halacha - Walking In-front of Someone Davening Shemona Esrei

1. 
   

   I read somewhere that shtenders, chairs, tables and benches aren’t considered an interruption between the one davening and one passing before him unless the shtender is 10 טפחים tall by 4 טפחים wide. Where is the halachic source for this?

   
   


2. 
   

   I also read that even if there is an interposition of 10 טפחים and 4 טפחים wide one should be strict not to pass before someone davening. Where is the halachic source for this?