Overview
ISO 12162:2009 specifies the classification, designation and design coefficient for thermoplastics materials in pipe form intended for pressure applications. The standard defines how to derive long‑term strength values and convert them into a Minimum Required Strength (MRS) classification and a Categorized Required Strength (CRS) for alternative temperatures and times. It also gives the method to calculate design stress using a design coefficient (C). ISO 12162 applies where hydrostatic resistance and time‑temperature performance are key design drivers.
Key topics and requirements
- Long‑term hydrostatic strength (LTHS) and its 97.5% lower confidence limit (LPL) are the basis for material classification. ISO 9080 is used for extrapolation.
- MRS (Minimum Required Strength): defined at 20 °C and 50 years, rounded down to preferred-number series (R10 or R20). The MRS classification number is 10×MRS (e.g., PVC‑U 250 = 25 MPa).
- CRS (Categorized Required Strength): analogous to MRS but for other temperatures (θ) and times (t); used where design conditions differ from 20 °C/50 years. CRS values are given in Annex A.
- Design coefficient (C): a safety/usage factor that accounts for service conditions and system effects not captured by LPL. ISO 12162 specifies minimum C (Cmin) values for common polymers (examples include PE all types 1.25; PVC‑U 1.6; PP homopolymer 1.6; PB 1.25; ABS 1.6).
- Design stress calculation:
- Based on MRS: σs = MRS / C
- Based on CRS: σs,θ,t = CRSθ,t / C
Results are rounded down to the next lower R20 series value.
- Designation rules: material symbol per ISO 1043‑1 plus classification number (e.g., “PVC‑U 250”).
Applications and users
ISO 12162:2009 is used by:
- Pipe and fittings manufacturers for material selection, product marking and system design limits.
- Design engineers and specifiers calculating allowable stresses for pressure piping systems.
- Standards committees and testing laboratories relying on standardized classification and extrapolation (ISO 9080) methods.
- Regulatory bodies and procurement teams that require documented long‑term performance criteria for thermoplastic pressure piping.
Typical applications include water distribution, industrial fluid transport and other pressure piping where long‑term hydrostatic performance is critical.
Related standards
- ISO 9080 - Determination of long‑term hydrostatic strength by extrapolation
- ISO 1043‑1 - Plastics symbols (material identification)
- ISO 10508 - Guidance for hot/cold water piping systems
- ISO 16422 - PVC‑O pipe specifications
Keywords: ISO 12162:2009, thermoplastics materials, MRS, CRS, design coefficient, design stress, long‑term hydrostatic strength, pipes and fittings, pressure applications, ISO 9080.
Open preview (PDF)Thermoplastics materials for pipes and fittings for pressure applications — Classification, designation and design coefficient