Lighting Design Calculator | IS 3646 / IS 1944

Room Dimensions

IS 3646 Pt.1 — Lumen Method

Length (L) m

Width (W) m

Height (H) m

Work Plane Ht. m

Mounting Ht. m above WP

Floor Area m²

Room Index (K)

K = (L × W) / [Hm × (L + W)]

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Space Type & Target Illuminance

Space / Activity Type (IS 3646 Table 1)

Required Illuminance (E) lux

IS 3646 Classification

Luminaire Specifications

Luminaire Type

Lumens / Luminaire lm

Watts / Luminaire W

Luminaire Efficacy lm/W

Spacing:Height Ratio (SHR)

Number of Lamps / Fitting

Utilization & Maintenance Factors

Surface Reflectances (for UF calculation)

Ceiling ρc %

70%

Wall ρw %

50%

Floor ρf %

20%

Light Loss Factors

Environment / Maintenance Schedule

Utilization Factor (UF) — override

Maintenance Factor (MF) 0.70

Utilization Factor (UF — auto) —

Luminaire Layout Plan (Room View)

— Calculate to render layout —

Calculation Results

Fill in room dimensions &
luminaire data, then click
Calculate

Environment	MF
Very clean (hospitals, labs)	0.80
Clean (offices, schools)	0.70
Normal (light industrial)	0.65
Dirty (workshops, plants)	0.55
Very dirty (foundries)	0.50

Environment

Very clean (hospitals, labs)

0.80

Clean (offices, schools)

0.70

Normal (light industrial)

0.65

Dirty (workshops, plants)

0.55

Very dirty (foundries)

0.50

Space	Min. Uo
General interior spaces	0.60
Escape routes	0.40
Road (P1/P2)	0.40
Road (P3/P4)	0.35
Road (P5 residential)	0.30

Space

Min. Uo

General interior spaces

0.60

Escape routes

0.40

Road (P1/P2)

0.40

Road (P3/P4)

0.35

Road (P5 residential)

0.30

Space	LPD W/m²
Office (open plan)	10.5
Classroom	11.0
Retail / Shop	14.0
Hospital ward	10.5
Workshop / industrial	14.0

Space

LPD W/m²

Office (open plan)

10.5

Classroom

11.0

Retail / Shop

14.0

Hospital ward

10.5

Workshop / industrial

14.0