guild
Past At-Large Director of the Chimney Safety Institute of America
Past Secretary, National Chimney Sweep Guild
Past Secretary, Chimney Safety Institute of America
Member, National Chimney Sweep Guild Technical Advisory Council
Member, Chimney Safety Institute of America Certification Committee
Past Chairman, CSIA Chimney Safety Education Brochures Committee
Past Chairman, NCSG Nomination Committee

Publications:
SWEEPING Magazine, The Journal of Chimney & Venting Technoloty, A Publication of the National Chimney Sweep Guild
SNEWS, The Chimney Sweep News
THE KANSAS SWEEP, The Voice of the KS Guild of Professional Chimney Sweeps

Education/Credentials:
BA, Wichita State University
C.S.I.A. Certified Chimney Sweep
C.S.I.A. Certified Dryer Exhaust Technician
N.F.I. Woodburning Specialist
N.F.I. Gas Specialist
Chimney Diagnosis & Documentation Seminar
Ahren's Masonry Restoration School Graduate
Advanced Gas Certification
Master Gas Certification
Licensed Mechanical Contractor
Pellet Appliance Specialist
Venting Design Specialist
Dale Carnegie Course Graduate

Awards and Honors:
Superior Dealer Award, Ventinox Chimney Lining Systems

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