1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 7885 : 1997 Incorporat
2、ing Amendment No. 1 ICS 65.040.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Code of practice for Safe entry into silosBS 7885 : 1997 This British Standard, having been prepared under the direction of the Engineering Sector Board, was published under the authority of the
3、Standards Board and comes into effect on 15 May 1997 BSI 08-1999 The following BSI references relate to the work on this standard: Committee reference MHE/9 Draft for comment 90/75973 DC ISBN 0 580 26896 9 Amendments issued since publication Amd. No. Date Comments 10521 August 1999 Indicated by a si
4、deline Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee MHE/9, Continuous Mechanical Handling Equipment, upon which the following bodies were represented: Agricultural Engineers Association Association of Consulting Engine
5、ers Automated Material Handling Systems Association British Aggregate Construction Materials Industries British Coal Corporation British Rubber Manufacturers Association Ltd. Coke Oven Managers Association Cranfield University Electrical, Electronic, Telecommunications and Plumbing Union Electricity
6、 Association Mechanical Handling Engineers Association Solids Handling and Processing Association Ltd.BS 7885 : 1997 BSI 08-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 References 1 3 Safety and access equipment 1 4 Operations prior to entry into silos 3 5 M
7、eans of access into a silo 4 6 Safety precautions when working in silos 5 7 Rescue 7 Table 1 Types of defect in harness sets 3 List of references 8ii BSI 08-1999 BS 7885 : 1997 Foreword This British Standard has been prepared by Technical Committee MHE/9. It is intended to give guidance on the prepa
8、ration of individual codes of practice relating to particular silos. This British Standard provides guidance on preparation for entry into and the safety precautions necessary when working in a silo whether for maintenance or because of operational problems. Some of the detailed recommendations cont
9、ained in this British Standard may not be necessary for the safe operation of certain open silos (hoppers) of stout design (ratio of height to width less than 1.5). The decision not to follow details of the code of practice should only be made after a risk assessment has been carried out and appropr
10、iate procedures adopted. As a code of practice, this British Standard takes the form of guidance and recommendations. It should not be quoted as if it were a specification and particular care should be taken to ensure that claims of compliance are not misleading. Compliance with a British Standard d
11、oes not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 8, an inside back cover and a back cover. The BSI copyright notice displayed throughout this document indicates when the document was la
12、st issued. Sidelining in this document indicates the most recent changes by amendment. BSI 08-1999 1 BS 7885 : 1997 1 Scope This British Standard gives recommendations on operations prior to entry into a silo, bunker, bin or hopper; safety and access equipment for use therein; means of access; and s
13、afety precautions when working in, and affecting rescue from, a silo, bunker, bin or hopper. NOTE 1. Statutory provisions covering safe means of access to elevated and confined working spaces are contained in the Mines and Quarries Act 1954 1, the Factories Act 1961 2 and regulations made under thes
14、e. The Health and Safety at Work etc. Act 1974 3 and regulations made under this have general requirements for safe systems of work including means of access and egress. 2 References 2.1 Normative references This British Standard incorporates, by dated or undated reference, provisions from other pub
15、lications. These normative references are made at the appropriate places in the text and the cited publications are listed on page 8. For dated references, only the edition cited applies: any subsequent amendments to or revisions of the cited publication apply to this British Standard only when inco
16、rporated in the reference by amendment or revision. For undated references, the latest edition of the cited publication applies, together with any amendments. 2.2 Informative references This British Standard refers to other publications that provide information or guidance. Editions of these publica
17、tions current at the time of issue of this standard are listed on the inside back cover, but reference should be made to the latest editions. 3 Safety and access equipment 3.1 Fall arrest and work positioning systems, lanyards and full body harnesses Work positioning systems should conform to BS EN
18、358, full body harnesses should conform to BS EN 361 and lanyards should conform to BS EN 354. They can be used in conjunction with fall-arrest devices to form a fall arrest system which should conform to BS EN 363. The use of other means of providing safe access is not precluded. NOTE. General requ
19、irements for instructions for use and for markings are given in BS EN 365. 3.2 Anchorage lines An anchorage line is used to provide attachment to the structure of the silo and a lanyard is then used between the anchorage line and the safety harness worn by the operator. For anchorage lines, anti-sta
20、tic nylon rope, 16 mm in diameter, should be used as a prepared length. One end should be finished off with an eye splice formed around a nylon thimble, and the other end whipped and oversheathed with a ferrule. The line should be long enough to allow the whole working area to be covered. In the eve
21、nt of a fall, to reduce the possibility of the operator swinging sideways into contact with the surrounding surfaces, the line should be fixed to an anchorage point as near as possible vertically above the working area. The anchorage point should also be high enough above the working area to allow c
22、ompletely unobstructed movement at all times to any safety device attached to the line. The line should be fixed to the anchorage point using a terminal fitting through the eye splice. WARNING. There is evidence that the failure of nylon ropes in fall-arrest situations relates directly to the tying-
23、off of the rope to structural steel members. Therefore, no line should be looped around structural steel members as the sharp edges could damage the line. A shackle, karabiner chain sling, wire rope or girder clamp should be used. In use, surplus line should not be allowed to rest on the material as
24、 this could cause damage to the line in the event of material fall. 3.3 Lanyards A lanyard is used to connect the safety harness to the anchorage line. It provides an effective and authorized means of restricting the depth of a fall. CAUTION. It is important to recognize that the length of the stand
25、ard lanyards which connect the safety harness to safety lines is critical and should not be exceeded. The following practices have the effect of increasing the potential fall distance to an unacceptable level and should be avoided: a) extending the length of lanyards to give increased mobility in th
26、e silo; b) using lanyards designed for other harnesses; c) failing to weight the free end of a static safety line which would allow it to be picked up by the personal mobile arrester when ascending, so leaving a loop of free line above the climber; d) withdrawing lengths of safety line to the top of
27、 the silo prior to descending. Wherever possible lanyards should not be attached to points on the waist belt of safety harnesses for the following reasons: 1) these attachment points are not certified to withstand arresting forces in a fall; and 2) in a fall situation the arresting forces could caus
28、e serious injury.2 BSI 08-1999 BS 7885 : 1997 | 3.4 Safety anchors Before any safety belts, harnesses and safety lanyards are adopted, limitations on the use of safety or security anchors in conjunction with these should be recognized and understood. All anchors should conform to BS EN 795. Connecto
29、rs should conform to BS EN 362. Guided type fall arresters should conform to BS EN 353-1 or BS EN 353-2. Retractable type fall arresters should conform to BS EN 360 and energy absorbers should conform to BS EN 355. WARNING. The speed responsive mechanism of some devices may mean that an operator wou
30、ld not be supported by such a device in the event of a slow collapse of loose granular material and could thus become buried. 3.5 Rope ladders Rope ladders can form a very effective means of providing temporary access into silos provided the operator is attached to a line. However, the difficulty of
31、 climbing freely suspended rope ladders makes it unrealistic to use them for great depths. 3.6 Boatswains chair The Boatswains chair or similar sitting harness provides a means of allowing an operator to enter a silo to carry out inspection and minor maintenance without the need for sophisticated ha
32、ndling equipment. However, the long lengths of rope involved and the physical effort necessary for an operator to hoist out of the silo creates a limitation on its use to about 30 m. A safety line with a safety anchor should always be used in conjunction with a Boatswains chair to protect the operat
33、or in the event of losing control of the rate of descent. Even when the Boatswains chair incorporates fall-arrest capability, tasks in the silo may require an operator to leave a chair, in which case a separate safety harness and the appropriate lines should be provided. Boatswains chairs should con
34、form to BS 2830. 3.7 Rescue line A rescue line is a fibre rope which is attached to the safety harness worn by the operator in the silo with the other end controlled by the person at the top of the silo. 3.8 Safety belts Safety belts should not be used where a free fall could occur as major injuries
35、 are likely to result. 3.9 Safety harness 3.9.1 General Safety harnesses should be worn by any person when at work where there is a danger of falling from a height; in particular, they should be worn unless the person is otherwise adequately protected against falling during any work in a silo. 3.9.2
36、 Issue and storage Sufficient safety harnesses should be available for use by persons who may need them. A person should be appointed to look after harnesses which should be properly stored in a ventilated place away from steam pipes or other direct sources of heat. During storage, no part of the eq
37、uipment should be subjected to unnecessary strain or pressure, and the equipment should be kept free from contact with sharp objects, corrosive substances and other possible causes of damage. Immediately after use, a harness should be returned to its place of storage; but if it is wet it should be d
38、ried out without means of direct heat, at or near normal room temperature, and where necessary cleaned ready for further use. Any person required to wear a safety harness in the course of regular duties should be provided with a personal issue which fits properly and which should not have unauthoriz
39、ed modifications. 3.9.3 Use The wearer should be satisfied that the safety harness is in a satisfactory condition before use, and should be trained in its proper fitting and use. The wearer should ensure that the harness is properly anchored and that all snap hooks or similar fastenings are locked.
40、The anchorage should be at least as strong as the harness itself taking into account the least favourable direction of pull which can be applied by the harness. Anchorage points should be carefully selected: for example, they should not be on conveyance suspension gear above a detaching hook or such
41、 that there may be relative movement between the place on which the person is standing and the anchorage point. NOTE. General requirements for use and marking are given in BS EN 365. 3.9.4 Examination Each time before wearing the safety harness, the user should make a visual examination to ensure th
42、at it is serviceable. Every harness set issued for use, whether or not it has been used previously, should be thoroughly examined at regular intervals, by a suitably trained and authorized person who is not the normal user. NOTE. It is recommended that inspections of harness sets are carried out on
43、a monthly basis. BSI 08-1999 3 BS 7885 : 1997 During the examination, particular attention should be paid to detection of the types of defect given in table 1. Table 1. Types of defect in harness sets Area of harness set Defect Webbing Cuts, tears, or abrasions; undue stretching; deterioration; dama
44、ge due to heat, acids or other corrosive substances Sewing Broken, cut or worn threads Hooks Damage, wear, corrosion, distortion or faulty springs Chains Damage, wear or corrosion When any defect is found during examination, the harness should be immediately withdrawn from service and the matter rep
45、orted to a competent nominated person. A withdrawn harness should not be put back into service until the necessary repairs have been effected and the harness has been cleared by a competent nominated person. When a harness is discarded because of irreparable damage or other cause, it should be destr
46、oyed. 3.9.5 Maintenance Safety harnesses should be maintained according to the manufacturers instructions. In general, harnesses should be stored dry and clean in a suitable place away from sunlight and contaminations from oil, acids and other corrosive substances. 3.9.6 Reports and records A test c
47、ertificate should be issued by the manufacturer for each harness, both when new and after the manufacturer or a nominated examining agency carries out any examination, service or repair. These certificates should be retained. Each harness should be marked with a serial number for identification; and
48、 a history card or sheet, bearing the serial number and containing the following information, should be kept for each harness: a) a summary of the examination and reports; b) details of manufacturers certificates issued when new and subsequent certificates issued after each examination and service;
49、and c) records of withdrawal or repair with details of the reason and repairs. 4 Operations prior to entry into silos 4.1 General Each installation or silo should have its own individual system of work, and these should be prepared in advance of each occasion when it is necessary to enter into a silo so that the planned detail of entry can be agreed by all concerned. The system of work should be appropriate to the tasks which can be foreseen as necessary in the silo. The system of work should be approved by the appropriate safety officer and circulated to all the per
