Knob removal force

I didn’t know where to stick this question, so I’ll put it here.

I’m designing a knob for one of our heaters. I found a description about a safe knob size as far as a swallowing hazard for children. Is there a standard for a safe removal force for knobs?

Thanks!

the standards we used at one former employer were:
A. If part is SMALLER than choketube, then
removal force must be GREATER than 30lbs
B. If part is does not fit in choketube, then
I think 10 lbs removal force(may have been
15, sorry it’s been awhile, but sure about A)

Good info, I’m not sure when I’ll need it, but I know someday I will. Thanks!