fire is a huge concern for me as I've read that drawing high amounts of watts can often melt plugs and sockets.
I was intending to have a PC connected to the Network switch so that I could easily log into the miners and change any config settings as needed. A laptop does seem like a more portable solution, thanks i will take that in consideration.
Can you tell me if you think that "miner hosting" solutions are worth considering? I've seen a place offering Power for 0.03khw which is marginally cheaper then my supplier (will be close to a micro hydro plant).
You need 200~250v check the amp rating of the units you intend to use, and make sure things do not exceed 80% capacity.
Most Asic miners (except Canaan until recently) come bundled with their own computer controller attached, they do not need a PC or raspi. The controllers are usually simple ARM cpus with Linux running cgminer or variant of with a web ui.
I don't know about trusting others with your mining equipment, especially when you already have a good place.
Each S9 is said to need 250CFM, make sure you move enough air for all of them. Cooling is unnecessary, but its nice if you can filter the dust from the air to lower maintenance needs. Humidity should be above 20% and below 70%, ambient temperature 0°C to 40°C iirc.
MicroBT's Whatsminer M20 is not so power hungry and is very efficient, the monster would the the M20S, but i think the M20 is better for ease of use and install. Note that the M20S is physically larger and heavier as well. BTW those probably need more CFM each per unit...