3.3.3.2 parasitic power of the controls only during the time with the lamps off Pci stand-by power for any controls and/or any battery charging power consumed by an emergency lighting
Total energy used for lighting
Total estimated energy
The total estimated energy required for a period in a room or zone shall be estimated by the following equation:
An estimate of the lighting energy required to fulfil the illumination function and purpose in the building (W L,t) shall be established using the following equation:
To estimate the parasitic energy (W P,t) needed for charging emergency lighting and standby energy for lighting controls in a building, the following equation must be utilized.
NOTE 1 The total lighting energy can be estimated for any required period t (hourly, daily, weekly, monthly or annually) in accordance with the time interval of the dependency factors used
NOTE 2 For existing buildings, W P,t and W L,t, can be established more accurately by directly and separately metering the energy supplied to the lighting (see Clause 5)
NOTE 3 This estimation does not include the power consumed by control systems remote from the luminaire and not drawing power from the luminaire Where known this should be added
NOTE 4 Equation (8) does not include the power consumed by a central battery emergency lighting system.
Total annual energy used for lighting
The annual lighting energy needed for building illumination (W L) and the annual parasitic energy (W P) for emergency lighting and standby lighting controls must be calculated using specific equations.
Lighting Energy Numeric Indicator (LENI)
W is the total annual energy used for lighting [kWh/year];
A is the total useful floor area of the building [m 2 ]
General
Lighting consumption can be accurately measured through various methods, including: a) using kWh meters on dedicated lighting circuits; b) employing local power meters integrated with lighting controllers in a lighting management system; c) utilizing a lighting management system that calculates and shares local energy consumption data with a building management system (BMS); d) implementing a lighting management system that provides energy consumption data per building section in an exportable format, such as a spreadsheet; and e) adopting a lighting management system that tracks operational hours, dimming levels, and correlates this information with its internal load database.
NOTE The measured value may be compared with the real kilowatt hours consumption measured during commissioning of the building.
Load segregation
The network of a BMS/lighting management system shall provide the same function in segregation as in the power distribution.
Remote metering
a Remote metering is recommended for buildings having completely segregated power distribution systems b Remote metering in buildings can also be used for more intelligent (lighting management) systems to provide data
NOTE Annex A gives examples of metering methods
6 Calculation of lighting energy in buildings
Installed lighting power
General
There are two forms of installed power in buildings, luminaire power and parasitic power
Luminaire power, which provides power for functional illumination shall conform to EN 12193 for lighting of sports facilities and EN 12464-1 for lighting of indoor work places
Parasitic power, which provides power for lighting control systems and for charging batteries for emergency lighting shall conform to EN 1838.
Luminaire
Luminaires and electrical components of luminaires shall be designed and constructed in accordance with the relevant parts of EN 60598, EN 60570 and/or EN 61347.
Luminaire power (P i )
The total rated power (in watts) of a specific luminaire should be obtained in accordance with Annex B.
Parasitic powers (P ci and P ei )
Parasitic power should be obtained in accordance with Annex B.
Calculation methods
Quick method
When using the quick method of estimation of the annual lighting energy estimation for typical building types, Equation (9) shall be used
NOTE 1 The energy requirement estimation by the quick method will yield higher LENI values than that obtained by the more accurate comprehensive method described in 6.3
NOTE 2 If the national values are not available, use the default values for t D, t N, F c , F D , F O and W p are given in Annexes E, F and G.
Comprehensive method
The comprehensive method allows for a more accurate determination of the lighting energy estimations for different periods e.g annual or monthly
When using the comprehensive method of lighting energy estimations Equation (6) shall be used for the required period t
NOTE 1 The daylight dependency factor (F D) for a room or zone can be determined as described in Annex C
NOTE 2 The occupancy dependency factor (F O) for a room or zone can be determined as described in Annex
NOTE 3 This method may be used for any periods and for any locations provided that the full estimation of occupancy and daylight availability is predicted
Use standard operating hours Determine correction factor
For each month Determine Monthly daylight supply factor
F month = F Determine impact for control system F
I = De (Equation C7) Determine Daylight Penetration I (Table C1 b))
Figure 2 — Flow chart illustrating the determination of the daylight dependency factor F D,n in a zone
6.2.2.2 Determination of the daylight dependency factor F D,n
To determine the daylight dependency factor \$F_{D,n}\$ for the \$n\$th room or zone, utilize the methods outlined in Annex C for both annual and monthly time periods, following the process depicted in the flow chart (Figure 2).
The daylight dependency factor \( F_{D,n} \) for a room or zone in a building is calculated based on the daylight supply factor \( F_{D,S,n} \) and the daylight-dependent electric lighting control factor \( F_{D,C,n} \) This relationship is expressed through a specific equation.
F D , S,n is the daylight supply factor that takes into account the general daylight supply in the zone n
It represents, for the considered time interval, the contribution of daylight to the total required illuminance in the considered zone n See C.3.1.3 and C.3.2.2;
F D , C,n is the daylight control factor that accounts for the daylight depending electric lighting control system’s ability to exploit the daylight supply in the considered zone n see C.4
NOTE 1 F D , ncan be determined for any time period (annual, monthly or hourly) The factor needs to be adjusted according to the period of the operation time at daytime t D
NOTE 2 Other daylight supply systems that rely on enhancements to increase or make possible daylight penetration beyond the perimeter zones are available These are not explicitly covered in this European Standard but may be calculated by using daylight factors or other methods for the calculation of F D
NOTE 3 In zones without daylight availability, F D = 1
NOTE 4 The method given in Annex C can be used to consider location and climate dependent aspects of daylight supply
6.2.2.3 Determination of occupancy dependency factor F O,n
The occupancy dependency factor F o,nfor a room or zone should be determined by the methods described in Annex D.
Determination of constant illuminance factor F c
The determination of the constant illuminance factor F c for a room or zone can be determined as described in Annex E
7 Benchmark of lighting energy requirements
When designing new or refurbished buildings, it is essential to estimate the total lighting energy requirements using default values outlined in Annex F These benchmark data indicate the potential installed power density needed for lighting various building types, ensuring that necessary and desired lighting criteria are met While the values represent averages for the entire building, they can significantly differ across individual rooms or zones.
Lighting design is constantly evolving, significantly impacting energy requirements for illumination Various influencing factors are detailed in Annex H, categorized under specific headings.
A lighting control system used locally to work places to provide individual lighting comfort by adjustment to meet personal preferences
A lighting system to take non-visual biological effects into account by automatic changing of light level, direction and colour temperature
Light pipes are reflective tubes that direct sunlight and daylight from apertures in the building roof to luminaires in the interior
• Lighting installations with scene setting
A lighting system that permits pre-setting of various illumination scenes in time and location for different activities in a room or zone
Implementing daylight-guiding systems can lead to significant energy savings by ensuring adequate daylight reaches deeper areas while effectively managing glare and preventing overheating.
1 primary power 4 kWh lighting meter
2 kWh meter other circuits 5 lighting circuit
Figure A.1 — kWh meters on dedicated lighting circuits in the electrical distribution
In Figure A.1, the kWh meter for lighting operates in parallel with the kWh meter for the rest of the electrical installation, resulting in the total building's consumption being the sum of both meters.
In Figure A.2, the kWh meters for lighting on various floors are connected in series with the building's central kWh meter, which records the overall energy consumption, including that of the lighting.
W = W light metered = ∑all floors (kWh @ date – kWh @ (date – 12 months)) [kWh/year] (A.2)
Local kWh meter values (as in Figure A.2) could be read and totalled by a Building Management System No corrections for occupancy or control types are necessary
2 kWh meter – total power 5 kWh meter – lighting circuit 1
3 power circuit 1 6 kWh meter – lighting circuit 2
Figure A.2 — Building with segregation of lighting circuits per floor and separately measured
Figure A.3 — Volt and ampere meters coupled to the inputs of the lighting controllers
NOTE 1 Some systems include a power factor meter
Local power meters coupled to or integrated in the lighting controllers of a lighting management system Information on the local consumed energy is made available to a building management system
In Figure A.3, volt and ampere meters, or watt meters, are installed on the power input of each lighting controller These controllers measure the local energy consumption by integrating the voltage and current values over time.
The bus line transmits energy consumption data to the central computer of the lighting or building management system, enabling the processing of this information The central computer can generate and export energy consumption figures, such as monthly usage per area and total lighting consumption over a 12-month period, in formats like spreadsheets.
W = W light metered = ∑all controllers ∑12 months (kWh local) [kWh/year] (A.3)
A lighting management system is essential for tracking operational hours and dimming levels, linking this data to its internal database of installed loads This system can provide valuable information to a Building Management System (BMS) for enhanced reporting or offer the data in an exportable format.
The lighting controller sums the time per lighting load proportionally per output and makes these values available via the bus line
NOTE 2 Energy consumption of luminaires not controlled by the lighting control system is not measured NOTE 3 Energy consumption of luminaires indirectly controlled via external contactors is measured
Measurement method of total power of luminaires and associated parasitic power
Introduction
For accurate energy performance calculations related to lighting in buildings, it is essential to utilize the rated luminaire input power and rated parasitic input power Rated power values should be rounded to the nearest whole number for values of 10 W and above, while those below 10 W should be rounded to two significant figures Additionally, these values must fall within a tolerance of ± 5% of the claimed value.
Test measurement of luminaire power during normal operation
The purpose of the test is to assess the total input power of the luminaire during normal operation, along with the associated parasitic power, which includes standby input power for controls, sensing devices, and charging power for emergency lighting circuits These measurements should be conducted under standard reproducible conditions that closely resemble the intended service conditions of the luminaire Ideally, electrical measurements of the luminaire should occur during photometric tests.
Standard test conditions
Test conditions for photometric measurements should be in accordance with EN 13032-1:2004, 5.1, 5.2 and 5.3.
Electrical measuring instruments
Volt meters, ampere meters and watt meters should conform to the requirements for Class Index 0,5 or better (precision grade).
Test luminaires
The luminaire should be representative of the manufacturer’s regular product The luminaire should be mounted in the position in which it is designed to operate.
Test voltage
The test voltage at the supply terminals to the luminaire should be the rated voltage of the luminaire in accordance with EN 13032-1:2004, 5.2.2.
Luminaire power (P i )
The luminaire power \( P_i \) must be determined based on the guidelines outlined in sections B.1 to B.6 or as specified by the manufacturer This value should account for losses in all lamps, ballasts, and other components, reflecting the normal full output operating mode or the maximum light output when the luminaire is equipped with dimming control gear.
Luminaire parasitic power with lamps off (P pi )
The luminaire parasitic power, denoted as P pi, refers to the rated power of the luminaire when it operates solely in standby mode In the case of controlled luminaires, this power is directed to the detectors, while for emergency luminaires, it represents the steady-state power required for battery charging.
Emergency lighting luminaire parasitic input power (P ei )
The parasitic power \$P_{ei}\$ for charging batteries in emergency luminaires must equal the declared rated power of the luminaire when it operates solely in battery charge mode.
Lighting controls standby parasitic power (P ci )
The luminaire parasitic power P ci for standby operation of the lighting controls and detectors without operating the lamps should be the declared rated parasitic power of the luminaire.
Default luminaire power for existing lighting installations
In existing buildings, the luminaire power (\$P_i\$) can be estimated using two methods: a) for lamps operating directly on mains supply voltage, such as incandescent and self-ballasted fluorescent lamps, the power is calculated as the lamp rated power multiplied by the number of lamps in the luminaire; b) for lamps connected to the mains supply through a ballast or transformer, the power is estimated as 1.2 times the lamp rated power multiplied by the number of lamps in the luminaire.
Default parasitic energy for existing lighting installations
In existing buildings, the annual parasitic energy consumption can be estimated at 1 kWh/(m² × year) for emergency lighting and 5 kWh/(m² × year) for automatic lighting controls, resulting in a total of 6 kWh/(m² × year).
Determination of the daylight dependency factor F D,n
General
This annex outlines a simplified method for calculating F D,S,n, F D,C,n, and consequently F D,n, focusing on vertical façades with fenestration and rooflight solutions The approach is applicable for both annual and monthly assessments.
In accordance with 6.2.2.2, the daylight dependency factor F D,n is determined as a function of the daylight supply factor F D,S,n and the daylight dependent artificial lighting control factor F D,C,n
The procedure outlined in Figure C.1 consists of five key steps: first, segmenting the building into zones with and without daylight access; second, assessing how room parameters, façade geometry, and external obstructions affect daylight penetration using the daylight factor; third, predicting energy savings potential through the daylight supply factor \( F_{D,S,n} \), which depends on local climate, maintained illuminance, and daylight factor; fourth, evaluating the utilization of available daylight based on the type of lighting control, represented by the daylight control factor \( F_{D,C,n} \); and finally, converting the annual daylight value \( F_{D,n} \) into monthly values.
Use standard operating hours Determine correction factor
For each month Determine Monthly daylight supply factor
F , month = F Determine impact for control system
I = De (Equation C7) Determine Daylight Penetration I (Table C1)
Figure C.1 — Flow chart illustrating the determination of the daylight dependency factor F D,n in a zone
Building segmentation: Spaces benefiting from daylight
Spaces must be divided into a daylight zone (A D,j) and a non-daylight zone (A ND,j) When a zone receives daylight from multiple facades or rooflights, the most favorable scenario can be assumed for the superimposed daylight zone for simplicity Additionally, it is acceptable to superimpose the daylight factor used to classify daylight supply based solely on the type of daylight aperture, whether it be a facade or rooflight, as outlined in sections C.3.1 and C.3.2.
The maximum depth of a daylight zone, denoted as \$a_{D,max}\$, is calculated using the formula \$a_{D,max} = 2.5 \times (h_{Li} - h_{Ta})\$ [m] In this equation, \$h_{Li}\$ represents the height of the lintel above the floor, while \$h_{Ta}\$ indicates the height of the task area above the floor.
The maximum depth of the daylight zone, denoted as \$a_{D,max}\$, is determined from the interior surface of the exterior wall, extending perpendicularly towards the considered façade If the actual depth of the calculation zone is less than this maximum depth, the space depth can be defined as \$a_{D}\$ Additionally, if the actual space depth is less than 1.25 times the calculated maximum depth, the real depth of the calculation space may be utilized for \$a_{D}\$.
Thus, the sub-area A D,j of the daylight space j results as follows:
A Dj = a D × b D [m 2 ] (C.3) where a D is the depth of daylight zone [m]; b D is the width of daylight zone [m]
The width of the daylight zone, denoted as \$b_D\$, typically aligns with the interior width of the building's façade or the calculation sector, excluding internal walls When windows are present only in specific sections of the façade, the daylight zone's width for that section is determined by the width of the windowed area plus half the depth of the daylight zone Geometric relationships are depicted in Figures C.2 and C.3.
Figure C.2 — Large faỗade opening with moderate room depth
Figure C.3 — Small faỗade opening with larger room depth
Daylight zones are typically defined as the areas directly beneath rooflights that are evenly distributed across the roof surface For individual rooflights and adjacent zones to uniformly distributed rooflight sectors, the sub-zones of the task area are considered daylight if they fall within a distance of D,max, where D,max is defined as D,max ≤ (h R – h Ta) towards the nearest edge of a rooflight Here, h R represents the clear room height of the space being evaluated with the rooflight.
For surfaces within the space of calculation not receiving any daylight: F D = 1 (C.5)
Differentiation between vertical faỗade and rooflight
When determining whether an aperture is classified as a window or a rooflight, any openings with glazed sections positioned entirely above the room's ceiling should be categorized as rooflights.
Daylight supply
Vertical faỗades
The daylight supply F DS,n is evaluated separately for vertical faỗades and rooflights
Daylight supply of a zone benefiting from daylight depends on the geometric boundary conditions described by the transparency index I T, the depth index I De and the obstruction index I O
The transparency index I T of the part of the building, which can benefit from daylight, is defined by:
A C is the area of the faỗade opening (carcass opening) of the considered space [m 2 ];
A D is the total area of horizontal work planes benefiting from natural lighting [m 2 ]
The depth index I De of the space, which can benefit from natural lighting is defined by:
The obstruction index I O accounts for effects reducing light incident onto the faỗade Examples of obstruction:
by other buildings and natural obstacles such as trees and mountains;
the building itself including simple courtyard and atrium designs;
horizontal and vertical overhangs attached to the faỗade;
The obstruction index I O should be obtained using the following equation:
I O = I O,OB x I O,OV x I O, VF x I O,CA x I O,GDF (C.8)
NOTE 1 If the correction factor for the courtyard and atria is less than 1, then the correction factor for linear obstructions I O,OB = 1 where
I O is the correction factor obstruction;
I O,OB is the correction factor for linear obstructions;
I O,OV is the correction factor overhang;
I O,VF is the correction factor for vertical fins;
I O,CA is the correction factor courtyard and atria;
I O,GDF is the correction factor for glazed double faỗades
For simplicity the obstruction can be evaluated for a window in the middle of a faỗade Obstruction influences should be averaged
I O,OB, I O,OV, I O,VF, I O,CA, I O,GDF can be obtained as follows:
Figure C.4 — Definition of obstruction angle γγγγ O,OB
The obstruction angle is calculated from the center of the carcass opening, measured at the outer plane of the building shell, as shown in Figure C.2 To determine the correction factor for linear obstructions, specific calculations can be applied.
I O,OB = cos(1,5 × γO,OB) for γO,OB < 60° (C.9)
I O,OB = 0 for γO,OB ≥ 60° (C.10) where γO,OB is the obstruction angle (°) from horizontal in accordance with Figure C.4
NOTE 2 Although there is daylight entry above 60° it has no impact on energy saving
The horizontal overhang angle is measured from the center of the carcass opening at the outer plane of the building shell, as illustrated in Figure C.5 The correction factor for overhangs can be calculated using this measurement.
I O,OV = cos(1,33 × γO,OV) for γO,OV < 67,5° (C.11)
I O,OV = 0 for γO,OV ≥ 67,5° where γO,Ov is the horizontal overhang angle (°)
Figure C.6 — Definition of vertical fin angle γγγγ O,VF
The obstruction angle for vertical fins is calculated from the midpoint of the relevant carcass opening, measured at the outer plane of the building shell, as illustrated in Figure C.6 The correction factor for vertical fins can be derived using this measurement.
I O,VF = 1 - γO,VF/300° (C.12) where γO,VF is the vertical fin angle (°)
Courtyards and atria come in various designs, with this model focusing on four-sided structures However, three-sided and linear atria may enhance daylight access in nearby indoor areas A more thorough analysis can confirm the potential for improved daylight conditions.
The geometry of the courtyard and atrium is defined by the well-depth index, represented by the formula: \[w_{i_d} = \frac{h_{At}(l_{At} + w_{At})}{2l_{At}w_{At}} \]In this equation, \(w_{i_d}\) denotes the well-depth index, \(h_{At}\) is the height from the floor level of the adjacent space to the top of the atrium or courtyard (measured in meters), while \(l_{At}\) and \(w_{At}\) represent the length and width of the atrium or courtyard, respectively, also in meters.
Figure C.7 — Quantities for defining the well-depth index
The correction factor for courtyards and atria can then be obtained by:
I O,CA = τAt x k AT,1 x k AT,2 x k AT,3 (1 – 0,85 w i_d ) for atria (C.15)
NOTE 3 Although there is daylight entry it has no impact on energy saving where τAt is transmission factor of atrium glazing for normal incidence; k AT,1 is the factor accounting for frames of atrium roof; k AT,2 is the factor accounting for dirt on atrium roof; k is the factor accounting for not normal light incidence on atrium roof (0,85, in general
The equation for the overall transmission of a glazed double façade is given by \$I_{O,GDF} = \tau_{GDF} \times k_{GDF,1} \times k_{GDF,2} \times k_{GDF,3}\$ (C.16) In this equation, \$\tau_{GDF}\$ represents the transmission factor, while \$k_{GDF,1}\$, \$k_{GDF,2}\$, and \$k_{GDF,3}\$ are factors that account for the frame, dirt, and non-normal light incidence, respectively, with \$k_{GDF,3}\$ typically set at 0.85, which is generally sufficient.
Vertical and horizontal barriers in the façade gap can be represented by the parameters I O,Ov and I O,VF The accumulation of dirt on the glazing within the gap of glazed double façades is minimal, allowing for the use of factor k 1 (refer to Equation (C.19)) for the main façade plane, resulting in k GDF,2 = 1 Additionally, the factor for the frame of the glazed double façade is defined as k GDF,1 = light transmitting area/carcass opening (C.17).
Only the part of the glazed double faỗade projected onto the transparent main (inner) faỗade plane is considered in the determination of k GDF,1
From the geometric indices I T, I De and I O the access of the zone to daylight can be estimated for the carcass faỗade opening:
D C is the daylight factor for carcass faỗade opening (i.e without fenestration and sun- protection system)
The combination of high depth indices (I De) and low transparency indices (I T) can lead to negative values for D C in this approximation Therefore, D C should either be adjusted to zero or calculated using more precise methods.
NOTE This will only occur for small daylight factors for which energy savings will be difficult to determine
The influence of fenestration and shading systems on indoor lighting levels can be assessed through facade type-dependent correlations of daylight coefficient (D C) with anticipated energy demand This involves deriving the daylight supply factor (F Ds) based on the facade system In cases where such dependencies are unavailable, a simplified estimation should be made by correlating fenestration properties without considering the shading system to the expected energy demand.
The daylight factor (D) for a zone is expressed as a percentage and is influenced by several factors The direct hemispherical transmission of fenestration (τ D65) plays a crucial role, while k 1, typically set at 0.7, accounts for the frame of the fenestration system Additionally, k 2, which usually has a value of 0.8 but can reach 1.0 for self-cleaning glazing, considers the impact of dirt on the glazing Furthermore, k 3, generally valued at 0.85 for standard glazing, addresses the effects of non-normal light incidence on the façade For reference, Table C.1a provides luminous transmittance values for various glazing materials used in vertical applications.
Depending on how to judge the impact of the fenestration and sun-protection system, therefore using either D c or D the daylight penetration can be rated in accordance with Table C.1b
Table C.1a — Typical values of the transmittance ττττ D65 of transparent and translucent building components
Triple glazing 2,0 0,70 0,63 0,75 low-e glazing, double glazed 1,7 0,72 0,60 0,74 low-e glazing, double glazed 1,4 0,67 0,58 0,78 low-e glazing, double glazed 1,2 0,65 0,54 0,78 low-e glazing, triple glazed 0,8 0,50 0,39 0,69 low-e glazing, triple glazed 0,6 0,50 0,39 0,69
NOTE The data in Table C.1a is only for indication For accurate data contact the manufacturer or supplier
The impact of the fenestration and sun-protection system can be judged by using either D c or D the daylight penetration as indicated in Table C.1b
Table C.1b — Daylight penetration as function of the daylight factor
(access of the zone to daylight)
The daylight supply factor F D,S can be approximated as a function of latitude γSite for latitudes ranging from 38° to 60° north by the following relation:
Where a and b are coefficients for determining the daylight supply factor F D,S γSite is latitude angle of building location [°]
Table C.2a provides the coefficients a and b for various maintained illuminance and daylight penetration classifications The relationship between γSite and F D,S at a maintained illuminance of 500 lx is depicted in Figure C.8 Additionally, Table C.2b presents the daylight supply factor F D,S for specific locations throughout Europe, applicable for daily operation hours from 0800 hours.
1700 hours For longer daily day time operating periods the values should be multiplied by a correction factor of 0,7 For longer non-daylight periods during the operating time the following applies
F D,S,n = 0, i.e F D,n = 1 From the annual daylight supply factors, monthly values can be derived using the procedure in accordance with C.5
Table C.2a — Coefficients for determining the daylight supply factor F DS for vertical faỗades as function of daylight penetration in zone n and maintained illuminance Ē m
Figure C.8 — Daylighting supply factor F DS for vertical faỗades as function of the site latitude γγγγ and daylight penetration for a maintained illuminance Ē m of 500 lux
Table C.2b — Daylight supply factor F DS for vertical faỗades as function of the daylight penetration and the maintained illuminance Ē m for different sites
Daylight supply factor F D,S ranges from 0 to 1
[°] weak medium strong weak medium strong weak medium strong
Rooflights
The daylight supply for vertical façades is initially assessed using the daylight factor Subsequently, the daylight supply factor is calculated based on the daylight factor, maintained illuminance, and the orientation and tilt of the glazed roof openings.
In rooms with rooflights the mean daylight factor ( D j ) is given by the following equation: j ext D65 Obl,1 Obl,2 Obl,3 Rb R
A Rb is the area of the rooflight openings (area of carcass opening) [m 2 ];
A RG is the floor area of considered space [m 2 ];
The external daylight factor, denoted as \$D_{ext}\$ [%], is influenced by several factors including the luminous transmittance of scattering roof glazing, represented as \$\tau_{D65}\$ Additionally, framing is accounted for with a factor \$k_{Obl,1\$ (typically 0.8), while dirt is considered with \$k_{Obl,2\$ (also typically 0.8) The factor for non-perpendicular light incidence is represented as \$k_{Obl,3\$ (usually 0.85) Finally, the utilization factor, denoted as \$\eta_{R}\$, is determined according to Tables C.5 and C.6.
This procedure is suitable for clear glazing, with Tables C.3a and C.3b providing luminous transmittance values for rooflight materials These tables serve as a reference, and for precise information, it is recommended to consult the manufacturer or supplier directly.
Table C.3a — Benchmark values for luminous transmittances U , g , τ D65 for different plastic glazing materials often used in rooflights
“A” individual rooflights, glazed, “B” continuous rooflight, glazed
Acrylic glazing, single skin clear 5,4 0,85 0,92
Acrylic glazing, single skin opal 5,4 0,80 0,83
Acrylic glazing, double skin clear 2,7 0,78 0,80
Acrylic glazing, double skin opal/clear 2,7 0,72 0,73
Acrylic glazing, triple skin clear 1,8 0,66 0,68
Acrylic glazing, triple skin opal/opal/ clear 1,8 0,64 0,60
Polycarbonate structured sheets are available in various configurations and thicknesses, offering a range of options for different applications The 6 mm double skin sheets come in clear and opal, with thermal insulation values of 0.86 and 0.78, respectively For enhanced durability, the 8 mm double skin sheets provide clear and opal options with thermal values of 0.81 and 0.70 The 10 mm double skin sheets, also available in clear and opal, have thermal values of 0.85 and 0.70 Moving to triple skin options, the 10 mm sheets in clear and opal have thermal values of 0.69 and 0.62, while the 16 mm triple skin sheets offer values of 0.69 and 0.55 The quintuple skin sheets in 16 mm and 20 mm thicknesses provide thermal values of 0.52 and 0.70 for clear, and 0.46 for opal Lastly, the 25 mm quadruple skin sheets have thermal values of 0.62 for clear and 0.53 for opal, while the sextuple skin sheets in the same thickness offer a thermal value of 0.67 for clear.
Polycarbonate-structured-sheet, sextuple skin, 25 mm opal 1,45 0,46 0,44
Table C 3b — Benchmark values for luminous transmittances U , g , τ D65 for different glass type glazing materials often used in rooflights
“A” individual rooflights, glazed, “B” continuous rooflight, glazed
A 4 mm float glass 16 mm air
4 mm float glass Clear double pane 2,8 0,79 0,81
A 4 mm toughened glass 16 mm Argon Clear double pane
4 mm float glass w coating Low-e 1,2 0,59 0,76
A 4 mm toughened glass 14 mm Argon Clear double pane
A 4 mm toughened 14 mm air Clear double pane
33.1 laminated float glass w coating Low-e, Sun protection 1,2 0,27 0,42
16 mm air, 6 mm float glass
16 mm air, 8 mm float glass
16 mm air, 6 mm float glass
16 mm air, 8 mm float glass
16 mm air, 6 mm float glass
16 mm air, 8 mm float glass
16 mm argon, 6 mm float glass
16 mm argon, 8 mm float glass
16 mm argon, 6 mm float glass
16 mm argon, 8 mm float glass
16 mm argon, 6 mm float glass
16 mm argon, 8 mm float glass
B 6 mm toughened glass (extra clear) Clear double pane 1,5 0,61 0,79
18mm Argon, 33.1 laminated float glass
B 6 mm toughened glass (green) Clear double pane 1,5 0,38 0,64
18 mm Argon, 33.1 laminated float glass
B 6 mm toughened glass (grey) Clear double pane 1,5 0,34 0,39
18 mm Argon, 33.1 laminated float glass
B 6 mm toughened glass (extra clear) Clear double pane 1,5 0,55 0,78
18 mm Argon, 44.1 laminated float glass
The external daylight factor D extis defined as follows:
E F is the illuminance on the outer surface of the rooflight in the plane of the glazing for overcast sky conditions (lux);
E ext is the unobstructed horizontal outdoor illuminance at overcast sky conditions (lux)
The factor for determining framing k Obl,1 is derived similarly to vertical façades In the case of individual rooflights, the construction devices also encompass upstands The value of k Obl,1 represents the ratio of the light input area A.
Fs = a s x b s, i.e the top opening of the upstand less further opaque construction elements of the individual rooflights or continuous rooflights, to the area of carcass opening
Rb in accordance with Figure C.2
In saw tooth lighting sections where the carcass opening does not align with the intersection of the shed body and roof, the area of the carcass opening is calculated using the formula \( A_{Rb} = h_G \times b_{Rb} \), where \( h_G \) is the height and \( b_{Rb} \) is the width of the light input area The framing factor \( k_{Obl,1} \) accounts for additional opaque construction elements within the carcass opening For reference, Table C.4 provides external daylight factors \( D_{ext} \) at a ground luminous reflectivity \( \rho_B \) of 0.2 for various tilt angles of the shed glazing.
Table C.4 — External daylight factor D ext as a function of the slope angle of the glazed shed roof γγγγ F at a ground luminous reflectivity ρ
G of 0,2 (without obstruction) Slope angle γ
The utilization factor \$\eta_R\$ is calculated based on the type of rooflight and the room index \$k\$, defined by the formula \$k = \frac{a_{R,j} \times b_{R,j}}{h_{R} \times (b_{R,j} + a_{R,j})}\$ (C.22) In this equation, \$a_{R,j}\$ represents the room depth in meters, \$b_{R,j}\$ denotes the room width in meters, and \$h_{R}\$ is the height difference between the room and the working plane.
Rooflights can be categorized into distinct types, as illustrated in Figure C.9a, b, c, while shed roofs are depicted in Figure C.10 Continuous rooflights are considered a specific case of individual rooflights For continuous rooflights with a ratio of \$\frac{a_s}{b_s} > 5\$, it is recommended to use the utilization factor for \$\frac{a_s}{b_s} = 5\$ Utilization factors for various configurations of rooflights and shed roofs are detailed in Table C.5 and Table C.6.
The key parameters for the aperture include its clear length (a) and clear width (b), both measured in meters Additionally, the upstand or well is defined by its clear length (a Rb) and clear width (b Rb), also in meters, along with its height (h_s) and the angle (γ) of the upstand, measured in degrees.
Key h G a s and b s [m] h W total height of construction [m] γ F angle of glazing to horizontal [º] γ ω angle of roof to horizontal [º]
Figure C.10 — Quantities for describing the geometry of shed roofs
Table C.5 — Utilization factor η R in % for rooflights as a function of the room index k and the geometric parameters for the light-shaft of the rooflight a s /b s 1 2 5 1 2 5 h s /b s 0,25 0,25 0,25 0,5 0,5 0,5 γγγγ w k
Table C.6 — utilization factor η R in % for shed roofs (saw tooth roofs) as a function of the room index k and the geometric parameters h G / h W 1 0,5 γγγγ F 30 45 60 90 30 45 60 90 γγγγ W 30 45 60 75 45 30 45 60 75 30 45 60 75 30 45 60 75 45 30 45 60 75 30 45 60 75 k
The classification of the daylighting supply for rooflights is given in Table C.7
Table C.7 — Classification of the daylighting supply as a function of the daylight factor D j
Criterion Classification of the daylighting supply
NOTE * Values > 10 % should be avoided because of the danger of overheating
If the daylight factor has been obtained by using other validated methods, it can be used instead of
Equation (C.1) to identify the classification of the daylighting supply (in accordance with Table C.6)
Here, the daylight factor is the mean value on the working plane
D,S,n may be determined by using tables similar to those shown in Table C.8 Variable sun protection systems are not considered The data have been computed from hourly based weather datasets of the specified city locations A simple interpolation as for vertical faỗades is not possible For maintained illuminance values < 300 lux the values for 300 lux should be used for F
D,S,n, and for maintained illuminances > 750 lux, the values for 750 lux should be used.
The data depending on the classification of the daylight supply, the maintained illuminance, different orientations and slope angles
The following daylight factors have been used in the calculations: low: 3 %, medium: 5,5 %, good:8,5 %
Table C.8 presents the daylight supply factor \( F_{D,S,n} \) for rooflights across various cities, with a specific focus on Athens, located at a latitude of 38° The maintained illuminance levels (lux) are categorized by orientation and slope angles For horizontal rooflights, the factors range from 0.86 to 1.00, indicating strong daylight supply South-facing rooflights show a slight decrease in factors, with values between 0.80 and 0.99 East and West orientations maintain similar trends, with factors ranging from 0.39 to 0.99, while North-facing rooflights exhibit the lowest values, from 0.18 to 0.99 This data highlights the importance of orientation and slope in optimizing daylight supply in architectural design.
The EN 15193 standard provides a detailed table (C.8b) outlining the daylight supply factor for Lyon, located at a latitude of 46° This table specifies the maintained illuminance levels in lux across various conditions, categorized as weak, medium, and strong The illuminance values range from 0.33 to 0.96, reflecting the effectiveness of daylight in different scenarios For instance, under strong conditions, the maintained illuminance can reach up to 0.96 lux, while in weak conditions, it may drop to as low as 0.33 lux This data is crucial for optimizing natural light usage in architectural design and energy efficiency.
The daylight supply factor in Bratislava, located at a latitude of 48°, varies based on orientation and slope angles For horizontal surfaces, the maintained illuminance (lux) values range from 0.70 to 0.94 across different classifications of daylight supply, including weak, medium, and strong In south-facing orientations, the values are slightly lower, with a maximum of 0.94 and a minimum of 0.67 East and west orientations show similar trends, with maintained illuminance values reaching up to 0.94 North-facing surfaces exhibit the lowest values, with a maximum of 0.94 and a minimum of 0.30, indicating a significant variation in daylight availability based on orientation and slope.
EN 15193: Table C.8d — Daylight supply factor in Frankfurt (latitude 50°) Maintained illuminance (lux) cation of t supply les (°) Ē m 00 Ē m P0 Ē m u0 w eak m edi um strong w eak m edi um strong w eak m edi um strong 0, 88 0, 95 0, 97 0, 78 0, 89 0, 94 0, 66 0, 82 0, 0, 85 0, 94 0, 96 0, 73 0, 87 0, 93 0, 62 0, 79 0, 0, 81 0, 91 0, 95 0, 68 0, 83 0, 91 0, 57 0, 74 0, 0, 75 0, 88 0, 93 0, 61 0, 77 0, 86 0, 51 0, 67 0, 0, 56 0, 72 0, 83 0, 44 0, 59 0, 7 0, 35 0, 49 0, 0, 84 0, 93 0, 96 0, 71 0, 86 0, 93 0, 58 0, 77 0, 0, 78 0, 91 0, 95 0, 63 0, 81 0, 9 0, 5 0, 7 0, 0, 7 0, 87 0, 93 0, 53 0, 74 0, 85 0, 41 0, 6 0, 0, 46 0, 67 0, 81 0, 33 0, 5 0, 65 0, 24 0, 38 0, 0, 82 0, 93 0, 95 0, 69 0, 85 0, 92 0, 55 0, 75 0, 0, 76 0, 9 0, 95 0, 59 0, 8 0, 89 0, 45 0, 67 0, 0, 66 0, 85 0, 92 0, 45 0, 71 0, 83 0, 31 0, 54 0, 0, 38 0, 63 0, 78 0, 23 0, 41 0, 6 0, 15 0, 28 0,
The daylight supply factor in London, located at a latitude of 51°, varies based on orientation and slope angles For horizontal surfaces, the maintained illuminance (lux) ranges from 0.66 to 0.94, depending on the daylight supply classification, which includes weak, medium, and strong categories South-facing slopes show maintained illuminance values between 0.64 and 0.93, while east/west orientations exhibit values from 0.40 to 0.93 North-facing slopes have the lowest illuminance, ranging from 0.31 to 0.93 These variations highlight the importance of orientation and slope in optimizing natural light in architectural design.
EN 15193: Table C.8f — Stockholm (latitude 59,65°) Maintained illuminance (lux) ification of light supply les (°) Ē m 00 Ē m P0 Ē m u0 w eak m edi um strong w eak m edi um strong w eak m edi um strong 0, 75 0, 82 0, 86 0, 66 0, 76 0, 81 0, 56 0, 69 75 0, 82 0, 86 0, 67 0, 76 0, 81 0, 58 0, 70 0, 74 0, 81 0, 85 0, 65 0, 75 0, 80 0, 56 0, 69 72 0, 80 0, 84 0, 63 0, 73 0, 79 0, 54 0, 67 66 0, 76 0, 81 0, 56 0, 68 0, 75 0, 47 0, 60 72 0, 81 0, 85 0, 62 0, 74 0, 80 0, 51 0, 66 0, 70 0, 80 0, 84 0, 58 0, 71 0, 79 0, 47 0, 63 66 0, 78 0, 83 0, 53 0, 68 0, 77 0, 42 0, 58 58 0, 72 0, 79 0, 43 0, 60 0, 71 0, 32 0, 49 71 0, 80 0, 85 0, 60 0, 72 0, 79 0, 49 0, 64 0, 67 0, 78 0, 84 0, 54 0, 69 0, 77 0, 40 0, 59 63 0, 76 0, 82 0, 45 0, 66 0, 75 0, 32 0, 53 53 0, 70 0, 78 0, 34 0, 56 0, 68 0, 23 0, 41
Daylight dependent artificial lighting control, F D,C
F D,C,n measures the effectiveness of a control system in utilizing the available daylight potential, represented by F D,S,n It is important to note that F D,C does not account for the power consumption of the control gear For further details, refer to Table C.9, which presents the correction factor F D,C for daylight supply.
Table C.9 — F D,C,n as a function of daylight penetration
F D,C,n as function of daylight penetration
Control of artificial lighting system weak medium strong
NOTE The daylight sensor should be mounted in a suitable position to detect the relevant variations in daylight
Monthly method
Monthly values of the daylight dependency factor F D,n can be obtained from the following equation:
F D,n = 1- ( F D,S,n x F D,C,n x c D,S,n ) (C.23) where c D,S n is the monthly redistribution factor and given in Table C.10
Table C.10 — Monthly redistribution factor c D,S n as function of daylight penetration
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec weak 0,38 0,68 1,02 1,36 1,56 1,62 1,53 1,39 1,13 0,77 0,28 0,28 medium 0,47 0,80 1,05 1,30 1,46 1,42 1,40 1,35 1,16 0,89 0,35 0,35
Summertime daylight can meet all of the daytime lighting requirements Since F D,S,n x F D,C,n - determined on a yearly basis – is weighed with monthly redistribution factors, for all months with
F D,S,n x F D,C,n x cD,S,n > 1, the difference (F D,S,n x F D,C,n x cD,S,n - 1) has to be summed up and has to be redistributed equally onto the monthly values F D,S,n x F D,C,n x c D,S,n for those months which hold
F D,S,n x F D,C,n x c D,S,n < 1 Eventually this process has to be iterated
Determination of occupancy dependency factor F O
Introduction
This section describes the analysis and rules to be followed to determine F O Whatever type of control system is used, if F O is taken as 1,0, no further analysis is needed.
Detailed determination of F O
In the following cases, F O should always be equal to 1
When lighting is controlled centrally, it means that multiple rooms can be illuminated simultaneously through a single automatic system, such as a timer or manual switch, which can operate for an entire building, a floor, or all corridors This concept applies regardless of the type of switch used, whether it is automatic or manual, centralized or individual for each room.
If the area illuminated by a group of luminaires that are (manually or automatically) switched together, is larger than 30 m 2
Exceptions are meeting rooms where this area limitation does not apply (see below)
In specific scenarios, the factor F O must remain below 1 This applies to meeting rooms, regardless of the area served by a single switch or detector, provided they are not centrally controlled with luminaires in other spaces Additionally, in other rooms, if the illuminated area by a luminaire or a group of luminaires, which are switched on together (either manually or automatically), does not exceed 30 m² and all luminaires are located within the same room Furthermore, for systems equipped with automatic presence or absence detection, the coverage area of the detector should closely match the illuminated area of the luminaires it controls.
In both cases, also the conditions with respect to timing and dimming level outlined below should be fulfilled (If these conditions are not satisfied, F O = 1.)
In these instances, F Oshould be determined as follows:
Where F A is the proportion of the time that the space is unoccupied Figure D.1, illustrates the impact of these equations
The default value of F OC is established based on the lighting control system, as outlined in Table D.1 Meanwhile, the default value of F A is set at either the building or room level, as specified in Table D.2.
Table D.1 — F OC values Systems without automatic presence or absence detection F OC
+ additional automatic sweeping extinction signal 0,95
Systems with automatic presence and/or absence detection F OC
For systems without automatic presence or absence detection the luminaire should be switched on and off with a manual switch in the room
An automatic signal may also be included which automatically switches off the luminaire at least once a day, typically in the evening to avoid needless operation during the night
Automatic presence and absence detection systems operate under several scenarios: a) 'Auto On / Dimmed' mode activates luminaires when presence is detected and dims them to 20% output within 15 minutes after the last detected presence, fully turning them off after another 15 minutes; b) 'Auto On / Auto Off' mode turns on luminaires with detected presence and switches them off entirely within 15 minutes after the last presence; c) 'Manual On / Dimmed' mode requires manual activation of luminaires, which will dim to 20% output if not turned off manually within 15 minutes after the last presence is detected.
Table D.2 — Sample F A values Overall building calculation Room by room calculation
Building type F A Building type Room type F A
Offices 0,20 Offices Cellular office 1 person
Open plan office > 6 persons sensing/30 m 2 Open plan office >6 persons sensing/10 m 2 Corridor (dimmed)
Entrance hall Showroom/expo Bathroom Rest room Storage room/cloakroom Technical plant room Copying/server room Conference room Archives
Classroom Room for group activities Corridor (dimmed) Junior common room Lecture hall
Staff room Gymnasium/Sports hall Dining hall
Teachers' staff common room Copying/storage room Kitchen
Recovery ward Operating theatre Corridors Culvert/conduit/(dimmed) Waiting area
Entrance hall Day room Laboratory
Assembly hall Smaller assembly room Storage rack area Open storage area Painting room
Overall building calculation Room by room calculation
Building type F A Building type Room type F A
Hotels and restaurants 0 Hotels and restaurants Entrance hall/lobby
Corridor (dimmed) Hotel room Dining hall/cafeteria Kitchen
Sales area Store room Store room, cold stores
Stairs (dimmed) Theatrical stage and auditorium Congress hall/exhibition hall museum/exhibition hall Library/reading area Library/archive Sports hall Car parks office - Private Car parks - Public
2 Manual On/Off Switch + additional automatic sweeping extinction signal, and Auto on/Dimmed
3 Auto On/Auto Off and Manual On/Dimmed
Figure D.1 — F O as a function of F A for the different control systems
Table D.3 — F O values as a function of F A for the different control systems
Manual On/Off Switch + additional automatic sweeping extinction signal
Auto On/Dimmed 1,000 0,975 0,950 0,850 0,750 0,550 0,650 0,450 0,350 0,250 0,000 Auto On/Auto Off 1,000 0,950 0,900 0,800 0,700 0,600 0,500 0,400 0,300 0,200 0,000 Manual On/Dimmed 1,000 0,950 0,900 0,800 0,700 0,600 0,500 0,400 0,300 0,200 0,000 Manual On/Auto Off 1,000 0,900 0,800 0,700 0,600 0,500 0,400 0,300 0,200 0,100 0,000
NOTE 1 These include e.g classical meeting rooms in office buildings and hotels, classrooms, cinemas, pubs
NOTE 2 For e.g programming purposes, this can be rewritten as a single expression:
The absence factor, denoted as F o, varies between 0 and 1, representing the portion of the reference operating time (t D + t N) when a building or room is unoccupied Typically, sleeping hours are regarded as equivalent to absence In cases where the building or room is consistently occupied during the reference time, this factor is not applicable.
F A would be 0,0 As a limit value, if a building or room would nearly never ever be entered into, F A would tend towards 1,0
The table presented outlines values for \$F_{OC}\$ based on different lighting control systems, indicating that alternative values can be established for other system types It is important to note that the "off-time" of luminaires, relative to the reference operating time (\$t_D + t_N\$), cannot exceed \$F_A\$ Additionally, the "off-state" due to daylight is excluded from this consideration but is accounted for in \$F_D\$ Consequently, \$F_O\$ cannot exceed \$1 - F_A\$.
F OC should be at least 0,80.
Motivation for the choice of FO functions
The aim of the use of the F O factor is to give a (rudimentary) appreciation of the energy efficiency of the lighting control system F O depends on 2 factors:
the type of control system;
the degree of absence of the room or the building
The simple model (i.e the shape of the curves) is purely empirical
F O decreases as the room/building is less and less occupied, i.e as F A becomes larger
For values of F A below 0,2, the slope of the curves is different to make them all converge to F O = 1,0
For values of F A greater than 0,2, the slope of the curves is different to make them all converge to
Also the values of F OC are purely empirical
Integrating qualitative considerations into lighting systems enhances energy efficiency and user satisfaction Adding an 'automatic sweeping extinction signal' to manual on/off switches ensures that luminaires do not remain lit after users leave, addressing the limitations of purely manual systems While automatic dimming systems consume more energy than those that turn off completely, there is a demand for such systems in large spaces where users prefer not to have lights extinguished in unoccupied areas Additionally, automatic systems often activate unnecessarily when brief entries occur, leading to wasted energy Systems that rely on manual switches are more efficient, as they only activate when needed and can turn off detection systems along with the lights, significantly reducing parasitic power consumption during off-hours.
NOTE Daylight influence on switching behaviour, during room occupation time, is taken into account in the factor F D
Determination of the constant illuminance factor F C
Introduction
All lighting installations begin to deteriorate and decrease their output immediately upon installation To account for this decay, the design of the lighting scheme incorporates an estimated decay rate, referred to as the Maintenance Factor (MF) The Maintenance Factor (MF) represents the ratio of maintained illuminance to initial illuminance.
To ensure compliance with specified task illuminance, the scheme must deliver an initial illuminance that is higher by a factor of 1/MF The maintenance factor (MF) is composed of various components, including LLMF, LMF, and RSMF For comprehensive details on the derivation of MF, refer to IEC 97.
Dimmable lighting systems can automatically adjust and reduce luminaire output to maintain the required illuminance, known as "controlled constant illuminance" systems These systems not only lower energy consumption and power demand but also compensate for light output decay over time by increasing input power Maintenance is necessary when power demand matches installed power, which includes cleaning luminaires, changing lamps, and cleaning room surfaces Figure E.1 demonstrates how variable power supply compensates for the declining maintenance factor to sustain constant maintained illuminance throughout a maintenance cycle.
Power for constant illuminance factor
The power for constant illuminance factor is the ratio of the actual input power at a given time to the initial installed input power to the luminaire.
Constant illuminance factor (F c )
The constant illuminance factor measures the average input power over a specific duration compared to the initial installed input power of a luminaire, typically calculated over one complete maintenance cycle.
MF is the maintenance factor for the scheme
EN 15193 provides benchmark values and lighting design criteria essential for effective lighting solutions The criteria outlined in EN 12464-1 and EN 12193 must be adhered to for optimal lighting performance Key lighting requirements focus on enhancing comfort, well-being, and user acceptance For improved lighting design, it is crucial to consider these requirements, which are detailed in Table F.2.
The formula for calculating the installed lighting power density load in a building, as per EN 15193:2007, is given by \$$e = \frac{F_{cì} P_{N}}{1000} \left[ (t_{D} x F_{Dì} F_{O}) + (t_{N} x F_{O}) \right] + 1 + \frac{5}{t_{yì}} \left[ t_{y} - (t_{D} + t_{N}) \right] \text{ [kWh/(m}^2 \text{ year)]}\$$where \( e \) represents the constant illuminance control system, which can be either manual or automatic.
Table F.2 — Lighting design criteria class
Maintained illuminance on horizontal visual tasks (Ē m horizontal) 5 5 5
Appropriate control of discomfort glare (UGR) 5 5 5
Avoidance of flicker and stroboscopic effects 3 3 3
Appropriate control of veiling reflections and reflected glare 3 3
Avoidance of harsh shadows or too diffuse light in order to provide good modelling 3 3
Proper luminance distribution in the room
Special attention of visual communication in lighting faces (Ecylindrical) 3
Special attention to health issues (Note) 3
5: has to comply with required values from Tables 5.3 in EN 12464-1:2002
3: has to conform to verbally described requirements from EN 12464-1
NOTE Health issues may even require much higher illuminances and therefore higher W/m 2
The maximum power density load (PN) connected to the lighting design class is given in the benchmark Table F.1
The default values for annual operating hours relating to building type are given
Table G.1 — Default annual operating hours relating to building type
Building types Default annual operating hours t D t N t O
NOTE National values may be substituted where necessary
The default values for impact of daylight for buildings with controls is given in Table G.2
Table G.2 — Impact of daylight for buildings with controls
Photo cell dimming – with daylight sensing 0,9
Restaurant, wholesale and retail Manual 1,0
Photo cell dimming – with daylight sensing 0,8 NOTE 1 Assumes at least 60 % of the lighting load is under the given control
NOTE 2 National values may be substituted where necessary.
The default values of occupancy for buildings with controls is given in Table G.3
Table G.3 — Impact of occupancy for buildings with controls
Education Automatic ≥ 60 % of the connected load 0,9
Retail, manufacture, sports and restaurant
Hospital Manual (some automatic control) 0,8
NOTE 1 Automatic controls with presence sensing should be allocated at least 1 per room and in large areas at least one per 30 m 2
NOTE 2 National values may be substituted where necessary
Individual dimming
Additional energy savings can by made when using a localised lighting system with individual dimming in the work place
Individual dimming enhances workplace lighting comfort by allowing adjustments to meet personal preferences and optimal luminance distribution This approach can lead to energy savings ranging from 0% to 40%.
Algorithmic lighting
The lighting industry acknowledges the significance of designing lighting systems that consider non-visual biological effects, particularly their influence on hormone regulation in the human body Future updates to the EN 12464-1 standard are anticipated to include these non-visual biological effects of artificial lighting.
To enhance biological effects through lighting, it is essential to use higher lighting levels than those needed for visual purposes, particularly during the morning and early afternoon Utilizing cool white light (up to 6,000 K) can significantly limit these higher levels During times when less biologically effective lighting is needed, warmer color temperatures can be gradually reduced to the minimum required for vision This dynamic adjustment of lighting levels, direction, and color temperature throughout the day is known as "algorithmic lighting." These systems employ various colored light sources or multiple color temperatures within a single luminaire, allowing for proportional dimming to achieve desired light levels and color temperatures.
In algorithmic lighting installations, the total installed lighting load often exceeds that of non-algorithmic systems However, these systems typically do not operate at maximum demand for extended periods Consequently, the actual power consumption generally ranges from 30% to 70% of the installed load, depending on the specific lighting scheme employed.
Light pipes
Utilizing daylight pipes, also known as tubular daylight guidance systems, can lead to significant energy savings by directing natural light into dark areas of a building These systems effectively channel daylight through attic obstructions and can illuminate multiple stories, reaching spaces that traditional façade or rooflight systems cannot.
Light pipes are basically a metal or plastic tube that delivers daylight from the roof into the building The typical light pipe includes
1) a roof-mounted plastic dome or a glazed window frame which captures sunlight,
2) a reflective tube that stretches from the dome to the interior ceiling and
3) a ceiling-mounted diffuser that spreads the light to the room
There are a number of systems available: Either with flexible reflective tubes or with rigid reflective tubes.
Lighting installations with scene setting
In various environments, such as conference rooms and offices, activities throughout the day require adaptable lighting to enhance productivity For instance, in conference rooms, lighting needs may shift from presentations to discussions and individual tasks, while office settings may involve reading, computer work, and collaborative discussions This adaptability is achieved through "scene setting," where specific lighting configurations can be activated, often remotely Since different settings are not used simultaneously, the total installed power is not fully utilized To accurately assess energy consumption over time, it is essential to predict the average usage of each lighting setting corresponding to specific activities.
=∑ × + × [W] (H.1) t s = t Setting 1 + t Setting 2 +…… [h] (H.2) where t s is the total operating time of the scene setting [h]; t setting is the envisaged setting in use;
W setting is the total power of all luminaires forming part of the envisaged setting [W].
Daylight guidance
Vertical faỗades
Deeper areas in laterally lit spaces frequently experience inadequate daylight, leading to increased reliance on expensive artificial lighting and higher cooling loads due to additional heat gains Conventional shading systems can further diminish natural light, necessitating artificial lighting even when outdoor light is abundant Daylight guiding systems offer a valuable design solution for enhancing energy efficiency, with various technical options currently available.
In Central Europe, an effective strategy for managing daylight involves utilizing the upper quarter or third of transparent façade elements to redirect direct sunlight via the ceiling into deeper areas, minimizing glare in workspaces This approach enhances the overall illumination of the space Lamellas can be adjusted in a "cut-off mode" to block direct sunlight, while systems with prismatic elements utilize light refraction principles It's essential to incorporate additional controls for positioning these optical components, considering factors like orientation and façade obstructions In certain European climates, static light shelves serve as viable alternatives Although systems designed for concentrating and guiding diffuse light have been developed photometrically, they have yet to see widespread implementation.
informative) List of Symbols
1 primary power 4 kWh lighting meter
2 kWh meter other circuits 5 lighting circuit
Figure A.1 — kWh meters on dedicated lighting circuits in the electrical distribution
In Figure A.1, the kWh meter for lighting operates in parallel with the kWh meter for the rest of the electrical installation, resulting in the total building's consumption being the sum of both meters.
In Figure A.2, the kWh meters for lighting on various floors are connected in series with the building's central kWh meter, which records the overall energy consumption, including that of the lighting.
W = W light metered = ∑all floors (kWh @ date – kWh @ (date – 12 months)) [kWh/year] (A.2)
Local kWh meter values (as in Figure A.2) could be read and totalled by a Building Management System No corrections for occupancy or control types are necessary
2 kWh meter – total power 5 kWh meter – lighting circuit 1
3 power circuit 1 6 kWh meter – lighting circuit 2
Figure A.2 — Building with segregation of lighting circuits per floor and separately measured
Figure A.3 — Volt and ampere meters coupled to the inputs of the lighting controllers
NOTE 1 Some systems include a power factor meter
Local power meters coupled to or integrated in the lighting controllers of a lighting management system Information on the local consumed energy is made available to a building management system
In Figure A.3, volt and ampere meters, or watt meters, are installed on the power input of each lighting controller These controllers measure the local energy consumption by integrating the voltage and current values over time.
The bus line transmits energy consumption data to the central computer of the lighting system or the building management system This central computer processes the information, providing energy consumption figures per area per month and for the total building lighting over a 12-month period, all in an exportable format like a spreadsheet.
W = W light metered = ∑all controllers ∑12 months (kWh local) [kWh/year] (A.3)
A lighting management system is essential for tracking operational hours and dimming levels, correlating this data with its internal database of installed loads It provides this information to a Building Management System (BMS) for comprehensive reporting or offers it in an exportable format for further analysis.
The lighting controller sums the time per lighting load proportionally per output and makes these values available via the bus line
NOTE 2 Energy consumption of luminaires not controlled by the lighting control system is not measured NOTE 3 Energy consumption of luminaires indirectly controlled via external contactors is measured
Measurement method of total power of luminaires and associated parasitic power
For accurate energy performance calculations regarding lighting requirements in buildings, it is essential to utilize the rated luminaire input power and rated parasitic input power Rated power values should be rounded to the nearest whole number for values of 10 W and above, while those below 10 W should be rounded to two significant figures Additionally, these values must fall within a tolerance of ± 5% of the claimed value.
B.2 Test measurement of luminaire power during normal operation
The test aims to assess the total input power of the luminaire during normal operation, including parasitic power for controls, sensing devices, and emergency lighting circuits This evaluation is conducted under standard reproducible conditions that closely resemble the intended service environment of the luminaire Ideally, these electrical measurements should coincide with photometric tests.
Test conditions for photometric measurements should be in accordance with EN 13032-1:2004, 5.1, 5.2 and 5.3
Volt meters, ampere meters and watt meters should conform to the requirements for Class Index 0,5 or better (precision grade)
The luminaire should be representative of the manufacturer’s regular product The luminaire should be mounted in the position in which it is designed to operate
The test voltage at the supply terminals to the luminaire should be the rated voltage of the luminaire in accordance with EN 13032-1:2004, 5.2.2
The luminaire power \( P_i \) must be determined according to sections B.1 to B.6 or as specified by the manufacturer This value should account for losses in all lamps, ballasts, and other components, reflecting the normal full output operating mode or the maximum light output when a dimming control gear is included in the luminaire.
B.8 Luminaire parasitic power with lamps off ( P pi )
The luminaire parasitic power, denoted as P pi, represents the rated power of the luminaire when it operates solely in standby mode For controlled luminaires, this power pertains to the energy supplied to the detectors, while for emergency luminaires, it refers to the steady-state power required for battery charging.
B.9 Emergency lighting luminaire parasitic input power ( P ei )
The parasitic power \$P_{ei}\$ for charging batteries in emergency luminaires must equal the declared rated power of the luminaire when it operates solely in battery charge mode.
B.10 Lighting controls standby parasitic power ( P ci )
The luminaire parasitic power P ci for standby operation of the lighting controls and detectors without operating the lamps should be the declared rated parasitic power of the luminaire
B.11 Default luminaire power for existing lighting installations
In existing buildings where the luminaire power (\$P_i\$) is unknown, it can be estimated using two methods: a) for lamps operating directly on mains supply voltage, such as incandescent and self-ballasted fluorescent lamps, the power is calculated as the lamp rated power multiplied by the number of lamps in the luminaire; b) for lamps connected to the mains supply through a ballast or transformer, the estimated power is 1.2 times the lamp rated power multiplied by the number of lamps in the luminaire.
B.12 Default parasitic energy for existing lighting installations
In existing buildings, the annual parasitic energy consumption can be estimated at 1 kWh/(m² × year) for emergency lighting and 5 kWh/(m² × year) for automatic lighting controls, resulting in a total of 6 kWh/(m² × year).
Determination of the daylight dependency factor F D,n
This annex outlines a simplified method for calculating F D,S,n, F D,C,n, and consequently F D,n, focusing on vertical façades with fenestration and rooflight solutions The approach is applicable for both annual and monthly assessments.
In accordance with 6.2.2.2, the daylight dependency factor F D,n is determined as a function of the daylight supply factor F D,S,n and the daylight dependent artificial lighting control factor F D,C,n
The procedure outlined in Figure C.1 consists of five key steps: first, segmenting the building into zones with and without daylight access; second, assessing how room parameters, façade geometry, and external obstructions affect daylight penetration using the daylight factor; third, predicting energy savings potential through the daylight supply factor \( F_{D,S,n} \), which depends on local climate, maintained illuminance, and daylight factor; fourth, evaluating the utilization of available daylight based on the type of lighting control, represented by the daylight control factor \( F_{D,C,n} \); and finally, converting the annual daylight value \( F_{D,n} \) into monthly values.
Use standard operating hours Determine correction factor
For each month Determine Monthly daylight supply factor
F , month = F Determine impact for control system
I = De (Equation C7) Determine Daylight Penetration I (Table C1)
Figure C.1 — Flow chart illustrating the determination of the daylight dependency factor F D,n in a zone
C.2 Building segmentation: Spaces benefiting from daylight
Spaces must be divided into a daylight zone (A D,j) and a non-daylight zone (A ND,j) When a zone receives daylight from multiple facades or rooflights, the most favorable scenario can be assumed for the superimposed daylight zone for simplicity Additionally, it is acceptable to superimpose the daylight factor used to classify daylight supply based solely on the specific type of daylight aperture, whether it be a facade or rooflight, as outlined in sections C.3.1 and C.3.2.