Can You Put a Propane Tank Under an Awning?

A propane cylinder can go under an awning, a permanently installed tank cannot. NFPA 58, the Liquefied Petroleum Gas Code, allows cylinders (the 20 lb grill bottle and the 100 lb cylinders a supplier swaps or fills beside the house) under a building only where "the space is open to the atmosphere for 50 percent of its perimeter or more." An ordinary patio awning, open on three sides, passes. Larger ASME tanks fail: the code says their relief discharge must not end "in or beneath any building."

Passing the 50 percent test is not the end of it. Under the awning, the cylinder's relief valve still has to be 3 ft sideways from a patio door or window below it and 5 ft from the awning's motor, its outlet and any other source of ignition. On most patios those distances, not the awning, decide where the cylinders go.

Why you read both "never under an awning" and "half open is fine"

Propane101, a widely linked propane explainer, says "propane tanks have to be installed out from under an awning or part of a building overhang," because an ASME tank's relief valve vents propane straight up. That is true, for ASME tanks. NFPA's own fact sheet on placing containers puts it the other way round under the heading "Decks and Overhangs": "Tanks are permitted to be placed under an overhang provided the area is open on at least 50% of the sides," citing paragraph 6.4.4.1, which is the rule for cylinders "in outdoor areas that are protected from the weather."

Both statements are accurate, about different containers. The word "tank" covers both in everyday speech, so the two answers get repeated about the same grey 100 lb cylinder. The deciding question is not the size of the awning but what kind of container sits under it: a DOT cylinder (portable, stamped with a DOT specification, up to the 100 lb size in most homes) or an ASME tank (the horizontal or larger vertical tank that stays put and is filled from a truck).

The rules by container, side by side

NFPA 58 measures containers by water capacity, not by how much propane they hold. Manchester Tank's cylinder catalog (09/2022) lists a 20 lb cylinder at 47.6 lb of water capacity and a 100 lb cylinder at 238 lb, which is about 5.7 and 28.5 gal. Both are far under the 125 gal line where the separation table starts asking for distance from the house. The figures below are from the 2017 edition as printed in NFPA's fact sheet, with the overhang rule from the documents that still carry it:

The opening distance counts only openings "below the level of such discharge," that is, lower than the relief valve. A patio door runs from the floor up, so part of it is always below the valve. The ignition distance runs "in any direction," which includes up.

Cylinders: the 50 percent test, worked on a patio awning

The fact sheet works the rule as an area calculation. For a covered space 12 ft on each side with 8 ft walls, the total wall enclosure area is 12 x 8 x 4 = 384 sq ft, and at least half of that, 192 sq ft, must be open. On a typical patio it is easier to count by length of perimeter, since the open sides are usually open full height.

The example uses the awning extended. NFPA 58 makes no allowance for a cover that rolls up, so with a retractable awning plan for the position that encloses the cylinders the most. The same arithmetic catches the accessories that turn an awning into a room: drop shades and side screens, lattice, a pergola with curtained sides, or a row of planters along the open edge. Each one is counted as closed perimeter while it is in place.

Then the 3, 5 and 10 ft distances decide the spot

Most covered patios sit in front of a door, so the opening rule usually binds first. Measure 3 ft horizontally from the relief valve, at the top of the cylinder, to the nearest edge of any door, window, crawl space vent or exhaust fan that is lower than the valve. A 100 lb cylinder against the wall beside a sliding door needs its valve 3 ft from the door frame.

The ignition rule is the one an awning adds to. NFPA's fact sheet draws a central AC compressor and a window air conditioner as sources of ignition, and the intake of a direct-vent appliance as an opening that needs the same 5 ft. A motorized awning brings electrical equipment of the same kind to the wall: the motor inside one end of the roller, the GFCI outlet it plugs into (see how much power a motorized awning uses), the switch, LED lights and a wired wind sensor. NFPA 58 lists none of them by name. We treat them all as ignition sources, so the motor end goes on the side away from the cylinders, and the outlet and switch at least 5 ft from the relief valve (10 ft for a cylinder filled in place).

The regulator on the wall has its own pair of numbers. The Propane Education & Research Council's technical pocket guide says a regulator at the side of a building "cannot be placed closer than three feet horizontally from any building opening, such as a window well, that's lower than the installed regulator," nor closer than five feet to "any source of ignition, such as an AC compressor or the intake to a direct-vent appliance." If the propane line enters the house under the awning, keep the awning's motor end and outlet 5 ft from that regulator as well.

Check other gas equipment on the same wall too. A natural gas meter has its own 36 in zone set by the utility, a furnace or water heater vent wants the awning kept clear of its exhaust, and an AC condenser is both a reason to move the awning and, for propane, an ignition source 5 ft from the valve.

ASME tanks: out from under, and the overhang rule

For a permanently installed ASME tank the answer is no in every case. Under 125 gal water capacity, 6.4.4.2 requires that the discharge from the relief devices "shall not terminate in or beneath any building." From 125 gal up, the separation table adds 10 ft from the house (25 ft above 500 gal), which on its own keeps the tank out from under all but the deepest covers.

Some jurisdictions add a rule aimed squarely at covers. Alabama's LP-Gas Board adopted the 2020 edition with section 6.4.4.6 written into it, and Mercer Island's fire marshal (Washington) prints the same text as a footnote to its separation table. For an ASME container of 125 gal or more:

1. The distance is measured from a point found by "projecting the outside edge of the overhanging structure vertically downward to grade."
2. That distance must be at least 50 percent of the table distance: 5 ft for a 125 to 500 gal tank, 12.5 ft for 501 to 2,000 gal.
3. It applies only when the overhang extends more than 5 ft from the building.
4. It does not apply when the overhang is 50 ft or more above the relief valve outlet.

Patio awnings almost always project more than 5 ft. A 10 ft deep awning beside a 500 gal tank therefore moves the tank at least 5 ft beyond the awning's front bar or end, measured on the ground, not just 10 ft from the wall. A 4 ft window awning or a short door canopy does not trigger the rule, though the tank still has to meet the 10 ft separation from the house. If you are choosing where an awning goes on a house that already has a tank, mark that 5 ft line before you settle the awning's width and projection; how to measure for an awning covers the rest of the wall.

Under a deck instead of an awning

A raised deck is the other cover cylinders often end up under, and the same 50 percent rule applies. Shipley Energy, a propane supplier, adds a height to it in its homeowners guide: the deck "must be FULLY open on two sides meaning at least 50% of the total space underneath is free and clear of lattice, bushes, etc.," and "at least 8' tall from the base of the tank to the bottom of the deck joist to allow for free movement and proper operation of the pressure relief valve." None of the NFPA texts checked sets a height. Shipley's 8 ft is a supplier rule, and a supplier may set stricter rules than the code for the containers it serves, so ask yours. An awning over a deck (see deck awnings) counts as one more cover on the same space.

Shipley's wording makes the point the 50 percent rule exists for: lattice and bushes close the perimeter just as walls do. It adds that fences around a tank should leave the bottom quarter of the tank exposed all the way round, so gas from a release can spread out.

Local rules that go further

NFPA 58 is the floor. Fire districts add to it, and two of the documents checked do:

• Combustibles. Mercer Island requires weeds, grass, brush, trash "and other combustible material" to be kept "not less than 10-feet from LP tanks in any-direction," and the Cosumnes Fire Department in Sacramento County requires a plan note that combustibles stay 10 ft from any propane tank, citing California Fire Code 6107.3. Neither names awnings. Whether acrylic or polyester awning fabric overhead counts as combustible material within 10 ft is a question to put to your fire marshal before you hang an awning over a tank or a tank under an awning.
• Distance to the house. Cosumnes keeps single residential tanks under 500 gal at least 10 ft from buildings, property lines and public ways, citing California Fire Code Table 6104.3, where the NFPA table allows 0 ft below 125 gal.
• Permits. Mercer Island requires a fire construction permit for "any sized tank serving a fixed appliance," and Cosumnes requires a stamped site plan showing the tank's distance to structures and ignition sources.

Cosumnes also keeps aboveground containers 6 ft from the vertical plane beneath overhead lines over 600 volts. A house's own 120/240 V drop is well under that; the awning's own clearance to it is in how close an awning can be to the service drop.

Older building codes could add their own distance from openings. Connecticut's State Building Inspector ruled in 2003 that under the 1995 CABO One and Two Family Dwelling Code a tank needed 3 ft (DOT) or 5 ft (ASME) from any building opening, whether or not the opening was below the relief valve, which "precludes the location of a tank under a window." That code is long superseded, but it shows why an inspector may ask for more than the NFPA figure.

The grill bottle and the patio heater

The 20 lb cylinder most people mean when they ask this question is usually attached to something. Then two sets of rules apply, and the appliance's are stricter. A gas grill under fabric is a no for reasons that have nothing to do with the cylinder; the clearances are in can you grill under an awning. A propane patio heater needs 2 to 3 ft from the top of its reflector to the fabric (see patio heater clearance under an awning), and a gas fire table has its own overhead figure in fire pit under an awning. A turkey fryer is stricter still: its manual keeps the cylinder 20 in from the burner and the whole setup 10 ft from the house and out from under the awning, as set out in can you use a turkey fryer under an awning. A spare cylinder kept for the grill follows the cylinder row in the table: under an open awning is acceptable, 3 ft from the door and 5 ft from the motor end and outlet.

A standby generator running on propane brings both problems at once, a tank and an engine. Its manufacturer's overhead rules are in generator under an awning.

Where this answer stops applying

• The code text was read through public copies. NFPA 58 itself is a paid standard. The figures here come from NFPA's own fact sheet (2017 edition, published March 2018), Alabama's adopted 2020 text and fire department handouts. Your state may enforce a different edition with amendments.
• Awnings are not named. No NFPA text checked uses the word awning. The 50 percent test is written for cylinders "underneath any building," and the overhang rule for "the portion of a building that overhangs." An attached patio awning is read as part of the building. A freestanding awning away from the house may be judged differently; ask the local fire official.
• Not every jurisdiction keeps the overhang rule. The 5 ft and 12.5 ft figures were found in Alabama's adoption and Mercer Island's handout. Where it is not in force, the separation table and the relief valve distances still apply.
• Indoors and enclosed patios. Nothing here covers a cylinder in a screened porch, sunroom or garage. Once the perimeter is less than half open, the cylinder rule above already says no.
• Commercial patios. Everything here is for homes. Restaurants and other businesses face the fire department's commercial rules on propane, especially for heaters under canopies (see restaurant awnings).

Frequently asked questions

Can I keep a 20 lb propane tank under my patio awning?

Yes, if the space under the awning stays open to the air on at least half its perimeter, which an awning with open sides does. Keep the cylinder's valve 3 ft sideways from the patio door and 5 ft from the awning motor, its outlet, an AC compressor or any other ignition source.

Can 100 lb propane cylinders go under a roof overhang?

Yes under NFPA 58, with the same 50 percent open test, 3 ft from openings below the valve and 5 ft from ignition sources (10 ft if a truck fills them in place). Some suppliers set stricter rules for cylinders they fill; Shipley Energy, for example, wants 8 ft from the tank's base to the deck joists above.

How far does a 500 gallon propane tank need to be from an awning?

At least 10 ft from the house, never under the awning, and where your state or city enforces the overhang rule, at least 5 ft horizontally beyond the awning's edge if the awning projects more than 5 ft from the wall.

Sources and further reading

• National Fire Protection Association: Fact Sheet: Placing LP Gas Containers (NFPA 58, 2017 edition, March 2018; copy hosted by Tehama County, California)
• Alabama Liquefied Petroleum Gas Board: Rule 530-X-2-.06, adoption of NFPA 58 (2020 edition) with amended sections including 6.4.4.6 (effective December 13, 2021)
• City of Mercer Island Fire Marshal's Office: Standards for Installation of Propane Tanks (08-2020)
• Cosumnes Fire Department: FPCS-1019, Residential Propane Tank Plan Submittal, Permit and Inspection Requirements (revised 10/9/2024)
• Propane Education & Research Council: The Propane Technical Pocket Guide
• Manchester Tank: Portable DOT Steel LP Gas Cylinders, 5 lb to 100 lb, Catalog 49500 (09/2022)
• Shipley Energy: Complete Guide to Propane for Homeowners (2023)
• Connecticut Office of the State Building Inspector: State Building Code Interpretation I-2-03 (April 2, 2003)
• Propane101: Propane Tank Distance Rules and Requirements