BS 8411:2007
$167.15
Code of practice for safety nets on construction sites and other works
| Published By | Publication Date | Number of Pages |
| BSI | 2007 | 36 |
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 3 | Contents Introduction 1 1 Scope 1 2 Normative references 1 3 Terms and definitions 2 4 Layout and applications 4 5 Planning of net installations 11 6 Erection, use and dismantling 14 7 Care and maintenance of safety nets 20 Annexes Annex A (informative) Legal considerations 25 Annex B (informative) Assessing the reliability of safety nets 26 Annex C (informative) Competence, supervision and training 29 Bibliography 31 List of figures Figure 1 – Eaves bagging to avoid waisting 8 Figure 2 – Typical attachment device 10 Figure 3 – Maximum deflection for nets greater than 35 m2 in area 18 Figure 4 – Typical UV test tag 21 Figure 5 – Typical repair tag 21 List of tables Table 1 – Classification of nets according to mesh size and energy absorption 5 |
| 4 | Foreword |
| 5 | Introduction 1 Scope 2 Normative references |
| 6 | 3 Terms and definitions 3.1 anchorage device 3.2 anchor point 3.3 bagging 3.4 border rope NOTE See also BS EN 1263-1. 3.5 catching width 3.6 class 3.7 competent person |
| 7 | 3.8 containment net containment sheet NOTE Containment nets and sheets are also known as debris nets. 3.9 coupling rope NOTE This is sometimes referred to as a lacing rope. 3.10 eaves bagging 3.11 initial sag 3.12 karabiner 3.13 laced joint 3.14 mesh cord NOTE This is often referred to as mesh rope. 3.15 mesh size 3.16 net system 3.17 safety net 3.18 safety zone 3.19 supporting framework 3.20 test cord NOTE Test cords are only present in knotted nets. 3.21 test mesh NOTE Test meshes are present in knotless nets and occasionally in knotted nets. |
| 8 | 3.22 tie rope 3.23 under-rolling 3.24 waisting 4 Layout and applications 4.1 Layout 4.1.1 General |
| 9 | 4.1.2 Classification of safety nets Table 1 Classification of nets according to mesh size and energy absorption |
| 10 | 4.1.3 Positioning parameters and net selection a) Safety nets are manufactured to absorb safely falls of up to 6 m; however, they should always be rigged as close as possible … b) Where safety nets are used as the primary form of protection, i.e. where falls would not be prevented by other means, they should preferably be not more than 2 m below the working level. c) Where used in system “T”, safety nets should normally only be used as a secondary form of protection to supplement the use of… d) Where safety nets conforming to class A and in system “S” are subject to falls greater than 2 m, their individual area should… e) Where nets are to protect persons falling from an edge of an area, they should extend for a suitable catching width appropriate to the likely horizontal trajectory of anyone falling from that edge (typically 3 m). f) The desired working life of a net in any particular location should be taken into account when selecting the appropriate net … 4.2 Applications 4.2.1 New roof construction |
| 11 | NOTE Guidance on this is given in Advisory Committee for Roofwork publication ACR[CP]001 [1]. |
| 12 | Figure 1 Eaves bagging to avoid waisting |
| 13 | 4.2.2 Refurbishment NOTE 3 Guidance on working on fragile roofs is given in Advisory Committee for Roofwork publications ACR[CP]001 [1] and ACR[CP]002 [2]. 4.2.3 Formwork and pre-cast concrete works |
| 14 | Figure 2 Typical attachment device 4.2.4 Metal decking 4.2.5 Bridgework |
| 15 | 5 Planning of net installations 5.1 General NOTE Attention is drawn to the Construction (Design and Management) Regulations 2007 [3] (see A.5). 5.2 The role of the designer of the permanent works a) avoid design details that can make nets difficult or dangerous to erect, e.g. poor access, structures that are unable to support sufficient temporary loads, lack of positions for tying off; b) design suitable fixing points on the drawings to facilitate rapid erection and removal of safety nets and ensure that these will carry the characteristic loadings; c) calculate the likely forces on the structure due to the self-weight of the net assembly and the impact of a falling person, and assess the effect, if any, on the structure (see BS EN 1263-2:2002, Figure 3); d) specify additional bracing or other support if appropriate; e) take into consideration the need for access during rigging and striking when determining sequence of erection, and inspection when nets are to be used for long periods (i.e. greater than 12 months). |
| 16 | 5.3 The role of the supplier and erector 5.3.1 Suppliers 5.3.2 Erectors a) their training and competence (see Annex C for information on supervision, training and competence); b) the plant they intend to use, e.g. mobile elevating work platforms (MEWPs); c) the access facilities they will require, e.g. surface preparation; d) the requirements for anchorage of the nets and any actions needed to ensure that these are suitable and sufficient; e) the requirements for the maintenance of clearance distance below the safety net at all times (even after the erector has left site); f) the methods of rescue; g) the means of protecting anyone below; h) confirmation that the safety nets and other equipment have undergone a suitable maintenance regime (including having been subject to periodic testing) and will have a sufficient energy absorption capacity for the period while they are in use. 1) check that the anchorages provided are adequate; 2) ensure that the nets, when erected, are fit for purpose; 3) ensure there is adequate clearance under the net. |
| 17 | 5.4 The role of the principal contractor a) ensure that the following issues are covered in the construction phase health and safety plan, and that they are taken into account in determining the sequencing of work: b) ensure that the erectors are competent to erect the nets. If there is no proof of competence, they should not be allowed to start work (see Annex C for information on supervision, training and competence); c) advise what the net will be used for; d) indicate what provision has been made for anchorages and explain what tests, if any, have been carried out to verify that the anchorages are adequate. 1) ensure that the nets supplied for a project will perform as required for the duration of the project by checking that the most recent test certificate for the net predicts an acceptable working life; 2) check that the supporting certification that should accompany the nets is current and appropriate for the net application. |
| 18 | 5.5 CDM co-ordinators a) where safety nets are identified as a specific precaution to protect against a significant risk (i.e. the risk of falls from … b) systems are in place to facilitate cooperation between the various relevant designers associated with the work. 6 Erection, use and dismantling 6.1 General 6.2 Wind load |
| 19 | 6.3 Erection 6.3.1 General |
| 20 | 6.3.2 Provision of access to the net 6.3.3 Net area 6.3.4 Coupling ropes 6.3.5 Border ropes 6.3.6 Net cord tension and corner stress |
| 21 | 6.3.7 Supporting frameworks 6.3.8 Deflection of the net |
| 22 | Figure 3 Maximum deflection for nets greater than 35 m2 in area 6.3.9 Fixing and anchor points NOTE 1 Guidance on the strength of fixings is given in BS EN 795. |
| 23 | NOTE 2 The positioning requirements of BS EN 1263-2 are the “maximum permissible” but it is always good practice to minimize any… 6.3.10 Ties and karabiners 6.4 Dismantling |
| 24 | 7 Care and maintenance of safety nets 7.1 Examination 7.1.1 Prior to rigging 7.1.2 Periodic testing NOTE 1 Users of this British Standard are advised to consider the desirability of testing by an appropriately qualified third-party organization. |
| 25 | Figure 4 Typical UV test tag 7.2 Repair Figure 5 Typical repair tag |
| 26 | 7.3 Inspection 7.3.1 Site inspection a) All maintenance and repair work on safety nets and their anchorages shown to be required by the site inspection should be carried out by a suitably competent person. (See 6.3.9 and 7.2.) b) The nets and the net assembly should have appropriate certification as described in this British Standard. Checks should be made to ensure that such certification has been carried out and that it is current. c) Checks should be made to see if there are any distortions in the line or appearance of the net and any supporting frameworks. d) Checks should be made of whether the net has been used to arrest a fall or loaded in any way (usually this will show as a local deformation in the net). e) Checks should be made on whether all the anchorages remain intact and in good order. f) Checks should be made on whether the net is clear of debris or, if it contains debris, whether this has damaged the net. (Immediate action should then be taken to remove the debris and carry out any necessary repairs.) g) Checks should be made on whether any meshes or mesh cords have been cut. Where this is the case, the net should be immediatel… |
| 27 | NOTE Discoloration, or lack of coloration, can be a misleading indication of the safety net’s condition. 7.3.2 Mechanical damage a) dragging over rough surfaces; b) contact with sharp edges; c) stacking material on the net; d) accumulation of debris in the net; e) persons jumping or throwing objects into the net; f) supporting framework being struck by a moving load; g) unauthorized interference with any part of the net assembly. 7.4 Storage |
| 28 | a) be stored in dry conditions; b) be protected against UV or other radiation sources; c) not be stored close to sources of heat; d) not be stored in places where they could come into contact with aggressive materials/substances (acids, dyes, solvents and oil, etc.). 7.5 Identification and recording |
| 29 | Annex A (informative) Legal considerations A.1 General A.2 The Work at Height Regulations 2005 a) to prevent a fall from occurring, where this is practicable; or b) if the possibility of a fall cannot be completely eliminated, to minimize the height and the consequences of any fall that might occur. A.3 Health and Safety at Work etc. Act 1974 A.4 Management of Health and Safety at Work Regulations 1999 A.5 Construction (Design and Management) Regulations 2007 |
| 30 | a) Clients are required to ensure that those they appoint to carry out work on their project are competent, are adequately resou… NOTE These duties apply to both the initial construction and future maintenance of a building. b) Taking account of all other design considerations, designers are required to avoid foreseeable risks and, in doing so, elimin… c) The CDM coordinator is required to identify and collect the pre-construction information and advise the client if surveys nee… d) Principal contractors are required to prepare a construction phase health and safety plan. They are required to ensure that a… Annex B (informative) Assessing the reliability of safety nets B.1 Background information |
| 32 | B.2 Calculations NOTE 1 In order for the net assembly to be subject to forces no greater than those investigated in the German research it is ess… NOTE 2 For normal forms of construction, Cn and Dn are taken as zero. |
| 33 | Annex C (informative) Competence, supervision and training C.1 General C.2 Competence C.3 Supervision C.4 Training NOTE Training in the design, erection, maintenance and use of safety net assemblies is available within the industry. Informatio… a) For simple, repetitive applications of a straightforward nature (such as securing safety nets across a house void), a basic knowledge or understanding is appropriate, such as to know and understand the recommendations in this British Standard. |
| 34 | b) For more general and varied rigging applications, using specific access equipment, a greater understanding of the mechanics o… c) Finally, those involved in the inspection of a rigged safety net systems should be able to confirm whether the net and the su… |
| 35 | Bibliography [1] ADVISORY COMMITTEE FOR ROOFWORK. Recommended practice for work on profiled sheeted roofs. ACR[CP]001. Manchester: Advisory Committee for Roofwork, 2003. [2] ADVISORY COMMITTEE FOR ROOFWORK. Guidance note for safe working on fragile roofs. ACR[CP]002. Manchester: Advisory Committee for Roofwork, 2005.1) [3] GREAT BRITAIN. Construction (Design and Management) Regulations 2007. London: The Stationery Office. [4] GREAT BRITAIN. Work at Height Regulations 2005. London: The Stationery Office. 2) [5] GREAT BRITAIN. Health and Safety at Work etc. Act 1974. London: The Stationery Office. 2) [6] GREAT BRITAIN. Management of Health and Safety at Work Regulations 1999. London: The Stationery Office. 2) [7] BECKER, K., LOBERT, H. et al. Optimisation of intercepting devices – Biomechanical stress limits of humans. Bochum, Germany: Deutsche Montan Technologie (DMT), 1991. |
