FD30 vs FD60 Fire Doors: Which Rating Does Your Building Need?

FD30 or FD60 is one of the first questions in any fire door project, and one of the most misunderstood. The number is simple; knowing which one a given opening needs is where buildings go wrong.

What the ratings mean

FD30 means the doorset resisted fire for 30 minutes in a standard test; FD60 means 60 minutes. Testing is done against BS 476 Part 22 or the European standard EN 1634-1, on the complete assembly: leaf, frame, seals, hardware and glazing together. That is why a fire door is really a doorset, and why swapping a rated leaf into an unknown frame does not produce a rated door.

Where FD30 is typically right

• Flat entrance doors in most residential blocks
• Corridor and stairwell doors subdividing escape routes
• Internal doors onto protected hallways in HMOs
• Most office, retail and classroom doors within a protected route

Where FD60 usually appears

• Riser cupboards and service shafts, where fire can travel between floors
• Plant rooms, bin stores and other high fire-load rooms
• Doors protecting single stairways in taller buildings, where the strategy demands it
• Commercial settings where insurers or the fire strategy specify 60 minutes of compartmentation

Who decides?

Not the door supplier. The building’s fire strategy and fire risk assessment set the required compartmentation, and the door inherits its rating from the wall it sits in: a 60-minute wall needs a 60-minute doorset. If the strategy is silent, Approved Document B and the risk assessor’s judgement fill the gap. When we quote an installation, we confirm the rating opening by opening rather than assuming one rating for the whole building.

Smoke control: the S suffix

You will also see FD30S and FD60S. The S means the doorset also restricts cold smoke, via combined seals and tighter threshold gaps. Escape-route doors are commonly specified with the S variant, because smoke, not flame, is what makes stairs unusable in the first minutes of a fire.

The cost logic

FD60 doorsets cost more, so over-specifying wastes budget, and under-specifying fails compliance. The clean sequence is: confirm the requirement per opening from the strategy, then buy exactly that. A survey across the building first means you order once, correctly.