Changes

[[File:45 degs.PNG|thumb|Schematic of pipes and connectors]]

[[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.

*The recommended distances between clean outs is based on advice for filter beds in the Ontario Building Code<ref>Province of Ontario. (2018). O. Reg. 332/12: BUILDING CODE. Retrieved February 23, 2018, from https://www.ontario.ca/laws/regulation/120332</ref>. However, the access capabilities of difference apparatus and contractors varies and designers are advised to take advice from maintenance operators in this matter.  

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

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