Inspection cover access

[psyflux]

Here's another one with the cover off to help give some perspective...

 

[psyflux]

So why is it dry now?

Thats where it gets a little bit interesting. The sewer actually has two routes which forms a square. The entry from the house always prefers the other route and they both join at one of those small manholes then go off to a septic tank.

 

[Newboy]

Hydrogen sulphide will not but smells bad so few would breath a dose by choice.

It also has the unusual property that at comparatively low concentrations (c.120 ppm) the olfactory nerve is paralysed within a few seconds so the smell of the gas seems to disappear

 

[Newboy]

If you must go down the manhole have someone nearby keeping an eye on you.

A when you pass out down a chamber what does the person watching you do?

Hold their breath, jump in and lift you out?
Call for medical assistance and hope that they arrive and extract you from the chamber within four minutes?

 

[Hugh Jaleak]

As part of my job working for a water company, I have been trained in entry to 'Confined Spaces', which includes chambers such as those you have pictured. With the addition of a Septic tank on the end of the run, makes them even more likely to possibly contain pockets of Hydrogen Sulphide.

H2S deadens the human sense of smell in concentrations making it even more deadly, (as you cant smell it so think it isn't present!), and at a level of just 1000 PPM, (parts per million) a single breath can kill. Exposure to lesser levels wont do you any favours, and the treatment and procedures for dealing with an exposure to H2S are not pleasant as I have been reliably informed. Even lower levels of 50-100 ppm can cause permanent eye damage, and levels of 300-500ppm can cause death.

Without at the very least using a gas monitor to ascertain the atmosphere in any chamber involved with sewerage is safe, I would strongly advise under no circumstances do you attempt to enter.

 

[Agile]

Interesting the square design of the pipework.

I have not seen those oval covers before.

How do they look from the side? Two pics from side and end?

I am wondering what tool you could make to lift them from above.

Tony

 

[Hugh Jaleak]

Clay access pipe. (Also available in plastic I believe.)

 

[psyflux]

They are about an inch thick and have a dinosaur like ridge on the back, but no holes so you can't hook them. I'd need to go down the hole again to remove one for pics and i've been frowned upon for doing that

 

[Hugh Jaleak]

Chap, one of my colleagues was taken seriously ill at work last year, (and sadly died earlier this year without regaining consciousness), as (we believe) a result of exposure to H2S. Another was hospitalised after inadvertently exposing himself to a dangerous level of gas, both of these incidents took place at ground level! H2S is heavier than air, and will collect at the lowest points.

There has been another serious incident in recent days involving a confined space, we can only warn you of the dangers.

 

[Dan Robinson]

But of course the OP knows better. They always do.

Sorry to hear about your colleagues.

 

[psyflux]

I'm sorry to hear that and I do take your advice very seriously. Believe me i wouldnt of just jumped down that hole if i'd read this first!
As its not active i was probably very lucky and there weren't any bad smells down there. I'd been flushing it all with gallons of clean water prior too.

If i do need to go down again would cycling the air in the hole with something like a leaf blower be advisable?

 

[Agile]

Hugh, do you have any photo of the cover?

What was the source of the H2S which killed/injured your colleagues?