Changes

*Underdrain access structures/cleanouts, which may be maintenance holes or vertical standpipes connected to the perforated pipe, must be included in the design for periodic inspection and flushing of the perforated pipe. Negotiating 90 degree bends will be troublesome for most push camera and jet nozzle cleaning equipment, so it is preferable that 45 degree pipe couplings be used instead.  

*Underdrain access structures/cleanouts, which may be maintenance holes or vertical standpipes connected to the perforated pipe, must be included in the design for periodic inspection and flushing of the perforated pipe. Negotiating 90 degree bends will be troublesome for most push camera and jet nozzle cleaning equipment, so it is preferable that 45 degree pipe couplings be used instead.  

Cleanouts are "''a fitting access in a drainage system or venting system that is installed to provide access for cleaning and inspection and that is provided with a readily replaceable air tight cover''" (O.Reg 332/12: Building Code, 2022)<ref>Province of Ontario. (2018). O. Reg. 332/12: BUILDING CODE. Retrieved February 23, 2018, from https://www.ontario.ca/laws/regulation/120332</ref>.

'''Cleanouts''' are "''a fitting access in a drainage system or venting system that is installed to provide access for cleaning and inspection and that is provided with a readily replaceable air tight cover''" ([https://www.ontario.ca/laws/regulation/120332 O.Reg 332/12: Building Code, 2022])<ref>Province of Ontario. (2018). O. Reg. 332/12: BUILDING CODE. Retrieved February 23, 2018, from https://www.ontario.ca/laws/regulation/120332</ref>.

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In some cases where the underdrain layer has sufficient depth to accommodate it, a larger diameter perforated pipe (e.g. ≥ 300 mm) may be used to add further storage capacity to a [[bioretention]] or a [[bioswale]] project. Ultimately this idea may result in the use of [[infiltration chambers]] or other void-forming structures to create significant reservoir storage beneath a bioretention filter media bed or permeable pavement. Be sure to check with manufacturers about the compatibility of their systems with trees.

In some cases where the underdrain layer has sufficient depth to accommodate it, a larger diameter perforated pipe (e.g. ≥ 300 mm) may be used to add further storage capacity to a [[bioretention]] or a [[bioswale]] project. Ultimately this idea may result in the use of [[infiltration chambers]] or other void-forming structures to create significant reservoir storage beneath a bioretention filter media bed or permeable pavement. Be sure to check with manufacturers about the compatibility of their systems with trees.

==Underdrains for non-infiltrating practices==

==Underdrains for non-infiltrating practices==