Gas fittings and hoses used in Australian Caravans and Motorhomes use a number of different threads. They may seem hard at first, but a short read will give you enough information to purchase the correct part.
The following information is educational and general in nature only. Licensed Gas Fitters are required to install gas fittings into RVs.
All gas components on this website that have threads also have a list of other components that will connect to them. They are listed below each product description. This feature allows you to ensure all components from gas cylinder to gas appliance are compatible.
BSP threads are the most common and can be used for gas and water. The sizes are imperial.
To get a 100% seal with gas you use a yellow thread or Liquid thread seal. You can use white or yellow for water.
When used for water the most common one you will know around the home is on your garden tap. Most garden hose fittings come with a 3/4" BSP to 1" BSP adapter.
The size quoted for threads is indicative of the internal bore size, not the diameter of the thread.
Click here to print a Thread Sight Guide to lay your thread on.
Above: If you have an existing thread that looks like those above, you need to measure the outside of the male thread as shown. The male thread is generally tapered so that it gets tighter when screwed in.
9.5mm measured OD is Male BSP 1/8"
13mm measured OD is Male BSP 1/4"
16mm measured OD is Male BSP 3/8"
21mm measured OD is Male BSP 1/2"
26mm measured OD is Male BSP 3/4"
33mm measured OD is Male BSP 1"
Above: If it is a female fitting, measure the inside to determine the actual name. Measured sizes are shown as approx. mm
8mm measured ID is Female BSP 1/8"
11mm measured ID is Female BSP 1/4"
14mm measured ID is Female BSP 3/8"
19mm measured ID is Female BSP 1/2"
24mm measured ID is Female BSP 3/4"
31mm measured ID is Female BSP 1"
The male fittings are easily identified by the 45 degree flare at the end. These screw into either a SAE nut on the end of a copper pipe or a gas hose.
When used with copper pipe, the pipe is flared to 45 degree. The nut will not fall off and the copper section creates the seal between the nut and SAE 45 flare brass fitting. No thread tape is required with these fittings.
The Outside Diameter of the thread can be measured to give you the correct name of the fitting.
11mm measured OD is Male SAE 1/4"
13mm measured OD is Male SAE 5/16"
16mm measured OD is Male SAE 3/8"
Measure the Inside Diameter to get the correct name of the nut. The nuts always swivel. They have an inverted flare inside.
10mm measured ID is Female SAE 1/4"
11mm measured ID is Female SAE 5/16"
14mm measured ID is Female SAE 3/8"
The nut shown is a 5/16" nut because it fits on a 5/16" pipe.
The recommended pipe dia. for a typical gas installation within a Caravan or Motorhome is 5/16" copper pipe.
If you have a gas BBQ, Gas stove, Gas HWS, Gas heater and large Gas fridge - you may need 3/8" pipe, but your gas fitter can determine this.
Used on larger gas cylinders these have a Left Hand thread. Many male fittings have a rubber o-ring and must not be over tightened.
One notable difference with this thread is that gas will only flow after the fitting is fully inserted into the cylinder.
Often called Companion but used by other brands as well.
Used for removable gas appliances. The female fitting is used to supply the gas and comes in one size only. A rubber cap should be placed on these if subject to dust or dirt.
This is used at the end of gas pigtails that connect to a change-over value. The seal does NOT require thread tape.
So you might be connecting a new grill, patio heater, or fire table - whatever the case may be and you're probably thinking, "What size should my gas hose and brass fittings be?" Well, you're in luck because here at Barbecues Galore, we pride ourselves on having expertise in the area of gas fitting because we get it... this type of stuff is confusing. Together, we can figure out what you need.
Let's start with the common problems with measuring your gas fittings.
Many people unknowingly buy the wrong size of fittings for their natural gas or propane hose because they don't know how to measure it; or more accurately, they don't know which part to measure.
There are three commonplace measurements people take, but only one of them is right. First, there is the outside diameter (OD), the Nominal Pipe Size (NPS), and the inside diameter (ID) of the hose.
The measurement you want that corresponds with the name of your gas hose is the inside diameter (you can remember this because ID in this case means "inside diameter", but in many other case means "identification"). For example, a 3/8" LP/NG Hose will have the inside diameter of 3/8".
Now for the tricky part: How to measure a quick disconnect nipple and coupler
Your keen mind might have thought, "If the inside diameter is what we are measuring, how could the 3/8" quick disconnect have the same inside diameter of the 3/8" hose if one goes in the other?" Well my friend, it's because the world (of gas fitting) works in mysterious ways... but that's why we're here.
Fittings get their name based off of the hose they fit with. That being said, you're right - the inside diameters would not be the same. Thus, the inside diameter on the female end of the Quick Disconnect Nipple would have to be more closely similar to the outside diameter of the male end of your gas hose. For example:
Due to this, we advise you to make sure you know the proper measurement of your natural gas or propane hose first. With that, you'll be able to know the measurements of the Quick Disconnect Nipple and Coupler that you'll need. However, if it's the hose that you're looking for, you now know how to find which hose is needed and we've got them in 5', 10', 15', and 20' lengths.
You can then get the correct parts you need from our site by clicking here. You can also visit or contact any one of our five stores across Canada.
To continue learning, watch these videos here: