1          Additional aspects regarding the selection of risk reduction measures for electrical lighting

1.1      Introduction

During an initial, periodic or special inspection some checklist items can indicate the occurrence of a medium or high risk. In the event of a high risk occurrence measures are recommended to be taken to reduce the risk to a low level. In the event of a medium risk occurrence measures are recommended to be taken to reduce the risk to a low level. The type and scope of risk mitigating measures depend on the causes of the occurring risk. The method of action aimed at reducing the risk to a low level for individual nonconformities identified in the risk assessment checklist is presented below.

If the manufacturer has not fitted the machine with a spot light fitting, it may mean that the manufacturer considered that the ambient lighting of the room, in which the machine will be installed will suffice or that this aspect was not considered at all. However, the machine lighting, and particularly the areas in which visual work is performed must be lit sufficient to safely perform all the work activities. An unambiguous indicator is the compliance with the applicable regulatory requirements. This means that the minimum values are ​​specified in PN-EN 12464-1:2012 Light and lighting. Lighting of workplaces. Part 1: Indoor workplaces must assume the following electric lighting parameters:

-           operational illuminance;

-           uniformity of illumination;

-           occurrence of direct glare;

-           occurrence of reflective glare;

-           flickering and pulsating light;

-           stroboscopic effect;

-          colour rendering index.

Therefore, if additional lighting of the machine is provided with an independently selected spot light fitting, additional lighting of areas on the machine where activities are performed throughout the life of the lighting must meet regulatory requirements for these parameters.

1.2      Guidance for correct placement of spot light fittings

Typical visual tasks performed while operating the machine include:

-          positioning and fixing of the workpiece,

-          observation of the process,

-          setting and checking the values ​​on the scales and indicators.

Each of the visual tasks requires different lighting conditions. Under certain conditions, the ideal is a strong spotlight, in other the best solution is uniform lighting of a large area and an average level of illuminance. Some visual task require the holder of the fixture to be permanently secured, while for other the fixture should be adjustable (in one, two or three places). However, it is almost always necessary to adjust the inclination of the part luminaire containing the light source. A separate issue is the problem of a limited glare, elimination of a strobe effect, luminaire thermal insulation (especially for a incandescent or halogen source of light), protection against accidental contact of live parts and ingress of solids or water (IP rating), and the degree of electrical safety for the personnel (protection class).

Fig. 5.1. Proper additional lighting of a milling machine

Generally, it can be assumed that for the lighting of workplaces with e.g. a milling machine or a drilling machine, proper lighting can be achieved by the use of an appropriate luminaire – in this case with a narrow light distribution. Its correct mounting will provide good lighting of the visual work area and even reduces glare in the absence of structural elements designed to limit glare (Fig. 5.1).

       However, in the case of additional lighting of work stations of turning lathes elongated luminaire should be used with large illuminating area rather than a narrow light distribution (Fig. 5.2).

Fig. 5.2. Proper lighting of a turning lathe

The following photographs show examples of proper and improper lighting of a drilling machine, a milling machine, a grinder, an automatic turning lathe, a milling machine and similar machines.

a)                                                        b)

Photo 1. Lighting of a drilling machine

a) correct lighting from one (left) side without glare, 

b) incorrect lighting – a strip of bare fluorescent tubes causing glare.

Photo 2. The lighting of a grinder from the left side, careful setting of the luminaire prevents excessive dirt and glare exposure to employees

Photo 3. The lighting of a grinder on the right side, the luminaire is excessively exposed to dirt and causes operator’s glare.

Photo 4. The lighting of a turning lathe with a luminaire with a large illuminating area and a mounted glass protecting the light source from soiling

Photo 5. The lighting of a turning lathes with a narrow light beam luminaire, set in a manner which prevents illuminating the entire area of ​​the task (sometimes its position cannot be changed).

                                     a)                                                     b)

Photo 6. The lighting a milling machine using a spot light fitting with circular fluorescent lamp and a halogen lamp:

a)    with only the circular fluorescent lamp on

b)    with both the circular fluorescent and the halogen lamp on, visible additional illumination of the workpiece

1.3      Examples of the types of spot light fitting for lighting machinery

Based on the observations of the methods to implement local lighting of machines, it can be stated that the most commonly used luminaires are those with halogen light sources. These luminaires are fitted with various types of optical systems. The predominant type is the structure composed of a reflector (of various shapes and textures) and a transparent lampshade or, less commonly, dissipating or focussing elements. The most dangerous for the employee are spot light fittings with a halogen source without a filter that limits ultraviolet radiation.

Figure 5.3 shows an exemplary halogen luminaire fitted with aluminium, gloss polished parabolic louvre, which greatly reduces glare. The luminaire is made of aluminium with a heat shield and IP ratings: 20, 54 and 65. The luminaire, depending on the design (various types of mounting brackets) may be mounted anywhere on the machine.

Fig. 5.3. The louvre halogen luminaire for additional lighting of machinery

Another method for mounting the luminaire is shown in Figure 4. The luminaire is fitted with a suction cup, by means of which it can be attached to any flat part of the machine. The long, flexible handle allows providing additional lighting virtually to any area of ​​the machine. In addition, a metal cap on the halogen bulb is used, thanks to which the filament – the element with the highest luminance – is completely shielded. This reduces the glare from halogen sources and improves the uniformity of the illuminated surface. This luminaire is offered with 20, 50 and 75 W halogen bulbs and it has a narrow and deep light distribution and IP 54 rating.

Fig. 5.4.  Halogen luminaire for illumination of machines

The increasingly popular spot light fittings are LED sources. Their basic advantages are high durability, energy efficiency and focused light beam. Their design allows for easy mounting of these fixtures on machines. Examples of LED luminaires are presented in Fig. 5.

Fig. 5.5. Examples of the types of spot light fittings designed for additional lighting of machinery

Another group of spot light fittings are luminaires with a high luminous surface, which make use of compact fluorescent lamps as a light source. An example of such a luminaire is shown in Fig. 6. Two or three 6, 11, 15, or 2 x 18 W compact fluorescent lamps can be used in the luminaire. Protection rating - IP 54. Thanks to the long handle composed of two arms and three joints the luminaire can be directed to provide additional lighting of any area of ​​the machine.

Fig. 5.6. Example of a luminaire with large luminous surface to illuminate a grinder