Short Answers

Question 1

The scope of work of an Occ Hygienist

Answer 1

Identify harmful, unpleasant or uncomfortable factors
Measure the relevant factors
Interpretation of results and appraisal of risks
Control measures
Education
Research and development

Question 2

Materials Inventory

Answer 2

When considering potential health hazards in the workplace, the basic starting data should include a comprehensive record of all the materials on site including raw materials, intermediates, finished products, by products, waste materials and any significant combination thereof. These should then be linked to any processes in operation in the workplace.

Question 3

Two examples of engineering controls

Answer 3

Guarding on a machine that restricts access to nip points.

On tool ventilation when cutting materials that create airborne contaminants.

Question 4

Administrative controls in the hierarchy

Answer 4

Work processes, signage and PPE.

Question 5

Sampling in relation to Occ hygiene evaluation

Answer 5

Area, or static sampling, is used to measure the level of worker exposure to a substance at a fixed location over a given period of time.
Personal sampling measures the level of exposure for a specific worker over a period of time.

Question 6

Main types of collection devices for sampling gases and vapours

Answer 6

Direct measurement using colourmetric detector tubes, gas monitors or other “on the spot” devices for specific substances.
Indirect methods where air is collected from the work space and taken for lab based analysis such as absorption tubes, bubblers or diffusive samplers.

Question 7

Circumstances when area monitoring could be used

Answer 7

Although area samplers perform less well in determine exposure levels for individual workers, they can be useful in certain situations such as evaluating background concentrations and the effectiveness of control measures.

Question 8

K factors in ventilation

Answer 8

Due to incomplete mixing of ventilation air, a safety factor or mixing factor is used when designing required minimum airflow rates. This is known as K and is a value that takes account of ventilation effectiveness.

Question 9

Receiving hood Vs capturing hood

Answer 9

A receiving hood receives and contains contaminants such as a hood placed over a hot process.
Capturing hoods generate adequate airflow to capture and contain contaminants from the area outside the hood such as happens with slot hoods.

Question 10

Techniques for measuring the performance of ventilation systems

Answer 10

Measuring pressure differences using a device such as a manometer.
Measure air velocities with a device such as a pitot-static tube or an anometer.
Observing the path of the air flow using smoke tracers.

Question 11

Thermal equilibrium

Answer 11

The heat exchange between two physical bodies until their temperatures are equal. Also known as the Zeroth law of thermodynamics.

Question 12

4 types of heat tolerance

Answer 12

Acclimatisation, a change brought about by spending a short duration of time in a particular environment, approx 9 days.
Acclimation, a change brought about by spending a lifetime in a particular environment.
Adaptation, a change brought about by spending a generation in a particular environment.
Habituation, an altered perception of heat stress.

Question 13

3 categories of visual fatigue

Answer 13

Visual symptoms such as blurriness or double vision
Musculoskeletal symptoms such as sore neck and shoulders
Asthenopia, symptoms such as headaches and eyestrain

Question 14

Disability Glare

Answer 14

Is a loss of retinal image contrast as a result of intraoccular light scatter, or stray light. It has been described as a reduction of visual acuity due to light elsewhere in the field of vision

Question 15

Visual Acuity

Answer 15

Is a measure of how well people see, measured on an eye chart. A visual acuity of 20/20 is frequently described as meaning a person can see detail from 20 feet away, the same as a person with normal eyesight would see from 20 feet

Question 16

Speech Interference Level

Answer 16

Is the measure of suitability of an environment for speech. This is described as the average of sound pressure levels in the 3 octave bands, 500,1000 & 2000 hz. These are the bands most critical for speech

Question 17

3 types of noise

Answer 17

Discrete frequency noise (pure tones) as generated by rotating machinery. 
Broadband noise (random) best characterised as a rumble, hiss or roar.
Impact noise (impulse) best characterised as a transient acoustical event of a short duration ie a hand clap

Question 18

Advantages of personal Dosimeters

Answer 18

Provide measurement of noise levels for a specific worker.
Helps business manage OSH noise claims.
Results can be reported as compliance with OSH noise regulations.
Easy to use so no need for a noise assessor.
Can be clipped on easy and causes minimal disruption to work.
Used in restricted or controlled areas
Can measure and provide results in both LAeq and LCpeak.