TGSI Dimensional Measurement Assessments

Equal Access’s TGSI Dimensional Measurement consulting service provides accurate, independent measurements and assessments of TGSI’s by an ACA-accredited access consultant for dimensional compliance of tactile ground surface indicators as detailed in AS/NZS 1428.4.1.

At the start of the service, Equal Access will work with the client to confirm the scope of work, the appropriate sampling size, and the specific standard clauses to be assessed. Using a range of measurement devices, including a calibrated Tristimulus Colourimeter and industry best practice techniques, repeatable and defensible measurements will be recorded and processed to determine full compliance or otherwise with the requirements of the standard.

High resolution photograph(s) of the TGSI(s) will be provided with scale references, a full list of recorded measurements and a technical report detailing the level of compliance achieved with reference to the specific clauses of the standard. When assessing TGSIs we include a review the top and bottom diameter of the truncated cone, the height of the cone above the bottom surface, the spacing between the cones, the pattern repeat and module size for the tiles, the dimensions and spacing of the longitudinal strips, the height of the bottom abutment and any chamfers, the thickness and material of the substrate.

The critical performance criterion is the luminance contrast between the TGSI and the surrounding surface, measured in accordance with the Standard. To enable specifiers to do this, we can provide Light Reflectance Values (LRVs) as measured to AS 1428.4.1. We also record any deviations from the manufacturer’s data sheet and any design factors that could affect the product’s long-term performance under different environmental conditions.

Our experience to undertake a Standard Verification service is often requested by manufacturers who wish to have verified certain aspects of the technical files associated with their products, by architects/specifiers/design teams who wish to ensure that products supplied will perform to specified requirements once installed, and by assets owners/certifiers who require an independent and evidence based audit of performance against the requirements of a standard for statutory or contractual purposes. We do not endorse products. Our role is to provide measured evidence, interpret this against the relevant Standard and offer practical advice on remediation where required.

The report includes an Executive Summary and presents measured values together with their associated tolerances. The report is illustrated with annotated photographs showing the points at which measurements were taken. Where luminance testing has been undertaken, the results will be included. The report will state whether the product complies with or does not comply with the specified criteria. For non-conformance, statements of likely accessibility implications will be provided, along with practical remediation options. For manufacturers, we can also provide advice on sampling plans for quality control during production and advice on how to present measurement results in their product declarations and asset registers.

Importantly, our consultants are independent and can provide an objective record of a product for tenders, certificate applications, or to assist in negligence disputes. Reducing the risk of non-compliance and clarifying whether your product complies with the relevant requirements at an early stage in its development or upon installation is what TGSI Dimensional Measurement consulting services can offer.

Whether it is a one-off evaluation of a single product, a verification service for a large batch of products in a production environment or an onsite evaluation of installed tactile ground surfaces, we can provide the necessary measurements and a clear, authoritative report to support compliance with relevant regulations and good practice.

Don’t hesitate to get in touch with us to discuss your specific requirements, and we can advise you on sample sizes, whether we need to perform laboratory luminance measurements and how we can deliver the information to suit your asset management or knowledge graph infrastructure.