Lighting Design Why Maintenance Factors Matter

Lighting Design - Why Maintenance Factors Matter

Lighting Design - Why Maintenance Factors Matter · Peter Thorns © ZLD

Lighting Design - Why Maintenance Factors MatterWhat does a lighting design guarantee?

Task visibility

Practical

Glare control

Energy Efficient

Managed

Colour

Modeling

Contrast

Effective

Atmosphere

Ambience

StimulatingSatisfaction

SafeErgonomic

Integrated

ColourfulHealthyInteresting









Lighting in the workplace: Good practice

39 Both interior and exterior lighting need to achieve a reasonable uniform illuminance in all relevant working areas, ie illuminance across any given task area needs to be uniform. For more information see CIBSE Code for lighting.

Minimum lighting recommendations

93 The illuminance needed depends on how much detail needs to be seen. It also depends on the age of the worker, and the speed and accuracy by which the task needs to be performed. These performance- related requirements and light levels are detailed in the CIBSE Code for lighting.



Ceiling

ρ

= 0.7 - 0.9

Em = 30 lux, Uo = 0.1

Walls

ρ

= 0.5 - 0.8

Em = 50 lux, Uo = 0.1

Floor

ρ

= 0.2 - 0.4

0.3-0.7

0.6 minimum

50%-60% w/p

30%-90% w/p

(Purple text – values as in SLL Lighting Guide 7)



Task areaImmediate surround – width at least 0.5m around the task area

Background area – width at least 3m (within the limits of the space)



Task visibility

Practical

Glare control

Energy Efficient

Managed

Colour

Modeling

Contrast

Effective

Atmosphere

Ambience


SafeErgonomic

Integrated




maintained illuminance

minimum average illuminance

NOTE 1 Value below which average illuminance should not fall.

NOTE 2 It is the average illuminance at the time maintenance should be carried out.

From EN 12665:2011



The lighting scheme should be designed with an overall maintenance factor (MF) calculated for the selected lighting equipment, environment and specified maintenance schedule.

The MF has a great impact on energy efficiency. The assumptions made in the derivation of the MF shall be optimized in a way that leads to a high value. Guidance on the derivation of MF for artificial lighting systems can be found in CIE 97-2005.


Lighting Design - Why Maintenance Factors MatterWhat is managed?

Task visibility

Practical

Glare control

Energy Efficient

Managed

Colour

Modeling

Contrast

Effective

Atmosphere

Ambience


SafeErgonomic

Integrated



Lighting Design - Why Maintenance Factors MatterScheme maintenance cycle

The light levels in an installation depreciate over time

This is dependant upon ?




This is dependant upon

-Ageing of the lamp-Lamp failures-Dirt on the luminaire-Dirt on light reflecting surfaces




This is dependant upon- Ageing of the lamp- Lamp failures- Dirt on the luminaire- Dirt on light reflecting surfaces

These combine to make up the scheme maintenance factor

“ratio of the average illuminance on the working plane after a certain period of use of a lighting installation to the average illuminance obtained under the same condition for the installation considered conventionally as new”(CIE 17.4:1987)














This is dependant upon-Ageing of the lamp-Lamp failures-Dirt on the luminaire-Dirt on light reflecting surfaces

The maintenance cycle specifies-When the luminaire is cleaned-When the lamp is replaced-When reflecting surfaces are cleaned

The scheme maintenance factor is the worst case relative illuminance over this maintenance cycle




Lighting Design - Why Maintenance Factors MatterScheme maintenance cycle – lamp lumen maintenance factor (LLMF)

Ageing of the lamp

Let us assume for an office area annual operating hours are 2500 hours (BS EN 15193:2007)

If we decide to change the lamps every 4 years that is the equivalent of every 10,000 hours



91%



Ageing of the lamp

Let us assume for an office area annual operating hours are 2500 hours (BS EN 15193:2007)

If we decide to change the lamps every 4 years that is the equivalent of every 10,000 hours

So the lamp lumen maintenance factor is 0.91


Lighting Design - Why Maintenance Factors MatterScheme maintenance cycle – lamp survival factor (LSF)

Lamp failures

Let us assume in our office area we do not do spot lamp replacement, but bulk replace the lamps

We decided to change the lamps every 4 years



95%



Lamp failures

Let us assume in our office area we do not do spot lamp replacement, but bulk replace the lamps

We decided to change the lamps every 4 years

So the lamp survival factor is 0.95


Type Luminaire type Luminaire description

A Bare batten Bare lamp luminaires

B

Open top housing (natural ventilated and “self cleaning” types)

Direct-indirect luminaries without cover, direct-indirect luminaries with indirect reflector and closed optical device, wallwashing luminaries (vertical opening), wall mounted luminaries open top and base, downlights with open top

CClosed top housing (unventilated)

Recessed and surface mounted luminaries (e.g. with louvers), downlights, spotlights

D Enclosed IP2X

General purpose luminaries with closed covers and optics

E Dust proof IP5X

Dust proof IP5X (protected, clean room luminaries)

FIndirect lighting and uplight

Free standing, pendent, wall mounted uplighters with closed base, cove lights

GAir handling and forced ventilated

Air handling body and optic used with air-conditioning or ventilation systems

Lighting Design - Why Maintenance Factors MatterScheme maintenance cycle – luminaire maintenance factor (LMF)

Dirt on the luminaire

Luminaire types are classified according to the table shown (extracted from CIE 97:2005)




Luminaire types are classified according to the table shown (extracted from CIE 97:2005)

These are used to reference a table of luminaire maintenance factors

TypeLuminaire type Luminaire description

A Bare batten Bare lamp luminaires

B

Open top housing (natural ventilated and “self cleaning” types)

Direct-indirect luminaries without cover, direct-indirect luminaries with indirect reflector and closed optical device, wallwashing luminaries (vertical opening), wall mounted luminaries open top and base, downlights with open top

C

Closed top housing (unventilated )

Recessed and surface mounted luminaries (e.g. with louvers), downlights, spotlights

D Enclosed IP2X

General purpose luminaries with closed covers and optics

E Dust proof IP5X

Dust proof IP5X (protected, clean room luminaries)

FIndirect lighting and uplight

Free standing, pendent, wall mounted uplighters with closed base, cove lights

GAir handling and forced ventilated

Air handling body and optic used with air-conditioning or ventilation systems



Environments are split into very clean (VC), clean (C), normal (N) and dirty (D)

A maintenance value is read by determining the luminaire type and environment, and then deciding the cleaning interval

Elapsed time between cleanings in years

0 0.5 1.0 1.5 2.0 2.5 3.0

Environment

Luminaire type Any VC C N D VC C N D VC C N D VC C N D VC C N D VC C N D

A 1 0,98 0.95 0.92 0.88 0.96 0.93 0.89 0.83 0,95 0.91 0.87 0.80 0.94 0.89 0.84 0.78 0,93 0.87 0.82 0.75 0.92 0.85 0.79 0.73

B 1 0,96 0.95 0.91 0.88 0.95 0.90 0.86 0.83 0,94 0.87 0.83 0.79 0.92 0.84 0.80 0.75 0,91 0.82 0.76 0.71 0.89 0.79 0.74 0.68

C 1 0,95 0.93 0.89 0.85 0,94 0.89 0.81 0.75 0,93 0.84 0.74 0.66 0,91 0.80 0.69 0.59 0,89 0.77 0.64 0.54 0,87 0.74 0.61 0.52

D 1 0,94 0.92 0.87 0.83 0.94 0.88 0.82 0.77 0,93 0.85 0.79 0.73 0.91 0.83 0.77 0.71 0,90 0.81 0.75 0.68 0.89 0.79 0.73 0.65

E 1 0,94 0.96 0.93 0.91 0,96 0.94 0.90 0.86 0,92 0.92 0.88 0.83 0,93 0.91 0.86 0.81 0,92 0.90 0.85 0.80 0,92 0.90 0.84 0.79

F 1 0,94 0.92 0.89 0.85 0.93 0.86 0.81 0.74 0,91 0.81 0.73 0.65 0.88 0.77 0.66 0.57 0,86 0.73 0.60 0.51 0.85 0.70 0.55 0.45

G 1 1,00 1.00 0.99 0.98 1,00 0.99 0.96 0.93 0,99 0.97 0.94 0.89 0,99 0.96 0.92 0.87 0,98 0.95 0.91 0.86 0,98 0.95 0.90 0.85


Environment Activity or Task area

Very Clean

Clean

Clean rooms, semi conductor plants, hospital clinical areas, computer centres

Offices, schools, hospital wards

NormalShops, laboratories, restaurants, warehouses, assembly areas, workshops

DirtySteelworks, chemical works, foundries, welding, polishing, woodwork



The environment type for the application can be determined using the table shown. However these should be adjusted if the conditions are different from the norm



For our example we will decide to clean the luminaires every 2 years

An office is normally considered a clean environment

Assume we are using a recessed luminaire, which is luminaire type C

Therefore our luminaire maintenance factor is 0.80

Elapsed time between cleanings in years

0 0.5 1.0 1.5 2.0 2.5 3.0

Environment

Luminaire type Any VC C N D VC C N D VC C N D VC C N D VC C N D VC C N D

A 1 0,98 0.95 0.92 0.88 0.96 0.93 0.89 0.83 0,95 0.91 0.87 0.80 0.94 0.89 0.84 0.78 0,93 0.87 0.82 0.75 0.92 0.85 0.79 0.73

B 1 0,96 0.95 0.91 0.88 0.95 0.90 0.86 0.83 0,94 0.87 0.83 0.79 0.92 0.84 0.80 0.75 0,91 0.82 0.76 0.71 0.89 0.79 0.74 0.68

C 1 0,95 0.93 0.89 0.85 0,94 0.89 0.81 0.75 0,93 0.84 0.74 0.66 0,91 0.80 0.69 0.59 0,89 0.77 0.64 0.54 0,87 0.74 0.61 0.52

D 1 0,94 0.92 0.87 0.83 0.94 0.88 0.82 0.77 0,93 0.85 0.79 0.73 0.91 0.83 0.77 0.71 0,90 0.81 0.75 0.68 0.89 0.79 0.73 0.65

E 1 0,94 0.96 0.93 0.91 0,96 0.94 0.90 0.86 0,92 0.92 0.88 0.83 0,93 0.91 0.86 0.81 0,92 0.90 0.85 0.80 0,92 0.90 0.84 0.79

F 1 0,94 0.92 0.89 0.85 0.93 0.86 0.81 0.74 0,91 0.81 0.73 0.65 0.88 0.77 0.66 0.57 0,86 0.73 0.60 0.51 0.85 0.70 0.55 0.45

G 1 1,00 1.00 0.99 0.98 1,00 0.99 0.96 0.93 0,99 0.97 0.94 0.89 0,99 0.96 0.92 0.87 0,98 0.95 0.91 0.86 0,98 0.95 0.90 0.85


Lighting Design - Why Maintenance Factors MatterScheme maintenance cycle – room surface maintenance factor (RSMF)

Dirt on light reflecting surfaces

For the effect of dirt on the room surfaces three pieces of information are required

-Surface reflectance’s- Environment cleanliness (as for the luminaire maintenance factor)-Room surface cleaning interval

A table of room surface maintenance factors is then consulted



reflectances environment 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00

0.80/0.70/0.20 very clean 1.00 0.97 0.96 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95

clean 1.00 0.93 0.92 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91

normal 1.00 0.88 0.86 0.86 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85

dirty 1.00 0.81 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80

0.80/0.50/0.20 very clean 1.00 0.98 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97

clean 1.00 0.95 0.94 0.94 0.94 0.94 0.94 0.94 0.94 0.94 0.94 0.94 0.94

normal 1.00 0.91 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90

dirty 1.00 0.86 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85

0.80/0.30/0.20 very clean 1.00 0.99 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98

clean 1.00 0.97 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96

normal 1.00 0.94 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93

dirty 1.00 0.91 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90

0.70/0.70/0.20 very clean 1.00 0.97 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96

clean 1.00 0.94 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92

normal 1.00 0.89 0.87 0.87 0.87 0.87 0.87 0.87 0.87 0.87 0.87 0.87 0.87

dirty 1.00 0.83 0.81 0.81 0.81 0.81 0.81 0.81 0.81 0.81 0.81 0.81 0.81

0.70/0.50/0.20 very clean 1.00 0.98 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97

clean 1.00 0.96 0.95 0.94 0.94 0.94 0.94 0.94 0.94 0.94 0.94 0.94 0.94

normal 1.00 0.92 0.91 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90

dirty 1.00 0.87 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86

0.70/0.30/0.20 very clean 1.00 0.99 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98

clean 1.00 0.97 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96

normal 1.00 0.95 0.94 0.94 0.94 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93

dirty 1.00 0.92 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91

0.50/0.70/0.20 very clean 1.00 0.98 0.97 0.97 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96

clean 1.00 0.95 0.94 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93

normal 1.00 0.91 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89

dirty 1.00 0.85 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84

0.50/0.50/0.20 very clean 1.00 0.98 0.98 0.98 0.98 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97

clean 1.00 0.97 0.96 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95

normal 1.00 0.94 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92

dirty 1.00 0.89 0.89 0.88 0.88 0.88 0.88 0.88 0.88 0.88 0.88 0.88 0.88

0.50/0.30/0.20 very clean 1.00 0.99 0.99 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98

clean 1.00 0.98 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97

normal 1.00 0.96 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95

dirty 1.00 0.93 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92





-Surface reflectance’s- Environment cleanliness (as for the luminaire maintenance factor)-Room surface cleaning interval


So if we assume-Reflectance’s 70/50/20-Office environment, therefore clean-A cleaning interval of 5 years



reflectances environment 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00

0.80/0.70/0.20 very clean 1.00 0.97 0.96 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95

clean 1.00 0.93 0.92 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91

normal 1.00 0.88 0.86 0.86 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85

dirty 1.00 0.81 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80

0.80/0.50/0.20 very clean 1.00 0.98 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97

clean 1.00 0.95 0.94 0.94 0.94 0.94 0.94 0.94 0.94 0.94 0.94 0.94 0.94

normal 1.00 0.91 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90

dirty 1.00 0.86 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85

0.80/0.30/0.20 very clean 1.00 0.99 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98

clean 1.00 0.97 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96

normal 1.00 0.94 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93

dirty 1.00 0.91 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90

0.70/0.70/0.20 very clean 1.00 0.97 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96

clean 1.00 0.94 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92

normal 1.00 0.89 0.87 0.87 0.87 0.87 0.87 0.87 0.87 0.87 0.87 0.87 0.87

dirty 1.00 0.83 0.81 0.81 0.81 0.81 0.81 0.81 0.81 0.81 0.81 0.81 0.81

0.70/0.50/0.20 very clean 1.00 0.98 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97

clean 1.00 0.96 0.95 0.94 0.94 0.94 0.94 0.94 0.94 0.94 0.94 0.94 0.94

normal 1.00 0.92 0.91 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90

dirty 1.00 0.87 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86

0.70/0.30/0.20 very clean 1.00 0.99 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98

clean 1.00 0.97 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96

normal 1.00 0.95 0.94 0.94 0.94 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93

dirty 1.00 0.92 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91

0.50/0.70/0.20 very clean 1.00 0.98 0.97 0.97 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96

clean 1.00 0.95 0.94 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93

normal 1.00 0.91 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89

dirty 1.00 0.85 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84

0.50/0.50/0.20 very clean 1.00 0.98 0.98 0.98 0.98 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97

clean 1.00 0.97 0.96 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95

normal 1.00 0.94 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92

dirty 1.00 0.89 0.89 0.88 0.88 0.88 0.88 0.88 0.88 0.88 0.88 0.88 0.88

0.50/0.30/0.20 very clean 1.00 0.99 0.99 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98

clean 1.00 0.98 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97

normal 1.00 0.96 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95

dirty 1.00 0.93 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92





-Surface reflectance’s-Environment cleanliness (as for the luminaire maintenance factor)-Room surface cleaning interval


So if we assume-Reflectance’s 70/50/20-Office environment, therefore clean-A cleaning interval of 5 years

Therefore the room surface maintenance factor is 0.94



So for this example the scheme maintenance factor would be

MF = LLMF * LSF * LMF * RSMF

MF = 0.91 * 0.95 * 0.80 * 0.94

MF = 0.65



So for this example the scheme maintenance factor would be

MF = LLMF * LSF * LMF * RSMF

MF = 0.91 * 0.95 * 0.80 * 0.94

MF = 0.65

This means to ensure that the installation never falls below the maintained light level (assuming the maintenance schedule is adhered to) we must OVERLIGHT the area to 154% of the design level. So for example

Maintained light level = 500lx

Initial light level = 769lx


Optical IP rating

Pollution category

Exposure time (years)

1.0 1.5 2.0 2.5 3.0

IP2X High 0.53 0.48 0.45 0.43 0.42

Medium 0.62 0.58 0.56 0.54 0.53

Low 0.82 0.80 0.79 0.78 0.78

IP5X High 0.89 0.87 0.84 0.80 0.76

Medium 0.90 0.88 0.86 0.84 0.82

Low 0.92 0.91 0.90 0.89 0.88

IP6X High 0.91 0.90 0.88 0.85 0.83

Medium 0.92 0.91 0.89 0.88 0.87

Low 0.93 0.92 0.91 0.90 0.90


Note that the example given was for interior lighting.

For exterior lighting no room surface maintenance factor is used.

The luminaire maintenance factor is calculated differently, according to the table shown.


Lighting Design - Why Maintenance Factors MatterHow do we calculate the effect of our maintenance schedule?

It also means we need to define a maintenance schedule

Change lamps 4 years

Clean luminaires 2 years

Clean room surfaces 5 years

If we do not convey this to the customer we cannot guarantee the light levels

(If the customer requires a set maintenance factor, for example 0.8, we should then take no responsibility for the maintenance regime and can only guarantee light levels at start of life)

Lighting Design - Why Maintenance Factors Matter · Peter Thorns © ZLD24

Using control to offset maintenance factors

Constant Illuminance

To improve the efficiency of an installation the lighting can be controlled to only produce the correct amount of light at any time.

At start of life the lights are dimmed, as the installation ages the dimming is gradually reduced


2

11% MFsavings


Using control to offset maintenance factors

Maintenance factor : 0.65

%savings= 1-[(1+MF)/2]

%savings= 1-[(1+0.65)/2] = 0.175

Saving : 17.5%


2

11% MFsavings


Lighting Design - Why Maintenance Factors MatterLooking at maintenance factors – main influences

Change the lamp

Clean the luminaire

Clean the room


Lighting Design - Why Maintenance Factors MatterLooking at maintenance factors – tracking them through time


Lamps and Gear

Looking at maintenance factors – tracking them through timeLighting Design - Why Maintenance Factors Matter

Clean room surfaces : 6 yearClean luminaires : 2 yearGroup relamp : 2 yearMF : 0.79

L80 @ 40,000 hoursClean room surfaces : 6 yearClean luminaires : 2 yearSpot replacementMF : 0.72


Lamps and Gear

Looking at maintenance factorsLighting Design - Why Maintenance Factors Matter





Lamps and Gear

Looking at maintenance factorsLighting Design - Why Maintenance Factors Matter




Building Type

Installation life to 100,000 hours (years)

100,000 / to

Offices 40

Education 50

Hospitals 20

Hotels 20

Restaurants 40

Sports 25

Retail 20

Manufacturing 25


Lamps and Gear

Looking at maintenance factors – initial lighting levelsLighting Design - Why Maintenance Factors Matter




Em 500 lxEinitial 633 lx




Lighting Design - Why Maintenance Factors MatterLooking at maintenance factors – effect of room surfaces Clean room surfaces every 4 years instead of 6 years


Lamps and Gear

Looking at maintenance factors – effect of room surfaces Clean room surfaces every 4 years instead of 6 years










0.79

0.69



0.79¦

0.79

0.69¦

0.69


Lighting Design - Why Maintenance Factors MatterLooking at maintenance factors – effect of room surfaces Change luminaire type to an indirect solution


Lighting Design - Why Maintenance Factors MatterLooking at maintenance factors – effect of room surfaces Clean room surfaces every 6 years (indirect)

0.79 direct¦

0.74 indirect

0.69 direct¦

0.65 indirect


Lighting Design - Why Maintenance Factors MatterLooking at maintenance factors – effect of room surfaces Clean room surfaces every 4 years instead of 6 years (indirect)

0.74 @6¦

0.74 @4

0.65 @6¦

0.65 @4




Lamps and Gear

Looking at maintenance factors What influence does relamping period have?


Clean room surfaces : 4 yearClean luminaires : 2 year

Group relamp : 2 yearMF : 0.79







Lighting Design - Why Maintenance Factors MatterLooking at maintenance factors What influence does relamping period have – 2 years to 4 years?

0.69¦

0.69

0.79 T26@2¦

0.70 T26@4


Lamps and Gear

Looking at maintenance factors What influence does relamping period have?


Clean room surfaces : 4 yearClean luminaires : 2 year

Group relamp : 4 yearMF : 0.70







Lighting Design - Why Maintenance Factors MatterLooking at maintenance factors What influence does lamp technology have – T26 to T16?

0.79 T26@2¦

0.70 T26@4

0.70 T26@4¦

0.76 T16@4


Lighting Design - Why Maintenance Factors MatterLooking at maintenance factors What influence does luminaire cleaning interval have?


Lighting Design - Why Maintenance Factors MatterLooking at maintenance factors What influence does luminaire cleaning interval have?

0.76 T16@2¦

0.73 T16@4

0.69 LED@2¦

0.64 LED@4


Lighting Design - Why Maintenance Factors MatterLooking at maintenance factors COST

Clean room surfaces : 6 yearClean luminaires : 2 yearGroup relamp : 4 year


Lighting Design - Why Maintenance Factors MatterLooking at maintenance factors COST

Clean room surfaces : 6 yearClean luminaires : 4 yearGroup relamp : 4 year

~170

~80


Lighting Design - Why Maintenance Factors MatterLooking at maintenance factors Reducing installation life from 15 years

4x18W T8Clean room surfaces : 6 yearClean luminaires : 4 yearGroup relamp : 4 yearMaintenance factor 0.67


LED L70@50,000 hrsClean room surfaces : 6 yearClean luminaires : 4 yearSpot replacementMaintenance factor 0.64

LED L80@40,000 hrsClean room surfaces : 6 yearClean luminaires : 4 yearSpot replacementMaintenance factor 0.67






Lighting Design - Why Maintenance Factors MatterLooking at maintenance factors Reducing installation life from 15 years to 10 years



LED L70@50,000 hrsClean room surfaces : 6 yearClean luminaires : 4 yearSpot replacementMaintenance factor 0.72 (0.64@15)

LED L80@40,000 hrsClean room surfaces : 6 yearClean luminaires : 4 yearSpot replacementMaintenance factor 0.74 (0.67@15)






Lighting Design - Why Maintenance Factors MatterLooking at maintenance factors

Cleaning room surfaces more frequently makes little difference

However changing luminaire distribution does

Changing the luminaire cleaning interval has an impact

For conventional sources changing the lamp life has a large impact

The lifetime of LED cannot be over- extended



So for sensible use of modern technology it really comes down to cost through life



If I can reduce maintenance times I can save money – luminaire design!



Accessibility will have a big influence on maintenance costs

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Task visibility

Practical

Glare control

Energy Efficient

Managed

Colour

Modeling

Contrast

Effective

Atmosphere

Ambience


SafeErgonomic

Integrated




A design without....

-A maintenance factor

-Calculated according to a documented maintenance schedule

-Presented to the customer as part of the solution

....is a guess!


Documents

Lighting Design Why Maintenance Factors Matter