Facebook friend request limit ban?

[LewbJob]

What triggers the ban on sending friend requests on facebook? Is it # per day, them selecting they don't know you out of facebook or? There are a lot of people I want to add that I know in real life but I don't want to be banned for sending too many. What is the best way to accomplish that?

[Ronnie]

Dont send too many request in a day, make sure that they wont reject your request, if people reject your request also the reason for Friend request block.