I know you asked about speed, but the only standard my local range instructor requires to take advanced classes is 45 shots in 4" at 10 yards with no misses. Accuracy only, take as long as you want between shots. From there he teaches speed. With a little practice that should be easily doable.

I don't know if that is THE standard but it's their standard.

As far as speed goes, I think the only standard is as fast as you can while controlling your shots.

Personally I use a sharpie to draw out a 4x6 box on my silhouette targets, I go with a rectangle because you should have less horizontal movement than vertical. I practice shooting faster and faster with a full magazine while staying within that box, if I go outside the box then I tone it down. Always stay in control. Somedays I'm gelling with the ammo and recoil and getting tremendous split times with good accuracy, other days not so much. But all of it makes me more comfortable with my firearm and more confident.