Does an A2-s1, d0 board give a wall 60 minutes’ fire resistance?

No. A2-s1, d0 is the board’s reaction to fire. The minutes come from a tested wall system — the studs, layers, insulation and fixings together — not from the board alone.

Can I swap a fire board for another with the same classification in a rated wall?

Not automatically. The rated minutes were tested with specific boards. A like-for-like reaction-to-fire class and EN 520 type is necessary but not sufficient; you need the system manufacturer’s confirmation for the substitution.

What do s1 and d0 mean?

They are sub-classes of the EN 13501-1 reaction-to-fire rating: s1 is the lowest smoke-production band and d0 means no flaming droplets or particles.

Where is fire resistance specified in UK building work?

It is a system requirement addressed through Approved Document B (in England) and the relevant fire-test standards, met by a tested build-up — which is why board-for-board changes need the system evidence to follow them.

Reaction to fire vs fire resistance

Are 'A2-s1, d0' and '60 minutes' the same kind of fire rating?

No — and conflating them is the most common specification error in drywall. They describe different things, tested in different ways, and only one of them belongs to the board.

Reaction to fire (EN 13501-1) describes how the board material itself behaves in a fire — A2-s1,d0 means limited combustibility, little smoke, no flaming droplets. It is a board property, not the fire resistance (in minutes) of a finished wall.

Fire resistance is how long a complete tested wall build-up — studs, layers and boards together — holds back fire, in minutes. It belongs to the whole system, not to any single board: swapping boards inside a rated build-up needs manufacturer confirmation.

Reaction to fire: a board property (EN 13501-1)

Reaction to fire measures how a material itself behaves when exposed to fire — how readily it ignites and contributes fuel, how much smoke it gives off, and whether it sheds flaming droplets. It is expressed as a Euroclass under EN 13501-1.

The main class (A1, A2, B, C, D, E or F) ranks combustibility, from A1 non-combustible down to F.
The “s” suffix (s1, s2, s3) grades smoke production, s1 being the least.
The “d” suffix (d0, d1, d2) grades flaming droplets, d0 being none.

Most gypsum plasterboard is A2-s1, d0: of limited combustibility, very little smoke, no flaming droplets. That is a genuinely useful property — but it is a property of the sheet, and it does not, by itself, tell you how long a wall built from it will hold back a fire.

Fire resistance: a system property (minutes)

Fire resistance is how long a complete, tested build-up — studs or framing, insulation, the number and thickness of board layers, the fixings and joints — resists fire, measured in minutes to EN 13501-2. For a non-loadbearing partition it is quoted against integrity and insulation criteria, for example EI 30, EI 60, EI 90 or EI 120.

The number is earned in a furnace test of one specific assembly. Change the studs, the layer count, the board or even the fixing pattern and you are, strictly, outside the tested system unless the manufacturer’s test evidence or an assessment covers the change.

The practical consequence for substitution

This is where the two ideas must not blur. Swapping one board for another inside a fire-rated partition is not automatically valid, even when both boards carry the same reaction-to-fire class and the same EN 520 type. The rated minutes were established with particular boards; a substitution needs the system manufacturer’s confirmation to inherit them.

drywallDB reflects this directly: it compares boards on their declared properties, but it shows a fire-systems caveat on any comparison involving a fire board, and the substitution document it generates states plainly what is and is not being claimed. In UK practice the system’s fire resistance is what Approved Document B and the relevant test standards are concerned with — the board’s reaction to fire is one input to that, not a substitute for it.

Frequently asked questions

Does an A2-s1, d0 board give a wall 60 minutes’ fire resistance?: No. A2-s1, d0 is the board’s reaction to fire. The minutes come from a tested wall system — the studs, layers, insulation and fixings together — not from the board alone.
Can I swap a fire board for another with the same classification in a rated wall?: Not automatically. The rated minutes were tested with specific boards. A like-for-like reaction-to-fire class and EN 520 type is necessary but not sufficient; you need the system manufacturer’s confirmation for the substitution.
What do s1 and d0 mean?: They are sub-classes of the EN 13501-1 reaction-to-fire rating: s1 is the lowest smoke-production band and d0 means no flaming droplets or particles.
Where is fire resistance specified in UK building work?: It is a system requirement addressed through Approved Document B (in England) and the relevant fire-test standards, met by a tested build-up — which is why board-for-board changes need the system evidence to follow them.

Related guides

EN 520 board types explained — What do EN 520 Type A, D, E, F, H, I, P and R mean?
Rw — airborne sound insulation — What does the Rw number on a partition system mean?
Plasterboard weight: kg/m² and per board — How heavy is a plasterboard, and why do brands declare it differently?

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