Hello!
> Is there any difference in the runway length required for safe operation
Philosophically, there is no difference. It is either safe or it isn't.
Legally, there is indeed a big difference. Private flights are allowed to calculate their runway length requirements using the aeroplane operators manual alone. Commercial operators have to "factor" the figures from the manual, i.e. they need to multiply the values supplied by the manufacturer with a safety factor in order to determine wether or not the operation can legally be done. One such factor that often has to be applied is 1,67. But there are others.
Rumour has it however, that once EU OPS are fully established and will replace JAR OPS, factoring will have to be applied to some non-commercial operations as well.
Greetings, Max