Fundamentals of workplace lighting
Restoring mosaics, repairing jewellery or creating display
panels for the next exhibition - different activities
demand different levels of light, in order to support the
visual task in accordance with standards: This can be
between 500 and 1500 Lux, depending on how intricate the
detail work is. DIN EN 12464-1 provides information about
the recommended levels.
For workstations with difficult visual tasks, general
workplace lighting is usually insufficient and additional
individual workstation lighting must be used. Compact
fluorescent tubes with electronic ballasts (EBs) offer an
energy efficient solution.
In order to prevent visual acuity from being compromised,
distracting reflections on tools and workpieces should be
prevented. Lamps with reflector grids can provide focused,
glare free lighting.
The difficulty of the visual task is determined by
lightness/darkness and colour contrast, by the minuteness of
the details as well as by the speed and duration, at which
the contrast is perceived. The more difficult the visual task
is, the higher the level of lighting must be.
Compact fluorescent tubes without integrated electronic ballast
The plug base distinguishes the other sub-category of the
family of compact fluorescent tubes, to which compact
fluorescent tubes with integrated ballasts also belong. These
short and compact lamps have become a popular alternative to
rod shaped fluorescent lamps, particularly in commercial
lighting applications. Unlike lamps with an integrated
ballast, the ballast is placed inside these lamps.
The use of electronic ballasts (EBs), as compared to
magnetic ballasts, has a more favourable energy balance.
Electronic ballasts also come in a special, dimmable version;
dimming is only possible with lamps with a 4-pin base.
2-, 4- and 6-tube lamps
Flat 4-tube lamp
Flat 2-tube lamp
Power consumption (W)
5 - 42
18 - 36
18 - 55*)
Luminous flux (Lumens)
250 - 3,200
1,100 - 2,800
1,200 - 4,800
Luminous efficacy (Lumens/W)
50 - 76
61 - 78
67 - 88
warm white / daylight white (ww, dw)
Colour reproduction index (Ra)
80 - 90
G23, G24, 2G7, GX24
*) 40 W and 55 W with EB only
Electronic ballasts for fluorescent lamps (standard)
Electronic ballasts (EBs) for fluorescent lamps stand for
modern lighting technology, for cost and energy savings and
for comfort. Dimmable EBs also make it possible to infinitely
regulate brightness. Then there are magnetic ballasts. For
compact fluorescent lamps with an integrated ballast
(energy-saving lamps), the device is built-in to the light.
With fluorescent lamps and compact fluorescent lamps without
and integrated ballast, the ballast is actually a component
of the bulb itself.
EBs have the best energy balance. Most notably, these lamps
(lamps with EB) offer increased luminous and system efficacy.
When powered with EBs, the effective operating life of the
lamps is extended and decrease in luminous flux is reduced.
It is seldom necessary to replace the bulbs, as the
luminescent material and electrodes are subjected to less
EBs start lamps quickly, silently and without flickering.
They offer consistent, even light and are largely resistant
to fluctuations in voltage and frequency. As they can also be
powered with direct current, EBs can be switched to battery
operation and used for emergency lighting if power is cut. If
an EB fails, it is automatically isolated.
Light as a factor in productivity
An investment in good lighting for production facilities is
well worth the cost. Two studies by the Technical
University of Ilmenau (1997 and 2000) document improved
performance, less fatigue, fewer rejects and significantly
fewer working accidents as the result of higher levels of
light. Research reports and long-term studies have
concluded: 600 Lux is the recommended level of illuminance
for typical industrial workplaces.
Better lighting improves productivity for difficult visual
tasks by more than 50 percent. The error rate is
simultaneously reduced. In addition, the test subjects report
feeling mentally fit for a longer period of time. The
correlation between working accidents and lighting levels is
also documented in statistics from government safety
organisations: Two-thirds of all recorded workplace accidents
occur at workplaces with light levels below 500 Lux.
The varied requirements for lighting levels for different
types of workstations in carpenter's workshops are
fulfilled by workstation specific general lighting with a
defined allocation of lights per workstation. When general
lighting alone is configured to provide evenly distributed,
high levels of light in the entire space for the flexible
layout of workstations and alternative use of the room,
this is an exception to the rule. However, modern,
configurable lighting systems for workstation oriented
lighting also offer flexible solutions for the relocation
of machines and workbenches.
Lights should be mounted parallel to the plane of windows,
respective to the incidence of daylight. This requires that
machines and workbenches be set-up parallel to windows.
Lateral incidence of light is important here. This is why
lights must be installed at the sides of work surfaces.
Tools and workpieces are more visible when the lighting
creates minimum shadowing. Reflections off smooth machinery
or charts in the worker's line of sight should not
compromise visual tasks.
Fine detail and inspection work require high levels of
light. Additional lights - suspended lamps, individual
workstation lamps or machine lamps - are used at
workstations with difficult visual tasks. These lamps
supplement general lighting, and thus should only be
switched on when needed. The use of compact fluorescent
tubes with electronic ballasts (EBs) saves energy costs.
Reflector grids ensure focused, glare free lighting.
Individual workstation lamps should not create distracting
reflections on tools and workpieces.
Additional lamps in the carpenter's workshop are also
necessary for the inspection of surfaces. Their light
should be directed at a grazing angle and create heavy
shadows. This enables scratches to be detected, even in
Dust, sawdust and material fibres accumulate in every
carpenter's workshop. Lamps are only protected from this if
they have a type of protection equivalent to at least IP50
(dust protected). The internal generation of heat from the
lamps must also be limited in order to prevent deposits of
flammable materials from igniting. They are labelled with
the fire protection symbol "D" in a triangle on the top.
The use of these lamps is mandatory in rooms where dust is
a hazard, so essentially in the entire workshop.
In rooms or areas in which paint, polishing agents and glue
with liquid solvents are used, there is a risk of
explosion. In such cases, the use of explosion protected
("Ex" in a circle) lamps is mandatory - for carpenter's
workshops "zone 20-, 21- or 22-lamps".
General lighting in the workshop
Balanced general lighting is a prerequisite for good visual
acuity and optimum visibility. It is primarily determined
by the level of light. In every museum workshop -
irrespective of the specific task - illuminance should be
around 500 Lux.
General lighting is usually installed according to the
specific nature of the workplace, and ideally with lateral
incidence (light shining onto the workbench from the
sides). Lights with fluorescent lamps are well suited for
this, arranged in rows or as a light-band system in larger
workshops or factories. Supplemental individual workstation
lamps can be switched on to increase the level of
Is there falling dust, saw dust or material fibres in the
workshop? Then operational safety is an important subject.
It is generally recommended to use lighting with a higher
level of protection: Lights with protection type IP54, for
example, are protected from dust and splash water. In such
cases, the internal generation of heat from the lamps must
also be limited in order to prevent deposits of flammable
materials from igniting. The fire protection symbol "D"
located in a triangle on the top indicates this property.
Areas up to 6 metres high
For halls from four to six metres high, light ring systems
fitted with fluorescent lamps or other lamps are the most
economical solution for general lighting. It is important
that bright light is distributed over a wide area. As
precise as light distributing reflectors allow, use these
lamps in halls up to six metres high as well, but with
focused luminous intensity distribution at this height. A
combination of these lamps and high intensity discharge
lamps can be a practical alternative in halls of this
Operating the lamps with electronic ballasts (EBs) saves
energy. With an annual usage of even 4000 hours - or a
typical 2-shift operation - EBs save a more than a fourth
of energy costs. The cost of a new system with EBs can be
recovered in as little as two and a half years, even faster
in 3-shift operations due to the longer operating hours.
EBs save energy, because they reduce the connected load of
the system (lamp plus ballast) to below that of the nominal
output of the lamp: A 58 W fluorescent lamp with EB has a
power consumption of only 50 W, the thermal dissipation
loss of the EB is 5 W. So the system consumption is only 55
Areas over 6 metres high
Hall heights above six metres require particularly bright
light, and thus economical lamps: Metal halide lamps or
high pressure sodium lamps with an output of 250 - 1000 W
generate so much light, so that even from great heights an
adequate level of brightness reaches the working level.
Reflective hall lights have a rotationally symmetrical and
far reaching luminous intensity distribution. If vertical
high intensity illuminance for inclined surfaces is
required, additional lights for fluorescent lamps must be
Metal halide lamps unify compact dimensions, high luminous
flux, very high light output and good colour reproduction
qualities with a longer operating life to provide a
cost-effective source of lighting. High pressure sodium
lamps also have very high light output, but are
distinguished by even greater luminous efficacy - depending
on specific lighting requirements with colour reproduction
index Ra = 80 to 89, 60 to 69 or 20 to 39.
In higher warehouses, there is always the danger of
high-stacked goods or tall shelving units shadowing light
from the ceiling and only allowing a small portion of the
light to reach the aisles in between. This problem is
resolved through the use of special reflectors in
reflective hall lights for high intensity discharge lamps
or in lights for high intensity fluorescent lamps with Ø of
16 mm (preferably ring light systems). The reflectors
direct light into the aisles and also provide vertical high
intensity illuminance, which makes it easier to perform the
vertically oriented visual tasks (e.g. reading, locating
goods) associated with managing inventory. Reflective hall
lights for warehouses also have glare protection for when
they are viewed from below.
If all of the areas of a high warehouse are not used
uniformly, it is sensible to use energy saving switching
options such as those for lower height storage areas.
Lighting for storage areas
Lights for fluorescent lamps, which are suspended in ring
light systems at shelf unit height over the centre of the
aisle. Energy can be saved if different, scenario-based
supplemental switching options are provided:
With zone switching, lighting predominantly remains
switched off for less frequented storage areas.
With two-stage lighting - the first stage switches on
every second lamp, the second all lamps - lighting
levels can be adapted to the type of work as needed.
For example, if individual storage areas are only used
as transport routes on some days and light is not
needed for reading and locating items.
With the installation of proximity sensors (motion
detectors) in individual storage areas. They
automatically switch on the lights when they are
needed. Flicker-free, instant-on light requires the use
of lamps with electronic ballasts (EBs). The lights
switch off when no motion has been detected for a
pre-set period of time.
If the warehouse administration work area is in close
proximity to the shelving units, it should be sufficiently
screened. This is necessary in order to prevent the
lighting from creating a glare on the computer screens of
the administrative staff. Their workstations must be
illuminated like other office areas.
For further information visit www.hse.gov.uk
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