A new explosion-proof fluorescent light fitting has been produced for the Chevron operated Gorgon project in Australia, that satisfies the health and safety requirements of the plant operator while ensuring minimum disturbance to the local sea turtle population. Graham Doran of COOPER Crouse-Hinds explains
More than 20,000 explosion-proof (Ex Zone 1 and Zone 2) fluorescent light fittings will be supplied for installation on the Liquefied Natural Gas (LNG) and domestic gas plant under construction as part of the Gorgon project.
Not only do these light fittings have to meet strict health and safety requirements in terms of explosion protection, they also have to ensure that disturbance of the local population of sea turtles caused by artificial light sources is minimised. This posed enormous engineering challenges for the lighting supplier.
COOPER Crouse-Hinds’ standard eLLK 92 fluorescent light fitting with special cover and light filter will be installed in general illumination duties across the gas plant. COOPER Crouse-Hinds will supply four different types of eLLK 92 light fitting, including its 2 x 18W, 2 x 36W standard, and 2 x 36W with battery back-up versions.
The project involves the phased construction of three, five million tonnes per annum (MTPA) Liquefied Natural Gas (LNG) plants on Barrow Island, as well as a domestic gas plant with the capacity to provide 300 terajoules per day to supply gas to Western Australia.
The local turtle population
Barrow Island is an important nesting area for sea turtles, and ongoing conservation efforts are reflected in the stringent environmental conditions set by the state and Australian governments as part of the Gorgon Project approval process.
It is vital that any artificial light should not disturb the turtle hatchlings’ orientation towards the sea. As Graham Doran, director, Europe Global Projects Group at COOPER Crouse-Hinds, explained, “Having to ensure that our lighting solution meets the needs of different groups involved in the Gorgon Project – environmental, health and safety, and engineering – is a real challenge. One group of people wants a lighting solution that is as bright as possible so that plant personnel can carry out their work in safe, bright lighting conditions, whereas another group of people require anti-reflective lights that are as dim as possible in order to protect the sea turtles.”
Primary lighting requirements
In terms of the Gorgon processing plant, any lighting supplied must adhere to a strict set of requirements. In this case, the primary requirements are that the main light output is greater than 560nm in order to prevent turtles being attracted to the artificial light. The light fittings also have to be fit for use in hazardous industrial, Zone 1 and Zone 2 environments.
Another primary lighting requirement on Gorgon is that the colour rendering index (CRI) of the lighting has to ensure safe working conditions for plant personnel, as Willi Steckel, product line manager, Lighting (IEC) at COOPER Crouse-Hinds, explained, “The CRI index measures how well a colour can be identified by the human eye under artificial light conditions. We had to make sure that our proposed lighting solution at 560-600nm could meet these requirements, so that plant personnel would still be able to identify the specific colours of safety escape signs and other colour critical warning lamps. For example, a light source with a CRI of 20-25 would mean that the human eye could barely distinguish whether the colour was black, green or blue. It was therefore absolutely critical that the light fittings met these stringent requirements.”
According to Steckel, in order to solve the CRI issue, 20 to 30 different light filters were tested on the eLLK 92 light fitting. He continued, “After we found the appropriate filters, we then tested which one would give us the best colouring with the fluorescent tube. This part of the product testing alone took eight months to complete. Finally, once we had a good selection of matches, we commenced the UV resistance testing of each filter type.”
This stage of the testing also involved more than 1,000 hours of colour fade tests carried out in accordance with European Standards (Light Fastness Tests).
“The other primary requirement was that general illumination lighting would not be directed upwards from the plant into the sky, creating a halo effect around the plant, which would distract the sea turtles. We therefore developed different shielding arrangements depending on the mounting angle of the light fitting. Normally, a light fitting faces downwards but there are situations on a plant where a light may need to be mounted sideways and so for these units, we had to en-sure that the light was supplied with the correct shielding for that particular mounting position,” added Steckel.
Minimal maintenance costs
To make use of the long life of the light fitting components, long life tubes were selected, which offer 60,000 hours between inspection intervals. This ensures minimal servicing and maintenance costs for the plant operator.
The lighting units also had to meet certain wind speed requirements in the event of any unexpected cyclones on Barrow Island. This meant that the eLLK 92 had to be tested in the laboratory at wind speeds of up to 320km/h, in order to simulate a potential cyclone.
In summing up the project, Steckel said, “In my 40 years of working for this company, I cannot re-member a project like this one in terms of the complexity of the primary and secondary lighting requirements. The engineering challenges that we’ve had to overcome on this project required all engineering and technical disciplines within COOPER Crouse-Hinds. It was a real collaborative effort here. Everyone here that is involved in the project has been completely driven and motivated to meet these unique challenges and project requirements.”