... pipe fittings manholes frame and grate ISO2531 pipe fittings as per ISO2531/EN545/EN598/BS4772. manholes, ISO2531 pipe fittingsMaterialDuctile iron GGG500-7StandardISO2531/ ... Certificate, if need, we could provide Certificate Paper. Standards:ISO2531,EN545,EN598,BS4772 Material:ductile iron; grey iron; customer's ... your own logo on the product, it is ok ISO2531 manholes--ductile iron pipe fittings