BS ISO 21138-3. Plastics piping systems for non-pressure underground drainage and sewerage. Structured-wall piping systems of unplasticized poly(vinyl chloride) (PVC-U), polypropylene (PP) and polyethylene (PE). Part 3. Pipes and fittings with non-smooth external surface, Type B— 55 стр.
BS ISO 21138-2. Plastics piping systems for non-pressure underground drainage and sewerage. Structured-wall piping systems of unplasticized poly(vinyl chloride) (PVC-U), polypropylene (PP) and polyethylene (PE). Part 2. Pipes and fittings with smooth external surface, Type A— 57 стр.