Up Periscope!

[Flyfisher]

Does anyone know what this could be?
It looks like some form of ventilation shaft, but for what?
The second photo shows how far away from the house (and any other buildings) it is, so I'd be surprised if it's anything to do with the current drainage arrangements, but I don't really know.

 

[skier-hughes]

Nuclear bunker?

 

[Penners]

Looks like a breather pipe from a septic tank to me. Have you tried digging around near it, or probing the ground with a steel rod?

 

[Flyfisher]

I haven't had the chance to have a further 'prod' around it as yet.

Should all septic tanks have breather pipes? The one that is definitely in active use is on the other side of the house and hasn't got a similar breather that I can find.

What would the normal 'drop' of a foul drain be? If it is an old septic tank, it would have to be very deep to be so far away from the house. Would this be typical?

As for a nuclear bunker, well there are USAF bases all over East Anglia . . .

 

[Lime]

This type of ventilator was used above a manhole that held an "interceptor" just prior to the pipes entering a main sewer or septic tank.
They were commonly fitted upto the 1960s.
The ventilator was supposed to work only one-way just like a modern air admittance valve.
Inside the ventilator a flap of mica was hinged over the grill so that normally it was shut (preventing sewer gas escaping) but when a partial vacuum occurred in the manhole the mica flap opened allowing air into the pipe.
the reason that these ventilators were used was a worry that gases could be sucked through the interceptor from the main sewer or tank.

 

[Flyfisher]

There is no obvious sign of a manhole cover. I'll have to have a closer rummage through the undergrowth. Would the ventilator typically be right above the manhole? If not, how far away might it be?

 

[Lime]

Typically it would be next to the nearest wall or fence.
bluntly, the manhole could be anywhere because these vents needed to be vertical so it was usually placed next to a flat surface. In your case it looks as though the choice was next to a tree!

I notice it is perched on a what looks like a cast iron pipe.
That is exactly what my old septic tank used on a house of many years past.
The outflow fed straight into a ditch.
When the sides of the ditch were widened by a dragline tractor the machine caught the pipe and, because the pipe was so strong and long, the dragline pulled the driver's cabin into the water. :lol:

 

[Flyfisher]

Yes, I had noticed the separate pipe, although I wasn't sure of its significance. Since there is nothing else nearby, I guess it must be something to do with the house, which is interesting given the distance. There are no walls or fences nearby and none within 40 years of living memory.

However, it is within about 10m of an old chalk pit that was dug, we believe, for the chalk 'bricks' used during a later addition to the house. I wonder if the outflow pipe could lead to the pit? More investigation in the undergrowth is clearly needed!