Whatever gas you use, if you don't have underfloor storage, make sure that you have ventilation in the floor where you store the bottle. The gas is heavier than air, so flows down if there is a leak of any kind and can accumulate at low level undetected (unless you are in the habit of standing on your head, sniffing the floor), with potentially explosive results. [xx(]
This is more of a problem on boats, where vents at the lowest point tend to let in the damp, [:0] but you cannot be too careful in a van.
This is more of a problem on boats, where vents at the lowest point tend to let in the damp, [:0] but you cannot be too careful in a van.