Could someone tell me how to achieve regular fire drills at a tennis club please, it is inappropriate to evacuate paying customers and the premises are mostly occupied with players and members throughout the day. How could a fire drill be achieved without inconveniencing them? 

Find a quiet time! Shopping Centres, Leisure Complexes and similar have to do them and turf paying customers out once a year (or twice if best practice).

Alternatively explore this alternative to the traditional drill https://www.ioshmagazine.com/article/whats-drill