I did the calculations at college around fourty seven years ago, when I did the City snd Guilds Construction Technician course and gained the qualification, including calculating the probability of black mould developing in a corner of a room. 

It was something I was going to get back up to speed with some years ago when the Domestic Ventilation Competent Person Scheme was launched and a few years later I bought a combined laser thermometer and humidity meter, which will test and determine it whilst on site, it is in with my air flow anometer, I will try and show it to you later.

I ended up installing lots of extractor fans, as I worked for walk in bathroom companies for nearly seven years and other customers, including landlord, but didn't do much black mould investigation work.

Thanks Sparkingchip, I'll take a look at the DVCP scheme. The use case for what we're looking at is commercial in lots of residential spaces.

Thanks Sparkingchip, I'll take a look at the DVCP scheme. The use case for what we're looking at is commercial in lots of residential spaces.