Can foam insulation be used to fill behind plasterboards or similar?

As our foam insulation system is a spray applied system it reacts very quickly when applied, this prevents the foam from simply falling off a sprayed area. Due to the reaction times, spray foam cannot easily be used to ‘fill’ or ‘inject’ an area behind plasterboards or similar. As a basic rule of thumb, in order to spray an area you need to be able to see it.