The Society of Light & Lighting held a Masterclass at The Building Centre yesterday.
The welcome was given by Iain Macrae, SLL President. He urged those of the delegates who were not already SLL members to join, pointing out that it was politicians who push power legislation but that they have little understanding of how it all works. He stressed that lighting design should be carried out by qualified professionals and that being a SLL member would give you an edge to possibly influence political decisions, in the future.
Iain handed over to David Barnwell of Holophane who gave a very interesting talk on the fundamentals of optical design, explaining how the material surrounding a lamp can control the light to give maximum efficiency, to direct the light at the task and to reduce glare and discomfort.
David demonstrated both specular and diffused reflection with the use of a piece of aluminium. By bending the sheet, the light could be either spread or concentrated. We were shown how a parabola will reflect light in a parallel manner and Snell’s law was explained by the use of a light refracting prism.
David talked about street lighting, where 70W high pressure sodium lamps have been replaced with LED units 50% of energy can be saved. However, high pressure sodium lighting provides more surround lighting so when they are replaced by LED units in the existing columns dark areas can be created in between.
Duncan Abbot of WILA Lighting was next to take to the podium and explained SLL Code for Lighting March 2012 which incorporates European Standard EN12464-1 Lighting of Indoor Workplaces. The main change is the requirement to light the task rather than the whole work surface which would be 456 LUX, 0.93. Surrounding lighting 493 LUX, 0.87. Background lighting -541 LUX……
Lack of contrast in lighting within the workplace can be tiring to the occupants. Higher levels of reflectance of surfaces has been adopted by the Standard because this will reduce the lighting levels required. Best Practice: Ceiling 0.3 – 0.9, Walls 0.5 – 0.6, Floor 0.2 – 0.4.
Cylindrical Illumination was mentioned which provides illumination on the workplace occupants both seated and standing.
Duncan gave dates for lighting trends which was interesting for the uninitiated such as I. 1879 Edison was accredited with inventing the incandescent lamp producing 15 Lumens per watt. 1938 the Fluorescent tube was introduced. 1959 saw the birth of the halogen lamp. In 1965 Sodium vapour lamps were introduced and then in 1996 the first white LED’s were developed. Red and blue had been around before this used a indicator lights on appliances etc.
OLEDs ( Organic Light Emitting Diodes) were touched upon as a development that could become bigger in the future. Producing 100 lumens per watt and with a life expectancy of 10,000hrs they are still very expensive but Duncan predicted that their price will drop by 25% year on year.
Helen Loomes of TRILUX was an afternoon speaker who also spoke about the new requirements for workplace lighting. She mentioned the possible difficulties in designing lighting without knowing where the workstations would be positioned and suggested some solutions to this including using portable lighting. She showed case studies demonstrating this and also talked about the importance of colour rendering which has been proven to affect our well-being.
Kevin Stubbs of Thorn Lighting talked about the importance of integral lighting controls which he said were key to reducing energy costs. Also an efficient maintenance schedule should be adherred to which should be worked out according to how clean or dirty the environment is. Currently LED lamps lose efficiency with age, so with a three year maintenance programme it might be advisable to change lamps halfway through the schedule. A delegate questioned the practicalities of such an action as technology is moving so fast that when changing lamps and drivers, often like for like replacements are no longer available. Kevin said that in three years we should have developed an LED lamp that would be at least 20% more efficient than those currently available. He agreed that stability was needed in the market and this wouldn’t happen until technology slowed down a bit.
Mike Simpson of Philips Lighting gave a fascinating insight into the lighting design for the Olympic Park sports venues, provided by Philips. The roof of the Olympic Stadium had to be raised another 10 metres at an extra cost of 5 million pounds in order to get the floodlights at the right height so that they wouldn’t glare in the camera lens. There was also a problem with lights being in line with the diving board in the Aquatic Centre which would have obliterated the action from our TV screens. 20 floodlights had to be turned off in the Velodrome to avoid skip glare, that is the reflective surface glare bounced off the wooden track which would have spoiled the TV coverage. Lighting levels and colours had to be evened out for the TV cameras too. Three phase lighting had to be used to prevent flicker on the TV slow motion sequences caused by the uneven ratio between the higher frequency lighting controllers.
This very informative day was concluded by a slightly more light-hearted address by Paul Traynor of the Light Bureau. Paul is very energy conscious and talked about ethical consumerism. He ran through some very interesting lighting projects that he has been involved in from the secret wartime tunnels beneath Dover Castle to Tower 42 in London.
Regrettably, I was unable to stay for the evening event entitled London’s Legacy – A Celebration In Light but judging by the tweeted picture below it was very well attended and I trust a resounding success.
— SLL (@SLL100) October 11, 2012