Masonry units, segmental pavers and flags-Methods of test-Method 19: Determination of bow

AS/NZS 4456.19:2003: Masonry units, segmental pavers and flags-Methods of test-Method 19: Determination of bow

Ensuring the dimensional integrity and consistent quality of masonry units, segmental pavers, and flags is paramount for the durability and aesthetic appeal of constructed surfaces. AS/NZS 4456.19:2003 provides an essential, authoritative method to quantify a critical geometric characteristic: bow. Understanding and applying this standard is vital for professionals involved in the specification, manufacturing, and quality assurance of these building materials.

What is AS/NZS 4456.19:2003?

AS/NZS 4456.19:2003 is an Australian/New Zealand Standard that specifies a definitive test method for determining the degree of bow in precast concrete flags. Developed by Joint Technical Committee BD-026, this standard provides a repeatable and reliable procedure to assess the flatness of paving units, ensuring they meet required dimensional tolerances for successful installation.

Scope & Purpose

This comprehensive standard governs the testing of precast concrete flags to ascertain their deviation from a flat plane, commonly referred to as bow. It outlines the precise apparatus, preparation, procedure, and calculation methods required for this assessment. The standard's primary purpose is to provide manufacturers and specifiers with a clear benchmark for product quality, ensuring that flags will lay true and avoid issues such as uneven surfaces or lipping once installed. It does not cover flags with textured faces or other masonry units beyond precast concrete flags.

Who Must Comply?

• • Primary audience: Quality Control Inspectors, Materials Engineers, Civil Engineers, Product Developers, and Laboratory Technicians involved with paving products.
• • Industries affected: Construction, Building Materials Manufacturing, and Paving and Landscaping sectors.
• • Compliance nature: While not always legally mandatory, compliance is highly recommended for product certification, quality assurance programs, and contractual specifications.
• • Enforcement: Compliance is typically checked by manufacturers' internal quality control departments, independent testing laboratories, and project certifiers or engineers during site verification.

Key Requirements Overview

• • The standard requires the use of a specifically designed notched steel straightedge, calibrated to suit the dimensions of the flag being tested.
• • Professionals must ensure measurements are taken along both diagonals of the flag, assessing both the wearing face and the rear face.
• • Key provisions include precise measurement of deviations from the straightedge at defined intervals, including ends and midpoint.
• • The bow is calculated as the difference between the maximum and minimum readings taken along each diagonal.
• • The standard mandates the recording of detailed test results, including individual measurements, calculated bow values for each diagonal, and the mean and standard deviation, aligning with broader testing procedures in AS/NZS 4456.0.

Related Standards & References

This standard is part of a broader series of AS/NZS 4456 methods for testing masonry units. It is complemented by:

• • AS/NZS 4456.0: Provides the general introduction and a list of all testing methods within the series, offering context for AS/NZS 4456.19.
• • **AS/NZS