Line 53:
Line 53:
==Maintenance and inspection==
==Maintenance and inspection==
[[File:45 degs.PNG|thumb|Schematic of pipes and connectors]]
[[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 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.
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.