Testing & Laboratory

Physical Testing

A scope heading, not a single list of experiments; The following test families conduct the experiments.

Scope

Test families in Physical Testing

Physical Testingis a scope heading, not a single list of experiments. The following test families carry out the experiments in the scope; A complete list of each family is on its own page.

Physical Testing — What Does This Testing Field Cover?

The section below describes how the field of Physical Testing works. The conditions, sample requirements and acceptance criteria of the individual tests in this field are given on the relevant test pages.

Physical testing determines the measurable physical properties of a material or product: dimensions, mass, density, hardness, permeability, surface roughness, colour and optical properties. It addresses not the chemical composition but the BEHAVIOUR of the material and its measurable state.

This category is not a family of methods but a type of question, and it draws on several families: the physical measurements of mechanical testing, plastics and rubber testing, textiles, construction materials and packaging all intersect here. The same density measurement is made to different standards in plastics, in concrete and in textiles.

What physical measurements have in common is that the result is tightly bound to the MEASUREMENT CONDITIONS. Temperature, relative humidity, conditioning time and measurement rate change the result; many physical test standards therefore define the conditioning environment first and describe the measurement afterwards. A physical result without stated conditioning cannot be compared.

The second common feature is that the results are usually written into a data sheet rather than against an ACCEPTANCE RANGE. Density or hardness alone does not say conforming or non-conforming; the product standard or supply specification says what range these values must fall within.

Dimensional measurements are the most routine part of this category but the one that causes the most argument. If the measurement uncertainty is close to the tolerance range, the conformity decision becomes dependent on that uncertainty; for critical dimensions, the measurement uncertainty and the decision rule must therefore appear in the report.

Commonly confused in this field

A physical result without stated conditioning conditions cannot be compared; humidity and temperature are decisive for many materials.
The ASTM and ISO counterparts for the same quantity use different specimens and rates; the values are not treated as directly equivalent.
A physical measurement does not on its own give a conformity decision; the acceptance range comes from the product standard.
For results close to the tolerance limit, no decision can be made without taking measurement uncertainty into account.

Which decisions these results support