How close can i run the fill hose to a exhaust or heat source?
Certified LPG R67 approved fill hoses are made of various materials. These include copper pipe covered in plastic, you can have the traditional rubber SAE fill hoses ( which look like hydraulic hoses on a tractor ) and you have the thermoplastic pipe which is fitted by vehicle manufacturers and the like. There has never been and there is currently no R67 certification for the illegal stainless steel fill hoses ( as off 11/3/2020 )
No matter what your fill hoses is made of they all must be kept 100 mm (4 inch in old money) from any exhaust pipes and any heat sources. On a Motorhome and caravan that also includes the water heater or hot air blower exhaust etc. If you have to run the fill hose over an exhaust on a vehicle ( which you inevitably do ) you have to provide some mechanical protection in the form of a heat shield between the engines exhaust and the fill hose itself.
We always recommend is that the fill hose is kept as far away as possible from the vehicle catalytic converter which is in the exhaust as this needs to carry outs it function by getting extremely hot to burn off the unburned fuel from the engine, so in our opinion if you fitted any heat shield between the Cat and the fill hose it would not help and would be dangerous.
Fill hoses also should not be run through the habitational area / passenger compartment without being sealed at both ends and vented down and out of the vehicle inside a 30mm vent / Moplin tube ( GAS IT PT number GI-ACCS-027 ) which looks like vacuum cleaner hose. It should also be be protected from damage as far as is practical, be kept away from jacking points and fixed at no more than 600mm (2 foot) intervals. Fixings must be with purpose designed pipe clips and plastic strapping or good old trusty cable ties is not permitted.
Here is the link to the fill hose and accessories section on the GAS IT webshop
All the above legal requisition are covered in the ECE 67R legal document which covers the approval requirements and installation needs of LPG Autogas products on Automotive vehicles.