drainage envelope

drainage envelope

The materials which completely surround a pipe, providing support and/or protection.
References in periodicals archive ?
Comply with Pipe envelope Geotextile ISO 9863, 9864, and 12956 in terms of mass per unit area, pore size index, and wettability Drainage envelope Geotextile and None granular filter material Parameters DID manual (2009) Angle of drain 0.06 [degrees] installed Pipe envelope None Drainage envelope Granular filter material