Emergency Turns are so called because that's what you are going to do in event of an engine failure (which I would call an emergency!) in order to ensure compliance with performance requirements.
They are usually promulgated by the company when the straight climb out would make the RTOW too limiting.
In all the companies (UK) that I have flown for all our emergency turn procedures at specific airports were pre notified to ATC by the Nav Dept. Whether a specific controller on the day is aware of the company emergency turn is another matter!