Overview
ISO 7900:2006 specifies requirements for zinc- and zinc-alloy-coated steel barbed wire used in fencing, including conventional and reverse-twist barbed wire (two stranded line wires with tightly wound barbs) and barbed‑wire entanglement (BWE) (single line wire with barbs). The standard defines dimensional, mechanical and coating characteristics, sampling and test methods, packaging and purchaser information for consistent quality and performance of barbed fence wire.
Key Topics
- Wire types and geometry
- Conventional twist: two stranded line wires (typical lay ≈ 50 mm).
- Reverse twist (RT): two stranded line wires (typical lay ≈ 25 mm) with a required unwind resistance (no unwinding until 75% of nominal breaking load).
- Barbed-wire entanglement (BWE): single crimped line wire with four‑point barbs and specified coil forms.
- Dimensional and mechanical requirements
- Nominal diameters and tolerances defined (examples: conventional line wire 2.50 ±0.060 mm; RT line wire 1.70 ±0.050 mm; BWE line wire 3.00 ±0.070 mm).
- Minimum tensile strengths given in N/mm2 (MPa) and minimum strand breaking loads - these are mandatory acceptance criteria.
- Barb details
- Typical barb spacing: 75 mm ±10 mm or 100 mm ±10 mm (or by agreement); measured over at least 10 m.
- Barb projection: ~12.5 mm ±3.5 mm (conventional/RT); 15–20 mm (BWE).
- Barb ends cut at an angle not greater than 35° to the barb axis.
- Coating and corrosion resistance
- Zinc or zinc‑alloy coatings to be applied before fabrication per ISO 7989‑2, Class A for coating mass and adherence. If samples are taken from fabricated wire, specified coating mass may be reduced by 5%.
- Testing, inspection and sampling
- Tensile tests per ISO 6892; dimensional checks per ISO 8458‑1; coating assessment per ISO 7989‑1/‑2.
- Manufacturer quality control by statistical sampling or one reel in fifty.
- Packaging
- Reels: typical lengths 100 m, 200 m, 250 m or 500 m; BWE supplied in coils/bundles (specifications included).
Applications and Users
ISO 7900:2006 is used by:
- Fence manufacturers and wire-rod processors specifying product dimensions, coatings and mechanical properties.
- Procurement and specification engineers for agricultural, perimeter security, correctional and military barrier projects.
- Installers and contractors ensuring correct wire type (conventional, reverse-twist, BWE) and packaging for site use.
- Inspection bodies and QA teams conducting tests and verifying compliance.
Keywords: ISO 7900:2006, zinc‑coated barbed wire, zinc‑alloy‑coated, barbed-wire specifications, barbed‑wire entanglement, conventional twist, reverse twist, fence wire testing.
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