The new National Children's Hospital has been told it must install a more extensive sprinkler system. It had asked for permission not to, claiming it had already exceeded safety requirements.
The hospital had appealed against the condition imposed by the Fire Brigade but An Bord Pleanala ruled that sprinklers must be fitted throughout the building.
It said that, given the design, it would limit the size of any fire and provide extra time to escape.
An Bord Pleanala also imposed a new condition that if Christmas trees are to be installed in the atrium they must be artificial, fire retardant and a maximum height of 2.5 metres.
It removed two other conditions that the hospital had appealed against but said if there were any design changes to the atrium a new fire safety certificate would be required.