What is S.R. 16? Guidance on aggregates for concrete
S.R. 16 is a Standard Recommendation from the National Standards Authority of Ireland (NSAI). It gives guidance on the aggregates (the crushed rock, sand and gravel) used to make concrete in Ireland. It matters to homeowners because the minerals in the aggregate, such as pyrrhotite, are at the root of the damage to defective block homes.
What was published?
On 12 March 2026, NSAI announced the publication of:
- S.R. 16:2016+A1:2026 — Guidance on the use of I.S. EN 12620:2002+A1:2008 — Aggregates for concrete — Amendment 1
What is I.S. EN 12620?
I.S. EN 12620:2002+A1:2008 is the framework standard used when specifying or declaring requirements for aggregates used to make concrete.
It sets out the properties of aggregates from natural, manufactured or recycled materials, and mixtures of these. It applies to concrete for buildings, roads and civil engineering works. You can read about its limits on sulphur in where the mica narrative came from.
What does S.R. 16 add?
S.R. 16:2016 gives advice on using I.S. EN 12620 in Ireland. It recommends values or categories for aggregate properties, within the ranges that I.S. EN 12620 allows, for different end uses.
It is written for:
- aggregate manufacturers
- professional geologists
- specifiers and consultants
- engineers and architects
- providers of testing services for aggregates
What changed in the 2026 amendment?
Amendment 1 made these changes to S.R. 16:2016:
- It recommends a new test method for measuring the total sulphur in aggregates.
- It adds guidance on alkali-silica reactivity (ASR).
- It adds guidance for geologists on knowledge of the raw material.
- It adds guidance for geologists on dealing with deleterious materials.
NSAI thanked the NSAI/TC 153 Aggregates Panel for its work developing the amendment.
Does this change my assessment?
S.R. 16 is guidance for the people who produce, specify and test aggregates for new concrete. Homes already built with defective blocks are assessed under a separate standard, I.S. 465. If you are unsure whether either standard affects your application, ask your engineer.
Related articles
- UnderstandCheckThe science: what defective concrete isWhat defective concrete blocks are: how reactive minerals such as pyrrhotite make blocks expand, crack and crumble, and how I.S. 465 assesses homes.
- SchemeUnderstandLegalThe Enhanced Grant Scheme and its five remediation optionsWhat the Enhanced Defective Concrete Blocks Grant Scheme is, who runs it, the five remediation options, and the official documents to read.
- UnderstandCheckLegalWhat is I.S. 465, and how is it being reviewed?I.S. 465 is the Irish Standard for assessing, testing and categorising homes with defective blocks. What it says, and where its review stands.