Getting good seals on underground drainage what's the secret?

[SteamyTea]

3 hours ago, MikeSharp01 said:

I didn't think you could have molecules of oxygen only atoms.

That is noble gasses isn't it.

Everything else is a molecule.  With Oxygen being a right tart and sticking to almost everything.  Carbon is the same.

[Jeremy Harris]

Oxygen normally exists as molecular oxygen, O₂, rather than as atomic oxygen, O, in the atmosphere, or as a compressed gas.  Atomic oxygen isn't stable, and wants to bond to practically anything, including itself, whereas molecular oxygen is generally pretty stable, so dioxygen is quite happy to just stay around.  Trioxygen, O₃ or ozone, is highly reactive and will give up one oxygen atom to oxidise lots of stuff.  The reason that ozone is so reactive has to do with it wanting to rid itself of the extra oxygen atom as quickly as possible, and the affinity the released single oxygen atom has for lots of other atoms.

[jack]

O₂ is covalent bonding (as opposed ionic bonding such as for a salt), I seem to recall from the foggy depths of A-level chemistry.

[MikeSharp01]

So what does that mean for the seals around my joints - I thought the water test was used only if air test failed. I just re read PART H and the test has to be carried out after it is covered up so how does the BCO check the fall - I cannot imagine they want to make two trips?

 

Mike

[Jeremy Harris]

From what I can gather, building inspectors seem pretty laid back about drainage tests.  That was certainly my experience, and seemed to be that of our ground works chap, who couldn't see why I'd bothered to specify the drain test as a specific item.  I got the feeling that a fair bit of the time they don't even come out to check drain tests now, and I suspect that has a lot to do with the fact that modern plastic drain pipe systems are pretty foolproof.  I think the whole concept of the drain pressure test goes back to the days when short lengths of clay pipe with lots of joints were the norm, as they can very easily leak if they aren't laid properly.

[ProDave]

Another difference between England & Scotland?  They are very hot on drain tests here, they like to see the drain before it is covered and see the pressure test at the same time. They even wanted to pressure test the drain run to the static caravan that arguably was not permanent.

 

Though when I came to connect the final 3M section when the treatment plant went in, they were not available, and not the slightest bit interested in any of the pipework coming out of the treatment plant.

[SteamyTea]

2 hours ago, JSHarris said:

Oxygen normally exists as molecular oxygen, O₂

Is that because it has two free electrons in the outer shell that are happy to pair up with another two free electrons on another oxygen atom.

Something like this (I never really got the hang of chemistry as it always seemed to be a memory test)

Edit:

Actually not quite right as it should show either two new pairs of electrons (as there are 4 free ones) or one new pair and two free ones (one on each atom shell).

 

Edited June 7, 2018 by SteamyTea

[Nickfromwales]

4 hours ago, JSHarris said:

isn't stable, and wants to bond to practically anything,

Ah, my teenage years .........

[Jeremy Harris]

17 hours ago, SteamyTea said:

Is that because it has two free electrons in the outer shell that are happy to pair up with another two free electrons on another oxygen atom.

Something like this (I never really got the hang of chemistry as it always seemed to be a memory test)

Edit:

Actually not quite right as it should show either two new pairs of electrons (as there are 4 free ones) or one new pair and two free ones (one on each atom shell).

 

 

Pretty much.  To understand how chemistry works getting your head around the idea of valency is a great help.  Unfortunately, the classical way of illustrating "rings" of electrons around a nucleus tends to muck up things a bit, IMHO, as the reality is that the orbiting electron cloud isn't as neat and tidy as that, and when you chuck in the inherent uncertainty as to where any subatomic particle actually is (something we cannot know) things get even harder to get your head around.  The Wiki entry on valence is reasonably clear, but assumes a bit of understanding about atomic structure: https://en.wikipedia.org/wiki/Valence_(chemistry)