Guidelines on Using LPG Hoses

Selecting the Correct Hose Type

Hose applications can be classified as follows:

Where the hose is to go from a regulator fitted to a cylinder, either directly to an appliance or to pipework leading to an appliance, refer to Hoses for Connection to Regulators Fitted Directly to Cylinders. This typically includes cookers and cabinet heaters supplied from an adjacent cylinder, but also includes such items as hand-torches and blow-air heaters directly connected to cylinder regulators. This section also covers where hoses are made up to connect appliances to pipework (but again see the note above on avoiding this where possible). If you are considering using wire-braided armoured hose, read the section on Armoured Hoses, which warns on potential problems.

Where the hose is to be used for LPG in it's liquid form, such as for filling (cylinders, forklift trucks, cars, etc.) or using liquid LPG (LPG systems in cars or forklift trucks, grain-drying applications), refer to Hoses for Liquid LPG.

Where two or more cylinders are connected to a regulator, the outlet of which is then piped off to supply the gas appliances, special hoses are used to connect the cylinders to the manifold - refer to Cylinder Manifold Pigtails.

Catering equipment in commercial kitchens and restaurants, as well as domestic cookers connected to a pipework supply, are often connected using special hoses with a bayonet fitting on one end which allows them to be "unplugged" from the gas supply, such as for cleaning behind them - refer to Bayonet Fitting Disconnectable Hoses.

If in doubt, or in any cases not covered here, consult your gas supplier who should be happy to advise you on the correct hose for your application.

Hoses for Connection to Regulators Fitted Directly to Cylinders

In these cases, the hose is subject to less pressure because the regulator reduces the gas pressure from the cylinder. For a number of reasons, hoses should generally be limited to 0.5m (18 inches) in length. Particularly with cookers, longer lengths run the risk of the hose inadvertently passing across a hot source, such as the oven vent on the back of a cooker. Longer runs than 0.5m should be made using pipework. The only exception is where absolutely necessary, which is for hand-torches and portable blow-air heaters. High-pressure hose must be used for high-pressure regulators (refer to Flogas LPG Cylinder Regulators, if necessary): high-pressure LPG hose should be stamped "BS 3212/2", low-pressure LPG hose should be stamped "BS 3212/1". For more information on these regulators and hoses, see Flogas LPG Cylinder Regulators

Warning: Make sure the hose is the correct diameter for the nozzle you are using. Note that if the hose is too large, a hose clip will NOT tighten it up sufficiently, because LPG hose is not sufficiently soft to allow it to be compressed to any extent. The hose should be a snug to tight fit on the nozzle BEFORE you put on the hose clip. There is also a problem fitting hose to a nozzle that is too large for it - in forcing it on, you will snap the braiding that is built into the hose. This leads to the hose being extremely weak adjacent to the nozzle, and instead of any movement being spread along the length of the hose, all the flexing will occur at the concentrated weak point, causing it to fail there.

Hoses for Liquid LPG

You MUST obtain these from an LPG company or a company specialising in your particular application (such as a vehicle LPG converter) as these have to be made to a higher specification than other hoses and require very experienced personnel to determine their suitability. Working on liquid LPG also requires additional training and knowledge that general gas contractors would not have.

Bayonet-fitting Disconnectable Hoses

These are in relatively widespread use and are available from suppliers of catering equipment, among other sources. They are disconnected by pushing the bayonet fitting in slightly, turning it, and pulling it back, similar to the way you remove an ordinary bayonet-fitting light-bulb from it's socket. As it unplugs, a sealing mechanism shuts off the gas supply to the hose. Warning: there are two types, one for LPG and one for Natural Gas, and they are NOT interchangeable. LPG versions have a large red band or a red stripe on the (usually black) hose, Natural Gas ones do not. If you use a Natural Gas one on LPG, it will rapidly deteriorate and leak.

Armoured Hoses

There are a number of problems with wire-braided armoured hose which restricts their applicability. The first is that over time, during which the hose has been repeatedly flexed, the wire strands can break and the sharp ends can then puncture the hose. This means that these hoses should NOT be used indoors where a subsequent gas leak could accumulate. The second problem is that the condition of the hose is hidden by the wire braiding, so that if it does deteriorate, it will not be easily spotted. The only advantages that wire-braided hose have are that the wire braiding offers some protection where the hose would be regularly rubbed on the ground or other surface, and also the hose has a bit more protection if it comes in contact with hot sources. It's general, it's use should be limited to portable outdoor equipment where these issues arise, such as gas hand-torches. Repeated contact with hot sources should be avoided by design; for appliances such as braziers, use steel pipe instead of hose where the supply is close to the brazier; where this method cannot be used, consider fitting a heat shield.