Heaters
From British Juggling Convention Wiki
http://www.speedyhire.com/Heating-&-Cooling/Heaters/Propane-Forced-Air-Heater/p-1-42-49-393/#
a spring BJC will need around 3 of these for a white frame marquee and 2 for a Big top
over a 4 day BJC each heater will empty 2 47kg propane cylinders