Swinley Bottom Roundabout Building with Windsock

[PaddyZulu]

Passed by there recently and was intrigued as to the reason for the windsock, looks newish so fulfilling a current purpose I assume.

Although they have carried out some deforestation lately there doesn't look enough room to swing a cat let alone land a chopper.

Anyone in the know please?

[SVTRick]

Not sure what the site is however on most AWTW (Advanced Water Treatment Works) you have a Windsock.
I the event of a Chlorine Gas Escape (they have big pressurised tanks of the stuff) you are trained to escape
up wind rather than down.