Thaum koj paub qhov ua tau zoo ntawm cov teeb pom kev zoo thiab tag nrho cov wattages nws xav tau, koj tuaj yeem suav tag nrho lumens ntawm tag nrho cov kis las. Piv txwv li, luminous efficiency ntawm lub teeb coj teeb yog 155LM / W, yog li tag nrho lumen ntawm 1300W yuav yog 1300W x 155LM / W=201,500 lumens.
Tsis tas li ntawd, muaj lwm txoj hauv kev los xam lumens. Koj yuav tsum paub qhov illuminance koj xav tau thiab qhov luaj li cas ntawm qhov chaw yuav illuminated. Los ntawm qhov no, peb paub ntau npaum li cas lumens tag nrho qhov chaw xav tau. Piv txwv li, thaj tsam ntawm lub tsev hais plaub ntaus pob tesniv yog 100 square metres, thiab qhov xav tau illuminance yog 300lux, yog li tag nrho lumens xav tau yog 30, 000 lumen.
Kev suav nrog square meters
Lub beam ΦV nyob rau hauv lumens (lm) yog sib npaug zos rau illuminance Ev nyob rau hauv lux (lx) multiplied by deg cheeb tsam A nyob rau hauv square meters (m2):
ΦV(lm)=Ev(lx) x A(m2)
Lub luminous flux ΦV nyob rau hauv lumens (lm) yog sib npaug rau illuminance Ev nyob rau hauv lux (lx) multiplied los ntawm 4 πtimes lub vojvoog r ntawm lub square sphere nyob rau hauv meters (m):
ΦV(lm)=Ev(lx) x (4⋅π⋅r2(m2))
Kev suav nrog square feet
Lub luminous flux ΦV nyob rau hauv lumens (lm) yog sib npaug rau 0.09290304 lub sij hawm lub illuminance Ev nyob rau hauv lux (lx) multiplied by deg cheeb tsam A (ft2) nyob rau hauv square feet:
ΦV (lm)=0.09290304 x Ev (lx) x A (ft2)
Lub luminous flux ΦV nyob rau hauv lumens (lm) yog sib npaug rau 0.09290304 ntawm lub illuminance Ev nyob rau hauv lux (lx) multiplied los ntawm 4π lub sij hawm lub square sphere radius r nyob rau hauv ko taw (ft):
ΦV(lm)= 0.09290304 × Ev(lx)x(4⋅π⋅r(ft)2)
