The new National Children’s Hospital has lost its appeal against a requirement to install a sprinkler system throughout the €1 billion development.

The National Paediatric Hospital Development Board (NPHDB) had argued that the existing fire safety design already exceeded current standards.

The board argued that extending the sprinkler system to all areas of the hospital would add up to €2 million in extra costs.

It was already going to cover children’s' accommodation, canteens and the basement.

However An Bord Pleanála rejected the appeal against a decision by Dublin City Council and ruled that the sprinkler system should be installed throughout.

Members of the planning board voted four to three to reject the appeal, saying the sprinklers would limit the size of the fire, control its spread, provide additional time to escape, limit damage and be beneficial in terms of "operational continuity" in having it throughout the building.

It also ruled that a new fire certificate would be required if the atrium's design is changed and that Christmas trees are artificial, fire retardant and under 2.5 metres high.

Construction of the new hospital is due for completion in 2022.

The new hospital will be seven-storeys high with 470 beds and 2,000 staff.

The new facility is being built on the St James's Hospital campus, and is due to open around 2021.

It will take over the services of the existing three Dublin children's hospitals: Our Lady's Children's Hospital in Crumlin; Temple Street Children's University Hospital in the city centre; and the National Children's Hospital at Tallaght.

In a statement, the NPHDB said that it will comply with the ruling.

It said the planning board had overruled its own inspector by requiring the additional measures and said their existing fire safety measures already exceeded regulations.