3D Model — Orbit & Inspect
Anatomy of a Roof Anchor Point
Base Plate
Steel plate bolted or welded to the structural member. Distributes load forces across a wider area to prevent pull-through failure.
Post / Stanchion
Vertical steel post rising from the base plate. Provides the attachment height needed for lanyard connection and fall clearance calculations.
D-Ring / Attachment Eye
The connection point at the top of the post where the lanyard or SRL clips on. Must allow free rotation to prevent lanyard twisting under load.
Fixing Bolts
High-tensile bolts securing the base plate to the structural member. Must be torqued to manufacturer specification. Chemical anchors used in concrete.
Structural Member Connection
The anchor must be fixed to a load-bearing structural element — steel beam, concrete slab, or engineered timber. Never attached to purlins, battens, or sheet metal alone.
Types of Anchor Points
| Type | Description | Use Case |
|---|---|---|
| Permanent (Fixed) | Bolted or welded to structure | Rooftops, plant rooms, facades |
| Temporary (Portable) | Weighted base or clamp-on | Short-term work, no penetration |
| Single-Point | One attachment eye, one worker | Most common roof anchor |
| Horizontal Lifeline | Cable strung between anchors | Long roof runs, multiple workers |
Temporary anchors must still meet the 15 kN rating requirement. They are NOT a lesser standard — they are simply removable.
Rating & Load Requirements
All fall-arrest anchor points must comply with AS/NZS 1891.4:
Minimum Anchor Strength
Equivalent to approximately 1,530 kg of force
| Requirement | Detail |
|---|---|
| Minimum strength | 15 kN (AS/NZS 1891.4) |
| Installation | By competent person per manufacturer specs |
| Load testing | Must be tested before first use |
| Certification | Tag with install date, installer, next inspection |
| Max persons per anchor | 1 (unless rated for more) |
| Re-inspection interval | At least every 12 months by competent person |
Critical Rules
- Only use certified anchor points — never improvise an attachment point
- Check for corrosion and damage before every use — visual and tactile inspection
- Never attach to pipes, handrails, or non-structural elements — they will fail under fall-arrest loads
- Max 1 person per anchor unless the anchor is specifically rated and certified for multiple connections
- Never modify an anchor without engineer approval — drilling, welding, or bending voids certification
- Confirm the anchor type matches your system — fall arrest, restraint, and rope access have different requirements
Common Fatal Mistakes
- Clipping onto a purlin or roof batten instead of a structural member
- Using a restraint-rated anchor for fall arrest
- Attaching two workers to a single-person anchor point
- Using an anchor with no certification tag or expired inspection
Spacing & Pendulum Effect
Anchor placement must prevent workers from reaching an unprotected edge — even at full lanyard length.
Pendulum (Swing Fall) Risk
θ = angle from directly below the anchor point
- Work directly below the anchor wherever possible to minimise swing distance
- If you must work to the side, a fall will create a pendulum swing toward the point directly below the anchor
- Swing falls can slam workers into structures — walls, columns, plant equipment
- Position anchors so the worker cannot reach an unprotected edge at full lanyard extension
- Use a shorter lanyard or SRL when working near edges to limit swing arc
- Multiple anchors may be needed on large roof areas to keep workers within safe zones
Inspection & Rejection Criteria
Inspect anchor points before every use. Remove from service if ANY of the following are found:
Reject Immediately If
- Loose fixings: bolts that can be turned by hand or show movement
- Corrosion: visible rust, pitting, or flaking on post, base plate, or bolts
- Bent post: any deformation of the stanchion indicating previous loading
- Cracked base plate: weld cracks, stress fractures, or plate deformation
- No certification tag: no tag = no proof of installation or testing = no use
- Modified without engineer approval: any drilling, welding, grinding, or alteration voids the certification
- Evidence of previous fall arrest: anchor has absorbed a fall — must be re-certified before reuse
Good Condition Indicators
- All bolts tight and correctly torqued
- No corrosion, cracks, or deformation
- Post straight and plumb
- D-ring rotates freely, no binding
- Certification tag present with current inspection date
- Base plate flush against structural member, no gaps
Applicable Standards
| Standard | Title |
|---|---|
| AS/NZS 1891.4 | Industrial fall-arrest systems and devices — Selection, use and maintenance |
| AS/NZS 1891.1 | Industrial fall-arrest systems and devices — Harnesses and ancillary equipment |
| AS 4488 | Industrial rope access systems |
| WHS Reg 2017 | Part 4.4 — Falls (NSW/harmonised jurisdictions) |
AS/NZS 1891.4 is the primary standard governing anchor devices for industrial fall-arrest systems in Australia and New Zealand. All anchor points must be designed, installed, tested, and maintained in accordance with this standard.