Week nine

Question 1

Core temperature

Answer 1

A fundamental principle is that workers should be able to maintain thermal balance in the environment in which they are working, whilst carrying out their work. Thermal balance refers to the body’s ability to balance metabolic heat production and rate of heat loss, to a achieve core temperature of approximately 36-37oC body temperature.

Question 2

Glare

Answer 2

results when there is a high level of contrast between the intensity of light in the foreground and background, for example, if a bright window is positioned behind a computer screen.

Question 3

Luminance

Answer 3

(brightness) is the amount of light reflected back to the eyes from the
surface of objects in the visual field (Candela/m2)

Question 4

Noise annoyance

Answer 4

The recommended limit for noise levels over an 8 hour shift is 85 dB and for peak noise levels is 140 dB. However, sound below this threshold can result in annoyance or interruption in concentration and communication. The following table offers suggested maximum noise levels to reduce annoyance for a selection of tasks (adapted from Grandjean, 1988).

Activity
Unskilled physical work, e.g. cleaning 80 dB(A)
Skilled physical work, e.g. garage work 75 dB(A)
Physical work with high precision requirements 60 dB(A)
Simple administrative work, with communication requirements 60 dB(A)
Administrative work with intellectual content, e.g. drawing and design 55 dB(A)
Concentrated intellectual work, e.g. library 35 dB(A)

Question 5

Radiant temperature

Answer 5

Hot surfaces such as a roof radiate heat and can affect thermal comfort. Steps must be taken whenever the radiant temperature of these surfaces differs by more than four degrees from the air temperature (see climate control, p. 82).
Provide shade to reduce radiant heat load (plant trees, build awnings, issue wide-brimmed hats)

Question 6

Visual acuity

Answer 6

refers to the eye’s ability to resolve detail. Examples include reading very fine print or identifying a person across the street. Acuity is largely dependent on the accommodation of the eye. The ability to resolve detail deteriorates with age.