Environmental aspects

Besides the ergonomical design of a product or a workflow, there are several environmental factors which may affect your fitness at work. These environmental factors have some subjective part (personal comfort zone) but there are some basic aspects which should be kept in mind for an optimal working atmosphere.

Light

Why is light important?

Light has a direct effect on your eyes and an indirect effect on your concentration. Too weak light stresses the eye muscles (constant re-focusing), resulting in rapid fatigue. You may know this effect from reading a book with dim lights.
The same effect happens when high precision tasks like pipetting are to be done – resulting in a higher risk for errors like swapped samples or wrong volume settings. Too bright light has similar effects.

 

Light illuminance

The illuminance of light can be measured. This light power is the summed-up luminous flux incident on a surface.  The luminous flux is measured per base area.

The illuminance is measured in lux [lx]. An alternative unit is "lumens per square metre" [lum].
In some countries, a non-metric unit of illuminance is used, the foot-candle [fc].

 

Color of light

The color of light is measured in Kelvin. Based on EN 12464-1, three areas can be differentiate

 

  • warm-white light:below 3,300
  • neutral white light: 3,300 to 5,300
  • Day light white light: above 5,300 K

 

Type of light sources

Standard bulb versus neon lamp versus LED

 

Light power at working area

The EN 12464-1 provides some information about minimum light power at standard working spaces.
Office desks should have in general at least 500-1,000 Lux.
Technical drawings shuld be done with at least 750 lux.
For laboratory work there are currently no official recommendations, but the 750 lux should be a good starting point.
Keep in mind to have more light for high precision tasks (compare to doctors at surgeries!)
If working with electronic instruments like centrifuges or pipettes adjust the brightness of the display. Too bright displays in a dimmed room may disturb the eyes.

 

Natural day light

Never forget: The best light comes from outside!
Daylight with it`s unique spectrum regulates physiological processes as well as the circadian rhythm of humans.
Thus a good laboratory has big windows with blinds against direct sunlight.

Noise

Noise is a very complex topic and has several impacts on your personal comfort zone.

Noise in general disturbs concentration and – in case of long-term strain - may lead to cardio-vascular diseases. In general, it is recommended to keep the noise-level as low as possible in order to ensure stress-free and concentrated work.
Besides the absolute noise level, the frequency of the noise level has some subjective effect. Very high as well as very low frequencies can stress a person.

 

Noise measurement

The absolute noise level is measured in dB(A).
Keep in mind that an increase of 10 dB(A) is felt as a doubling of the subjective noise level.
As a rule of thumb, a modest talking with 40 dB (A) is felt to be 8x louder than normal breathing with 10 dB (A).

 

Noise level10

  • dB (A) – normal breathing, sound of leaves
  • 20 dB (A) – whispering
  • 30 dB (A) – buzzing of a fridge
  • 40 dB (A) – muted talking; disturbs sleeping; disturbs learning / concentration
  • 50 dB (A) – normal talking, normal sound-level of a room, dish washer
  • 60 dB (A) – stress limit / tolerance level, talking loudly
  • 65 dB (A) – elevated risk for cardio-vascular diseases
  • 70 dB (A) – noise from housekeeping
  • 75 dB (A) – bell of a bicycle
  • 80 dB (A) – strong street noise, vacuum cleaner, kids shouting
  • 85 dB (A) – ear protection mandatory at work, hair dryer
  • 90 dB (A) – car horn
  • 100 dB (A) – buzz saw, disco music
  • 110 dB (A) – fast train nearby, pop concert
  • 130 dB (A) – threshold for pain, hearing impairment possible, jet-plain nearby
  • 160 dB (A) – eardrum may burst, bang of air-bag unfolding

 

There are some recommendations for office work:

  • Highly concentrated work: The daily average noise-level should be below 35-40 dB (A)
  • Low concentrated work: The daily average noise-level should be below 55 dB (A)

Unfortunately, there are no dedicated and commonly known thresholds for lab work. Still, you may keep the office values as a benchmark value.

Air Ventilation

Influence air
Following factors influence our wellness:

  • Temperature
  • Relative humidity
  • Air movement
  • Air quality

For bureaus following recommendations apply:

  • Temperature: 21-22 °C but not higher than 26 °C
  • Relative humidity: 40-60 % Air movement: 0.1-0.15 m/s are optimal at 21 °C
  • Air quality: Beware of gases, chemical aerosols, dusts and CO2

In order to improve air quality open the windows for 10 min daily if allowed in your lab.