With the industrial galvanized steel hand rail on the mezzanine floor we chose to use the side mounted system fixing it directly onto the lip channel joists instead of the top mounted type which would need much longer bolts to go through the 50mm thick decking making it less stable. Our standard 40 degree staircase rail is always top mounted directly onto the lip channel stringer with stiffener plates welded in place to strengthen the stringer/rail at that point. The staircase rail as well as the top rail ends on a wall where we could bolt it directly to the wall using wall brackets thereby also making the rail more rigid.
If racking were to be used on an open grid steel deck such as this we would suggest that steel base plates be put under the 'feet' of the frames in order to spread the load. With shelving units it is possible to put the bottom shelf directly on the bottom thereby using the shelf itself to spread the load. A heavy point load on the steel deck would cause it to possibly dent. The joist centres on an open grid steel deck of this type is further apart than with a timber deck thereby reducing the amount of steel beams but at the same time necessitating the use of foot plates under point loads in order to spread the load.