Choosing hanger rod and studs by material and duty: zinc-plated steel for dry interiors, grooved snap-to-length rod for productivity, acid-resistant A4 for washdown and marine, nylon where isolation or chemistry demands, plus stud lengths, coupling nuts and load sense.
| Material | Stocked | Duty |
|---|---|---|
| Zinc-plated steel | M8 × 1000, M10 × 1000, 2 m lengths (M10 × 2000) | Dry interiors — the default hanger rod |
| Grooved steel (snap-length) | M8 grooved, M10 grooved | Volume installation — snaps clean at the groove, no sawing/dressing |
| Acid-resistant (A4 class) | M6 × 1000, M8 × 1000 | Washdown, coastal/marine, chemical plants |
| Nylon | M8 × 1000, M10 × 1000 | Electrical isolation, aggressive chemistry, zero-rust finishes — light loads only |
Studs (set lengths of rod) cover machine fixing and standoffs without cutting: M8 from 30 to 200 mm (M8 × 30, M8 × 80, M8 × 200), M10 to 150 mm (M10 × 100, M10 × 150); acid-resistant studs for the same duties as A4 rod (cut from A4 rod or stocked lengths like M8 A4).
Hanger-rod capacity in building services is set by the weakest link — usually the anchor or the clamp, rarely the rod: an M8 steel rod's tensile capacity dwarfs what a drop-in anchor in 25 MPa concrete will deliver. Practical rules: services suspension on M8 for single pipe runs, M10 for trapezes and multi-service racks; derate for vibration and for any bending (rod takes tension only — a rod loaded sideways by a pulled pipe is a spring, so brace long drops); and let the project's support schedule, where one exists, override habit. Spacing comes from the supported system — pipe spacing from the clamp guide, tray/ladder spacing from the tray maker.
Cut rod square and dress the end (grooved rod exists to skip this); run a nut over the cut before installing to prove the thread. Double-nut (jam) connections that must not loosen under vibration, or use the flange/serrated hardware. In corrosive areas every component matches the A4 class — one zinc washer in a stainless drop is the corrosion cell that stains the ceiling. And label load-tested drops where the project requires proof-loading; the tag outlives the handover binder.