posted signage

we are building a campus of buildings (non-school) that has a non smoking policy except in one designated outside area. In order to get into the campus you have to pass through security which has a posted no smoking sign at the entrance. The designated smoking area within the campus has a designated smoking area sign. Do the other buildings in the campus need to have posted no smoking signs and if so, do they need to clearly state "no smoking within 25 feet of the building except in designated outdoor smoking areas"? or can they just have 'no smoking' with the symbol?