As per BS 2790 (Design and manufacture of shell boilers of welded construction),

Design for gusset stays as per clause 3.8.8.3 , the angle V must not less than 60 degrees and shall be arranged radiually along tube sheet within angle 15 to 30 degree b/w stays.

My question is how to calculate the QUANTITY of gusset stays to end plate.

The one thing in my mind is just make tubesheet layout and allow some breathing space, after that place the gusset stays as given/selected angles as per code, and quantity will be as permitted by tubes layout ( tubes bundle not intercepted). It doesn't look strong reason to me, kindly help.

Greetings