Traditional incandescent bulbs are cheap to purchase but have poor efficiency, short life and high running costs.
Industrial
Introduction
The key objective in an industrial environment is to provide sufficient levels and quality of light for staff to perform tasks efficiently, accurately and safely. But they need to feel comfortable too.
With this in mind, there are a number of cost effective and basic initiatives you can take:
- Maximise natural daylight levels while avoiding glare and potential overheating (if skylights are used, use a daylight sensor if using daylight panels)
- Install task-specific lighting over work areas
- Light walls and ceilings with bright room surface finishes, so people can efficiently and safely move around the space
- Provide the correct colour rendering and colour temperature to improve the feeling of comfort
- Allow zoning so staff can dim lights or switch them off when they are not required, thereby saving electricity
- Focus on energy efficiency, user comfort and safety on night shifts.
The right amount of light
Reflectance
Lamps
Controls
Task lighting
Retrofitting
Emergency lighting
Controls
Next steps
The right amount of light
Lighting levels for industrial tasks can vary from 40 lux for general and circulation areas up to 800 lux and higher for very fine detail. As a rule of thumb, any task that requires illuminance higher than 400 lux should be lit with specific task based lighting.
For balanced brightness, it’s important to have high reflectance surfaces on the ceiling and upper walls. White painted surfaces can save up to 50% of the energy required to light the same space if its reflectance is poor.
Lamps
Most industrial lighting is based on high intensity discharge (HID) lamps: metal halide, high pressure sodium or mercury vapour. HID lamps have been popular because their extremely high light output reduces the need for light fittings. Some of these can be used with special dimming control gear but this is often expensive.
Mercury vapour lamps
These are not recommended because of poor colour, colour rendering and extremely low luminous efficacy. If your workspace currently uses these lights, we recommend you upgrade to new technology for better light quality and lower operating costs.
High pressure sodium lamps
These offer the highest luminous efficacy of HID sources. But sodium lamps are not the most efficient when it comes to quality of light. So restrict their use to areas where colour temperature and colour recognition are not important (eg. a distribution warehouse).
Metal halide lamps
These fall into two categories: probe start and pulse start. The probe start variety is low cost and very common, although it has been banned from production in the USA due to poor efficiency; whereas the pulse start variety offers you 20% increased efficiency (albeit at a higher price). The inability of these lamps to instant-start severely limits the use of occupancy sensors and other switching methods that can save energy.
Linear fluorescent lamps
These are becoming the lamp of choice. You get more light than from typical high bay or low bay pendant type fixtures, plus other benefits such as:
- Dimming (all you need is the right control gear)
- Multi-level switching
- High level of lamp redundancy (meaning the light fitting still provides adequate light should one lamp fail)
- Excellent lumen maintenance (95% output at 40% life compared to 60-70%).
Note that winter temperatures can cause some high output T5 fittings to take some time to warm up to maximum efficiency and where the ambient temperature is so low the lamp chamber is unable to achieve 35°C, light output can be considerably reduced. In areas where low temperatures are likely, T5 amalgam lamps are recommended as these operate effectively across a wider temperature range.
Task lighting
Consider task lighting in areas where the illuminance required for tasks or maintenance of automated plant is significantly higher than that required for the surrounds. Task lighting can provide higher lighting levels, reduce energy use and eliminate shadows created by machines or workers themselves.
Retrofitting
It is possible to retrofit existing T12 and T8 fluorescent installations with T5 lamps in order to improve efficiencies. This is a relatively new technology and the process needs to be undertaken with care as some products may not work in all installations or not perform as expected and have other undesirable characteristics. This level of conversion may also have implications with regard to any warranties that may apply to the existing fittings and associated new components.
Emergency Lighting
Emergency lighting is required by law in all buildings over 300sqm in size. It may also be required in smaller buildings by virtue of the type of premises. There are a number of misconceptions about emergency lighting. Well maintained fittings will each run for a week for about 20c or less of power to charge the emergency batteries. A typical modern EXIT sign will be rated at about 5W and carry similar minimal running costs. A large installation older than 5 years will probably have the potential to show savings if upgraded to a low energy type. Such a change will also reduce maintenance costs as longer life lamps would be used.
Controls
There are significant limitations to using control systems with HID lamps, given they do not start instantly. HID lamps are also very difficult to reliably dim, in terms of maintaining constant colour and colour temperature.
In high activity areas make sure:
- The lighting level is constant when the building is occupied
- When it's unoccupied, use a time-switch control or computer system to ensure all non-essential lighting is off.
And in medium activity areas:
- Reduce light levels in unoccupied areas, rather than complete darkness (this will help maintain acceptable contrast ratios)
- Switch fixtures to a lower light level on occupancy or operator-activated systems.
In terms of specific equipment:
- New ballast technology for fluorescent lamps significantly improves the life of lamps that are switched frequently
- Two-level controls work well for metal halide systems – when the high level is switched on, the lamps ramp up quickly and return to optimum color and light output.
- Photo-sensor controlled fluorescent dimming systems or high/low metal halide systems are effective and comfortable ways to optimise energy use in high daylight areas.
Next steps
If you want to take the lead on energy efficient lighting for your business:
- Talk with a registered lighting professional to assess your specific needs
- Ask them to specify the most appropriate energy efficient lighting designs and lamp options to meet your business needs
- Make sure you get a clear cost/benefit analysis of the different efficient lighting options available including payback period/ROI and lifecycle costs (including maintenance costs).
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Replace all lamps at once
Consider group relamping. Fluorescent lamps can lose 20%-30% of their light output over their service life. Many lighting experts recommend replacing all the lamps in a lighting system at once. This saves labour, keeps illumination high, and avoids stressing any ballast with dying lamps.