Lighting construction sites

Temporary electrical supplies provided on construction sites can save many man hours of labour by providing the energy required for fixed and portable tools and lighting which speeds up the completion of a project. However, construction sites are dangerous places and the temporary electrical supply which is installed... 

The health and safety regulations make the main contractor responsible for the health, safety and welfare of all workers on the construction site. The main contractor must put in place a health and safety policy for each construction site and provide guardrails, working platforms, lighting, toilets, hand-washing facilities, first aid and site accommodation. There is also a duty to wear head protection on-site, including electricians. 

Subsection 611-03 recognises that many installations do not have isolating switches and are fed from the supply company s combined cut-out, neutral link and sealing box on the end of the service cable, so in such cases electrical maintenance is restricted to qualified persons. The restriction does not apply to relamping if an isolating switch is available. Supplies are sometimes taken from street furniture to feed temporary installations such as market stalls, Christmas decorative street lighting and small roadworks. Subsection 611-06 requires no impairment of the safety of the permanent installation so it must not be overloaded and the connection must be safe. The temporary installation should comply generally with section 604 for construction sites. 

From an historical perspective, the problem with electrical safety on construction sites largely began after World War II when portable electric tools, electrically powered plant and electric lighting came into general site use. Up until the 1960s, there was no purpose-designed electrical distribution system available, so the main contractor would usually ask the electrical subcontractor to provide a minimum installation at minimal cost. 

Such batteries are in widespread use as button cells based on alkaline electrolyte, as mentioned in Table 1.11, as power sources in hearing aids, but also as larger cells with slightly acid electrolyte, e.g. in warning lights at road construction sites. They are described in Chapter 15 to some detail. 

On the construction site of a process plant, pipework prefabrication and site erection were already well advanced when a number of significant surface defects on piping material came to light, potentially putting into doubt the integrity and safety of the... 

Single-stage dry air cleaners are suitable for light to medium dust conditions on such applications as road vehicles and electric generators. Heavy duty units are intended for use under heavy dust conditions, such as those found on construction sites and construction and agricultural equipment. Heavy duty cleaners for large tracked vehicles and for heavy construction equipment often incorporate multi-cell cyclones to act as precleaners. 

Using these individual databases, shown in Figure 8.7 as the black, gray, and light gray boxes, RACHEL combinatorially generates potential derivatives within the constraints of the active site. In doing so, an immense number of diverse chemical structures may be constructed and tested in a defined and controlled manner. 

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