AN TOPIC ILLUMINATING

01 Dec 2004

The way we light ports and terminals has become something of an issue in recent years as public enquiries linked to new port construction have sought to curb what is seen as unwanted additional illumination of the night-time sky. Furthermore, with operational margins under pressure, operators are seeking ways of cutting costs, albeit by not compromising either operating efficiency or security. Alex Hughes investigates.

Consultant Dennis Hepworth is one of Royal Haskoning's experts in the field of maritime terminal lighting, having assisted port authorities and terminal operators in maritime facilities both within the UK and overseas. "In a lot of cases when I am brought in to analyse terminal lighting, I can usually find ways to save the operator money without necessarily compromising safety, " he insists. "Quite exactly how much depends in part on the lighting system already in place. Instances of over-lighting a particular area are all too common and waste limited financial resources by overinflating both energy bills and overall operational costs."

He adds that in some cases further investment could also produce longer term savings, although this is not always well viewed since many terminals just want to reduce their existing energy costs whilst maintaining an effective and safe lighting system. This means having to re-use existing towers, but not re-position them.

"In this type of case, I have to reconfigure the existing network.

Nevertheless, I would also make a case for the erection of additional variable height towers or columns mounted with lower lamp wattages to get the lighting distribution and uniformity that is required."

In fact, advice to clients can range from recommending changes to the type, rating and control of luminaires for operational and general movement areas, to increasing lighting in defined zones where particularly intensive or hazardous operations take place. Substantial improvements can also be made to the efficiency of many systems by the simple expedient of changing the height and/or spacing of the masts.

So called light pollution and its impact upon the surrounding environment has become a real issue, stresses Hepworth. Controlling the impact of lighting on the environment, especially in terms of securing planning permission, is placing ever greater pressure on terminal operators to actively eliminate or minimise any potential light spillage.

Manufacturers have also had to improve their luminaire designs by making use of flat glass construction to reduce direct upward light output. "A lot of older installations that I come across do generate 45glare, light trespass and sky glow which impacts upon the surrounding environment, " stresses Hepworth, although pointing out that the UK's Institution of Lighting Engineers does issue practical advice to lighting designers via its web site on how to reduce and prevent this, as well as specifying lighting control parameters for different categories of environmental zones.

Hepworth also underlines additional problems inherent in all shoreside locations. The saline atmosphere, he says, is highly corrosive and can result in unexpected life reduction in some luminaires and lighting masts, even to the extent of the luminaire itself breaking off and plunging to the ground if maintenance is neglected.

"The luminaires have to be built of material sufficiently resistant to enable them to function in such a harsh environment. They also have to be sealed to prevent the ingress of moisture, since this can degrade the reflectors, connectors and electrical components within."

In fact, most luminaires can last from 15 to 25 years, but this really depends on construction materials, design, components and how they have been subsequently maintained, while the overall working environment has a huge influence too.

While no manufacturer limits output of lighting wholly to the maritime sector, a number of industrial suppliers do have a suitable range of products for most terminals, explains Hepworth, citing CU Phosco, Philips, Sill, Abacus and Thorn as typical of the major suppliers to the industry. "There are slight differences in performance between them, resulting in varied output and light distribution through reflector design."

Nevertheless, an established terminal operation could benefit directly by replacing its existing lighting system with the latest low cut-off-luminaires whilst also reducing the overall impact on the environment, says Hepworth, who points out that the means of achieving this would however depend on any external constraints that were being imposed on the port or whether a new opportunity had arisen to replace old luminaires, whilst reconfiguring or redeveloping a new area.

"Some ports do replace older, but not life-expired equipment, with modern luminaires. This may be a result of environmental pressure but may have the added bonus of improving the commercial bottom line, " says Hepworth, adding that computer monitoring of lighting systems is not presently an inherent feature of the industry either.

Most lights are hardwired with remote operation restricted to the control of several luminaries on the same tower or to the operation of a group of luminaires, although this is a very basic procedure consisting of little more than remote manual switching, timer or photocell control.

"The requirement to illuminate large areas of a container terminal generally necessitates the utilisation of high lumen output long life discharge lamps such as high pressure sodium lamps of up to 2,000 watts and lighting columns that can be 50 metres high. These discharge lamps can require several minutes to achieve their maximum light output and therefore are not ideally suited for control by movement detection, or similar techniques as can be effectively achieved in a domestic security lighting situation with halogen lamps, " says Hepworth, justifying the lowtech approach adopted by the industry to date.

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