soil and vent system

[ron connal]

Hi guys, I am aware this is a long shot but I am trying to identify a soil and vent system I have never come across before, can you help?
Its a black rigid material, from the outside it looks like black painted asbestos but its not. Its installed in a domestic property built around 1960, when I took it out it is jointed with a taper fit and when I cut it, it's like a rubberoid material.

Any clues?

 

[Ermintrude]

Bitchuthene or some form of acorn soil?

 

[kirkgas]

Pitch fibre

 

[Grumpy old Plum]

hi it sounds like pitch fibre this was never meant to be used on the soil only on the vent pipe

 

[kirkgas]

hi it sounds like pitch fibre this was never meant to be used on the soil only on the vent pipe

Not so sure about this, we had loads of them all over Glasgow in multi-storey buildings