This OC describes current good practice in the handling of flat glass and refers inspectors to further sources of information on the subject.
1 The handling of flat glass involves the risk of serious personal injury. HSE experience has shown that although the risk is higher in factories where flat glass is manufactured, serious accidents continue to happen in premises where glass is subsequently handled and processed. This OC details certain key factors to which attention should be paid if the number and severity of accidents are to be minimised.
2 The angle of inclination of sheet glass in racks is critical. Bowing and venting (a term given to the sudden breaking of glass) will occur if the angle of lean is too great from the vertical, but sheets will be unstable and be pulled over by draughts if the angle is too small. An angle of 3o- 5o from the vertical appears to be the optimum, although racks tend to be designed for a lean of 5o so that a loaded mechanical grab can approach at 3o from the vertical. A good standard of racking is illustrated in the documents listed at paras 9(1) and (2).
3 Mesh fencing or other barriers should be provided at the sides of racks to contain any glass that might suddenly vent and fall out sideways during handling. Several serious accidents have occurred through failure to provide such fencing. Where access is foreseeable, persons must be able to gain free egress from any area into which glass might vent. Access into the area between glass and side fencing must be prevented.
4 In modern premises glass is usually handled by lift trucks or overhead travelling cranes. Occasionally, 4-wheeled trolleys (with 2 wheels in the middle and one wheel at each end) are still used and these continue to cause accidents. Because of their design they are less stable than trolleys with wheels (either 4 or 6) at each corner, and topple more easily. Glass sheets must therefore be loaded evenly on each side of the trolley and the operators fully trained to ensure safe movement.
5 A wide range of container frames is available which enable glass to be loaded onto vehicles with relative safety. When glass is carried and secured manually onto vehicles, however, extra care should be taken to ensure that the load does not fall sideways during loading. The same applies to the unloading of glass subsequently.
6 Large sheets of glass are routinely handled using vacuum lifting frames. These can involve the risk of being struck by falling glass and the following precautions are advised:
(1) Guide handles should be as far as possible from the glass or should be provided with protective screens;
(2) A warning device should be provided to indicate loss of vacuum before there is imminent danger of grip being lost; and
(3) The use of a vacuum appropriate to the thickness of the glass. If a full range of glass sheets (for example 2 mm to 12 mm) is to be handled, at least 2 vacuum settings should be employed. This is to avoid unnecessary deflections or possibly breakage of thin glass at the suction pads due to excessive vacuum.
7 A well developed practice is to distribute glass in packs rather than on frames. Packs are usually of smaller sized sheets (typically 1.8-2.5 metres x 3.2 metres), weigh up to 2.5 tonnes, and use wooden gusset cases or end caps to hold the glass in place. Wire straps keep the end caps in place. Both types of pack may be lifted using two-legged wire slings under the wooden lugs at the end of each case. The sling angle is critical, however, with 90oas the optimum. If the angle deviates significantly from 90o, either the lugs are pulled off vertically or the frame is stressed at the upper edge beyond design limits.
8 Packs of glass should be stored on level flooring and with a depth (ie thickness) to height ratio of at least 1:6. When stored singly, packs should be provided with side supports.
9 Further useful reference material is listed below. Copies of these documents are available on loan from the Chemical Manufacturing and Glass NIG, Merseyside Area Office.
(1) Pilkington Glass Warehousing Manual 1976;
(2) Glass Handling, Storage and Transport Code of Practice. The Glass and Glazing Federation, 44-48 Borough High Street, London SE1 1XB; and
(3) "Handling glass in the flat glass industry" - video tape and users' guide. Glass Training Limited, BGIRA Building, Northumberland Road, Sheffield.
10 All equipment included in the activities mentioned in this circular is covered by a European "c" standard currently in the course of preparation. This will not be a harmonised standard under the Machinery Directive which will fill in the details of the relevant essential health and safety requirements.(amended by OM 1993/73)
11 In the manufacture and in the subsequent processing of flat glass, venting and cuts from glass edges are foreseeable. Safe systems of work are essential for all operations including the loading and securing of loads, and these should be clearly laid down. The provision of adequate training, instruction and supervision are also key factors and failure to provide these has led to several serious accidents. Appropriate protective clothing should be worn when glass is handled manually unless it can be shown that the risks are negligible.
8 June 1993
DISC NO; FODA1.EDT/J124/05.93/DH
(NEW DISC REF: J:\EDITORS\CA1\J124MY93.SAM)
Glass: handling: safe systems of work.