BS ISO 13268:2022 Thermoplastics piping systems for non - pressure underground drainage and sewerage — Thermoplastics shafts or risers for inspection chambers and manholes — Determination of ring stiffness
1970BS ISO 13268:2022 Thermoplastics piping systems for non - pressure underground drainage and sewerage — Thermoplastics shafts or risers for inspection chambers and manholes — Determination of ring stiffness
2010BS ISO 13268:2010 Thermoplastics piping systems for non-pressure underground drainage and sewerage - Thermoplastics shafts or risers for inspection chambers and manholes - Determination of ring stiffness