MAINTENANCE

There’s a maintenance plan. It’s just that no one follows it. Francis Pearce looks at whether it’s possible to design out one of lighting’s biggest bugbears.

Lighting designers are doomed to disappointment as their expertly designed schemes gradually unravel through spec-busting and inadequate maintenance. No one sets out to produce patchy lighting with lamps out here and there and colours drifting like wonkily executed tie-dye, but that’s what often happens as carefully calculated and optimised maintenance schedules corrode though penny-pinching or because they are just too much trouble to implement.

Rather than ignore the inevitable, might it be possible to design out maintenance entirely? It might be apocryphal but at least one local council believes so, according to lighting designer Kevin Theobald, who says that it was supposedly so convinced by the idea that LEDs would last forever and could be used anywhere and everywhere that it was seriously considering a massive one-time installation and disbanding its maintenance team.

‘Lighting maintenance is going to change over the next few years because there will be less to do with LEDs, but it’s not going to go away,’ says Geoff Coffin, sales and marketing director of Planned Lighting Maintenance. ‘If you went for a complete relamp and replaced every one in every fitting with T5s, CFLs and LEDs with 50,000-hour projected life spans, and new control gear, at 5000 hours use a year you could walk away for decade – in theory. But manufacturers’ failures can be up to 50 per cent, which means that in the best case you would still have to start replacing them after five years. In reality it would be well before that. ‘

Despite the current emphasis on the likely impact of LEDs in the market, manufacturers are admitting that conventional linear fluorescent and metal halide light sources will have a substantial part to play in lighting for some time to come as they are efficient, cost-effective and provide a better quality of light than an all-LED solution. With this in mind, it seems inevitable that maintenance will continue to be of vital importance in retaining the visual and design criteria of the original concept.

However misplaced that council’s faith in LEDs, the choice of lamp and luminaire does have a bearing on maintenance. The maintenance factor of an indoor lighting system is calculated by multiplying four things. Two are down to the choice of lamp technology: the drop in lumen output after a given number of burning hours and the percentage of lamp failures after a specific number of hours – the lamp survival factor (LSF). The other two are about cleaning, including how much the light output falls due to dirt on the luminaire.

Assuming what was specified by the designer has been installed, it is possible to design out one of these factors by replacing lamps as soon as they fail. This takes the LSF out of the equation. But predicting which individual lamps will reach a set percentage of their initial output first, and precisely when, is an art. It’s especially hard to do if they have been replaced piecemeal, yet many clients struggle with the idea that large-scale or total re-lamping might be better than calling out maintenance companies reactively.

The typical survival curve of most lamps means that while they are reliable to a certain juncture in their lives, once they go past that, they can go into critical failure, at which point it is difficult to keep reactive repairs up with the level of failure. At this point certain lamps will be out for long periods which means that in many case they will burn out the control gear supplying them. This multiplies the cost and complexity of any repairs and, furthermore, when a lamp has failed, but before the control gear fails, that control gear is still consuming energy – so not only are you not getting any light, you are paying for energy not to get any light.

Whatever design is installed, a planned approach to maintenance is always better than a reactive one, says Mike Thompson, managing director of Weblight, which provides design, installation and maintenance services to the lighting industry. ‘It allows the work to be undertaken when it suits the site, rather than when it is determined by failure levels. The planned approach very significantly reduces the cost of the work to be undertaken.’

Apart from psychological blocks to better maintenance there are often practical ones such as access. ‘It is pointless putting fixtures in difficult to access locations,’ says Theobald. ‘Even if a regime of towers or cherry pickers has been conceived it is worth considering how these will be implemented in the real world of the operator/maintenance staff. And it is essential to consider access and storage for any access equipment.’

Some engineering design solutions exist. In exterior lighting, there are base-hinged masts for floodlighting that tip down to the ground level so there is no need for climbing or high lifts, and titanium dioxide coatings are used to make lighting for airport runways and flyovers self-cleaning. They work by throwing off rainwater and carrying the dirt with it: the lotus effect. Over the past 20 years the continual improvement in the IP rating of external luminaires has meant that simple cleaning of luminaires has generally been dropped as they only need to be cleaned when the lamps are changed. The old problem of internal dirt obscuring the light output has to a large extent been eliminated.

Attempts at creating self-cleaning interior lighting include titanium-oxide-coated Japanese lanterns, but more practical applications are still on their way. They are evidently needed, especially as the current economic downturn is seeing less assiduous maintenance in ths area. ‘Cleaning is done less and less,’ says Coffin. ‘Since the recession hit, the number of “clean and relamps” we are asked do has halved.’

So is it maintenance or the client that needs to be designed around, if not out? Phil Sharman, managing director of Cygnia Maintenance recalls being called out to solve an issue with a retailer’s sign. ‘It had a daylight sensor so that it would light up at night but it had been put right next to a street lamp,’ he laughs. ‘You couldn’t make it up, could you?’

Lighting designers are doomed to disappointment as their expertly designed schemes gradually unravel through spec-busting and inadequate maintenance. No one sets out to produce patchy lighting with lamps out here and there and colours drifting like wonkily executed tie-dye, but that’s what often happens as carefully calculated and optimised maintenance schedules corrode though penny-pinching or because they are just too much trouble to implement.

Rather than ignore the inevitable, might it be possible to design out maintenance entirely? It might be apocryphal but at least one local council believes so, according to lighting designer Kevin Theobald, who says that it was supposedly so convinced by the idea that LEDs would last forever and could be used anywhere and everywhere that it was seriously considering a massive one-time installation and disbanding its maintenance team.

‘Lighting maintenance is going to change over the next few years because there will be less to do with LEDs, but it’s not going to go away,’ says Geoff Coffin, sales and marketing director of Planned Lighting Maintenance. ‘If you went for a complete relamp and replaced every one in every fitting with T5s, CFLs and LEDs with 50,000-hour projected life spans, and new control gear, at 5000 hours use a year you could walk away for decade – in theory. But manufacturers’ failures can be up to 50 per cent, which means that in the best case you would still have to start replacing them after five years. In reality it would be well before that. ‘

Despite the current emphasis on the likely impact of LEDs in the market, manufacturers are admitting that conventional linear fluorescent and metal halide light sources will have a substantial part to play in lighting for some time to come as they are efficient, cost-effective and provide a better quality of light than an all-LED solution. With this in mind, it seems inevitable that maintenance will continue to be of vital importance in retaining the visual and design criteria of the original concept.

However misplaced that council’s faith in LEDs, the choice of lamp and luminaire does have a bearing on maintenance. The maintenance factor of an indoor lighting system is calculated by multiplying four things. Two are down to the choice of lamp technology: the drop in lumen output after a given number of burning hours and the percentage of lamp failures after a specific number of hours – the lamp survival factor (LSF). The other two are about cleaning, including how much the light output falls due to dirt on the luminaire.

Assuming what was specified by the designer has been installed, it is possible to design out one of these factors by replacing lamps as soon as they fail. This takes the LSF out of the equation. But predicting which individual lamps will reach a set percentage of their initial output first, and precisely when, is an art. It’s especially hard to do if they have been replaced piecemeal, yet many clients struggle with the idea that large-scale or total re-lamping might be better than calling out maintenance companies reactively.

The typical survival curve of most lamps means that while they are reliable to a certain juncture in their lives, once they go past that, they can go into critical failure, at which point it is difficult to keep reactive repairs up with the level of failure. At this point certain lamps will be out for long periods which means that in many case they will burn out the control gear supplying them. This multiplies the cost and complexity of any repairs and, furthermore, when a lamp has failed, but before the control gear fails, that control gear is still consuming energy – so not only are you not getting any light, you are paying for energy not to get any light.

Whatever design is installed, a planned approach to maintenance is always better than a reactive one, says Mike Thompson, managing director of Weblight, which provides design, installation and maintenance services to the lighting industry. ‘It allows the work to be undertaken when it suits the site, rather than when it is determined by failure levels. The planned approach very significantly reduces the cost of the work to be undertaken.’

Apart from psychological blocks to better maintenance there are often practical ones such as access. ‘It is pointless putting fixtures in difficult to access locations,’ says Theobald. ‘Even if a regime of towers or cherry pickers has been conceived it is worth considering how these will be implemented in the real world of the operator/maintenance staff. And it is essential to consider access and storage for any access equipment.’

Some engineering design solutions exist. In exterior lighting, there are base-hinged masts for floodlighting that tip down to the ground level so there is no need for climbing or high lifts, and titanium dioxide coatings are used to make lighting for airport runways and flyovers self-cleaning. They work by throwing off rainwater and carrying the dirt with it: the lotus effect. Over the past 20 years the continual improvement in the IP rating of external luminaires has meant that simple cleaning of luminaires has generally been dropped as they only need to be cleaned when the lamps are changed. The old problem of internal dirt obscuring the light output has to a large extent been eliminated.

Attempts at creating self-cleaning interior lighting include titanium-oxide-coated Japanese lanterns, but more practical applications are still on their way. They are evidently needed, especially as the current economic downturn is seeing less assiduous maintenance in ths area. ‘Cleaning is done less and less,’ says Coffin. ‘Since the recession hit, the number of “clean and relamps” we are asked do has halved.’

So is it maintenance or the client that needs to be designed around, if not out? Phil Sharman, managing director of Cygnia Maintenance recalls being called out to solve an issue with a retailer’s sign. ‘It had a daylight sensor so that it would light up at night but it had been put right next to a street lamp,’ he laughs. ‘You couldn’t make it up, could you?’