I work on a project which deals with numerically modelling the ambient
hydraulics within siphonic roof drainage systems. A requirement for these
systems is that the sewer system they discharge into must be vented (to
ensure the siphonic action is "broken"). My talks with
designers/manufactures/installers within Europe has given us the impression
that assuming normal MH covers have sufficient venting is erroneous.
Typically any vents/pick holes become clogged with sand/silt and the edges
also become well sealed due to the weight of the traffic.
.........
Scott A.
Dr. Scott Arthur ( [log in to unmask] ),
Post. Doc. Research Associate - Siphonic Systems,
Department of Building Engineering & Surveying,
Heriot-Watt University, Edinburgh, EH14-4AS,
Scotland, UK.
Tel 0131 449 5111 x4653 or Fax 0131 451 3161
> -----Original Message-----
> From: [log in to unmask]
> [mailto:[log in to unmask]]On Behalf Of Bert van Duin
> Sent: 26 March 1999 06:17
> To: [log in to unmask]
> Subject: Value of pick holes in manhole lids on venting requirements
>
>
> Apologies for multiple postings.
>
> I am trying to find out if there has been any research/studies done on the
> "value" of pick holes in manhole lids from the perspective of venting
> sanitary sewers. We have a project in Regina, Saskatchewan,
> Canada (which,
> for your information is a very flat prairie city) that will involve trying
> to isolate the inflow into the sanitary sewers by plugging pick
> holes in the
> manhole lids. The problem we have is that almost all of the sanitary
> manholes are in depressions so are sources of inflow. The City of Regina
> wants to try to estimate the venting requirements so as to determine how
> many manhole lids that should not be plugged for venting purposes. The
> alternative is to plug them all and provide separate vents to the system
> (e.g. vertical pipes that end well above ground level adjacent to the
> street). Anyone with any comments?
>
> Thanks,
>
> Bert van Duin
>
> Bert van Duin, M.Sc., P.Eng.
> Urban Drainage Specialist
> Water Resources Engineer
> Water Resources & Civil Projects Division
> AGRA Earth & Environmental Limited
>
> 221 - 18th Street, SE
> Calgary Alberta T2E 6J5
> Canada
> phone: (403) 569-6587
> fax: (403) 248-1590
> e-mail: [log in to unmask]
> or [log in to unmask]
>
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