Gas Venting Sites

[tom775257]

Hello everyone!

The other day I thought I would go fly around a gas venting site, as shown on the chart (safe distance etc). It was a site with many large diameter pipes and equipment; with three large chimneys.

What are they for (yes, venting gas) but why would you want to vent gas? Is it natural gas that they vent? Judging by the number and size of pipes I guess it must be something to do with the natural gas distribution network.

Bizarre question I know, sorry if it has not got the required aviation content... but you seem to find lots of knowledgeable people on PPrune so someone might know....

[IO540]

A bit of updraught is always worth having :O

Nowadays every lamp-post over 10ft high has its own permanent Notam entry (especially if the bulb in it has packed up) so I wouldn't worry about it :O

[soay]

I was wondering the same as I avoided the one near Lancaster the other day. If anybody knows, do tell.

[Danny_manchester]

Hi the reason for these is as you say to vent off natural gas, mostly found as methane (CH4). Rather the same as you would find at an old colliary, to remove any excess gases. Some are fitted also with fans, to extract manualy, others just vent.

[Windy Militant]

They also act in a similar manner to flash arrestors used in Oxy Acetylene plant.
If things go really wrong they stop the shock wave running back along the pipe and act as a pressure release for the system.
If this happens there can be a flame/shock wave up to a couple of thousand feet blasting out of it. In the unlikely event you were right above it when it blew out it would really spoil your day.
There's been thread on this before where somebody posted pictures of a test firing pretty scary stuff.

[IO540]

About the same as flying 1000ft above and across the M25 on a really hot and calm summer day :O (a massive bump)

[Penguina]

I'm sure I remember a thread a year or two back by someone who had been frightened witless by quite a dramatic force from the updraught of one of these and had been moved to post on it. In fact, I remember a conclusion that he was going to get in touch with the CAA to suggest it gets put on a chart. Might have been on the way back from Old Warden heading south.

Can't remember any more and I might be wrong in remembering it at all, but if anyone else recalls it better maybe a link might be called for...

As for me, I've never noticed anything, though I try to avoid them.

[bookworm]

http://groups.google.co.uk/group/uk.rec.aviation/browse_frm/thread/43a0603094e3fb1f has some comments from someone working at a GVS and concerned about overflying aircraft. He made some comments about the nature of the hazard.

[Droopystop]

So if there is a high pressure vent, there must be certain conditions where the plume mixes with the air to give an explosive mixture. Fly your aeroplane through that and........ Also methane has a much lower density than air, and all that half rho v squared stuff will conspire against you. It would be interesting to find out where these effects are significant relative to the GVS on a still wind day.

I would imagine most GVSs (collieries, land fill sites etc) would be fairly benign, but a gas pipeline compressor facility would warrent a wide berth.

[Danny_manchester]

Hi, i will just add that you wouldn't get a concentrated sample of methane (natural gas) coming from a colliary at 1000ft. would just be a extreamly slow flow of gas, definatly not enogh to be an explosive mixture.

[machlimter99]

Does anyone know if they could take you to court due to flying near a GVS- below the suitible altitude- as printed on the charts???

[markflyer6580]

one just left of final for 21 at humberside,useful navaid,you can see it from 40ish miles or so on a nice day/eve.;)