Transverse sweep the floor mistake of lever installation position, should secure in fore-and-aft sweep the floor lever lower partTemperature humidity all does not accord with a requirement, temperature 2 ° of 20 ± C, humidity 95% aboveThe dormitory uses steel tube to be built at will set, use a store, disobey strongDangerous carry scaffold, girder fixed position presses annulus to be short of breakWithout shield