Appendix A INDUSTRIAL LIGHTING
Lighting is essential for making the work environment safe and for allowing staff to perform their tasks comfortably. It can be a significant energy user accounting for up to 40% of an organisation’s electricity bill. Even making small adjustments to lighting can significantly improve the working
environment, help reduce electricity consumption and, at the same time, minimise CO2 emissions and save money.
A.1 Identifying energy saving opportunities
Energy savings in lighting systems can be realised in a number of areas. When starting out looking for opportunities the following suggests a simple approach that could be used:
n Assess the lighting levels. Are the lighting levels suited to the application and can excess lighting be avoided?
n Assess the lighting technology type. Is it the most appropriate and efficient for the given application? Is the rendering and colour suited to the application?
n Assess light distribution. Is the majority of the light delivered to the intended work area and is it correctly dispersed over the work area? Are the most efficient luminaries used and properly cleaned and maintained?
n Assess the lighting controls. Ensure the lighting is controlled in such a manner as to only deliver the right amount of light to the right areas at the right times only.
Definitions:
Lamp: the source of the light (i.e. the bulb) Luminaire: a light fitting that incorporates the lamp Watt (W): Measure of electrical power used by the lamp.
Lumen (lumen): Measure of light energy emitted from a source.
Efficacy (lumens/W): the amount of light provided relative to the amount of energy used, once the lamp has reached full brightness. The higher the value the more light is gained for the same energy.
Colour rendering (Ra): the ability of a lamp to show surface colours accurately. The lower a lamps Ra value relative to an ‘excellent’ value of 100, the poorer the lamp’s colour rendering ability.
Colour temperature (K): Measure of the colour appearance of a light source ranging from ‘warm’ light (i.e. the light a candle produces) through to ‘cool’ light (i.e. a bright white fluorescent light).
Lamps below 3,300 K are classed as ‘warm’ whilst those above 5,300 K are ‘cold’.
Re-strike: the time taken for a warm discharge lamp to reach 80% of maximum light output when power is interrupted.
Appendix A – INDUSTRIAL LIGHTING
The following sections provide background information to assist in the assessment of lighting systems.
A.2 Recommended standard maintained illuminance
Providing lighting to higher levels than is necessary wastes energy and is expensive. Ideal lighting levels in industrial applications are presented in the table:
Illuminance (lux) Task / Activity / Interior 2 Healthcare ward night lighting
20 Unstaffed gangways
50 Remote operated processing, person-sized under-floor tunnels, cellars, underpasses, healthcare corridors (night), cable tunnels, indoor storage tanks 100 Circulation areas, entrance halls, corridors, rest rooms, store and stock rooms, healthcare wards (general), changing rooms, auditoria
150 Stairs, escalators, travelators, loading ramps/bays, staffed gangways
200 Toilets, foyers, lounges, plant rooms, switch gear rooms, turbine halls, archives, library bookshelves, monitoring automatic processes, dining rooms 300 General machine work, manufacture and assembly (rough), retail sales area, packing and handling areas, welding, office (lowest), reception desk,
filing, exhibition general lighting, sports halls, teaching areas
500 First aid rooms, laboratories, kitchens, writing, typing, reading, data processing, CAD workstations, conference/meeting rooms, offices (highest), switchboard, post room, medium machine work and assembly, general inspection areas, control rooms, retail till area, hairdressing
750 Grinding and engraving, fine machine work and assembly, critical inspection and repairs, paint spraying and polishing, technical drawing, ceramic decoration, meat inspection, chain stores
1000 Healthcare examination and treatment, colour inspection, precision decorative grinding and hand painting, precision assembly, quality control, typesetting, gauge and tool rooms, retouching paintwork, cabinet making
1500 Electronic workshops, testing, precision assembly, fine work and inspection
2000 Steel and copper engraving, assembly of minute mechanisms, finished fabric inspection 100/500 Entrance halls/enquiry desks
100 (at floor level) Corridors, passages and stairs
300-500 General offices and computer work stations 300/500/750 Rough/medium/fine bench and machine work
300/500/1000/1500 Rough/medium/fine/precision electrical equipment manufacture 100/300/300 Bulk storage/small item racking/packing and dispatch
Appendix A – INDUSTRIAL LIGHTING
A.3 Lighting power consumption
For lighting power consumption, general benchmarks have been set by surveying existing installations. The power consumption depends on the lighting level required, as shown below.
General Factory Lighting Benchmark Consumption (W/m²)
300 Lux 500 Lux
General lighting for open areas 5 – 6 8 - 10
For warehouse areas the power consumption benchmark is dependent on the aisle width and height.
Warehouse Lighting Aisle width
(m)
Mounting height (m)
Benchmark Consumption (W/m²)
300 Lux 500 Lux
1.2 4.5 8 14
2.4 6.5 8 16
3.0 8.0 9 17
A.4 Colour rendering and appearance
Colour rendering should be considered when selecting lighting. Each type of lamp provides a different colour of light. In general the more detailed work being performed the closer to white light will be required. Colour rendering is measured according to the Colour Rendering Index. Each lamp type is placed in a colour rendering group depending on its colour rendering index.
The colour appearance of a light source can range from ‘warm’ light (i.e. the light a candle produces) through to ‘cool’ light (i.e. a bright white
fluorescent light). Choosing a lamp with the wrong appearance can have disastrous results in businesses where identification or matching is important, for example, food processing, textiles and retail.
Appendix A – INDUSTRIAL LIGHTING
Colour Rendering Colour
rendering performance
Colour rendering ID
group
Colour rendering index (Ra)
Typical application
Excellent 1A =>90 Wherever accurate colour matching is
required, e.g. colour inspection
Good 1B 80-89 Wherever accurate colour judgements are
necessary , e.g. shops and offices
Moderate 2 60-79 Wherever moderate colour rendering is
sufficient
Poor 3 40-59 Wherever colour rendering is of little
significance
None 4 20-39 Wherever colour rendering is of no
importance Colour appearance
Colour appearance class
Correlate colour
temperature Typical application
Warm Below 3,300 K Domestic-type situations
Intermediate 3,300 – 5,300 K Combined daylight and electric light
Cold Above 5,300 Situations where a cool appearance is
required
Appendix A – INDUSTRIAL LIGHTING
A.5 Characteristics of different lamp types
The table below shows the characteristics of different lamp types commonly used in offices or production areas and workshops. For lighting in external areas, such as car parks and storage areas, low pressure or high pressure sodium lighting with photosensors is considered best practice.
Lamp Type General Colour Rendering Index (Ra) Task illuminance (Lux) Average installed power density (W/m²) Offices
Fluorescent – triphosphor 80-90 300 7
Fluorescent – triphosphor 80-90 500 11
Fluorescent – triphosphor 80-90 750 17
Compact fluorescent 80-90 300 8
Compact fluorescent 80-90 500 14
Compact fluorescent 80-90 750 21
Metal halide 60-90 300 11
Metal halide 60-90 500 18
Metal halide 60-90 750 27
Production areas, workshops
Fluorescent – triphosphor 80-90 300 4
Fluorescent– triphosphor 80-90 500 10
Fluorescent – triphosphor 80-90 750 14
Fluorescent – triphosphor 80-90 1000 19
Metal halide 60-90 300 7
Metal halide 60-90 500 12
Metal halide 60-90 750 17
Metal halide 60-90 1000 23
High pressure sodium 40-80 300 6
High pressure sodium 40-80 500 11
High pressure sodium 40-80 750 16
High pressure sodium 40-80 1000 21
Appendix A – INDUSTRIAL LIGHTING
A.6 Lighting controls
The use of lighting controls will depend on the area use. The decision tree below (section A.6.1) can be used to determine the best practice controls.
A.6.1 Movement sensors and heat sensors
These are used to detect whether people or vehicles are present. They work on movement or heat detection. Best practice is to have sensors for individual banks of lights or even on individual fittings.
Individual banks of lights will be fitted with controls from a single sensor if the bank of lights covers an area of similar usage, e.g. single sensor for lighting in warehouse racking. Where a switched bank of lights covers more than one area of use it is more cost effective to control individual fittings.
Consideration should be given to installing sensors in corridors, warehouses and storage areas. In these areas there is normally only temporary occupation and often for only a few minutes at a time.
Occupancy sensors are suitable for controlling fluorescent, compact fluorescent and induction lighting.
Occupancy sensors are not suitable for controlling high pressure sodium or metal halide lighting.
A.6.2 Photosensors
Photosensors are used to switch off lights where natural daylight is available. Best practice is to install these on light banks or fittings beneath skylights or next to windows. Individual banks of lights would be fitted with controls from a single sensor if the bank of lights covers an area of similar usage. Ideally the rows of lights should be placed in parallel to the windows and when there is adequate natural daylight available the row closer to the window will switch off or dim down.
For external lighting best practice is to switch external lighting off during daylight hours.
Photosensors can be used for all types of light fittings. It is important with photosensors to regularly clean the sensors to remove any layers of dirt.
A.6.3 Automatic control units
Where areas are not used 24 hours per day it is best practice to automatically switch off lighting when the area is unoccupied. This can be done by using sensors as mentioned above or with simple timer controls.
Appendix A – INDUSTRIAL LIGHTING
If time switches are fitted, make sure they have a programmable calendar and that working hours are correctly programmed in, including weekends, holidays etc.
A.7 Reviewing the properties of lighting systems
The following table presents a number of technical properties of lights and lighting systems. Consult this list when considering efficient lighting, particularly when thinking about a new design.
Consider How? Why
Illuminance Check the lux levels (lumens/m2) needed for different areas. Table in section 8 is a guide. Actual measurements can be made with a lux level meter.
The amount of light needed will depend on what activity is taking place in the area and regulation.
Consider how lamps age and work can out how long they are expected to be in place.
Old lamps emit less light for the same amount of energy. If lamps will be in place for a long time, illuminance may be affected.
Efficacy The higher the number, the more efficient the lamp The more light a lamp can produce, the fewer lights will be needed to meet needs.
Colour rendering and temperature
Check the Kelvin and Ra of the lamp. Choosing a lamp with poor colour qualities can have
disastrous results in businesses where identification or matching is important, for example, food processing, textiles and retail.
Lamp life Check the estimated hours of light. By measuring lamp life, you may find that a higher
capital expenditure is justified. Choosing long-life lamps for areas which are difficult to reach, could save on the maintenance costs in replacing them less frequently.
Ask suppliers about different control gear that might lengthen the life.
High frequency control may extend the life of the lamp.
Warm-up and re-strike times
Ask your supplier for details If an application needs a quick warm-up or re-strike,
such as security lighting, certain lamps will not be appropriate.
Luminaries Identify which luminaires are available / required for types of lamp, and check the light output ratio (LOR) of each.
Luminaires affect the direction and output of light from the lamp. Choosing efficient luminaires can reduce the number of lamps needed.
Appendix A – INDUSTRIAL LIGHTING
A.8 Lighting checklist
Lighting Systems Walkabout Checklist
Compile an inventory of lighting systems on site and prioritise according to annual energy use (size x running hours). Conduct the following checks on each system:
NOTE: Many lighting systems require specialist knowledge about their operation; always seek specialist help where you are uncertain about energy saving measures to implement as this will help prevent unintended outcomes.
Check Complete Y/N
Lamps
1. Identify opportunities to upgrade to higher efficiency lamps. Look to migrating to LED and T5 florescent technologies. Especially look to migrating away from mercury vapour lamps.
2. Where fluorescent lamps are installed check they are T8 or T5 types and are fitted with electronic ballasts.
3. Check that the lamp colour rendering and light appearance is appropriate for the work being carried out.
4. Can florescent lamps with quick on-off control be used in low use areas in place of high pressure sodium or metal halide lamps?
Luminaires, diffusers and shades - Maintenance
1. Check shades, diffusers and luminaries are clean and are cleaned on a scheduled basis.
2. Check all luminaires are suited to the application.
3. Look for opportunities to optimise use of natural daylight and eliminate any glare issues.
4. Check skylights are clean and are maintained on a regular basis. Natural daylight is free; maximising its use has very low cost and can realise significant savings.
Lighting systems
Consider the following control measures to switch lights off and / or reduce the numbers of lights in use:
a. automatic sensors / controls.
b. manual switch off.
c. use zone controls.
Look to apply the above control measures in the following contexts:
1. Review lighting levels, identify areas where levels are excessive.
2. Identify unoccupied areas / areas where occupancy is low (e.g. warehouses & storerooms).
3. Identify opportunities to use task lighting.
4. Identify opportunities to increase natural lighting including background lighting.
5. Identify opportunities to increase reflection of background light.
6. Check exterior lighting is off during daylight hours and that unoccupied areas are not lit.