B 4b Lumen Method
14
K. F. Chan (Mr.) ELEC 3105 1 LUMEN METHOD Utilization factor -- Ratio of flux received by reference plane to total rated lamp flux in the installation. Utilization factor of a lighting installation depends only on polar curve of the luminaire, the room geometry (represented by room index) and reflectances of the ceiling, wall and floor.
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Transcript of B 4b Lumen Method
K. F. Chan (Mr.) ELEC 3105 1
LUMEN METHOD
Utilization factor-- Ratio of flux received by reference plane to total rated lamp flux in the installation.
Utilization factor of a lighting installation depends only on polar curve of the luminaire, the room geometry (represented by room index) and reflectances of the ceiling, wall and floor.
K. F. Chan (Mr.) ELEC 3105 2
Maintenance factor –
-- LSF
-- LLMF
-- LMF
-- RSMF
K. F. Chan (Mr.) ELEC 3105 3
LUMEN METHOD
E= N x n x ø x UF x MF
A
where MF = LLMF x LSF x LMF x RSMF
E =Maintained illuminance, lux
A = Area, m2
Ø = Initial lamp flux, lumen
K. F. Chan (Mr.) ELEC 3105 4
K. F. Chan (Mr.) ELEC 3105 5
LLMF & LSF
K. F. Chan (Mr.) ELEC 3105 6
(Taken from Table 3.4 of CIBSE Code for Lighting, 2002)
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K. F. Chan (Mr.) ELEC 3105 8
K. F. Chan (Mr.) ELEC 3105 9
K. F. Chan (Mr.) ELEC 3105 10
LMF
K. F. Chan (Mr.) ELEC 3105 11
LMF
(Taken from Table 3.5 and 3.6 of CIBSE Code for Lighting, 2002)
K. F. Chan (Mr.) ELEC 3105 12
RSMF
K. F. Chan (Mr.) ELEC 3105 13
RSMF
(Taken from Table 3.7 of CIBSE Code for Lighting, 2002)
K. F. Chan (Mr.) ELEC 3105 14
