I know that pickets have to be spaced so that 4 inch sphere will not pass between them except that the triangle of the stair case and have to withstand a direct 200 lb force. But what is the code for the fastening method. Local building standard is two ring shank nails at top and bottom of picket and the fasteners should not line up. However, that appears to be the building standard but what is required?? I have a client whose deck is 18 feet in the air with only two nails total per picket.