Petrol stations & "minimum delivery 2 litres" - enforced?

[sebhaque]

I had a complete brain failure the other day. A friend of mine borrowed my car and it was running low on fuel. I gave her £60 to fill the tank - any change was hers to keep, but any extra was out of her pocket. It cost about £68 to fill up and she wasn't that bothered.

I went grocery shopping a few hours after she'd dropped the car back and forgot that she'd filled it up. I admit, it was my own fk up, but I pulled into the local Tesco to fill up without looking at the petrol gauge. I managed to get just under 1.5 litres into the neck before it started pissing out everywhere. I decided not to pour more fuel all over the floor and after having to cancel twice on the Tesco pay at pump (I docked the nozzle, pressed cancel, it asked me to confirm so I pressed it again), and was on my way. £1.65 of fuel in the neck and a rather embarrassed driver in the car.

My question - does anybody actually enforce the 2 litre rule these days? It would make sense when fuel was pennies per litre, but realistically if you pulled up at an Esso/Shell/Texaco/BP etc and only popped in a litre and a half, would anybody actually care?

[Trabi601]

It's part of the Weights & Measures certification of the dispenser.

Depending on flow rates, some dispensers are to carry the text 'minimum delivery 5 litres'.

I can only assume anything less than 2 or 5 litres could be inaccurate due to the flow rates.

(Eg. a Gilbarco SK700 pump with a ZVA slimline nozzle - quite a common configuration - is certified for minimum delivery of 2 litres, based on a flow rate of 40 or 80 litres / minute. If you want to up this to 120 litres / minute (ie. for HGV use) the certification moves to 5 litres minimum.)

[sebhaque]

Thanks for the reply - very informative! So realistically if your average consumer popped in and bought a litre of fuel (ignoring profit margins etc), they're entitled to do so but the garage has the fallback that if they were charged for 1.02 litres of fuel, then the Weights & Measures cert doesn't cover such a small delivery of fuel on consumer-standard equipment. Of course if they bought 50 litres and were charged for 53, then W&M would come into play.

This is why I love PH - arguments aside, there's a genuine source of knowledge and information too

[Trabi601]

That seems like a reasonable interpretation.

I've been doing a lot of work on pump configurations recently as part of our mobile payment service. Some models of pump can be trusted to cut off at an exact figure (eg. £20) - but others need a fairly large margin of error - and you'll find a requested £20 max. fill will cut off at £19.75 (for example).

I'm not hugely technically knowledgable, but there's something about non-dribble back-flow valves, which are expensive and not often specified when ordering a new pump. (A 4 hose pump is circa £20k delivered and installed)