TSE CEN/TR 16797-1

TSE CEN/TR 16797-1 is a technical report on how declared values are assessed statistically for the release, emission and/or content of dangerous substances in construction products. This part addresses the use of type-testing, further-testing and, under defined circumstances, the point at which no-further-testing may be justified. Its focus is the statistical interpretation of measured results, so product data can be judged in a consistent way rather than from a single measurement alone.

How declared values are judged statistically

In this technical area, a declared value is the stated level used to describe a product characteristic such as release, emission or content. Measured values naturally vary from test to test, so concepts such as central tendency, spread, repeatability and measurement uncertainty become important. This report provides guidance for assessing declared values against observed data and for deciding when the available evidence is sufficient to support the declaration.

What TT, FT and NFT mean in practice

• TT (type-testing) refers to the initial testing used to characterise a product type.
• FT (further-testing) refers to additional testing used to support or maintain the original assessment.
• NFT (no-further-testing) is the point at which additional testing may be waived when measured values are shown to be consistently and significantly below the declared values.
• For construction products, this kind of statistical guidance helps make dangerous-substance declarations more consistent and defensible, but it is not itself a product test method standard or a product-specific limit standard.