Paint coatings on common building substrates were considered to assess the potential for simplified reaction to fire solutions for standard paint systems. Combinations of substrate (concrete, plasterboard, plywood and medium-density fibre board) and paint systems (water-based and oil-based) were tested.
For some of the substrates tested, where sufficient specimens were included to provide resolution, a transitional paint thickness was observed. This increase in paint thickness was associated with an increase in indicated Group Number followed by a decrease in indicated Group Number with continued increasing paint thickness.
The potential protective versus less protective transitional behaviour observed for the paint thicknesses reported here needs further investigation to ensure appropriate application of test results being applied to ranges of paint coating thicknesses.
Reasonable comparability was observed between the plasterboard substrate real-world samples and the prepared samples for the test variables and analysis considered here.