Changes

==Maintenance and inspection==

==Maintenance and inspection==

[[File:Jet cleaning.jpg|thumb|Diagram of hydrojetting cleaning apparatus]]

[[File:Jet cleaning.jpg|thumb|Diagram of hydrojetting cleaning apparatus]]

To permit access by cameras or cleaning apparatus, 90 degree connector must not be used in underdrains. Instead 2 x 45 degree couplers, or preferably 3 x 30 degree couplers should be used instead. For the same reason, dual walled perforated pipes with smooth internal walls are necessary.

To permit access by cameras or cleaning apparatus, 90 degree connectors must not be used in subterranean underdrains. Instead 2 x 45 degree connectors, or preferably 3 x 30 degree connectors should be used instead.  

 

For the same reason, dual walled perforated pipes with smooth internal walls are necessary to reduce the potential snagging of maintenance equipment.  

*[[Wells]], of 100 - 150 mm diameter perforated pipe, should extend to the bottom of the facility.  

*[[Wells]], of 100 - 150 mm diameter perforated pipe, should extend to the bottom of the facility.  

*The exposed tops of all wells should be fitted with lockable caps.

*The exposed tops of all wells should be fitted with lockable caps.