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LPG POL valves and fittings

19 Apr, 2024 | Business LPG Blogs, Residential LPG Blogs

In this article:

Everything about LPG Pol gas valves, gas fittings, precautions, safety best practices, implementation and more.

POL Gas Fittings, POL Fitting, POL Valves Fittings, Cylinders & Gas Regulators

A POL gas fitting (POL fitting) is found on POL cylinders, POL valves, POL gas regulators and various POL connection fittings including hoses and adaptors. POL valve fittings are found on gas bottles ranging from small BBQ bottles to large commercial gas bottles.

POL Valve Fittings & Gas Bottle Fittings: What is a POL gas fitting? What is a POL Valve on Propane Tank

In summary:

• A POL gas fitting (POL fitting) is the most common type of valve & gas bottle fitting, in Australia, for most LPG gas cylinders from 4kg to 210kg, including 45kg LPG cylinders.

• POL refers to a type of gas valve and to gas bottle fittings that have a POL gas fitting (POL fitting).

• “POL” is an acronym for the company that first made the valves — Prest-O-Lite.

• A POL valve fitting on propane tank refers to the main valve and the same as a POL fitting on LPG gas cylinders.

• The POL gas bottle fittings connection is notable for its reverse — left-handed — thread.

• A pressure relief valve is incorporated within the POL valve for safety.
There are a few more features of the POL valve fitting of which you should be aware…

POL Gas Fitting – POL Fitting

A POL gas fitting (POL fitting) is an LPG gas connection fitting typically used on LPG (propane) gas cylinders. POL fittings can be found on larger size home gas bottles, as well as on BBQ gas bottles. POL is the acronym for the company that first made the valve fittings – Prest-O-Lite.

The female POL gas bottle fitting (POL fitting) is incorporated into a POL valve fitting on the LPG-propane cylinder, utilising a left-handed or reverse thread. The male POL gas fitting is used on pigtail connectors, BBQ gas regulators and other hose style connectors.

At one time POL gas bottle fittings were used in many countries, including the USA, but have faded in popularity. Now Australia is the most notable POL valve fitting user.

OPD Valves for Propane Tanks – Propane Tank Overfill Valve

An OPD propane tank has an OPD cylinder valve. OPD is the acronym for “Overfill Protection Device” or “Overfilling Prevention Device”. An OPD valve is best described as a propane tank overfill valve.

As the name suggests, an OPD valve has a protective mechanism, that prevents propane tank overfill, built into the valve.

OPD valves are used in the USA, instead of POL valves.

Gas Regulator Gas Pressure

A gas regulator controls the regulator gas pressure at which the LPG is delivered from the gas bottle.  BBQ gas regulators typically come equipped with an attached gas hose.

The gas regulator screws directly into the gas bottle whilst the gas hose is attached to the BBQ.

The standard BBQ gas regulator type in Australia is a gas regulator with a POL fitting, which has a male POL gas fitting (POL fitting is reverse or left-handed thread) that fits a ‘POL’ valve on the gas bottle.

POL Gas Fitting (POL fitting) – Gas Line Connection

The gas line pigtail or regulator has a POL gas fitting that screws into the large female threaded opening on the side of the valve. A POL fitting is unique in that it has a left-handed or reverse thread. So, to tighten a POL gas fitting, you turn the connector anti-clockwise.

Tightening is achieved either with a wrench or by turning a hand wheel.

You should always do a soapy water leak test after every POL fitting reconnection.

Gas Connection Seal – POL Gas Fitting (POL fitting)

The POL gas fitting (POL fitting) was originally designed as a metal to metal compression seal. However, some connectors are now manufactured POL fittings with rubber O-rings to further improve the seal.
The downside is that these can become damaged or deteriorate over time so they should be checked regularly.

Gas Valve Hand Wheel

Located on the top of the POL valve fitting, the gas valve hand wheel controls the flow of gas, once the connection is secure.
Turning the hand wheel anti-clockwise starts the flow of gas but you should avoid turning it hard to the open stop.
Opening the valve 2 or 3 turns is all you need.
You shut the gas off by turning the hand wheel clockwise, tightening firmly by hand only.

CAUTION: Never open the valve when unattached

Bleed Screw

POL valve fittings (POL fitting) are equipped with a bleed screw for decant filling, such as when having a BBQ bottle filled at a service station.

It is a small slotted screw on the side of the valve.

The filling technician opens the screw during filling to determine proper filling.

On the other hand, most large gas depots fill cylinders by weight, on digital scales, so the bleed screw is not used.

CAUTION: Never open the bleed screw on your gas valve

Dip Tube

The POL valve fitting (POL fitting) has a tube that sticks down into the cylinder, called a ‘dip tube’. It extends down to the bottom of the ullage area.

This tube is connected to the bleed screw and let’s the filling technician know when the cylinder is filled up to the ullage zone.

Ullage is the 20% unfilled space at he top of the gas cylinder that allows for expansion of the gas.

Pressure Relief Valve

The pressure relief valve is the single most critical safety feature on an LPG cylinder. It is incorporated within the POL valve fitting (POL fitting) and appears as the protrusion opposite the main connection.

It usually incorporates some kind of plastic dust cover that should be left in place.

Pressure relief valves are designed to relieve excess pressure that might result from overfilling or exposure to excessive heat or fire.

The function of a pressure relief valve is to keep a cylinder from rupturing in the unlikely event of excessive pressure build-up.

The pressure relief valves are held in the closed position by the force of a powerful spring inside.

As long as the pressure is less than that of the spring, the valve will remain closed.


Having the pressure relief valve releasing gas is a rare event.

Most people will never experience venting.

If the pressure rises beyond the force of the spring, the valve will open to vent the excess pressure.

If this happens, you may hear a hissing sound and see cold gas vapour being released.

Once sufficient pressure is released, the valve closes.

If this ever happens, just stay clear of the area and let the gas dissipate.

You should also call your LPG supplier, from a safe location, and advise them that your gas cylinder is venting gas.

Do not use your mobile phone, any electrical devices or other ignition sources near a venting gas cylinder.

BBQ Gas Bottle Fittings Incorporate POL Gas Fittings (POL fitting)

BBQ gas bottle fittings incorporate POL gas fittings and involve less components than home installations, with typical BBQ gas bottle fittings being a gas regulator with a POL fitting and a hose.

The gas regulator, with a POL gas fitting (POL fitting), and hose usually come as an assembly but hoses are also sold alone.

Some outdoor appliances also require Piezo electric ignitors, various fitting adapters, natural gas conversion kits,

BBQ Gas Leak Test

It is important to regularly leak test your BBQ gas bottle, gas regulator and hose.
Leaks from these items are frequently the cause of BBQ gas fires.

How to Test

Put some soapy water in a spray bottle.

Turn on the gas bottle without turning on the BBQ.

Next, spray the entire valve, gas regulator and hose assembly with the soapy water.

Bubbles will form if there is a gas leak and you may also smell the gas.

When done, rinse with clean water to remove the soap solution.

For more details, please see:  BBQ Gas Leak Test

Hot To Safely Attach or Change Your BBQ Gas Bottle

Connecting & Disconnecting Your Gas Regulator

The male connector of a gas regulator, with a POL gas fitting, has a reverse or left-handed thread. So, to detach, you turn the POL fitting clockwise and then anti-clockwise to re-attach.

Full step-by-step instructions:

How to Attach or Change Your BBQ Gas Bottle

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