BS 6073 is a British Standard that establishes comprehensive requirements for precast concrete masonry units, including both blocks and bricks. Part 1 of the standard, published in 1981, specifies materials, dimensional tolerances and minimum performance levels, while Part 2 provides methods for specifying these products in construction projects. The standard remains a key reference document in the UK construction sector, particularly for designers and specifiers working with concrete masonry systems.
What Does BS 6073-1 Specify?
BS 6073-1:1981 addresses the fundamental properties of precast concrete masonry units. The specification covers materials selection, dimensional tolerances and minimum performance criteria that manufacturers must meet. Appendices included in Part 1 detail test methods for measuring dimensions, determining compressive strength and assessing drying shrinkage—three critical parameters that influence both structural performance and long-term durability of masonry construction.
The standard applies to both concrete blocks and concrete bricks. These products are manufactured using cement, aggregates and water, often incorporating supplementary cementitious materials or lightweight aggregates to achieve specific performance characteristics. Unlike clay-fired bricks, precast concrete units rely on hydraulic curing and controlled manufacturing processes to develop strength and dimensional stability.
Performance Criteria and Test Methods
One of the defining features of BS 6073-1 is its inclusion of standardised test procedures. Compressive strength testing determines load-bearing capacity, a critical factor for structural applications. Dimensional measurement protocols ensure that units meet specified tolerances, which is essential for efficient laying and consistent joint widths. Drying shrinkage testing evaluates the extent of dimensional change as moisture content stabilises, helping to predict cracking risk in finished masonry.
These test methods provide a basis for quality assurance and enable comparison between products from different manufacturers. By defining minimum performance levels, the standard supports specification confidence and helps prevent substandard materials from entering the supply chain. For further context on concrete formulation and performance, see our article on shrinkage behaviour of concrete and mortar.
BS 6073-2: Specification Methodology
Part 2 of BS 6073, also published in 1981, complements the product specification by outlining how precast concrete masonry units should be specified within project documentation. This method-focused standard was prepared under the direction of the Cement, Gypsum, Aggregates and Quarry Products Standards Committee, which included representatives from a wide range of industry bodies, including the British Precast Concrete Federation, British Concrete Masonry Association, and various professional institutions.
The committee structure reflects the collaborative nature of standards development, bringing together manufacturers, specifiers, researchers and regulatory bodies. This multi-stakeholder approach ensures that the standard balances technical rigour with practical feasibility, addressing the needs of both producers and end users.
Application and Industry Context
BS 6073 is commonly referenced in specifications for residential, commercial and industrial masonry construction. Precast concrete units offer advantages in terms of dimensional consistency, fire resistance and thermal mass. They are widely used in loadbearing and non-loadbearing walls, partition systems and facade construction. The standard's emphasis on drying shrinkage is particularly relevant for preventing movement-related cracking, a common issue in masonry assemblies.
Although BS 6073 was published in the early 1980s, it has been subject to amendments and remains in active use. The standard is cited by other British Standards, including BS 5395-2:1984 on stairs, ladders and walkways, demonstrating its role as a foundational reference within the broader UK standards framework. For those working with mortar systems in conjunction with concrete masonry, related standards such as DIN EN 1015 on mortar testing provide complementary guidance.
Standards Development and Governance
The development of BS 6073 involved extensive input from cooperating organisations representing diverse sectors of the construction industry. These included consulting engineers, local authorities, quarry product associations, the Concrete Society, the Cement and Concrete Association, and research institutions such as the Building Research Establishment. This breadth of expertise ensured that the standard addressed material science, manufacturing practice, design requirements and site application.
The British Standards Institution publishes and maintains the standard, making it available in both PDF and hard copy formats. Although the standard itself is not freely accessible, it is widely used by specification writers, material testing laboratories and manufacturers seeking product certification.
Comparison with Modern Standards
While BS 6073 remains relevant, the European harmonisation process has introduced EN standards that now govern many aspects of concrete masonry product specification and testing. Nevertheless, BS 6073 continues to serve as a benchmark for UK-specific requirements and is often referenced in legacy specifications and building control documents. Understanding the relationship between British and European standards is essential for specifiers working on projects subject to both national and pan-European compliance frameworks.
For those interested in the broader context of standards and norms in the construction materials sector, exploring related topics such as Environmental Product Declarations (EPD) and performance-based specification can provide valuable insights into the evolving landscape of material documentation.
