Rockwool RB Slab

Rockwool RB slab is a rigid, resin-bonded, high-density rock wool board used to insulate flat and curved hot surfaces up to 650°C. Typical uses are boilers, storage tanks and industrial ducting, where a stiff slab holds its shape under cladding and keeps a uniform thickness across large areas.

Rockwool RB slab is rated for service up to 650°C. The fibers themselves have a melting point above 1000°C, but the resin binder and the need to keep the slab dimensionally stable set the practical service limit. For hotter surfaces, a higher-temperature layer such as Calcium Silicate Block & Pipe Section or Ceramic Fiber Blanket & Board is used next to the hot face.

RB slab is rigid at 96, 128 or 144 kg/m³ and rated up to 650°C; LRB slab is lighter and semi-rigid at 48 or 64 kg/m³ and rated up to 400-450°C; LRB roll is a wired mattress stitched to galvanized hexagonal netting, 64 to 128 kg/m³, up to 650°C depending on density. Choose RB slab for flat hot surfaces, LRB slab for light-duty lagging, and LRB roll for large or irregular equipment.

RB slab comes in 96, 128 and 144 kg/m³ and thicknesses from 25 to 150 mm, all in a 1000 mm x 600 mm size. Higher densities suit hotter surfaces and areas that need more rigidity or foot-traffic resistance, while thickness is set by the surface temperature, allowable heat loss and personnel-protection limit. The heat-loss calculator on this site helps estimate the thickness needed.

Yes, rockwool RB slab has a chloride content below 10 ppm and a pH of 7 to 9, so it is suitable for insulating stainless steel. It is also hydrophobic treated, with water absorption below 1% by volume, which helps keep moisture and leachable salts away from the metal surface, provided the weatherproof cladding is maintained.

Rockwool RB slab has a thermal conductivity of 0.033 to 0.040 W/mK at 50°C mean temperature and is non-combustible, Class A1 to EN 13501-1. It also has a sound absorption coefficient (NRC) of 0.90 to 1.00, so the same slab can reduce noise from ducts and equipment casings.

RB slab is fixed with pins, studs or wire and held with Insulation Band & Buckles, then covered with Aluminum Cladding Sheet & Coil secured by Self-Tapping Screw fixings. Joints should be staggered in multi-layer work. Outdoors, mineral wool always needs sealed weatherproof cladding; joints can be finished with Aluminum Foil Tape and Silicone Sealant.

Rockwool RB slab is supplied to ASTM C612, EN 13162 and IS 8183, and its fire rating is Class A1 non-combustible under EN 13501-1. If your project specification calls for particular test reports against these standards, tell us in your enquiry and we will confirm what is available for your order.

Rockwool RB slab ships under HS code 6806 10 00, which covers slag wool, rock wool and similar mineral wool articles. Slabs are packed in poly-wrapped bundles and palletized for sea freight. When enquiring, state density, thickness and quantity in square meters or slabs per size so the container load can be planned.