Plant excavation safety

The hazards associated with operations that involve more than one group can be reduced by the use of a permit system. O Driscoll has described the permit systems used in chemical operations many of these (hot work tank entry line breaking disposal operations excavations operation of material handling equipment and vehicles sprinkler-valve closing permit) are of interest in low-temperature plants. They are designed to permit the safe conduct of maintenance and repair functions. The use of written permits with copies to all groups concerned tends to increase the safety of potentially hazardous operations. Also, with use of written instructions, there is less chance for a misunderstanding. 

Careful planning and selection of plant and equipment to carry out earthworks is essential for both safety and economic reasons. A typical example is whether to use a crawler tracked excavator as opposed to a rubber tyred one. Both can excavate but the crawler can also act as a crane, possibly eliminating the need to bring extra specialised plant on to the site. A certificate of Exemption No. 2 applies and Form 2209 must be completed in detail before the machine is used as a crane. 

Two of the RADWASS principles refer to Protection of Human Health and to Safety of Facilities. Both recognise that management of radioactive waste must have regard to all relevant hazards. As well as those associated with ionising radiation, hazards may arise from the presence of toxic, corrosive, inflammable or biologically active materials. They may also be associated with operation of process plant and the excavation or mining of disposal frcilities. 

The German licensing procedure is usually a step-wise approach as indicated in Table 3.2. It means that the first step generally comprises an overall approval of the safety design concept of the plant, and is required for excavation of the pit, erection of a certain part of the main buildings, essentially the base mat and the walls up to zero level, and a so-called "preliminary positive overall appraisal" of construction, erection, and operation of the whole plant. This appraisal is explicitly required by the Atomic Energy Act. 

Description of hazard. Water plant operators and associated maintenance staff are exposed to possible death or injury when entering what is considered a confined space. Examples of confined spaces in the water industry are storage tanks, tunnels, vaults, meter pits, excavations, and process basins. These spaces are large enough for a worker to enter, have restricted means of enfry or exit, and may present hazards related to atmospheric conditions, engulfment, configuration, or any other recognized serious safety hazard. 

Standard Method of Measurement of Civil Engineering Quantities occurs where there is exceptional uncertainty as to the amount of pumping to be expected in an excavation and items are included in the Bills for the provision of pumps of specified capacity and for a specified time another occurs when there is a possible but not a certain need for compressed air working and special items are included for the provision and operation of specified compressed air plant. Where the cost of such measures is high and safety is affected this is one way of ensuring that a tenderer is not penalized by allowing for proper and adequate precautions in his offer. Perhaps a wider application of this principle would avoid unnecessary hazards on site. 

The majority of the fatal accidents in excavation work occur as a result of men being buried by the collapse of narrow trenches and this aspect of safety is discussed in some detail. However, because of the continuing increase in mechanization of construction work there has been an increase in the number of accidents concerned with transport and mobile plant. Fatalities from these causes increased from 18 in 1968 to 35 in 1969. The accidents included the death or injury of men run down by vehicles, crushed by mobile plant or falling with their vehicles into unguarded excavations. 

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