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6.9.2.1 Standard Types of Manholes

Table 6‑14 : Standard Types of Manholes

Standard Types of Manholes

Type

Description

Type A

Manholes up to 1.8m deep from lid to invert of the outlet and with nominal internal diameter (NID) 1050mm:

Type A1: Precast base with vitrified clay / reinforced concrete (VC/RC) connections;

Type A2: In-situ base with PE sewer connections;

Refer drawings WW208, WW209 and WW209A and their Tables for riser diameters

Type B

Manholes with depth from lid to invert of the outlet from 1.8m up to 3.0m and with nominal internal diameter (NID) from 1200mm to 2100mm:

Type B1: Precast base with VC/RC connections;

Type B2: In-situ base with PE sewer connections

Refer drawings WW210 and WW211 and their Tables for riser diameters

Note: Larger diameter manholes shall be provided depending on the number and size of branches, change of direction and the need for adequate benching.

Type C

Manholes with a nominal internal diameter of 1350mm to 2100mm for depths from lid to invert of the outlet exceeding 3.0m

Refer drawing WW212

Type D

Drop manholes for Type B and C manholes with an internal drop on a NB diameter 150mm sewer.

Internal drop shall be fixed firmly and durably to the manhole wall using stainless steel straps and fasteners, one at top, one at base and in between at 1m intervals.

Refer drawing WW213 for internal drop details

Type E

Drop manholes for Type B and C manholes with an external ramp

Refer drawing WW214

Note: Type E is the preferred type of drop manhole, over Type D

Type F

Manholes manufactured from Polyethylene (PE) / Polypropylene (PP) having a nominal internal diameter of not less than 1000mm may be used where:

  1. sewer outlet sizes are diameter NB 225mm, or less;
  2. the depth of the sewer is no more than 3.0m from the lid to invert of the outlet;
  3. the manhole is not located in trafficked areas;
  4. the Design Engineer provide evidence to prove that the approved manufacturer of the manholes allows this intended use (together with the Manufacturer's drawings); and

provided it's use is approved by the Wastewater Network Operations Manager.

 

Type G

Dry manholes (sealed channel manholes)

Refer clause 6.9.2.7 and drawing WW217