EN 772-3:1998

Overview

EN 772-3:1998 - Methods of test for masonry units, Part 3 - defines a European Standard test method for determining the net volume and percentage of voids in clay masonry units (including frogs and cells) by hydrostatic (underwater) weighing. Published by CEN, this standard is used to quantify internal voids in clay bricks and blocks as part of product characterization and quality control.

Key topics and requirements

• Scope: Applies to clay masonry units and explicitly includes features such as frogs and internal cells.
• Test principle: Uses hydrostatic weighing (underwater weighing) to determine net volume of the unit by comparing weights in air and when submerged - enabling calculation of displaced water volume.
• Calculation: From measured volume, the standard specifies how to derive the percentage of voids relative to the gross or apparent unit volume.
• Measurement focus: Targets accurate assessment of internal void space, not exterior dimensions or surface defects.
• Intended use: Provides a reproducible laboratory method suitable for routine testing and product specification.

(Note: EN 772-3:1998 sets the procedural and measurement principles. For full implementation details - apparatus, sample preparation and exact calculation formulas - consult the official standard text.)

Applications

• Quality control for manufacturers: Monitor consistency of clay bricks and blocks during production; verify that void content meets product specifications.
• Product classification and certification: Used by testing laboratories and certification bodies to support compliance with European product standards.
• Material performance assessment: Void volume is a key parameter affecting thermal insulation, mechanical strength, mortar bonding and water absorption characteristics; test data support design and specification decisions.
• Research and development: Useful in R&D when optimizing block geometry (frogs/cells) for structural or thermal performance.
• Regulatory compliance and procurement: Architects, civil engineers and procurement specialists reference void content data when selecting masonry units for buildings.

Who uses this standard

• Clay masonry manufacturers and process engineers
• Independent construction materials testing laboratories
• Product certification and conformity assessment bodies
• Architects, structural and building services engineers involved in material selection
• R&D teams developing masonry products

Related standards

• Other parts of the EN 772 series (methods of test for masonry units) and harmonized product standards for clay masonry provide complementary test methods and specification criteria.
• Refer to the official CEN documents for cross-references and implementation details.

Keywords: EN 772-3:1998, hydrostatic weighing, underwater weighing, net volume, percentage of voids, clay masonry units, masonry test method, CEN, brick testing, masonry quality control.