Departure
Certain speed limits other than 250 below 10000 are build into the SID design under Pans OPS. 250 is related to airspace class (read ATC and / or birdstrike)
It depends if it is a turning or straight departure and they are based on factoring the speeds of the PANS OPS Go-Around table for the category you are flying.
You can find them in JEPPESEN.