Design you can feel.
Access you deserve.
Most export enquiries MetalX receives reference one of three documents: the US ADA Standards for Accessible Design, the Australian and New Zealand standard AS/NZS 1428.4.1, or the international standard ISO 23599. They describe the same idea, a field of truncated domes to warn and a line of bars to guide, but the dimensions differ enough that a stud made for one can be rejected under another. This guide puts the three side by side.
| ADA 2010 §705 (USA) | AS/NZS 1428.4.1:2009 | ISO 23599:2019 | |
|---|---|---|---|
| Shape | Truncated dome | Truncated cone | Truncated dome or cone |
| Base diameter | 23–36 mm | 35 ± 1 mm | Not fixed; derived from top and slope |
| Top diameter | 50–65% of base | 25 ± 1 mm | 12–25 mm |
| Height | 5.1 mm (0.2 in) | 4–5 mm | 4–5 mm |
| Centre spacing | 41–61 mm; base-to-base gap at least 17 mm | 50 mm square grid | 42–61 mm |
| Field depth at hazard | 610 mm, full width | 600–800 mm, full width, 300 mm setback | Typically 600 mm minimum |
| Contrast | Visual contrast, light-on-dark or dark-on-light | 30% / 45% / 60% luminance contrast | Luminance contrast required |
| Directional bars | Not mandated (agency drawings) | 35 mm base, 25 mm top, 4–5 mm, 75 mm centres | 17–30 mm top, 4–5 mm, 57–78 mm spacing |
Our standard stainless steel stud (Ø35 mm, 4.5 mm high, 50 mm centres) and standard bar (35 mm wide, 4.5 mm high, 75 mm centres) match AS/NZS 1428.4.1 and sit within ISO 23599. For ADA projects we machine a separate truncated-dome profile with a smaller flat top and 5.1 mm height, available loose or on tiles, in stainless steel, aluminium and PU. Tell us the standard on the enquiry and we quote the right tooling.
It is not unusual for a Gulf tender to quote ADA dimensions in one clause and AS/NZS contrast percentages in another. When that happens, ask the engineer which profile governs and get the answer in writing before ordering. A sample of each profile costs little and settles the question quickly.
Usually not without confirmation. The AS/NZS 25 mm flat top is larger than 65% of a 35 mm base, and the 4.5 mm height is below the ADA 5.1 mm. MetalX makes a separate ADA profile for US projects.
Generally yes, because the ADA dimensions fall within the ISO ranges for top diameter, height and spacing. Confirm the contrast requirement separately.
It varies by consultant: ISO 23599 and AS/NZS 1428.4.1 are common, and ADA appears on US-designed projects. Check the specification and ask which governs if it mixes them.
Yes. The standard stud matches AS/NZS and ISO; a dedicated ADA truncated-dome profile is made to order in stainless steel, aluminium and PU, loose or on tiles.
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