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Direct vent chimneys or exhaust for gas fireplaces & gas fireplace inserts:
This article gives typical clearance distance requirements between the termination cap of a gas fireplace or fireplace insert and other building or site features such as windows, doors, other mechanical system components, air intakes, exhausts.
This article series describes side wall vent systems for conventional & mid-range-efficiency heating boilers, furnaces & water heaters. We include for comparison, low temperature side wall vent systems used by high efficiency or condensing boilers, furnaces & water heaters.
Clearance Distances for the Exterior Vent Termination of a Direct-Vent Gas Fireplace / Heater
[Click to enlarge any image]
The clearance distancess shown above and at the top of this page are between the vent termination cap of a gas fireplace and the air inlet side of an A/C or heat pump compressor/condenser. At CLEARANCE DISTANCE, HVAC a reader commented that his building inspector did not accept the safety of this installation. We agreed.
Reviewing manufacturer's installation instructions for a typical gas fireplace direct-vent exhaust termination cover or cap we find that the clearance distances to other building features or mechanical systems are similar but not necessarily identical to the Direct Vent Gas Appliance clearances given in the preceding table. This may be because that a typical gas fireplace heater does not use a power-exhaust vent or also because of different BTUH ranges.
Minimum Clearance Distance Requirements for the Exterior Vent Termination of a Gas Fireplace Heater8
Direct vent gas fireplace exhaust termination item clearance distance
Distance required (Canada)1
Distance required (USA)2
Clearance distance from gas vent termination cap to adjacent building
Clearance distance to vinyl surfaces such as vinyl siding or vinyl trim
Clearance above grade, veranda, porch, deck, or balcony
12" (30 cm)
12" (30 cm)
Clearance to window or door that may be opened
12" (30 cm)
9" (23 cm)8
Clearance to permanently closed window
Vertical clearance to ventilated soffit located above the terminal within a horizontal distance of 2 feet (61cm)
from the center line of the terminal (check with the local code)
Clearance to unventilated soffit
Clearance to outside corner: with approved Termination Caps
Clearance to outside corner: with Manufacturer's Special Termination Cap 6
1-6" (15cm)6, 8
Clearance to inside corner: with approved Termination Caps
Clearance to inside corner: with Manufacturer's Special Termination Cap 6
6" (15cm)6, 8
1-6" (15cm)6, 8
Clearance to each side of center line extended above [the gas] meter/regulator assembly
Clearance to [the gas] service regulator vent outlet
Clearance to non-mechanical air supply inlet to building or the combustion air inlet to any other appliance
9" (23 cm)
Clearance to a mechanical air supply inlet
3' (91cm) above if within 10' (3m) horizontally
Clearance above paved sidewalk or a paved driveway located on public property
Clearance under balcony, porch, or veranda
Opinions on Additional Recommended Cleareance Distances from a Direct Vent Gas Fireplace Exhaust Opening to other Building Features or Equipment
Distance to an air conditioner or heat pump compressor/condenser unit to the nearest point of a direct vent gas heater or gas fireplace exhaust
24 inches to 6 feet [Note 6]
Notes from the original source cited below:
1. CSA B149.1, Natural Gas and Propane Installation Code
2. ANSI Z223.1/NFPA 54, National Fuel Gas Code
3. A vent shall not terminate directly above a sidewalk or paved driveway which is located between two single family dwellings and serves both dwellings.
4. Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.
5. Clearance in accordance with local installation codes and the requirements of the gas supplier
5.a 3 feet (91cm) within a height of 15 feet (4.5m) above the meter / regulator assembly
5.b 3 feet (91cm) above - if within 10 feet (3m) horizontally
6. This is the author's OPINION considering that heat from the gas exhaust vent blowing onto an A/C compressor unit condensing coil could imact the coil's ability to condense refrigerant back to liquid form, affecting the condenser unit's efficiency and life. I'm considering the situation in which the hot gas exhaust blows onto the air intake side of a condensing coil. (Most modern condenser units draw cooling air in from the unit sides and push it out the unit's top). Also see CLEARANCE DISTANCE, HVAC
7. This is a Regency Fireplace Producucts termination cap; other manufacturers may have similar options. See the additional sources below.
8. Watch out: check with the manufacturer of your heater and venting system for specific venting instructions and clearances to combustibles or to other features as these distances may vary from one appliance and manufacturer to another. For example the Travis Industries direct vent clearances include some distances that are different from the tables given above.
DuraVent (and other manufacturers) warn that if a gas appliance, fireplace heater or other heater is not properly installed the system may be unsafe.
A major cause of vent related fires is failure to maintain clearances (air spaces) to combustible materials. It is of utmost importance that double wall direct vent pro be installed only in accordance with these [the manufacturer's] instructions.
Additional sources of direct vent gas fireplace clearance information:
DuraVent, "Direct Vent Pro Venting System for Direct Vent Gas Stoves and Fireplaces", M&G Duravent, Inc., Tel: 800-835-4429, Website: www.duravent.com, retrieved 2016/04/07, original source: http://www.duravent.com/docs/product/l954_w.pdf
Note: This gas fireplace insert installation manual expects the fireplact to be vented vertically through an existing chimney.
Excerpt: Venting system must be installed by a Mendota approved person according to Figure 3. pg. 8 with clamps securely in place and all joints leakproof.
R.H. Peterson Co., "REALFYRE PREMIUM GAS LOGS OWNER'S MANUAL" [PDF] Robert H. Peterson Co. 14724 East Proctor Avenue, City of Industry, CA 91746 USA Website: http://www.rhpeterson.com/, Tel: 800 332 3973
Travis Industries House of Fire, "4415 HO GSR2 (WITH SCREEN) INSTALLATION MANUAL", [PDF], Travis Industries, Inc., 12521 Harbour Reach Dr., Mukilteo WA 98275, USA (2014), retrieved 2016/04/07,original source: http://www.fireplacex.com/TravisDocs/100-01353.pdf
Question: what is the required clearance between adjacent houses & a neighboring direct vent fireplace?
Is there a minimum distance between brick houses in Toronto for venting termination of a fireplace using direct vent? - A.W., 12/30/2012
Reply: 4 feet or local codes
I have not found building code citations that refer to nearby or adjacent buildings when specifying clearances for direct vent fireplaces, though some of the fireplace installation manuals we reviewed specified a minimum of four feet to the nearest separate building.
It seems likely that your local building code inspector would agree that the clearance requirements for the building in which the fireplace is installed would set the minimum acceptable clearances that would then apply also to a nearby or adjacent building.
In other words, if the fireplace vent distances and position relative to your own building windows or doors were LESS THAN those to the windows & doors on the building where the fireplace is installed, and presuming for a moment that the fireplace was installed properly, meeting local building permit and code requirements, then a violation probably exists.
If the fireplace vent distances and position relative to your own building windows and doors is GREATER THAN those to the windows and doors where the fireplace is installed, and presuming for a moment that the fireplace was installed properly, meeting local building permit and code requirements, then a violation probably does not exist.
Take some some sharp photos of the installation that concerns you, or make a sketch and send those along and we may be able to comment further.
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 "Instructions for Installing FIELD Type AF Barometric Draft Controls," Form No. 31 DC 30666, Field Corporation, Mendota, IL 61342, web search 04/02/2011, original source: http://www.fieldcontrols.com/pdfs/04592700.pdf, Field Controls, Kingston, North Carolina 28501, Tel: 919-522-3031
 Tjernlund Draft Controls, A Series (single action for oil, solid fuel, and fan-assisted gas burners) and B Series (double action for gas heating appliances), web search 04/02/1011, original source: http://www.tjernlund.com/Tjernlund_8500490.pdf , Tjernlund Products, Inc., 1601 Ninth Street, White Bear Lake MN 55110-6794, Tel: 651-426-2993 or 800-255-4208 website: www.tjernlund.com Email: email@example.com
 "Gas Side Wall Power Venters", Tjernlund Corporation, 1601 9th Street
White Bear Lake, MN 55110-6794 Tel: 800-255-4208, Website: tjernlund.com/gassidewall.htm, Quoting: Side Wall Vent Systems save time and money and are excellent for electric to gas/oil, renovations, new construction or for replacing deteriorated chimneys. Side wall venting saves costly materials and labor on two, three or more story runs. It also increases living space by cutting out interior chases. Proven safety interlocks assure proper exhaust, a feature conventional chimneys do not offer in today's homes and buildings.
 "Oil Side Wall Vent Systems", Tjernlund Corporation, 1601 9th Street
White Bear Lake, MN 55110-6794 Tel: 800-255-4208, provides SS2 SideShot Wall Vent System. Website: .tjernlund.com/oilsidewall.htm Quoting: The SideShot® models SS1 and SS2 SideWall Vent Systems include the UC1 Universal Control ... [ and are ] designed for oil fired heating equipment or a deluxe gas vent system. Factory wired safety and operating controls allow simple interlock with any burner. ... SS2 features a self-cleaning stainless steel, backward inclined impeller and sealed ball bearing motor for virtually maintenance free installations.
Tjernlund Corporation also provides a Sidewall Venting sizing tool for oil fired heating equipment (www.tjernlund.com/Sizing/Oil.htm) and a separate tool for gas fired heating equipment (www.tjernlund.com/Sizing/gas.htm).
 Bradford White Sidewall Power Venter Kit, Field Controls, Tel: 252-522-3031, Website: www.fieldcontrols.com
 National Fuel Gas Code (Z223.1) $16.00 and National Fuel Gas Code Handbook (Z223.2) $47.00 American Gas Association (A.G.A.), 1515 Wilson Boulevard, Arlington, VA 22209 also available from National Fire Protection Association, Batterymarch Park, Quincy, MA 02269. Fundamentals of Gas Appliance Venting and Ventilation, 1985, American Gas Association Laboratories, Engineering Services Department. American Gas Association, 1515 Wilson Boulevard, Arlington, VA 22209. Catalog #XHO585. Reprinted 1989.
 "Tankless water heater side wall vent termination", Rheem Corporation, Website: http://www.rheem.com/products/tankless_water_heaters/
 "Gold™ CGs Gas-Fired Water Boilers Venting Supplement: sidewall direct exhaust, vertical direct exhaust, sidewall direct vent, vertical direct vent models
 "Be Alert, Keep Sidewall Vents Clear", Vermont Gas Corporation, P.O. Box 467, Burlington VT 05402 Delivery: 85 Swift St, South Burlington VT 05403. Phone: 802.863.4511.
Email: CustomerService@VermontGas.com, web search 4/1/2012, original source: vermontgas.com/winter/vents.html
 "Power Venting, SWG/CV Power Venter, ComboVent Power Venter, Field Controls, FIELD CONTROLS, LLC
2630 Airport Road
Kinston, NC 28504
 "Gas Fired High Efficiency Furnace Down Flow & Direct Vent (Sealed Combustion) Thermo Pride Model CMA1-50N & CMA2-75N Installation and Service Manual", Thermo Pride, Thermo Products LLC, PO Box 217, North Judson, IN 46366, Tel: 574-896-2133, retrieved 12/30/2012, original source: www.thermopride.com/pdf/mg-508.pdf, copy on file as Thermo_Pride_CMA1-50N_CMA2-75N_Installation_mg-508.pdf
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