Updated: Nov 15, 2020
Providing adequate lighting is a key consideration for the construction industry, particularly at this time of year. Aside from increasing the risk of accidents, poor lighting can cause eye strain, migraines and headaches, all of which can affect productivity and the bottom line.
Choosing the correct lighting for site goes beyond the fairly straightforward choice of light towers for outside areas, lights on tripods, small, portable task lights and so on, and into the more complex choice of the light source. This is because different light sources (ie halogen bulbs, fluorescent tubes or LEDs) have varying characteristics, which include the colour and shape of the light cast, energy efficiency, lifespan and cost.
Bearing all these factors in mind, there is a strong argument for switching to LEDs.
As well as the brightness of the light, it is also important to consider the colour (ie the temperature) of the light being produced. Generally, the more yellow the light, the more comfortable it is to work in over long periods. The closer to the red end of the spectrum, the more light is absorbed by the eye, so therefore the dimmer it appears. The higher the temperature, the whiter and brighter the light produced. At around 8,000K light becomes painfully blue and at 12,000K it begins to become purple. Output temperatures of commercially available lighting are:
2,700K: Incandescent bulb;
3,000K: Halogen floodlight;
4,200K: Fluorescent light/energy saving bulb;
5,500K: LED cool white (high contrast);
6,500K: LED bright/pure white (very high contrast).
For detail work, 5,500K-6,500K is usually most helpful, since it provides the highest contrast – hence making LEDs perfect for these tasks.
How the light is cast
A halogen bulb emits light in all directions, with some of that light reflected out of the back of the housing, while the light from an LED unit is more focused, typically within 120°, and therefore can appear much brighter (another reason why LEDs are ideal for detail work). However, this means that, while replacing a halogen spotlight with an LED is perfectly acceptable (and requires lower wattage, because an LED is more efficient), if a fluorescent lamp is being replaced, more care is needed, as spotlights and floodlights offer a very different light spreads. In these cases, LED lights must be positioned so that a similar spread of light is created or, when directly substituting a fluorescent tube light with an LED of similar design, it must cast light in the same way.
Despite producing high temperature light (typically between 5,500K and 6,500K, compared with 2,700K for incandescent bulbs), LEDs do not get hot, as almost all the energy is converted to light. This makes them much safer – in fact, some construction sites have banned high wattage halogen lights due the risk of fire and burns to workers.
LEDs are 95% efficient, compared with 5% for tungsten halogen bulbs and 85% for fluorescent tubes, which means they consume far less energy. And, while lighting plays a small role in an organisation’s overall emissions (between 5% and 10%), switching to LED lighting is easy and a ‘quick win’ for carbon savings.
Whole life costs
While the purchase price of an LED light may be higher than one using a conventional bulb, the whole-life costs are far lower. This is because conventional tungsten halogen lamps last between 2,000 and 4,000 hours; whereas LEDs can last up to 11,000 hours (depending on usage) and are more robust. As there are no bulbs to break, LEDs require less maintenance and there is less chance of damage.
The case for LEDs
LED lighting offers a number of advantages over conventional systems but this choice is made more difficult by the complex factors at play and the wide range of lighting sources and products available.
For the construction industry, considering the correct level of light, its colour and how it is cast can reduce accidents on site, make workers more efficient and minimise costs.
And, while there are no statutory requirements for employers to provide adequate lighting in the workplace, construction health and safety managers should look to the HSE’s Lighting at work (HG38), which is probably the most helpful as, along with general guidance, it gives minimum lighting levels for different construction activities. It is also advisable to speak to lighting manufacturers and suppliers, who will be able to help construction companies plan and specify lighting, to ensure teams remain safe and well, wherever and whenever they are working.
Exerpt from SHP Daily 8/10/2019