Changes

Perforated pipes are a common component of [[underdrains]] used in [[bioretention]], [[permeable paving| permeable pavements]], [[infiltration trenches]] and [[exfiltration trenches| exfiltration systems]].   

Perforated pipes are a common component of [[underdrains]] used in [[bioretention]], [[permeable paving| permeable pavements]], [[infiltration trenches]] and [[exfiltration trenches| exfiltration systems]].   

Pipes should have been manufactured in conformity with the latest standards by the Canadian Standards Association (CSA) or ASTM International.

Pipes should be manufactured in conformity with the latest standards by the Canadian Standards Association (CSA) or ASTM International.

*Perforated pipes should be continuously perforated, smooth interior HDPE (or equivalent material).

*Perforated pipes should be continuously perforated, smooth interior HDPE (or equivalent material).

**Wherever possible pipes should be ≥ 200 mm internal diameter to reduce potential of freezing and to facilitate inspections and maintenance with a push camera.  

**Wherever possible pipes should be ≥ 200 mm internal diameter to reduce potential of freezing and to facilitate inspections and maintenance with a push camera.