Need a mechanical engineer to satisfy current fire safety regulations

We have a 40 unit 5 storey apartment building in Kogarah which is overdue for it's annual fire safety certificate. All requirements have been satisfied as far as our fire safety supplier is concerned, but due to the nature of the new regulations and requirements, we have been told that we need to satisfy "air flow" requirements in stairwells etc Apparently we need a mechanical engineer to inspect and certify this aspect before our fire company can finalise the annual certificate.