HVAC Ventilation advice for choir going back indoors

Because of Covid, our choir has been rehearsing in an outdoor car park until now and we are aiming to go back to indoor rehearsals next week. We have found a space that will have us for 3 hours, once per week, and seems big enough to be safe.

We would like advice on ventilation from an HVAC engineer, and confirmation that our methodology is sound. We do not require you to be present on site.

The space doesn’t have windows that can open, but we looked at positive pressure ventilation, and considering getting a couple of powerful fans to bring fresh air in from the outside, as there are fire doors we can open.

We want to make sure people are as safe as possible and want to validate the method — we therefore set a small budget aside for this, which should cover the time for an HVAC engineer to look over the theory and confirm our thinking for our own peace of mind.

I can provide plans of the space and a more accurate description of our intention.