What lighting levels do I need ?
The Australian standard for required workplace illumination
AS 1680.1.2006
offer the following advice :
Class of Task
Recommended
Maintained
illuminance lux
Characteristics of the
activity / interior
Representative activities / interiors
Movement and
Orientation
40
Interiors rarely visited with visual
tasks limited to movement &
orientation
Corridors, cable tunnels, indoor storage
tanks; walkways
Rough
Intermittent
80
Interiors requiring intermittent use
with visual tasks limited to move-
ment, orientation & coarse details.
Staff change rooms; live storage of bulky
materials; dead storage of materials
needing care; locker rooms; loading bays
Simple
Workplace
tasks
160
Any continuously occupied interior
where there are no tasks requiring
perception of other than coarse
detail. Occasional reading of
clearly printed documents for
short periods.
Waiting Rooms, staff canteens; rough
checking of stock; rough bench and machine
work; enterance hall; general fabrication of
structural steel; casting concrete; automated
process monitoring; turbine halls.
Ordinary or
Moderately easy
work task
240
Continuously occupied interiors
with moderately easy visual tasks
with high contrasts or large detail
School chalkboards and charts; medium
woodworking; food preparation; counters
for transactions.
Moderately
Difficult work
tasks
320-400
Areas where visual tasks are
moderately difficult with moderate
detail or with low contrasts
Routine office tasks eg reading, typing,
enquiry desks. Inspection of medium work;
fine woodwork; car assembly
Difficult work
tasks
600
Areas where visual tasks are
difficult with small detail or with
low contrasts
Drawing boards; most inspection tasks;
proofreading; fine machine work; fine
painting and finishing; colour matching.
Very Difficult
work tasks
800
Areas where visual tasks are very
difficult with very small detail or
with very low contrasts
Fine inspection; paint retouching; fine
manufacture; grading of dark materials;
colour matching of dyes.
Extremely
Difficult
1200
Areas where visual tasks are
extremely difficult with extremely
small detail or low contrasts.
Visual aids may assist
Graphic arts inspection; hand tailoring;
fine die sinking; inspection of dark goods;
extra fine benchwork
Exceptionally
Difficult
1600
Areas where visual tasks are
exceptionally difficult with
exceptionally small detail or with
very low contrasts.
Visual aids will be of advantage.
Finished fabric inspection; assembly of
minute mechanisms, jewellry and
watchmaking.
What to look for in light meters
For accurate measurement of illuminance you should ensure your light meter should have cosine and color
correction. The cosine correction allows for the effects of light falling on the cell at oblique angles, colour correction
is needed in order to match the spectral sensitivity of the human eye.
There are a number of cheap lightmeters in India, they are both cheap in Rupee terms and in construction- they
have poor quality colour correction because of the lower quality colour correction filters they use. They tend not to
fit the red or blue ends of the CIE V, lamda curve. Errors as much as 500% can occur in high pressure sodium or
metal halide lighting.
