Hi,

I was wandering if there is any regulations for the type sizes for indoor Dry riser and Sprinkler stop valve signs. I am trying to purchase a sign but heard they should be at least 50mm but this seemed to big from the signs I have seen. Thank you for your time.

It's usually based on the distance the sign needs to be viewed from, 50mm letter height can give you around 10m viewing distance, smaller letters lesser distances.