UPVC Grey Pipes and Fittings are generally used for Agriculture Purposes. They are light grey in colour

Standards

PIPES

For Self Socketed Pipes : ISI - 4985:2000 (Elastomeric Sealing Rings confirming to IS - 5382:1985)
For Slotted Pipes : Dimension are as per IS - 4985:2000 and slot dimensions as per IS -2818:1992

FITTINGS

Standards for UPVC Grey Fittings:

a) IS:7834-1987 : for ISI marked fittings 
b) Other fittings : Only socket dimensions under general guidelines of IS-7834-1987