There's certainly a lot of variation in how the regs are enforced between different Building Control Officers, but as you can see in the forum, people certainly are being asked for airflow certificates for new builds.
WRT fixed-flow fans: the issue isn't really adjusting them, it's the install that can cause performance degradation. For a simple straight-out-through-the-wall bathroom extractor, there's not much to go wrong; when you've got ducting through the loft space, then you've got potential issues with type of ducting, number of bends, & all that kind of thing - particularly if other trades have been in behind you. I'm told that's the rationale behind the airflow tests & commissioning notice requirements in the regs - checking the whole fan install, not just relying on the numbers on the side of the box it came in.
It's been my experience that people aren't all that familiar with the rules on this stuff, but it's got a massive effect on the actual airflow the fan can supply. Hence the online course - the information is out there, but it's buried throughout 100s of pages of regs & guidance. I felt that having it in a simple, easy-to-digest form was a useful thing.
Good point on cost visibility, thank you; I'll get that made clearer on the website next week. For a sole trader, the cost is £80 - no other costs. We'll also loan you a free vane anemometer to do your first test with. If your building inspector is asking for an airflow test certificate or commissioning notice, I think it's a reasonable deal for a useful service - if you aren't too worried about Part F at the moment, then just bear us in mind for the future.
Enjoy your weekend, all
