@sri_srikrishna I think you need to consider density and a classroom might well "need" more than 6-12 ACH, or at least might consider higher ACH to be comparable mitigation as lower ACH in a less dense environment. But you do what you can of course, more is better than less.
@sri\u srikrishna我认为你需要考虑密度，一个教室很可能“需要”超过6-12 ACH，或者至少可以考虑在密度较低的环境中，较高的ACH可以与较低的ACH相比。但你尽你所能，当然，多多益善。