Refractory Castable Yield: Calculate Bags from Lining Volume
A practical way to estimate castable quantity using net lining volume, dry density, and a separate allowance for site losses.
Ordering castable by floor area alone misses the lining thickness and the volume occupied by anchors or openings. Start from the approved drawing and calculate the net volume of each lining zone. Keep dense and insulating layers separate because they have different dry densities.
Convert volume to a planning mass
For a simple wall, multiply length, height, and lining thickness in metres to obtain cubic metres. Multiply that volume by the relevant product density in kg/m³. For example, 1 m³ at 1,000 kg/m³ gives a planning mass of 1,000 kg before any site allowance. Confirm that the density on the datasheet applies to the intended casting or gunning method.
Add losses transparently
Rebound, formwork leakage, trimming, sample panels, and damaged bags are different causes of loss. Record the allowance used for each zone rather than applying one unexplained percentage to the whole purchase. Divide the final mass by the pack weight, round up to whole bags, and reconcile the order against the installation sequence.
If the geometry is irregular, take quantities from a drawing or measured takeoff and have the installer check them. Browse Royal's castables before fixing the grade and bag count.