Sealing plastic manhole rings

[mark]

I am installing a couple of small plastic manholes/inspection chambers about

325mm dia.

What is the proper way to seal between the riser rings for a water test?

The rings are a push fit without the gaskets of the larger diameter chambers..

mark

[Phil L]

They don't need sealing - the bottom one will be sat on concrete or a plastic moulded base, and the next one up will be about 150mm above this. If the manhole should ever fill up, a small amount of leakage into the soil is the least of your worries