STC SA 3 Flashcards
What is Occupational hygiene?
The science and art devoted to the anticipation, recognition, measurement, evaluation and control of those environmental factors or stressors arising from the place of work which may cause illness, disease, impaired health and wellbeing or significant discomfort and inefficiency among workers or among members of the community
Define the difference between a Hazard vs. risk?
HAZARD means a source of or exposure to danger. It is anything that can cause harm.
RISK is the probability or likelihood that injury or damage will occur.
Define the difference between Sampling vs. monitoring?
SAMPLING is a process consisting of the withdrawal or isolation of a fractional part of a whole. The taking of a sample is to estimate the extent or magnitude of the environmental stressors.
MONITORING means a continuing programme of observation, measurement and judgment of an environmental stressor. Monitoring include planning, carrying out sampling and recording of results to enable a judgment to be made regarding the adequacy of the control measures employed to safeguard the employee and the members of the community.
What are the Occupational exposure limits?
- Time Weighted Average Exposure Limit (TWAEL)
- Short Term Exposure Limit (STEL)
- Ceiling Exposure Values (CEV)
Explain TIME WEIGHTED AVERAGE (TWAEL)?
The limit to which an average employee can be exposed for a normal shift of 8 hours per day, 5 days a week without suffering any ill effects.
Explain SHORT TERM EXPOSURE LIMIT (STEL)?
Can be defined as a 15-minute TWA exposure which should not be exceeded at any time during a workday even if the 8 hours TWA is within the OEL-TWA. There should be at least 60 minutes between successive exposures in this range.
Explain CEILING EXPOSURE VALUES (CEV)?
Concentrations of the biological or chemical agent in the workplace air that must never be exceeded.
What does ALARA stand for?
As Low As Reasonably Achievable.
This term expresses the principle that the exposure to any hazardous material should not only be lower than the stated exposure limit but as low as it reasonably can be.
What is the Sk” notation?
This means that absorption through the skin is a significant route of entry for that substance.
What does the SEN notation stand for?
Sensitisers are those substances that can produce allergic reactions.
Occupational health= occupational hygiene + occ medicine + primary health care
What is meant by “stressors’ and what are the types?
The environmental factors, stressors or risks that may cause sickness, impaired health, discomfort or inefficiency in workers may be classified as chemical, physical, biological, ergonomic and psychological.
Give examples of Chemical Stressors?
Dust, Smoke, Fumes, Mist, Gases and Vapours.
DUSTS: Solid particles generated by handling or crushing of organic or inorganic materials.
SMOKE: A suspension of particles that often originates from combustion. Carbon or soot particles result from the incomplete combustion of carbonaceous material.
FUMES: Solid particles generated by the condensation of a gas, generally after volatilisation from a molten metal.
MISTS: Suspended liquid droplets generated during the condensation from the gaseous to the liquid state. It can also be formed when liquids are broken up into the dispersed state such as by splashing, foaming or atomising. Mists are formed when a finely divided liquid is suspended into the air.
GASES: Gases are formless fluids which occupy space and can be liquefied or solidified by the combined increase in pressure and decrease in temperature to below the critical temperature.
VAPOURS: The gaseous form of substances which are normally in the liquid or solid state at normal room temperature and pressure.
Give examples of Physical Stressors?
Physical stressors includes: Illumination, noise, vibration, thermal conditions, radiation, ventilation and indoor air quality.
Give examples of Ergonomic Stressors?
- Includes improperly designed tools or work areas.
- Improper lifting or reaching, poor visual conditions, or repeated motions in an awkward position may be responsible for accidents and inefficiency of workers in the occupational environment.
- Designing the tools and the job to be done to fit the person should be of prime importance.
Give examples of Biological agent Stressors?
A biological agent means any microorganism, cell culture or human endoparasite, including any which might be genetically modified, which may cause infection, allergy or toxicity, or otherwise create a hazard to human health. Typical stressors that can be encountered in the workplace include insects, rodents, viruses, bacteria and parasites.
Give examples of Psychological Stressors?
Include occupations which might endanger mental health. Examples of psychological health effects that can develop are neurosis, a condition caused by overloading the senses. This might lead to absenteeism, tiredness, sleeplessness, heart disorders, peptic ulcers and even asthma.
What is the Hierarchy of controls?
- Elimination
- Substitution
- Engineering controls
- Administrative control
- Personal protective equipment (PPE)
Define illuminance?
illuminance is the amount of light falling onto a surface.
Define Luminance?
Luminance is the amount of light reflected from a surface.
Define LUX?
The metric unit for illuminance. 1 Lux = 1,0 lumen/m2
Define Contrast?
Contrast is the relationship between the brightness of an object and its background.
Define Glare?
Glare is a visual condition where there is discomfort and/or a diminished ability to distinguish identifiable objects due to unsuitable illuminance diffusion or luminance limits, or as a result of extreme contrasts, simultaneous or successive, within the field
of vision. Any brightness within the field of vision with such characteristics would cause discomfort, annoyance, interference with vision or eye fatigue.
Define Direct Glare?
Direct Glare caused by luminous objects within the field of vision, e.g. windows, luminaries, etc.
Define Reflective Glare?
Reflective Glare produced by seculars reflection from the task itself or by the reflection of bright sources from surfaces near the task (e.g. shiny bench tops).
Explain the Stroboscopic effect?
is caused when the lighting of an object changes at an applicable
frequency and causes the apparent movement of the rotating object to differ from the real movement. A rotating blade may appear to be standing still or it may appear to be rotating in the opposite direction, leading to a safety risk.
Which Legislation and best practice covers lighting?
OHS Act 85 of 1993, Environmental regulations, section 3 Lighting and lighting schedule SANS 10114
Define Sound?
Is defined as any pressure variation (in air, water or some other medium) that the human ear can detect. Sound can also be defined as a stimulus that produces a sensory (auditory) response in the human brain.
Define Noise?
Is defined as usually sound that bears no information and whose intensity varies randomly in time. Noise is normally regarded as an unpleasant and unwanted sound.
What is considered to be a Noise zone?
An Area where the noise level is or exceeds 85dB (A) (SA) and 90dB(A) (USA).
What is a temporary threshold shift?
in hearing occurs immediately after exposure to significant loud noise. Quiet sounds can no longer be heard and the condition may last for minutes to hours.
What are the three main groups that noise can be classified in?
- Continuous Noise
- Interrupted Noise
- Impulse Noise
CONTINUOUS NOISE
Continuous noise occurs for example when an electric motor is switched on. This is a monotonous continuous sound with little variance in the frequency and intensity.
INTERRUPTED NOISE
Interrupted noise occurs when there are variations in sound levels due to the on-and-off switching of the machine during a production cycle. The nature of the sound is the same but it is alternated by periods of silence.
IMPULSE NOISE
Impulse noise has a unique feature in that it consists of a very intense sound lasting only a short period, e.g. a gunshot, hammer blows.
The NRR (attenuation) is conducted under controlled laboratory conditions and does not take into account?
A-weighting scale
Fitment
Bone induction
Wear and tear
How does Whole Body Vibration (WBV) Occur?
Occurs when a human body is supported on a surface which is vibrating and causes the body to vibrate.
What are some common sources of WBV?
Large numbers of workers are exposed to WBV with delivery vehicles, forklift trucks, lorries, tractors, buses and loaders as the most frequently reported sources of WBV. Vibration can be due to the machinery itself or the road surface.
Define HAVS?
Hand-arm vibration syndrome
What are the effects of HAVS?
- Prolonged exposure to vibration through the use of hand-held power tools and equipment leads to damage in several organ systems of the upper limb.
- Damage to the vascular system is a direct effect of the vibration on the blood vessels themselves. Such damage can cause impairment to the circulation.
- Neurological and muscular damage causes numbness and tingling in the fingers and hands. Neurological damage also causes a reduction in sensation to touch and temperature, as well as reducing grip strength and manual dexterity.
- The symptoms experienced from bone and joint damage are pain and stiffness in the hand, joints of the wrist, elbow and shoulder.
- Osteoarthritis and bone cysts occur in workers who are exposed to vibration from hand-held tools.
OHS Act, environmental regulations section 2. thermal requirements state that?
TWA WBGT measured over 1 hour must not exceed 30.
Define Ventilation?
Ventilation is actually a combination of processes which results in the supply and removal of air from inside a building.
What are the two types of Ventilation Systems?
General Ventilation.
Local exhaust ventilation.
General ventilation reduces airborne concentrations of chemicals by diluting the workplace air with cleaner air from outside. General ventilation can effectively remove large amounts of hot or humid air, or dilute low concentrations of low toxicity.
Local exhaust ventilation removes the contaminant rather than diluting it. This type of ventilation is only effective if it is located close to the source of the hazard.
What is Radiation?
Radiation is the emission or transmission of energy as waves or moving particles.
Define Occupational health?
The promotion and maintenance of the highest degree of physical, mental and social wellbeing of workers, prevention of disease, practised in a balanced synthesis of several disciplines including occupational hygiene, occupational medicine and biological monitoring.
Define Primary health care?
Primary health care involves the immediate treatment of minor/serious injury or illness, chronic diseases and minor ailments occurring at the workplace. It includes the referral of the
injured/sick employee to the relevant doctor or hospital for follow-up treatment to ensure rapid recovery. It also covers aspects related to social welfare/health education and rehabilitation.
Define Occupational medicine?
Occupational medicine is a specialist discipline within the context of occupational health. It deals mainly with the correlation/relationship between the worker and his/her work environment that may result in impaired or ill-health. Occupational medicine focuses on the prevention, diagnosis and treatment of illness or injury and the monitoring of adverse health effects associated with a particular type of work/exposure.
Define Occupational hygiene?
Occupational hygiene involves the anticipation, recognition, evaluation and control of conditions arising in or from the workplace, which may cause illness or adverse health effects.
Define Biological monitoring?
A planned programme of periodic collection and analysis of body fluids, tissues, excreta or exhaled air in order to detect and quantify people’s exposure to and their absorption of any
substance or organism that can cause adverse health effects.
Define Medical surveillance?
This is a planned programme of periodic examinations, which may include clinical examinations, biological monitoring and medical testing (of employees by an occupational health practitioner under supervision of an occupational health medical practitioner).
What are the Aims of Occupational Health Service?
The objectives are defined as:
- Protecting the workers against any health hazard which may arise from work or
conditions in which it is carried out. (protection and prevention principle).
- Adapting work and the work environment to the capabilities of workers (adaptation
principle) by placing them in jobs to which they are suited (inherent job requirement).
- Contributing towards workers’ physical and mental adjustment, social well being (health promotion principle) as well as their ability to conduct a socially and economic productive life.
- Minimising the consequences of occupational hazards, accidents and injuries and
occupation-related diseases (the cure and rehabilitative principle).
- Providing general healthcare services for employees and their families, both curative and preventive (the PHC principle) either on-site, or by providing means like health cover assistance, e.g. medical aid/social security.
The guiding principle should be to ensure as far as is reasonably practical:
- A safe and healthy workplace.
- The availability of adequate health care to all employees.
What is Occupational toxicology?
Occupational toxicology is the study of hazardous (chemical) substances that cause adverse health effects in workers.
Define Biological monitoring?
Biological monitoring is the measurement of a worker’s exposure to the toxic substance and the worker’s response to that substance.
What is a construction plan?
A construction plan is a schematic represéntation of a construction building/project, which is designed for a specific site/area to cope with a given situation.
What are the Criteria for a good layout?
As a result of many variables (type of lay-out whether process or production lay-out, final product produced, transport from plant, type of machinery used), hard and fast rules for a
successful layout cannot be supplied.
However, the following criteria could be applied during the planning stage: Flexibility Co-ordination Maximum use of volume Accessibility Visibility Visible routes Minimum distance Minimum handling One-way flow Minimum discomfort
What are the two main categories in which way fires can spread?
- direct spread of flames
2. indirect heat conduction.
What are the main subcategories under the Direct spread of flames?
- Flames spreading over a surface
- Falling objects
- Air-borne pieces of burning material
What are the main subcategories under the indirect spread of flames?
Radiation
Conduction
Convection/Heat currents
Fires fall into two categories according to?
a) the types of flammable materials present; and
b) the most suitable fire-extinguisher that can be used.
What are the four basic classes of fires and their examples?
The four basic classes are:
Class A: Fires where ordinary solid flammable materials are present, for example, coal, paper, plastic, wood and textiles (organic materials).
Class B: Fires where flammable liquids, lubricants and gases are present, for example, alcohol, benzene, oils, paraffin and petrol.
Class C: Fires of the A, B and D type in the presence of live electrical installations, for example, electrical cables, generators, transformers and switchboards.
Class D: Fires where metals are present, for example, magnesium, aluminium, sodium, potassium and lithium.
Which areas are classified as critical areas with regards to fire and fire prevention?
Flammable liquid stores
Spray-paint rooms
Every company should try to achieve the following three objectives with risk management?
- Financial: To reduce the ratio of total cost-of-risk and to maintain
the improvement over time.
*Resources: To conserve assets & preserve the physical health
of employees through safe working habits & work environment - Customers and public: To improve the enterprise’s image in the
minds of people it serves through reduction of an incident
causing conditions which affect its products
Define a Hazard?
A hazard is a condition, activity, object (material) or substance that has the ability to cause harm in certain circumstances.
This includes machinery, raw materials, work
methods, etc.
The Occupational Health and Safety Act, 85 of 1993 (OHSA) and the Mines Health and Safety Act, 29 of 1996 (MHSA) define it as a source of, or exposure to, danger.
Define a Risk?
Risk is the chance or likelihood of a hazard causing harm or damage to a person or to property or the environment.
The extent of the risk depends not only on the severity of potential harm to a person, property or the environment but also on other factors such as the number of people exposed.
The OHSA defines risk as to the probability that injury or damage will occur and the MHSA defines it as the likelihood that occupational injury or harm to persons will occur.
Define Pure Risk?
Pure risks are associated with hazards in ‘spheres such as health, safety, environment and security where success with risk control can be the removal of the hazard so that exposure is zero and no harm can result, i.e. no accidents, zero
product defects, no crimes. (Waring and Glendon, 1998, p4).
Define Speculative risk?
Speculative risks are associated with business, finance, investment, human resources, IT strategy and politics where success is always relative to that of the economy as a whole, the market sector, competitors and the power attributes of others (Waring and Glendon, 1998, p4).
Define Consequence?
The outcome of an event expressed qualitatively or quantitatively being a loss, injury, disadvantage or gain. There may be a range of possible outcomes associated with an event.
Define Frequency?
A measure of the rate of occurrence of an event expressed as the number of occurrences of an event in a given time.
The likelihood of a specified risk leading to a specific outcome/consequence.
Define Probability?
The likelihood of a specific outcome, measured by the ratio of specific events or outcomes to the total number of possible events or outcomes. Probability is expressed as a number between 10 and 1, with 10 indicating an impossible event or outcome and 1 indicating that an event or outcome is certain.
Define Severity?
The degree of harm or the nature of the consequence.
Define Exposure?
The extent or degree to which people i.e. include contractors, visitors, neighbours, customers, etc. or the environment is exposed to a specified risk.
Define Residual risk?
The risk that remains after taking into account the effect of the controls that have been applied.
Define Significant risk?
A level of risk that cannot/will not be tolerated by management and/or the workforce and needs to be controlled
Define Tolerable risk?
A level of risk that will be tolerated by management and/or the workforce. (The legislator’s expectations and the public’s perception typically will serve to reduce the tolerance for risk of any individual company.
