FIRE PLASTERBOARD

Fire-rated plasterboard goes by many names such as fire-resistant plasterboard, fireproof plasterboard, fire board or pink plasterboard and consists of an aerated gypsum core with glass fibre reinforcement and other additives encased in and firmly bonded to strong paper liners. In fact, the fire board is stronger, harder and heavier than standard plasterboard weighs 28.80kg (12.5mm) and 34.50kg (15mm). When exposed to fire, the chemically combined water absorbs the heat and is gradually released in the form of moisture vapour. One square meter of a 12.5mm gypsum board contains approximately two liters of water of crystallisation in the gypsum core. Its high water content provides up to 90% of the fire resistance protection of gypsum boards. Fire panel is coloured pink on the front and grey on the back and has tapers down the long edges. It is suitable for drylining internal surfaces which can be skim plaster finished or directly decorated. Boards come in standard lengths: 1800, 2400, 2700 and 3000mm. Only 2 thicknesses are available - 12.5mm and 15mm. Boards can be plastered with either Gyproc skimcoat, Skimcoat Short Set, Carlite Finish or Carlite Ultra. Tapered edge finish only occurs in two dimensions 12.5 x 1200 x 2400mm and 12.5 x 900 x 1800mm. All the boards may be cut using the ‘score and snap’ method. When choosing a fire resistant plasterboard, you should definitely not be guided by the price. Cheap fire plasterboard may not meet certain requirements, which at the end of the day can lead to a tragedy. The best solution seems to be buying fire plasterboards from famous, well known building merchants such as Selco, Wickes or B&Q, the more so because they sell boards from well known brands such as British Gypsum, Knauf, Siniat and Fermacell. Its price often depends on the supplier location near your project. The average cost of fire plasterboard is £16.44 per 8x4 size board which results in £5.71 per m2. 

FIRE PLASTERBOARD CALCINATION PROCESS

The process of dehydrating gypsum by heat is known as ‘calcination’. This commences at the surface exposed to the fire and proceeds gradually through the gypsum layer. Calcined gypsum formed on the exposed faces serves to retard the calcination process. Calcination becomes progressively slower as the thickness of the calcined material increases.

PLASTERBOARD FIRE RATING CHART

The effectiveness of fire-rated plasterboard is measured by the amount of time it resists fire before burning. Depending on the size, height, location and type of property, walls and ceilings need to provide 30, 60, 90 or 120 minute fire protection. When used in a partition or ceiling, two layers of 12.5mm fire plasterboard should provide up to 1 hour fire protection. In a partition where there are two layers of fire-rated plasterboard on either side, they will provide up to 120 minutes of fire resistance. The 15mm fire plasterboard as a single layer plasterboard will provide 60mins fire resistance. Generally speaking other products – such as insulation A1 or non-combustible classes, should be used in conjunction with fire-resistant plasterboard to add additional fire protection. For the purposes of the national Building Regulations, plasterboard is designated a ‘material of limited combustibility’ and is classified as a EuroClass A2 material. The surfaces of fire rated plasterboard are designated Class 0. That is why the board's excellent fire resistance rating makes it ideal for lining walls and ceilings in commercial spaces like offices and shopping centres. Fire-rated does not mean that this is completely fireproof plasterboard, merely that it has fire resistance. Fire resistance performance is based on complete systems such as a partition, wall or ceiling. Good quality fire board should comply with BS EN 520:2004+A1:2009 Type D & F standard and be Euroclass A2-s1, d0 classified. 

FIRE RESISTANT PLASTERBOARD BUILDING REGULATIONS

According to current Building Regulations all structural elements, such as walls, floors and beams should provide fire resistance of at least 30 minutes. This is usually achieved by using fire-rated plasterboard and plaster finishes at least 12.5mm thick or two layers of standard plasterboard at least 9.5mm thick and a plaster set finish. For the internal ceiling finishes, materials need to be Class 1-rated to prevent fire spread. Small rooms of up to 4m2 floor area and domestic garages up to 40m2 can be lined with Class 3 (D-s3 d2) materials. Fire rated ceilings should have double plasterboards with staggered joints. Garage ceilings with a room above should have 2 layers of fire plasterboard to be ‘fire ceiling’. Perhaps it is because a garage can be used to store fuel. In fact, 30mins separation is the minimum fire resistance that the building regulations require in 2 storey houses with integral garages , however 2 layers are normally needed to satisfy the fire insulation, integrity and load bearing resistance standards.

60 MINUTE FIRE RATED PLASTERBOARD

Fire resistant boards are commonly made up of gypsum, which contains small amounts of water (known as water of crystallisation). In a fire, this water is driven-off, helping to keep the temperature of the fire down, and preventing rapid fire spread. If the ceiling is plaster boarded, then 2x12.5mm thick boards are required to give 60 minutes fire resistance.

30 MINUTE FIRE RATED PLASTERBOARD

The guidance indicates that if installed correctly, 1x12.5mm fire plasterboard with a plaster skim will achieve 30 minutes fire protection. You may have to provide an additional skim coat or additional plasterboard to the ceiling. If you need 30 minutes from the plasterboard alone, you'll need at least plasterboard with enhanced fire resistance, with appropriate insulation above. You'd also need to put noggins between the joists to support the board edges. For instance one layer of 12.5mm Gyproc with appropriately sized joists and min 21mm tongue & groove softwood floorboards will give you 30 minutes FR. Sum it all up-two layers of fireline plasterboard with staggered joints will give an 1 hour protection and one layer half an hour.

FIRE BOARDS INSTALLATION

Fix boards with decorative side out to receive joint treatment and finishing treatment. Lightly butt boards together. Never force boards into position. Install fixings not closer than 13mm from cut edges and 10mm from bound edges. Position cut edges to internal angles whenever possible, removing paper burrs with fine sandpaper. Stagger horizontal and vertical board joints between layers by a recommended minimum of 600mm. Locate board edges to the centre line of intermediate framing where they are required for support or to maintain fixings.

FIRE PLASTERBOARD APPLICATIONS

These boards are intended to use for walls, ceilings on metal structures, steel posts and columns, shaft walls and other building elements in places where fire resistance is required. Boards are best used in places such as a fireplace casing. These typically includes domestic separating walls, rooms above garages and stairwells in multi-storey properties. In commercial buildings, it is typically used to protect shafts and voids.

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