Inspection Chamber reducers (sizes query)

[BotusBuild]

My groundworker has suggested reducing the diameter of the two large inspection chambers which will be in our rear garden down to 450 or 300mm.

 

So, I've been looking for a "reducer". The current twinwall chamber pipes that are in the ground measure about 680mm internal and 700mm external. I can't lay my hands on an invoice for said inspection chambers (one that won't be on the VAT reclaim!)

 

The largest reducer I can find online is 600mm (to various smaller sizes).

 

Should I be able to find a 700mm version?

 

Cheers

Bamboozled of Botus

[BotusBuild]

More sleuth work has found two unaccounted invoices (yay for the VAT).

 

Interesting thing is that the chambers are listed as 600mm !!!

[Alan Ambrose]

Could they have got a bit oval? I had a problem exactly like that way back.

[BotusBuild]

2 minutes ago, Alan Ambrose said:

Could they have got a bit oval? I had a problem exactly like that way back.

Maybe. I have two of them and have measured both, each across two diameters, so I think they're pretty much round.

 

NOTE: the invoice lists both as 600mm. For now I am assuming that they are classified as 600mm.

 

Its a bit like when you buy wood - nominal vs actual size 😀