your ceiling height of 2.6m is indeed the average. mine is only 2.5++m (25 year old flat) i understand that the safety clearance height is 7 feet, or about 214cm. That being said, the best is for you to stretch your arms up, and then measure, so that you will know what is the best safety clearance height for yourself. I'm 1.74m, and when I stretched up my arms, the clearance i'm comfortable with is 2.2m you do have to be careful when you buy your ceiling fans. i regretted not doing my own research properly and going ahead to buy ceiling fans from a particular company. at the company, i asked whether the fans were safe for installing in hdb flat with low ceiling, and the assistant said yes, no problem. in the end, when the fans were installed ... i could clean the fan blades without even having to tip toe. sigh ... from then on, i learnt my lesson, so right now i have to replace them. have to look for fans that come with the description 'Downrod: hugger' or low profile/flush mount fan.