BS EN 12620 — Aggregates for Concrete (Sharp Sand)

What BS EN 12620 covers

It is an engineering framework, not just a label: BS EN 12620 governs the particle shape, size grading and structural purity of both fine and coarse aggregates used in concrete and groundworks. It replaced the older British aggregate standard BS 882.

Grain shape is the key practical difference. BS EN 12620 sharp sand has angular grains that mechanically interlock when compacted, resisting lateral movement under load — which is why it is specified for paving beds and concrete. Soft building sand (covered by BS EN 13139) has rounded grains and is for mortar; using it under paving or in concrete is the wrong material.

Grain sizing — under the standard, aggregates are designated by a lower and upper sieve size (written d/D), so a fine aggregate is described by the mesh sizes that bracket the bulk of its grains rather than a single number.

Fines content — the proportion of ultra-fine silt and clay (the smallest particles) is limited, because excess fines trap moisture and weaken the cement binding, causing dusting, shifting and premature cracking. The standard uses defined category limits for this.

Weathering and frost resistance — the standard sets soundness requirements (such as the magnesium sulfate soundness test) so that aggregate grains resist the freeze–thaw expansion of UK winters and don't fracture inside a finished slab.

The standards page gives the testing and selection criteria; the volumetric maths stays on the tools — use the relevant calculator to work out weights and quantities for your job.