This article has been put together to allow the DIY person to design their Caravan or Motorhome, taking into account the rules that need to be adhered to, to get a gas compliance certificate.
In some instances a gas fitter may permit the running of pipework during construction by a DIY builder, but as the person responsible for certification, the gas fitter will need to have full access to all pipework and all junctions to ensure it complies. It is recommended to have your gas fitter examine your plans, prior to construction to ensure any new standards are met.
This is NOT a guide to allow you to be a gas fitter, it allows you to design your caravan or motorhome to adhere to AS-5601
Exceptions are generally excluded from this brief guide. This means that you may be able to be exempt from some of the rules by complying in other ways. If you are unable to make your design work by following this brief guide, you may need to buy the full AS 5601.2 or seek the advice of the Licensed Gas fitter at the design stage.
There is also a companion guide for those replacing regulators or pigtails .
Who can do the gas installation?
A licensed plumber who is certified to carry out gas fitting is required for the installation, relocation or replacement of any gas appliance as well as the installation, relocation or modification of pipework. Renewal of regulators and pigtails is generally accepted to be maintenance.
Where can I place a gas cylinder?
A cylinder CANNOT be installed inside a Recreational Vehicle (RV). An RV includes Caravans, Motorhomes, Camper Trailers.
1) A gas cylinder can be installed in a compartment that is sealed from the inside of the RV, but vented to outside.A Red Reflective LP Gas Storage sticker is require to be fixed adjacent to the compartment.
2) A gas cylinder can be mounted externally on a draw bar. It must be mounted vertically with the valve at the top.
The regulator is connected to the gas cylinder with a pigtail, min length 300mm. The regulator must be a two stage regulator mounted vertically to a rigid mount, with the vent pointing down. The pigtail should slope down from the regulator to the gas cylinder to prevent liquid gas reaching the regulator.
Regulators and Pigtails
There is a companion guide for those replacing regulators or pigtails that goes into more details about options.
All Pigtails sold by Caravans Plus, comply with AS 1869 Type C or exceed the standard.
Regulators must have a maximum outlet pressure of 3kPa. All regulators sold by Caravans Plus meet this requirement.
What size copper pipe should I use?
The size of the pipe depends on the distance the gas is required to travel and the appliances that will be connected, together with their gas consumption requirements. As this is a calculation that depends on the appliances you select, this should be verified with your gas fitter after your layout and appliances have been selected.
However as a rule of thumb and assuming the larger your RV is, then the bigger the appliances will be, most RV's up to 6 metres would use 5/16" copper pipe, and longer RV's may require 3/8" copper pipe.
There may also be a combination of sizes, where the main run may be 3/8" pipe and the branch lines to individual appliances may be 5/16".
1) Select the pigtail length and style.
2) Select the Regulator, Test Point and Change Over Valve.
3) Copper Pipe and copper saddles can be viewed here.
Where can pipe and junctions be placed?
Copper pipe must be located where it is not likely to suffer physical damage. If damage is likely, the pipe must be protected. A suitable method to prevent stone damage is to protect it within hose or pipe. The location must also ensure it cannot be damaged.
Where more than one appliance is to be installed, the main run of copper pipe shall be located outside the RV.
Each appliance shall have its own branch pipe.
Each branch pipe will enter the interior of the RV adjacent to the appliance.
Where a flexible hose is connected to an appliance, it shall not exceed 1200mm. More detail later.
Joins and junctions are not permitted within a sleeping area (or engine compartment).
Joins and junctions must be readily accessible for future maintenance.
There can be no joins between a main run and a shut-off valve on a branch to an appliance.
Pipe must be supported at least every 600mm in a horizontal run by non-ferrous metal clips. A maximum of 1250mm for vertical runs and a max of 150mm each side of a change in direction.
Where do I need to place valves? Can I use a gas hose?
Each appliance needs to have its own shut-off valve and it needs to be readily accessible.
Flexible hoses have a limited life span and are more easily damaged, so are discouraged. If essential they can be fitted only between a shut-off valve and an appliance. Max length inside an RV is 1200mm.
The standard appliance installation is fitted with copper pipe to provide maximum life span.
Gas Valves to isolate each appliance are listed below.
Are there restrictions on which gas appliances can be used and where?
Gas appliances must be Low Pressure, ie operate at or below 2.75kPa, when fitted inside an RV. All gas appliances shown on the Caravans Plus website are Low Pressure unless stated as High Pressure.
A flueless Gas Water Heater
CANNOT be used inside an RV.
Only Space (air) Heaters can be used where the combustion exhaust is sealed from the living area. Below is an example.
Where the RV has a fuel tank, other than diesel, you must ensure there is a minimum distance of one metre between the fuel filler cap or fuel vent and the appliance flue or combustion air inlet.
Installation instructions must also be met if they exceed the minimums set out in AS 5601. In particular installation instructions for fridges and heaters that require outside flue ventilation should be studied to ensure minimum distances from inlet vents, windows and annex areas are adhered to. For example you will not be able to allow combustion exhaust to enter an annex.
Appliances must be secured to prevent movement.
Wall mounted gas lights are rarely used since the advances in LED lights, however if this affects you, you should consult the AS 5601.
What are the ventilation requirements?
Gas appliances can be grouped into two sections:
1) Those where the combustion and exhaust is already sealed from the living area. e.g. Space heaters, *Most Fridges, Hot Water Systems
* All current model Dometic and Thetford Fridges are Room Sealed.
In this section, the ventilation requirements for the appliances are already met if you follow the instructions of sealing the room, providing external ventilation and flue for each appliance.
2) Those that are not room sealed. e.g. Cooktops, Ovens, **Some Fridges
**Many older gas fridges fit this category
In the second section, there are additional requirements based on the combined gas consumption of all other appliances.
There is a requirement to have two openings that are permanent and unrestricted.
These vents need to be at opposite ends or sides, one high, one low. Camper Trailers only need to meet this when open. Pop-Tops need to meet this with roof up and have one open vent even when roof is down.
The lower vent is usually within the door, and should never be sealed. The upper vents can be wall mounted or combined within permanently vented roof hatches.
The formula is A = 3xT
A is the ventilation AREA in square centimetres, that must be met.
T is the TOTAL gas consumption of all appliances in the area measured in Megajoules per hour (Mj or Mj/h).
If the appliance is rated in BTU instead of Mj, then divide BTU by 948 to get Mj
Examples of a couple of hatches that provide 50, 80 and 150 square centimetres of permanent ventilation each.
3) There is also a Minimum Ventilation Area that depends on the size of your RV, no matter what appliances are fitted.
Up to 4 metres long - 240 cm2
4 to 5 metres long - 300 cm2
5 to 6 metres long - 360 cm2
Over 6 metres long - 420 cm2
These are to be split 50% between upper vents (within 300mm of highest ceiling point) and lower vents (within 150mm of floor).
The CAMEC Odyssey Doors provide 238 cm2 permanent ventilation, so meet the lower vent requirements.
How much gas will I use?
Since you have now researched each appliance's gas consumption for the purpose of working out the ventilation requirements, you can also estimate how long your gas will last. Estimate the time used per day for each appliance, then total them up.
With appliances like stoves, remember you will rarely use all burners at once. With fridges, the operation time will vary depending on the outside temperature, how often you open the fridge and what the temperature on new items you add is. But make an educated guess. Water pump usage and HWS will depend on your maximum water storage.
An 8.5kg bottle (e.g. a swap size BBQ Bottle) will hold 17 litres of gas, that will provide approximately 420Mj of energy. So a Gas stove that uses 20Mj per hour, will burn for 21 hours on a full bottle of gas.
Reference: Guide to Gas Installations in Caravans & Motorhomes
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