Substandard electrical products are threatening life and property around the world. In this article, the SAFEhouse Association highlights luminaires, their industry requirements and standards.
Users have a vast choice of suitable luminaires for lighting interior and exterior areas. While product safety is important, so is the creation of a safe and attractive lighting installation that allows occupants to move around safely and perform their tasks efficiently.
Since the safety of products and their reliability are fairly clearly defined in standards and specifications, these can be determined through suitable testing and inspection. Although a luminaire’s photometric performance, its utilisation of light, its energy efficiency and lamp efficacy are often more difficult to determine, these are also important aspects to consider.
Choice of decorative luminaires is frequently based on the aesthetic appearance of the luminaire without any consideration of the light distribution and effectiveness of the light emitted from the luminaire. The advice of professional lighting designers is often required. The user must understand some basic concepts to assist in making a thoroughly considered choice. This is of great importance, especially in luminaire retrofit projects where the end result can prove to be a disastrous and costly exercise for the user or owner.
Basic lighting concepts
Light output, lumen (lm)
This denotes total amount of light emitted from a luminaire or light source.
Illumination, lux (lx)
The amount of light incident on a surface per unit surface area.
Lamp efficacy, lumen/Watt (lm/W)
The amount of light emitted from a bare lamp (lm) divided by the input electrical power (W).
Luminaire efficiency, percent or lm/input (W)
This is the light emitted from the luminaire divided by the light emitted from the bare lamp(s) used in the luminaire. For luminaires with non-replaceable light sources such as LED modules, the efficiency of the luminaire is expressed in lm/input W. When comparing luminaires, their efficiency values could be misleading as these depend on the light distribution of each luminaire.
Fig. 1: No insulating plate under the terminal block.
Efficiency values should only be used to compare luminaires with similar light intensity distributions.
Note that, where efficiency values for luminaires of 100% are claimed, the concept of replaceable light source was used for the calculation, which gives the incorrect value. In this instance the lm/input W value should be used for comparison purposes.
Light utilisation, percent
This is the percentage of light emitted from the luminaire that illuminates a specified area. Light utilisation of luminaires must be calculated for each application by the lighting installation designer to ensure optimum selection of luminaires (photometric data for luminaires can be obtained from the manufacturer).
Lamp life, hours
The rated lamp life of lamps is generally based on the average life of a sample of lamps burning under controlled conditions. It gives the number of burning hours at which 50% of the lamps in the sample have burnt out.
Glare
A condition of vision that is caused by luminance (brightness) that sufficiently exceeds the luminance to which the eyes are adapted and that causes annoyance or discomfort or reduction in visual performance and vision. Lighting installations that appear to be “bright and sparkling” could be an indication of excessive glare and may be detrimental to the performance and comfort of occupants.
Luminaire categories
Some of the main luminaire categories are:
Luminaire performance
The lighting performance of luminaires is of utmost importance for energy efficient operation and the creation of optimum lighting conditions in their specific applications. The effective use of luminaires can only be determined through appropriate lighting installation design for the luminaires on offer. Suppliers and lighting specialists should be consulted for such designs.
Fig. 2: No insulating plate under the terminal block. Wire insulation stripped back too far.
Retrofit of existing installations
In recent times, energy-efficiency has been the main driver to retrofit existing installations with lamps of higher efficacy. For luminaires with reflector systems and/or diffusers or lenses, any lamp-type change will affect the resulting light distribution significantly and may not meet light levels, uniformity and glare requirements. For more information, see the requirements of SANS 10114-1 Interior Lighting – Part 1: Artificial lighting of interiors. It is strongly recommended that retrofit proposals be tested for performance and safety requirements and that luminaires and components are purchased from reputable suppliers.
Modifications to existing luminaires render all previous approvals invalid and retrofit luminaires should comply with the relevant compulsory specification. This has become the responsibility of the electrical contractor doing the modification
Compulsory specifications for luminaires and lighting products
A new compulsory specification, VC9012 Electric luminaires, will be implemented shortly to separate luminaires from the present version of VC8055.
Various other standards for lighting, luminaires, lamps and lighting components are available. Information can be obtained from suppliers.
Fig. 3: No grommet on the inside
of the nipple.
Luminaire safety
Luminaire safety requirements are set to prevent harm to persons or damage to property mainly through fire, electric shock or burning. Users should be aware of important safety aspects in selecting luminaires, some of which are listed here:
Marking
Luminaires shall be marked with at least the following:
Insulation classification
Luminaires shall be one of the following classes:
The basic requirement is that no single failure can result in dangerous voltage becoming exposed so that it might cause an electric shock and that this is achieved without relying on an earthed metal casing. This is usually accomplished, at least in part, by having two layers of insulating material surrounding live parts or by using reinforced insulation such as insulating sleeves, grommets and bushings.
Construction
Fig. 4: No grommet on the base
of the fitting.
Luminaire components
Replaceable components such as lamp holders, control gear, capacitors, wiring and terminals shall comply with the requirements of the relevant IEC standards, if any. Ratings should be checked to establish that they suit the conditions that may occur in use.
Internal and external wiring
Conductor size shall be compatible with the electrical current experienced in normal use. Wiring shall be routed in such a way that damage to insulation due to high temperatures or chafing against sharp edges, screws or rivets is prevented. Additional protection may be required where wiring passes through joints, raising and lowering devices, telescopic tubes and similar parts. Adequate anchorages shall be provided for flexible supply cables or cords (see Figs. 3 – 6).
Fig. 5: No gland used to secure cable to fitting.
Earthing
Class I luminaires shall be provided with an earth terminal to which all accessible metal parts, which may become live in the event of an insulation failure, are connected permanently and reliably. The earth connection shall be locked against accidental loosening. Earthing terminals shall be of brass or a non-corrosive suitable metal, while contact surfaces shall be bare metal.
Protection against electric shock
Luminaires shall be constructed so that their live parts are not accessible when the luminaires are installed and wired as in normal use, and when they are opened as necessary for replacing lamps or starters, even if the operation cannot be achieved by hand. Basic insulated parts shall not be used on the outer surface of the luminaire without appropriate protection against accidental contact.
Thermal control
Under conditions representing normal service, no part of a luminaire (including the lamp), the supply wiring within the luminaire or the mounting surface shall attain a temperature that would impair safety.
Parts intended to be touched, handled, adjusted or gripped by hand while the luminaire is at operating temperature shall not be too hot for the purpose. Luminaires shall not cause excessive heating of lighted objects
Who polices the lighting industry in South Africa?
The Illumination Engineering Society of South Africa (IESSA) represents the interests of the South African lighting industry. The South African Bureau of Standards (SABS) sets the national standards and the National Regulator for Compulsory Specifications (NRCS) is mandated to set compulsory specifications and to carry out surveillance and compliance monitoring against these specifications.
Locally manufactured luminaires
Most decorative luminaires are imported but a wide range of decorative, commercial, industrial and luminaires for outdoor lighting are manufactured in South Africa. Reputable local manufacturers make a full range of luminaires and many manufacturers specialise in photometric design to provide optimal light distribution options for various applications.
Examples of substandard luminaires in South Africa
Reliable photometric data should be available for commercial, industrial, floodlighting and road lighting luminaires. If data cannot be provided, one can almost assume substandard performance. This applies particularly to retrofitted luminaires.
Inferior quality of luminaire construction such as floppy luminaire bodies and poor finishing are another indicator, as are flammable materials used in construction and terminal blocks.
Fig. 6: Wires not connected correctly;
will short on base.
A brief overview of LED lighting
LED lighting is a relatively new technology, and is fertile ground for unscrupulous and opportunistic suppliers to capitalise on the absence of a compulsory local standard for LED lamps and to make performance claims – mostly around lifespan and power-consumption – that will not be met.
Some facts
Some consequences
Contact Pierre Nothard, SAFEhouse, Tel 011 396-8140, pierren@safehousesa.co.za
