Everything about standards and legislation

Monitor glasses


According to the Council Directive 90/270/EEC, article 9, employers must provide employees with the opportunity to have an eye examination upon commencing work and at regular intervals or in the case of eye problems. If this examination shows that monitor glasses are needed, the employer must pay the costs of this.

The usual procedure within an organization is first to assess the workstation and the working behavior of the staff based on the following aspects:
- Monitor settings: see "Monitors" for more information.
- Lighting the workstation: irritating reflections must be prevented, and a suitable contrast between monitor and working environment must be sought. Note: in modern office environments it may be that the window surface area and therefore the amount of incident light is large. The monitor must in that case emit more light to provide a suitable contrast. For more information on choosing the right monitor, see "Monitor arms". Awnings and blinds can also improve this contrast. Too much light in the office is often more of a hindrance than too little light.
- Working habits: to avoid many eye complaints look away from the monitor twice an hour and focus on an object that is far away (Cheu, 1998).
If any changes made do not bring about the desired result, an eye examination must be scheduled. If the results of this examination give reason to do so, a referral to an optician or eye doctor must be made.



Monitors


The optimum monitor height is different in different countries. In the US, Great Britain, Belgium and the Netherlands (e.g. AI2), the norms and guidelines most commonly advise setting the upper side of the monitor at or just under eye level. In Scandinavian countries and Germany, placing the monitor lower is more usual. International norms also assume a lower monitor position (ISO 9241-5).
Our advice in this regard is to place the middle of the monitor at between 17.5° and 35° under eye height. This is based on an optimum balance between comfort, physical stress and productivity (Sommerich, 1998), where the optimum also depends on whether the user can type blind or not and his/her sitting posture.

To determine the optimum height, we must first determine what the eye height is. The monitor is then placed at or just under the eye height. For P90 (tallest 5% to the shortest 5% of the population) the eye height from the desk is between 48.6 cm and 61.4 cm (Dined, 2004). To place the monitor at eye height, a positioning range of between 48.6 and 61.4 cm, measured from the desk to the upper side of the monitor, is needed. To realize a viewing angle relative to the middle of the monitor of 17.5° and 35°, one must be able to place the monitor lower and so a larger range is therefore needed. A rule of thumb is therefore a range of 35-59 cm.

Council Directive 90/270/EEC
According to the Council Directive 90/270/EEC, article 9, employers must provide employees with the opportunity to have an eye examination upon commencing work and at regular intervals or in the case of eye problems. If this examination shows that monitor glasses are needed, the employer must pay the costs of this.

Minimum requirements for monitor workstations are stipulated in the Annex to the abovementioned norm:

Article 1.b of the Council Directive states that monitors must be freely movable and easy to adjust and tiltable. This can be achieved by, for example, mounting the monitor on a flat screen arm. The monitor may not form a whole with the keyboard (as is the case with laptops). This can be solved by using a separate monitor and keyboard + mouse possibly in combination with a docking station or by using a laptop holder in combination with a keyboard + mouse.

Article 2 contains guidelines regarding the organization of monitor workstations. Reflections on the screen must be avoided, suitable sunshades must be used and the equipment must not cause an annoying noise or heat.



Desk chairs


The anthropometric dimensions of Europeans are very varied: tall people, short, slim or wide. In Europe, the law stipulates that all desk chairs must comply with EN 1335. However, it does not stipulate that desk chairs must also be an ergonomic optimum solution for most VDU workers. A chair which complies with EN 1335 with respect to dimensions is only suitable for a small part of the population (< 35%). For this reason, the NEN institute has developed an advisory norm, the NPR 1813-2003. This norm is not binding. Chairs that comply with this norm are suitable for a large part of the population (De Groot, 2003).
EN 1335-1: minimum requirements for desk chairs required by law.
NPR 1813: norm with stricter requirements not required by law.

Norm EN 1335-1 NPR 1813
Armrests    
Width between the  armrests                    46-51 cm                                     36-51 cm                       
Height adjustability range 20-25 cm 20-31 cm
Armrest length Min. 20 cm Min. 20 cm
Armrest width Min. 4 cm Min. 5 cm
Norm EN 1335-1 NPR 1813
Leg support    
Seat height range 40-51 cm 40-54 cm
Seat depth 40-42 cm
Adjustable min. 5 cm        
 
38-48 cm
Seat depth adjustment range Min. 38 cm Min. 44 cm
Min. width of the seat Min. 40 cm Min. 40 cm
Back support    
Lumbar support adjustment range 17-22 cm 17-23 cm
Backrest height 22 cm Min. 37 cm
Height of the edge of the backrest above the seat Min. 36 cm Min. 43 cm
Backrest width Min. 36 cm Min. 36 cm
Drawing up to a desk    
Distance from the front edge of the seat to the front edge of the armrest                            Min. 10 cm Min. 20-24 cm
Subframe    
Max. length of feet + wheels Max. 36.5 cm Max. 36.5 cm
Tilt-safety limit Min. 19.5 cm Min. 19.5 cm
Swivel wheels Min. DIN 68131 No requirements
Norm EN 1335-1 NPR 1813



Document holders



The annex of the Council Directive 90/270/EEC states that a used document holder must be stable and adjustable, so as to minimize the need for uncomfortable head and eye movements.

Although it is not a binding legal requirement, the document holder should preferably comply with NPR 1813 as follows:
• One should use a document holder when working with documents, which can be used to hold the document to be read upright, so that one does not need to bend one’s head when reading the document.
• It must be possible to place the document holder anywhere on the work surface, as a function of the ergonomic requirements of the type of work.
• The tilt of the document holder must be set to between 25 and 75 degrees with respect to the horizontal surface (preferably adjustable).
• The support surface of the document holder may not be smaller than the dimensions of the document to be placed on it.
• The document holder must stand rigidly and not vibrate when using the keyboard.



Notebook Stands


The annex of the Council Directive 90/270/EEC stipulates a number of concrete requirements that a monitor workstation must satisfy. For example, a monitor may not form a single entity with the keyboard. So in the case of laptops, a separate keyboard must therefore be connected, possibly via a docking station.
In addition, the monitor must be easy to adjust and tiltable. The document holder must be stable and adjustable when in use.



Laptop bags


How much does the average filled laptop bag weigh?
In total, the weight of a laptop bag is between 4 and 6 kilograms. A laptop weighs between 2 and 4 kilograms. In addition, a laptop bag usually contains accessories: an adapter, paper(s), wallet, etc. In total, 1 to 2 kilos. Finally, the weight of the bag itself: between 1 and 2 kilograms.

How far can an average laptop bag be comfortably and safely carried?
Given the weight of 4 to 6 kilos, maximum 90 meters.

Maximum weight for 1-handed carrying (Mital et al., 1993; ISO 1128-I):

Distance Weight (kg)
30 meters occasionally: 6.5
60 meters occasionally: 6.0
90 meters occasionally: 6.0



Mental fatigue


According to the Council Directive 90/270/EEC, article 7, one must take regular breaks from VDU work to reduce the workload.
And article 3 of the same directive obliges employers to analyse the mental workload and, where necessary, take appropriate measures to remedy the risks found.



Mouse devices


No specific requirements for mouse devices are stipulated by law. The international norms are also fairly scanty: only ISO 9241-9 contains a number of guidelines regarding mouse devices, joysticks, trackballs, tablets, pen mouse devices and touchscreens. The most important two are given below.

“6.2.1 Mice
6.2.1.1 Sensor location
The motion sensing point (such as the rolling ball on the underside of a typical mouse) should be located under the fingers rather than under the palm of the hand.
NOTE: The term “finger” includes the thumb.

6.2.1.2 Button motion
The device should be designed such that during its intended use the fingers should be able to make contact and actuate buttons without excessive deviation from a neutral posture.
NOTE: “Excessive” means, for example, interfering with accuracy or causing muscular strain.

6.2.1.3 Button actuation
It should be possible to press the buttons on the mouse without reducing control of the device.

6.2.1.4 Resolution consistency
The resolution of a mouse should be independent of both the position of the device on the work surface and the position of the pointer on the display.
NOTE: However, the resolution may be changed by the software or the user.

“6.2.6 Styli and light-pens
“6.2.6.1 Grasp surface
The grasp surface of the stylus and light-pen should be slip resistant.

6.2.6.2 Activation force
For continuous input using styli, the force requirements to activate the stylus on a tablet should be not greater than 1.5 N.

6.2.6.3 Selector button force
The activation force of the selector button should be between 0.3 N and 1.5 N.



6.2.6.4 Contact area of selector button
A selector button should have a contact surface that contains a circular area with a diameter not less than 5 mm.

6.2.6.5 Size
Cylindrical styli and light pens should be between 120 mm and 180 mm in length and 7 mm to 20 mm in diameter.

6.2.6.6 Weight
Styli and light pens should have a mass between 10 g and 25 g.”



Keyboards



The keyboard must be placed separate from the monitor [Arboregeling (Dutch Working Conditions Regulation), article 5.1]. This also applies to laptop computers, if one works on them for longer than two hours a day. In this case, an external keyboard must be connected, possibly in combination with an external monitor. The underside of the keyboard must be rough so that is does not move when in use.

Furthermore, the keyboard must be as flat as possible, in any case no thicker than 35 mm in the middle and preferably less than 30 mm (at the point of the letters A, S, D and F) (ISO 9241-4). A flat keyboard prevents one from having to lift up one's arms too much and it also limits the degree of extension in the wrist due to an incorrect working technique, if no wrist support is present. If a wrist support is present, this also limits the degree of extension in the wrist.

The guidelines stipulate an angle of 0-12° (ISO 9241-4), a relatively small angle is important to prevent excessive extension of the wrists. For this reason, the legs of the keyboard should be folded up, especially with people who type blind.

To prevent the reflection of incident light, the keys may not be reflective. The keys can best have light tints with darker print on them. Indeed, darker characters on a light background are easier to read than the other way around.

The actuating force of keys may not be too great or too small, preferably between 0.5 and 0.8 Newton. Vertical movement may be 1.5 to 6 mm, preferably between 2 and 4 mm. The distance between the keys must preferably be 19 mm (from the heart of one key to the heart of the adjacent key). This may be less for other keys other than function keys, but never less than 15 mm. The alphanumeric part must be separated from the function keys either visually (in terms of color) and/or spatially (in terms of position) (ISO 9241-4).



Sit-stand worktables


The working height of a table must be adjustable from at least 60 to 82 cm (minimum 62-82 cm according to EN 527-1:2011) and for sit-stand worktables from 60 to 125 cm (minimum 62-120 cm according to DIN 2449).



Voice recognition




Tablet stands


Article 5.1 of the Working Conditions Provisions stipulates a number of specific requirements to which a computer workstation has to comply. The screen and keyboard, for example, have to be separate units, which is not the case with iPads because an iPad uses an integrated touchpad as a keyboard. This means that an iPad does not comply with the requirements stipulated for a computer workstation.



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