Convective heat test (EN 9151):
In previous posts, we’ve spoken about how we know if a fabric is “flame resistant” and valid to be used as PPE. We began explaining the horizontal flame test (EN 15025 – A1), but as you will imagine, there are much other tests involved to make such affirmation.
The regulation EN 11612, when speaking about protection against heat and flames, it basically measures 3 kind of different heat transmission:
- Contact (EN 12127)
- Radiant (EN 6942)
- Convective (EN 9151)
In this post we will focus on the EN 9151.
How can we quantify the resistance of a fabric against convective heat?
The test consists to put a fabric sample (in case of a “sandwich” of fabrics, the order of the layers is as it would be in a real garment) to an incident heat flux of 80 kW/m2 ± 5%.
The heat passing through the sample is measured by a calorimeter located above the fabric and in contact with it.
A rise of 24ºC ± 0.2ºC is considered to be a 2nd degree burn on human skin, so indeed, the test measures the time needed to do this increment.
The results are split in 3 levels:
a) B1: from 4 to <10 seconds
b) B2: from 10 to <20 seconds
c) B3: up to 20 seconds or more
To say that the test has been successful, the result shall be at least B1.