Vent Pipes-Petrol

[rivonia]

I raised this topic earlier in the year and a good debate followed. Since then I have done a little research.

I was blandly informed by this forum that the PETROL VAPOUR sinks and will escape out through the drain holes in the lazarette.

My question; why are there tall vent pipes at the petrol stations? If the vaour sinks- no need for a vent pipe to the tank!

Peter

 

[Mirror Painter]

You posted on my thread and I post on your

http://www.boatsafetyscheme.com/downloads/avoidingPETROL.pdf

"Petrol vapur is three times heavier than air". Could the petrol station vent pipes to let the air out?

 

[rivonia]

You posted on my thread and I post on your

http://www.boatsafetyscheme.com/downloads/avoidingPETROL.pdf

"Petrol vapur is three times heavier than air". Could the petrol station vent pipes to let the air out?

Hi, when I downloaded your http it just came out as gobbledeguke. No wording. Any way use stated the obvious that petrol vapour is heavier than air. Which means that it would sink out through the drains.

Cheers

Peter

 

[vyv_cox]

When the tank is filled with petrol it displaces air. Air has to go somewhere so it is vented high to avoid the possibility that petrol vapour will exit at low level and be ignited.

 

[Bru]

My question; why are there tall vent pipes at the petrol stations? If the vaour sinks- no need for a vent pipe to the tank!

Deja vu

See my other post on a similar topic - the vent pipes are there to allow for pressure changes in the tanks, primarily as they are emptied (when they are being filled, the vapour forced out of the tank is recovered back into the delivery tanker).

What goes in (mostly) and occasionally out of the pipes under normal circumstances is air rather than fuel vapour