... 1, The clear-span of BT20 is 20m.2, The length of BT20 could be 20m, 25m, 30m and +5m more ... , flame retardant to DIN4102 B1, M2, UV resistant.5, The maximum allowed wind speed is 100KM/h. The security and variability ... .8, Sizes available (the width of the big tent): 12m, 15m, 18m, 20m, 21m, 25m, 30m, 40m, 50m and 60m. Span ...