Machinery safeguards

Booth, R. T., Waring, A. and Raafat, H. M. N., Machinery safeguarding. Safety Technology Unit ST1, Occupational Health and Safety Open Learning, Portsmouth Polytechnic, Portsmouth (1989)... 

This kind of safefy framing is necessary for new operators and maintenance or setup personnel, when any new or altered safeguards are put in service, or when workers are assigned to a new machine or operation. Properly installed machinery safeguards, well-written safe work practices, and a strong training program are all important elements of a company s Machine... 

In the context of this book, the following B standards address the main electrical and control systems issues on, and systems used in, machinery safeguarding (in addition to the previously mentioned BS EN 954-1 and the lEC standard lEC 61508) ... 

The techniques described in these standards are aimed at machinery safeguarding but the principles also apply to control systems, particularly interlocking systems, which are used to safeguard electrical hazards. 

Elecric shock as a result of direct contact, means that a person makes contact with part of the circuit which is intended to be live. The only form of protection against direct contact is to prevent such contact in the first place. This can be achieved by following the same principles of risk assessment and machinery safeguarding discussed earlier, namely to provide fixed guards, enclosures or insulation. However, if access is foreseeable, then permit-to-work systems should be operated. It should be remembered that intrinsic safety is an absolute priority in removing the risk of shock injury. This can be achieved by reducing the system voltage in areas of likely contact to such an extent that it cannot result in an electric shock. 

The requirement for safety precautions when operating or working on all types of machinery cannot be overstressed, in that the likelihood of an accident occurring on moving machinery is invariably high. It is essential that all these who work on such machines are adequately trained as to the operation and the safeguards fitted. Regulations that must be complied with include ... 

Frequent testing of lubricants in service helps to safeguard the machinery. Samples of lubricant submitted for analysis must be representative of the total oil charge and to assist ship s engineers the CEC (Co-ordinating European Council) has drawn up a Code of Practice [26]. The Code of Practice aims to ensure that oil samples are drawn correctly, fully identified, do not become contaminated and are properly packaged for dispatch to the laboratory. 

Both the clearance and the reach criteria are one-tailed constraints, that is, they impose the limits in one direction only (Pheasant 1989). The clearance criterion points out when an object is too small. It does not, however, indicate when an object is too large. In some design problems, such as safeguarding of industrial machinery, the conventional criteria of clearance and reach are often reversed. 

In 1877, the Massachusetts legislature passed a law requiring safeguards for hazardous machinery. In the same year the Employer s Liability Law was passed, establishing the potential for employer liability in workplace accidents. 

During this year clauses relating to the fencing of machinery and the providing of other safeguards were incorporated into the Factory Act of 1802. The reporting of certain accidents was also included in the act. 

The history of safety may be traced back to ancient times, but in the modem context its serious beginnings appear to be in 1868, when a patent was awarded for the first barrier safeguard [1]. In 1877 the Massachusetts legislature passed a law requiring appropriate safeguards on hazardous machinery [1,2]. In 1931 H. W. Heinrich published a book on industrial safety entitled Industrial Accident Prevention [3], and in 1970 the United States Congress passed the Occupational Safety and Health Act (OSHA) [1,2,4]. 

All new machinery purchased since 1 January 1993 must comply with the Supply of Machinery (Safety) Regulations 1992 (SMSR) which incorporate the contents of the EU Directive on the approximation of the laws of the Member States relating to machinery (Machinery Directive, no 89/392/EEC and subsequent amendments). These Directives were aimed at removing barriers to the free movement of machinery between member states and used safeguarding as their criteria. 

PUWER applies to the safeguarding and safe use of all equipment, machinery and plant used in any work place. However, where machinery is concerned, any that was purchased after 31 December 1992 should comply vsnth the Supply of Machinery (Safety) Regulations 1992 (SMSR) (see Section 13.1)... 

Failure to adequately control energy accounts for many serious accidents in construction. Lockout/tagout procedures help safeguard employees from the unexpected start-up of machinery or equipment or release of hazardous energy while performing servicing or maintenance tasks. 

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