What are the CHS steel sizes available in New Zealand?

Circular hollow sections (CHS) for New Zealand projects are specified by outside diameter and wall thickness, with the grade and length stated separately. Published local supply tables include diameters from small structural tubes through large sections such as 508 mm OD. Available wall thicknesses and grades depend on the supplier and size. AS/NZS 1163 covers cold-formed structural hollow sections, including grades C250, C350 and C450 and their L0 variants. Confirm the exact size combination and project compliance requirements before ordering.

AS/NZS 1163 Standard for Structural CHS

AS/NZS 1163:2016 specifies production and supply requirements for cold-formed, electric resistance-welded structural steel hollow sections. It covers chemical composition, mechanical properties, manufacturing tolerances, testing and identification. Use the edition and amendments required by the project specification.

The prefix C identifies a cold-formed grade and the number indicates its minimum yield strength in MPa. L0 identifies the specified impact requirements at 0 degrees Celsius. For full-size 10 mm by 10 mm specimens, the minimum average of three results is 27 J and the individual minimum is 20 J. Reduced-size specimens have different limits, and thin sections require the applicable verification provisions. The L0 suffix is therefore not a universal statement that every specimen must absorb at least 27 J.

The minimum strength requirements for the main grades are:

• C250 and C250L0: Minimum yield strength 250 MPa; minimum tensile strength 320 MPa.
• C350 and C350L0: Minimum yield strength 350 MPa; minimum tensile strength 430 MPa.
• C450 and C450L0: Minimum yield strength 450 MPa; minimum tensile strength 500 MPa.

Manufacturing tolerances are addressed in Clause 7, including the applicable shape, mass and length tables. Check outside diameter, wall thickness, ovality, straightness and length against the relevant limits. A general percentage quoted without its dimensional conditions is insufficient for acceptance.

Detailed Breakdown of CHS Steel Sizes Available in New Zealand

New Zealand suppliers offer a range of CHS sizes, but a published section table does not guarantee that every size and grade is currently stocked. Distinguish local stock, indent supply and made-to-order production when comparing quotations.

Outside Diameter and Wall Thickness Reference

The table below gives selected diameter and thickness combinations found in published New Zealand supplier data. It is a reference for preparing enquiries, not a complete stock list or a statement of AS/NZS 1163 size limits. Confirm the grade, manufacturing standard and current availability for each combination.

Order a section as outside diameter by nominal wall thickness, followed by grade and length; for example, 168.3 mm OD by 6.4 mm wall. Stock lengths and cut-to-length options vary by supplier. Confirm nominal and actual dimensions, length tolerances and any coating allowance before fabrication.

Grade Selection and Application Logic

Select the grade using the structural design and project material specification. C350L0 may be specified where the required strength and impact properties suit the design. C450L0 offers higher minimum yield strength, but thinner walls or lower weight are not automatic: buckling, deflection, connections and fabrication requirements may govern. Seismic location alone does not determine a universal grade or impact-test requirement.

How AS/NZS 1163 CHS Compares with Other Structural Hollow Section Standards

As engineers look at global supply choices, they often see ASTM A500, EN 10219, and AS/NZS 1163 on the same project specification sheet. Knowing where these standards differ will help you avoid making mistakes that cost a lot of money.

ASTM A500 and EN 10219 use different grade systems and technical requirements. ASTM A500/A500M-23 Grade C round HSS has a minimum yield strength of 50 ksi in USC units. Similar strength levels do not establish equivalence. Compare chemistry, tensile properties, toughness, tolerances, testing and identification against the project specification before proposing a substitute.

For a New Zealand project, material acceptance must follow the approved design and applicable New Zealand Building Code compliance pathway. AS/NZS 1163 certification can support that assessment, but an EN 10204 Type 3.1 certificate alone does not establish building-code compliance. Alternative materials require the review and approval applicable to the project. Australian building requirements should be assessed separately for projects in Australia.

Sourcing Compliant CHS Steel for New Zealand Projects

It’s both a compliance exercise and a business exercise to find the right circular hollow section. Most of the time, procurement teams evaluate based on three levels: technical conformance, commercial terms, and supply chain reliability.

What to Verify Before Placing an Order

Before deciding to work with a CHS provider, experienced procurement managers go through these main proof steps:

• Product documentation: Request test certificates identifying the specified AS/NZS 1163 edition, grade, product dimensions and traceable material identification. Review the required chemical and mechanical results. Specify EN 10204 Type 3.1 separately where the contract calls for that document type.
• Inspection reports: Confirm the examinations required by the product standard and purchase specification. If additional weld NDT or third-party witnessing is required, define the method, coverage and acceptance criteria. NDT assesses the inspected region against specified limits; it does not prove the absence of every possible defect.
• ISO 9001 certification: Check the certificate’s validity and relevant scope as part of supplier qualification. Quality-system certification does not replace product testing or independently establish the accuracy of every supplied document.
• Dimensional records: Verify outside diameter, wall thickness, ovality, straightness and length against the applicable AS/NZS 1163 manufacturing tolerances and agreed order requirements.
• Galvanizing compatibility: Where hot-dip galvanizing is specified, agree coating requirements under AS/NZS 4680 as applicable. Review steel chemistry, fabrication details, venting and drainage with the galvanizer.

Agree these documentation and inspection requirements before ordering so that material release and site acceptance can be planned.

Lead Times and Logistics Realities

For imported CHS, separate production time, inspection release, ocean transit, customs clearance and delivery to site. Indicative sailing times from China to Auckland or Wellington may be 18 to 25 days, depending on the route and transshipment. Production and coating add to the total schedule. Confirm the actual delivery commitment for the specified dimensions, grade and inspection scope rather than deriving it from ISO 9001 certification.

Conclusion

CHS procurement for New Zealand starts with the required outside diameter, wall thickness, grade and length. Published section tables help identify potential sizes, while the project specification determines the required material and documentation. Confirm exact size availability, manufacturing compliance and traceability before releasing the order. The selected size range is a supply question, not a universal dimensional limit imposed by AS/NZS 1163.

FAQ

What outside diameters are standard for CHS under AS/NZS 1163 in New Zealand

Published local tables include small CHS diameters such as 26.9, 33.7, 48.3 and 60.3 mm, as well as larger diameters such as 168.3, 219.1, 323.9 and 508 mm. These are selected supply examples, not a complete mandatory range under AS/NZS 1163. Confirm the exact outside diameter, wall thickness and grade with the supplier.

Is C350L0 mandatory for seismic applications in New Zealand

There is no universal rule that every seismic application must use C350L0. The designer must select material strength and toughness for the applicable design standard, service temperature, section thickness and structural detailing. Where the approved design specifies an L0 grade, obtain the corresponding compliance documentation.

Can AS/NZS 1163 CHS be substituted with EN 10219 sections on a New Zealand project

Substitution requires the review and approval specified for the project. Compare the exact grade, dimensions, mechanical properties, impact requirements, tolerances and documentation. An EN 10219 certificate does not automatically demonstrate compliance with an order requiring AS/NZS 1163.

What documentation must a compliant CHS supplier provide

Request the product identification and test documentation required by AS/NZS 1163 and the contract, together with traceability to the supplied lengths. Specify dimensional reports, EN 10204 document type, quality-system certificates and additional third-party inspection where required. These are not all universal statutory requirements for every CHS order.

How do I verify that a supplier genuinely manufactures to AS/NZS 1163 rather than merely claiming compliance

Review representative test certificates, verify traceability from the supplied product to the test unit, and confirm the mill’s manufacturing and inspection capabilities. Independent inspection by an agreed organization can be included where required by the project.

Get a Certified AS/NZS 1163 CHS Quote from LONGMA Today

Since 2003, LONGMA has manufactured round steel pipe. Our facility covers 230,000 square metres, annual output exceeds 500,000 tonnes, and our team includes more than 60 senior technical engineers. For AS/NZS 1163 enquiries, we review the required ERW dimensions, grade and inspection scope before confirming supply. EN 10204 Type 3.1 documentation and additional inspection can be included as agreed. Standard and customized orders are typically quoted with 30-day and 45-day schedules respectively, subject to technical and order confirmation. Send your material schedule to info@ilongma.com.