Equipment strengths
Breaking strengths may vary depending on particular product specifications from different manufacturers. The following items show the Minimum Breaking Loads (MBL) allowable for each Equipment Standard.
Standard MBLs
| Equipment | MBL |
|---|---|
| EN 1891 A Low-stretch kernmantel rope, 10.5 mm Ø | 22 kN (2200 kg) |
| EN 362 Steel screwgate carabiner, 10 mm | 15 kN (1500 kg) |
| EN 12275 Q / EN 362 Maillon Rapide, 10 mm | 25 kN (2500 kg) |
| EN 566 Round webbing sling, 18 mm | 22 kN (2200 kg) |
| BS EN 1492-2 Choked webbing roundsling (WLL 1000 kg) | 56 kN (5600 kg) |
| EN 12278 Swing-side pulley | 15 kN (1500 kg) |
Devices in conjunction with rope (10.5 mm Ø Low Stretch, new)
| Device | Behaviour |
|---|---|
| Descender (e.g. PETZL ID) | Begins to slip at loads circa 6 kN (450 kg). WLL = 150 kg. |
| Ascender | Generally begins to damage the rope at loads circa 6 kN (600 kg). This figure can reduce to as little as 4.5 kN (450 kg) due to age and wear. During EN 567 testing, an ascender should hold a 400 kg load for 3 minutes. |
Working Load Limit (WLL)
The maximum load (as determined by the manufacturer) that an item of lifting equipment is designed to raise, lower or suspend.
Safe Working Load (SWL)
The maximum load (as determined by a competent person) which an item of lifting equipment may raise, lower or suspend under particular service conditions. The SWL can be lower than the WLL.
Factors of Safety in rope access
As a general rule:
- Wire slings, carabiners and Maillon Rapide connectors: SWL = 1/5 of MBL → FoS 5:1.
- Textile items (EN 566 / EN 795 B webbing slings, lanyards, ropes): WLL = 1/10 of MBL → FoS 10:1.
- Lifting slings (BS EN 1492-2): quoted WLL has FoS 7:1 (WLL 1000 kg = MBL 7000 kg).
- Items without a clear BL (ascenders, descenders): SWL = 1 person in normal use; 2 persons in a rescue.