Two-Stage LP or natural gas regulator requirements:

This article explains why, when, and where a two-stage gas regulator system is recommended at a building. Our page top photo shows a a large, remote, and centralized outdoor LP gas storage tank serving multiple homes in a small community in New York.

A second LP gas regulator was required at individual buildings.

Recommendations for use of two-stage gas regulation for LP or Natural Gas fuel systems

In this article series we provide descriptions and photographs of unsafe gas piping, regulators, or controls on heating systems, indications of unsafe or improperly operating gas appliances, gas meters, and other gas installation defects. This document also provides free sample draft home inspection report language for reporting defects in oil and gas piping at residential properties.

Gas Cylinder or Tank Regulators: Readers concerned with installing, inspecting, or testing LP Gas regulators which are found on outdoor above ground or buried gas cylinders used for storage of LP Gas on site should also see How to Inspect & Test LP Gas Tank or Cylinder Regulators.

Readers concerned with changing the fuel type between LP gas and natural gas for a gas fired appliance should see our safety warnings at GAS APPLIANCE CONVERT LP-to-NATURAL GAS.

General safety warning: improper installation and even improper inspection and testing methods involving natural or "LP" gas can involve dangerous conditions and risk fire or explosion. If you smell gas you should leave the building immediately and should do so without doing anything that could create a spark such as operating a light switch or telephone.

From a safe location, call your gas company's emergency line and/or your fire department. The text provided here is a working draft and may be incomplete or inaccurate.

Many residential LP gas installations will be found with a single gas pressure regulator at the storage tank.

A "two stage" LP gas regulation system uses two gas pressure regulators. Gas flows out of the LP Gas storage tank first through a "high pressure" regulation stage (usually installed right at the LP gas tank) and then through a second "low pressure" regulator as a second stage (usually installed close to the point of LP gas entry into the building).

Two stage LP gas regulation is required for certain installations but is less often found installed at single family residential properties. Experts recommend this "two-stage" regulation of LP gas installations, particularly where large LP tanks are installed above or below ground for several reasons:

• Large LP gas tanks will be located at a greater distance from the building
• Two stages of LP gas regulation helps assure steady, even gas pressure at each appliance in the building, making it easier to maintain the requisite typical eleven inches of water (equivalent pressure) at each appliance. That's because the low-pressure regulator being used to deliver gas at the proper pressure for the appliances is located closer to the appliances than if it had been installed right at the more distant gas tank.
• Two stage LP gas regulation can (slightly) reduce the LP gas system installation cost by permitting the use of smaller diameter gas piping between the first stage regulator (at the tank) and the second stage lower pressure gas regulator (at the building).
• Two stage LP gas regulation helps avoid gas delivery system freeze-ups in climates where low temperatures are common, because the expansion rate and gas flow does not have to occur all at one place (at the final regulator). Distributing the pressure drop across two devices means less pressure drop occurs at each individual regulator device, reducing the tendency to form frost in very cold weather.
• Use of two stage LP gas regulation permits a single high pressure line coming from the first regulator to deliver LP gas to multiple low-pressure regulators at diverse building locations, potentially improving LP gas appliance performance at a large building.
• Service people assert that there will be fewer service calls due to loss of gas pilot flame or requirements for gas burner adjustment where two stage regulation has been employed on an LP gas piping system.

Actual NG or LPG gas pressures vary: [Note: the exact pressure you see in the building at an appliance may vary from these numbers depending on the gas distribution piping system size, diameter, number of appliances served, number of appliances operating, regulator adjustment, and other factors.

See LP or Natural Gas Pressures for a table showing the range of variation in LP gas pressure in the tank at various temperatures. - Ed.]

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2018-10-03 by (mod) - proximity of the 2nd stage regulator to an outside light source?

I've never seen that explicit distance in a regulation or code.

On 2018-10-03 by deryck gilpin

what is the regulation governing proximity of the 2nd stage regulator to an outside light source?

On 2018-05-24 by (mod) -

For some pressure regulators, I think so. You need to find the brand and model of your regulator, and then look at the specifications for the inlet pressure to which it can be subjected.

On 2018-05-24 by Chuck

Is it possible to damage a 12” regulator by turning on the pressure valve at the LP tank without installing another low pressure regulator in front of the 12” water column regulator?

On 2018-03-15 by (mod) -

Maili

You need a conversion kit if your Appliance is set up for the fuel that is not the one that you are using. For example if your Appliance is set up for natural gas and you're going to use propane you need a propane conversion kit - and vice versa. That is nothing to do with the number of regulators installed.

On 2018-03-15 by Maili

If I have a gas dryer and install stage 1/2 combo regulator do I still need to buy a conversion kit for my dryer?

On 2017-02-10 by Anonymous

@Anonymous,
Line to garage too small

On 2017-02-10 by John

@John,
Line to garage to small.

On 2017-02-10 by John

@Edward,

On 2016-12-03 by Edward

We have a 1,000 gal propane tank that services 3 lines. One line to 16kw genny, 1/2" line to garage 100,000BTU modulating boiler with instantaneous hot water and 1/2" line to house with 150,000BTU boiler with inst. hot water, dryer, fireplace, range and bbq.

Total BTU's between 740,000 and 780,000. Linen to genny 17ft, house 40ft and garage 114ft. Garage boiler tested and checked repeatedly however in very cold weather the boiler in the garage will quit.

We have to reset. Code is lack of fuel supply. We tested by starting genny and boiler in garage quit.

Tank was at 27% and we were having issues with garage boiler so I shut of supply to house and boiler in garage started up just fine and ran until we got fill-up. 2nd stage reg has been changed 3 times on garage.

I've had 2nd and 3rd opinion as supplier says not a supply issue. One opinion says line to garage is too small and other says we should have 3 first stage regulators at tank.

Current first stage reg is a REGO and rated for residential and can handle our needs

. Current provider is now prepared to upgrade first stage reg to a commercial variety and change pigtail to hogtail hoping that this solves issue. They state they have never heard of this type of issue.

It appears that when genny or house calls for fuel, either during high usage, low tank supply or extreme cold, the garage line suffers and gets sucked dry. Any suggestions or ideas as to the actual problem.

On 2016-03-03 by (mod) - fire hazard can be if the supply to an appliace is to low?

Improper ignition, combustible gas leak, fire or explosion.

On 2016-03-03 by Anonymous

What fire hazard can be if the supply to an appliace is to low?

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Continue reading  at GAS REGULATORS for LP TANKS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• GAS APPLIANCE CONVERT LP-to-NATURAL GAS
• GAS APPLIANCE CONVERT REGULATOR NATURAL GAS-to-LP
• GAS COOKTOP INSTALLATION
• GAS REGULATORS & APPLIANCE / HEATER CONTROLS
• GAS REGULATOR ADJUSTMENT PROCEDURE
• GAS REGULATORS for LP TANKS
• GAS REGULATOR TEST PROCEDURES
• GAS REGULATORS, TWO STAGE
• GAS PRESSURES LP vs NATURAL GAS

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