Sewer Manholes – It’s Time for a Re-Think!

Annual Conference

The construction of gravity sewer networks using large concrete Manholes (MHs) between short lengths of sewer pipes is unnecessary, costly, dangerous to install and inspect, and encroaches on our narrow and scares service corridors. Besides, they often leak through the entry cover, riser joints and pipe connections, significantly contributing to inflow and infiltration. Concrete manholes also have a tendency to corrode over time and repair or replacement is expensive.

The introduction and acceptance of Maintenance Shafts (MSs) as a modern day replacement for large diameter (minimum DN1050) MHs is happening in Australia and elsewhere overseas. So why not New Zealand?

MSs comprise a DN225 or 300 PVC pipe shaft down to a PVC, PE or PP base that either has pre-ordered inlet outlet stubs for each individual location, or are manufactured to accommodate multiple entries at 45, 90 degrees on both sides of the base in addition to the straight through position.

The latest technologies for cleaning, condition checking and repairing sewer pipes no longer require maintenance staff clambering down manholes to carry out such tasks. It’s like medical operations using micro-surgery techniques which are quicker, safer, cleaner and less expensive than using the knife. All can be done remotely from the surface. This paper discusses the advantages of MSs in terms of price, installation cost, health and safety, I/I, maintenance and longevity. It also identifies changes to installation and maintenance practices needed for success.

Conference Papers

1.30 Sewer Manholes Its Time For A Rethink.pdf

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430 KB
08 Nov 2017

1.30pm M Christeller.pdf

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811 KB
08 Nov 2017