HSE: Industrial rope access - investigation into items of personal ...

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The ropes are all fundamentally of the same construction. Parameters that vary slightly between manufacturers include sheath thickness (expressed as a percentage of the total rope mass), the tightness of the sheath, the tightness of the sheath on to the core, and core construction. These combine to give the rope its feel and character. To create dynamic rope similar original fibres are used, but they are heat-treated before construction of the rope. This makes them retract (shrink) and become more elastic, giving them better ability to absorb dynamic shock loads. Different uses require ropes of different constructions: for heavy-duty use, e.g. in arboriculture, a thicker sheath may be required to counter the high levels of abrasion. All the tests (except on prusik knots) were carried out with new, unused ropes, which were conditioned before testing. The behaviour of ropes may be expected to change during their lifetime. Investigation of the performance of used ropes will require further research. During the test programme attempts were made to investigate the effect that various environmental factors have on rope strength. One sample of ropes was subjected to weathering, one to rust, and one to both weathering and bird droppings. Ideally, these ropes should then have had the worst sections subjected to an ultimate static strength test. However, due to the difficulty of achieving this (see section 2.3) the ropes were tested as short lanyards consisting of two overhand knots. A full description of the method is included under the heading of Knots (see Chapter 3). As the method was then identical for the termination knots, the results could be directly compared. 2.3 ULTIMATE STATIC STRENGTH By using Beal's static test rig in Vienne, France, it was possible to test ropes to their ultimate static breaking strength. Obtaining the ultimate static strength of a low stretch rope requires a special arrangement for gripping the ends of the rope. Each end of the rope is wrapped around a capstan before being fixed in a clamp. In this way the load in the rope at the clamp is reduced and slippage at the clamps is avoided. Due to time restraints only a small number of samples were tested, however these were sufficient to gain a representative result. The aim was to test both new samples of rope and some that had been damaged during the dynamic tests. The ropes that had been used in the dynamic tests on the Petzl Microcender rope adjustment device were chosen, as they showed localised damage to the sheath, which appeared to be severe. By placing the damaged section between the test capstans, it was possible to ascertain whether the damage affected the ultimate strength of the rope. Two initial tests carried out on new Edelrid 10.5 mm rope gave peak forces of 28.4 kN and 28.9 kN. A sample that had suffered light glazing showed no decrease in strength, while the sample that had been damaged in the Microcender tests showed a very slight strength decrease, breaking at 27 kN. Tests on a Microcender-damaged section of Beal 10.5 mm showed a lower strength of 24.5 kN. In the final test a piece of lightly glazed Marlow 10.5 mm rope was tested, which gave a high peak force of 31 kN. As all these figures are higher than even the strongest knot, it is reasonable to assume that even heavy glazing will not cause weakening of the rope to a point where it becomes dangerous. 9
These figures may be compared to the manufacturers’ stated breaking strengths given in Table 1. Manufacturer Diameter (mm) Table 3 Ultimate strength of low stretch ropes Force (kN) 10 Condition of rope (all low stretch) Edelrid 10.5 28.4 – 28.9 New, unused Edelrid 10.5 28.0 – 30.0 Light glazing Edelrid 10.5 27.0 Beal 10.5 24.5 Nominal damage (Microcender dynamic test) Nominal damage (Microcender dynamic test) Marlow 10.5 31.0 Light glazing 2.4 ROPES: SUMMARY Throughout the device testing programme clear differences were observed between the low stretch ropes. The Edelrid rope was the supplest and the most slick, while the Marlow rope was much stiffer. Devices on the latter tended to slip less. In dynamic tests on Type A and Type C rope adjustment devices, the greatest slippage was seen on Edelrid, the least on Marlow and with intermediate slippage on Beal. These differences can be explained by differences in manufacture. The main difference is that Edelrid ropes are, in effect, dry treated during their manufacture, although they are not marketed as such. This treatment reduces the effect of the conditioning that was given to all the ropes before testing. This is reflected in the manufacturers’ figures for shrinkage in water: Edelrid 2.3%, Beal 4%, Marlow 3.2%. When the ropes are soaked, the sheath shrinks and tightens around the core resulting in a stiffer rope. In the case of the Edelrid rope, this does not occur to the same extent and the rope remains supple, allowing easier slippage of devices. It can be surmised that slippage is likely to decrease with use, although this remains to be tested. As only one dynamic rope was used in the test programme, comparative testing was not possible. The main use was to test the strength and energy-absorbing abilities of knots. The other use was to test the performance of back-up devices if used on such a rope.
Page 1 and 2: HSE Health & Safety Executive Indus
Page 3 and 4: © Crown copyright 2001 Application
Page 5 and 6: 8.6 PETZL “ABSORBICA”..........
Page 7 and 8: 1.2 AIMS, OBJECTIVES AND SCOPE 1.2.
Page 9 and 10: 1.4.3 Verification For the tests to
Page 12 and 13: 2.1 INTRODUCTION 2 ROPES Ropes are
Page 16 and 17: 3.1 INTRODUCTION 3 KNOTS Terminatio
Page 18 and 19: Unlike the double overhand and doub
Page 20 and 21: It is unique in that it can be easi
Page 22 and 23: On most of the tests with low-stret
Page 24 and 25: Strength kN 26 24 22 20 18 16 14 12
Page 26 and 27: 3.4.2 Bird droppings Sections of ro
Page 28 and 29: 4.1 INTRODUCTION 4 ANCHOR FORCES Th
Page 30 and 31: 4.4 WORK POSITIONING A combination
Page 32 and 33: 4.6 RIGGING The technician remained
Page 34 and 35: 5.1 INTRODUCTION 5 ROPE PROTECTORS
Page 36 and 37: 5.7 COMPRESSED AIR FLEXIBLE HOSE PI
Page 38: Another point to recognise is that
Page 41 and 42: The IRATA Guidelines state that the
Page 43 and 44: Devices certified to BS EN 567 10 (
Page 45 and 46: In practice this type of test is us
Page 47 and 48: • Minimum static strength (sectio
Page 49 and 50: 6.2.5 Komet Stick Run Material: Ste
Page 51 and 52: 6.2.7 Petzl Rescucender Material: A
Page 53 and 54: 6.2.9 SSE Stop & Go Material: Alumi
Page 55 and 56: In the dynamic tests it did not per
Page 57 and 58: 6.2.13 Summary of test performances
Page 59 and 60: 6.3 TYPE B - ASCENDER DEVICES Figur
Page 61 and 62: 6.3.1 Camp Pilot Material: Aluminiu
Page 63 and 64: 6.3.3 Petzl Ascension Material: Alu
Page 65 and 66:
6.3.5 Kong Cam Clean Material: Alum
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6.3.7 Summary At present, most of t
Page 69 and 70:
6.4.2 Tests All devices underwent f
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The following table summarises the
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6.4.3 AML Material: Aluminium Weigh
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Performance in use: In use the devi
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Clockwise rotation of the handle tu
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Test performance: The static tests
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6.4.8 Troll Allp Material: Aluminiu
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Secondly, the bolt can first be adj
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Material Dynamic rope Low stretch r
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8.1 INTRODUCTION 8 LANYARDS (FALL A
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8.3 BH SALA Length 2 m Principle Te
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8.6 PETZL “ABSORBICA” Length 0.
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Description: The Spanset lanyard co
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9.3 BACHMANN KNOT Figure 55 Bachman
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9.5 FRENCH PRUSIK Figure 57 French
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9.7 PRUSIK KNOT Figure 59 Prusik kn
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11 FUTURE WORK This study has highl
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12 APPENDICES 101
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12.1 APPENDIX 1 PERSONNEL INVOLVED
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12.2 APPENDIX 2 QUESTIONNAIRE - SUM
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12.2.3 Hardware ratings Respondents
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12.2.5 Rope Protectors Table 14 Que
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12.3 APPENDIX 3 ROPE ABRASION Table
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12.4 APPENDIX 4 TEST MACHINES, LOCA
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12.4.4 Rope protectors cycling a lo
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Method for minimum static strength
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12.4.7 Lanyards • Static tests Te
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12.5 APPENDIX 5 ABRASION TESTS: REC
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I. Concrete edge, Lyon canvas prote
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N. Steel edge, PVC “rope bag” (
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T. Paving slab, roll module Start 1
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12.6 APPENDIX 6 KNOTS - STRENGTH TE
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Knot Table 21 Marlow 10.5mm rope (l
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12.7 APPENDIX 7 LANYARDS - STATIC T
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12.8 APPENDIX 8 TYPE A BACK-UP DEVI
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12.9 APPENDIX 9 TYPE A BACK-UP DEVI
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Device & rope type Rope brand SSE S
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12.10 APPENDIX 10 TYPE A BACK-UP DE
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12.11 APPENDIX 11 TYPE B DEVICES -
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Page 152 and 153:
Page 154 and 155:
12.14 APPENDIX 14 TYPE C DEVICES- D
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12.15 APPENDIX 15 TYPE C DEVICES -
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12.16 APPENDIX 16 TYPE C DEVICES -
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12.17 APPENDIX 17 LANYARD - DYNAMIC
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12.18 APPENDIX 18 PRUSIK KNOTS Bach
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French prusik Main rope Brand type
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CRR 364 ISBN 0-7176-2091-3 £20.00
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