Overview
ISO/TR 16913:1999 - Plastics pipes and fittings - Definitions of types of test - is an informative Technical Report issued by ISO/TC 138 (sub‑committee SC 5). Its purpose is to provide a consolidated list of definitions and abbreviations (adopted at CEN) for the different categories of tests used to judge properties of plastic pipes and fittings at stages from production through delivery. The report is descriptive (a Technical Report), intended to clarify terminology used in standards, certification and quality‑control processes for plastics piping systems.
Key topics
The document focuses on standardized test‑type terminology and related sampling concepts. Important items include:
- Categories of tests and their abbreviations:
- TT - Type tests
- PTT - Preliminary type tests (manufacturer)
- ITT - Initial type tests (by certification body)
- BRT - Batch release tests (before making a production campaign available)
- PVT - Process verification tests (periodic checks during production)
- AT - Audit tests (by certification bodies to confirm ongoing conformity)
- IT - Indirect tests (correlated alternate tests)
- WT - Witness tests (manufacturer tests supervised by certification representatives)
- Sampling and batch definitions:
- Definitions for material, composition (mixture), campaign of manufacture, lot, sample, sampling unit, test take, and specimen.
- Quality metrics and inspection levels:
- Definition and role of AQL (Acceptable Quality Level) for continuous lots/campaigns, and the concept of level of control (relationship between lot size and sample size).
- Informative nature:
- The report is explanatory, not prescriptive; it clarifies vocabulary used across standards and conformity assessment schemes.
Applications
ISO/TR 16913 is useful for anyone involved in the design, production, testing, certification or procurement of plastics piping systems:
- Manufacturers - to align in‑house testing and batch release procedures with recognized terminology.
- Testing laboratories - to interpret test‑type requirements and sampling terms consistently.
- Certification bodies and auditors - to apply or specify initial, audit and witness tests and to evaluate process verification regimes.
- Specifiers and purchasers - to define inspection/acceptance criteria in contracts and technical specifications.
- Standards developers - to harmonize terminology across related pipe and fitting standards.
Related standards
ISO/TR 16913 references sampling and quality standards for application of AQL and sampling plans:
- ISO 2859‑1 (sampling procedures for lot‑by‑lot inspection)
- ISO 3951 (sampling by variables)
It sits within the work of ISO/TC 138 (tubes, fittings and valves in plastics for fluid transport) and complements product and test method standards in that series.
Keywords: ISO/TR 16913, plastics pipes and fittings, definitions of types of test, type testing, batch release, process verification, AQL, sampling, quality control.