Sound Energy – Hearing Loss

The Problem

The Work Health and Safety legislation describes noise as any sound that has the potential to cause harm to a person’s health and safety. In Australia during the 2006 – 2007 year, the impacts of noise particularly in workplaces showed to be a clear issue for people in the workforce. Around 4000 claims were made for occupational noise-induced hearing loss in this year, where the average cost per claim equated to $11,200.  These claims however do not accurately sum up the issues that the impacts of noise energy have on people, as especially with the issue of loss of hearing, it takes time for signs of damage to become obvious. Furthermore, a 2006 report indicated that one million Australians were exposed to hazardous levels of noise, ultimately accounting for 16% of adult on-set hearing loss. Due to large issue noise has within workplaces, the Australian Safety and Compensation Council has declared occupational noise-induced hearing loss as one of the eight priory disease that industries and regulators are required to address (Groothoff 2012). Finally, the impact noises have on people who are constantly exposed to it goes further than loss of hearing, with annoyance, fatigue, hypertension, heart disease, tinnitus, and depression finding to be linked with the effect of noise exposure. Furthermore, exposure to noise also impacts on people’s work productivity and increases the risk of accidents in the workplace (Safe Work Australia 2010).

 

The Underpinning Science

Sound energy is linked with vibration, which is the reason people have the ability to hear. When a sound is made, the air around the object that is making the sound starts to vibrate. These vibrations are sound waves. As this air moves, energy from the sound being made travels in all directions. When this vibrating air reaches a person’s ears, it causes the air inside the ears to start vibrating as well. This vibration within the ears causes the sound energy to convert into sensations which the brain interprets as a type of noise (Woodford 2016).

While our ears are designed for the purpose of hearing, damage can easily occur if care is not taken.  Hearing loss can start to occur after exposure to a loud noise after an extended period of time. During this time, hair cells that line the basilar in the ear (shown in Figure 1) that work as sensory receptors for sound slowly become damaged. These hair cells do no regenerate once damaged. Loud noises can also damage a nerve known as the cochlear nerve, where the effect of loud noises can obstruct auditory signals from being sent to the brain (Martinez 2015).

Figure 1: Location of hair cells in ear

(Centre for Hearing, Speech and Language 2014)

Hazardous Situations

The problem with noise is that it is everywhere, and sometimes people do not have control over the noises they are hearing. There are many situations where noise can be hazardous, even outside of workplaces. Some hazardous situations include:

• At home – Mowing the lawn, loud sounds such as music from neighbouring houses, watching television on a high volume
• In workplaces – Machinery, alarms, vehicles (accelerating and backing up)
• In public – Traffic, sirens form emergency services vehicle, beeping horns, planes passing over

(Hearing Sense n.d.).

One good example of where loud noises are especially frequent are airports. Both people preparing a plane and directing it on the tarmac as well as passengers who come near the plane to board are exposed to extremely loud noises from the jet engines. For those who work around the planes, people will always see them wearing noise cancelling headgear in order to reduce the risk of hearing loss (Hearing Sense n.d.).

 

Measurements and Evaluation

With just about any hazard that has the potential to cause harm to someone, there are limits and thresholds associated with exposure to noise. Sounds are measured in units known as decibels. By measuring the decibels of a particular sound, it can be determined how long someone can listen to the sound before damage occurs. For sounds that measure at less than 75 decibels, it is unlikely for damage to occur even after an extended period of exposure. For sounds that measure at 85 decibels or more however, repetitive exposure to these sounds can cause damage which can lead to loss of hearing.  Ultimatley, the louder a sound is means the shorter amount of time it takes for damage to occur (NIDCD 2015). Figure 2 below displays the type of sounds associated with decibel measurements, as well as the level of sound associated with each. Generally, if something is as loud as or louder than a lawn mower, ear protection is required to avoid the risk of loss of hearing (Hearing Sense n.d.).

Figure 2: Decibel units associated with noise levels

(Hearing Sense n.d.)

Safety Strategies

Legislation and Standards

• Western Australia’s workers’ compensation legislation – requires all operators of noisy workplaces to test their workers’ hearing
• The draft Model Work Health and Safety Regulations – Specifies exposure standards for noise in terms of how long people are allowed to be exposed to certain noise levels
• AS/NZS 1269 Occupational Noise Management – Provides details on noise assessment, instrumentation, and evaluation of results and noise management
• Draft Code of Practice and the relevant sections of AS/NZS 1269 – outlines the information required to comply with regulated exposure standard to prevent noise-induced hearing loss
• AS/NZS 1270 Acoustics – Provides information regarding hearing protectors
• AS 2436 Guide to Noise and Vibration Control on Construction, Demolition and Maintenance Site – Provides information on noise and vibration hazards in construction-related professions

(Safe Work Australia 2010; Groothoff 2012)

Control Measures

• Implement procedures to reduce noise made in a process (eg. Instead of hammering metal to bend it, heat the metal and bend it with pliers)
• Sound proofing parts of buildings
• Use sound absorbing materials
• Replacing older, louder equipment with new and quieter equipment
• Use hearing protection – Earmuffs, moulded earplugs, ear canal caps
• Select appropriate hearing protection out of classes one to five according to the level of sound in a workplace (Table 1)

(Groothoff 2012)

(Groothoff 2012)

References

Centre for Hearing, Speech and Language 2014, May is better hearing and speech month, viewed 9 June 2016, http://www.chsl.org/prdocs/prhearingmonth0411.php

Groothoff, B 2012, ‘Physical Hazards: Noise and vibration’, OHS Body of Knowledge, viewed 9 June 2016, http://www.ohsbok.org.au/wp-content/uploads/2013/12/22-Hazard-Noise.pdf?d06074

Hearing Sense n.d., Causes of hearing loss, viewed 9 June 2016, http://hearingsense.com.au/causes-of-hearing-loss/

Martinez, J 2015, How can sound damage your ears?, viewed 9 June 2016, http://www.livestrong.com/article/137873-how-can-sound-damage-your-ears/

NIDCD 2015, Noise-induced hearing loss, viewed 9 June 2016, https://www.nidcd.nih.gov/health/noise-induced-hearing-loss

Safe Work Australia 2010, Occupational noise-induced hearing loss in Australia, viewed 9 June 2016, http://www.safeworkaustralia.gov.au/sites/swa/about/publications/Documents/539/Occupational_Noiseinduced_Hearing_Loss_Australia_2010.pdf

Woodford, C 2016, Sound, viewed 9 June 2016, http://www.explainthatstuff.com/sound.html

Electrical Energy – Electric Shocks

The Problem

Electrical energy is energy that exists as a result of moving electric charges, where the faster electric charges move, the more electric energy they store (Soft Schools 2016). Within Australia, the risks associated with electrical energy caused around 15 deaths a year from 2003 – 2008 and 91 emergency hospital admission from work-related electrical injuries from 2002 – 2004. Furthermore, from 2006 – 2007, 190 claims relating to contact with electricity were made, with five being fatalities, and 70% of claims serious enough to result in at least two weeks of absence from work (Ruschena 2012). In particular, interactions with electricity can result in electrical burns where an electrical current passing through a body heats tissue located along the length of the current flow, as well as thermal burns where being too close to heat caused by electricity results in a burn. Of course, one of the most common dangers of interacting with electricity are electric shocks, whereby being shocked can cause (along with burns) cardiac arrest, prevention of breathing, and muscle spasms. In a case where an electric shock has caused death, it is then referred to as electrocution (Health and Safety Executives 2016).

 

The Underpinning Science

The production of electricity includes a flow of electrons through a conductor caused by an electromotive force. An electric current refers to the movement of electric charges, while amperes (amps) are used to measure the intensity of an electrical current. The electromotive force causes the current to flow, whereby for a conductor of electricity, a higher voltage will mean a higher current flow (Ruschena 2012). Interestingly, while one would believe that 100,000 volts is more dangerous than 100 volts, this is not the case. In fact the danger of electricity, particularly with shocks lies within the electrical current (amps) forced through the body (Giovinazzo 1987).

 

Hazardous Situations

There are many situations where electricity can become a hazard. Some of these include:

• Exposed electrical parts
• Inadequate/poor wiring
• Damaged insulation
• Overloaded circuits (shown in Figure 1)
• Wet conditions

(United State Department of Labor 2016)

All of the hazardous situations listed can lead to a fire or someone being shocked, which can ultimately mean being burned, obtaining muscle damage, or even dying as a result. Electrical injuries occurring as a result of these types of hazards occur most frequently in manufacturing, retail and construction, while a very small amount occur in the actual electricity, gas and water industries (Ruschena 2012).

Figure 1: A hazardous overloaded circuit

(JP Electric 2016)

Measurements and Evaluation

The impact that contact with an electric current can have varies from person to person due to size and gender. Regardless of this however, there are certain measurements which define the expected outcome of an interaction with certain amounts of amps. This includes:

• 0.001 – 0.01 amps: mild sensation
• 0.01 – 0.1 amps: severe shock (painful shock, unable to easily let go of conductor, muscular paralysis, breathing difficulties)
• 0.1 – 0.2 amps: death
• 0.2 – 1.0 amps: severe burns and no breathing

(Giovinazzo 1987).

As it can be see, death occurs between 0.1 and 0.2 amps, but not necessary for 0.2 amps or more. This is because muscular contractions are so severe that the heart forcibly clamps during a shock that is this intense. The clamping of the heart prevents ventricular fibrillation from occurring which means that the chances of survival are fairly positive for a person who experiences a shock of this intensity (Giovinazzo 1987). It is important to note however that the presence of moisture such as wet clothes, as well as metal such as watches will increase the severity of a shock (Giovinazzo 1987).

 

Safety Strategies

Legislation and Standards

• Electrical Safety Act 2002
• Electrical Safety Regulation 2013
• Australian Electrical Standards
• Wiring Rules clause 4.5.2.3
• Work Health and Safety Regulations (WHS) – requires anyone conducting or undertaking a business must ensure a work environment without risks to health and safety, which means they should follow the legislation, regulations and standards mentioned above in order to do so
• AS/NZS 2210.1:2010 – requires certain footwear to be worn
• AS 2225–1994 – requires certain gloves to be worn
• The draft national WHS s 4.7.13 –  prohibits work on electrical apparatuses while the equipment is energised except in specified circumstances

(WorkCover Queensland 2016 ; Ruschena 2012).

Control Measures

• Ensure electrical circuits are not accessible through location (such as powerlines being elevate high to avoid contact with them)
• Use of circuit breakers and residual current devices as part of electrical circuits to protect against electrical faults
• Use of maintenance records, diagrams of designs, and plant and equipment records
• Wearing personal protective gear as shown in Figure 2, such as insulted glove, safety footwear, and work clothes that are made of natural fibres such as cotton or wool, or clothing that is made of treated/formulated synthetics

(Ruschena 2012)

Figure 2: Appropriate safety clothing for electrical work

(Electrical Engineering Portal 2012)

 

References

Electrical Engineering Portal 2012, 21 safety rules for working with electrical equipment, viewed 9 June  2016,  http://electrical-engineering-portal.com/21-safety-rules-for-working-with-electrical-equipment

Giovinazzo, P 1987, The fatal current, viewed 9 June 2016, https://www.physics.ohio-state.edu/~p616/safety/fatal_current.html

Health and Safety Executives 2016, Electrical injuries, viewed 9 June 2016, http://www.hse.gov.uk/electricity/injuries.htm

JP Electric 2016, Spring energy saving tips, viewed June 9 2016, http://jpelectric.com/category/electrical-maintenance

Ruschena, LJ 2012, ‘Physical hazards: Electricity’, OHS Body of Knowledge, viewed 9 June 2016, http://www.ohsbok.org.au/wp-content/uploads/2013/12/23-Hazard-Electricity.pdf?d06074

Soft Schools 2016, Electrical energy examples, viewed 9 June 2016, http://www.softschools.com/examples/science/electrical_energy_examples/20/

United State Department of Labor 2016, Big four construction hazards: Electrical hazards, viewed 6 June 2016, https://www.osha.gov/dte/grant_materials/fy08/sh-17792-08/electrical_english_r6.pdf

WorkCover Queensland 2016, Electrical safety laws, viewed 9 June 2016, https://www.worksafe.qld.gov.au/laws-and-compliance/electrical-safety-laws

 

Thermal Energy – Heat

The Problem

Thermal energy refers to the energy that originates from hot/cold environments. The main focus in terms of thermal energy will be on hot environments. Although the dangers of heat can be extreme, the effect that cold temperatures have on people can also be serious. Exposure to cold temperatures can cause illness, frostnip, and in serious cases, frostbite and death (Di Corleto 2012).

The dangers related to heat exposure are more frequent than those related to exposures to cold temperatures.  In Australia for example, although the data does not effectively identify the significance of the dangers connected to thermal energy in workplaces, 25 claims were made related to hot environments and 10 claims were made relating to cold environments in 2006 – 2007. Out of all claims made, two were fatalities as a result of exposure to heat. The effect of heat can have a range of outcomes involving impacts on health as well as physical impacts on a person’s body. Exposure to hot environments can cause heat stress whereby an increase in someone’s body temperature is influenced by the environment itself (air temperature, humidity, etc.), clothing, and activity. The results of heat stress can include heat stroke, heat exhaustion, heat cramps, heat rashes, and in some cases, death. Physical injuries such as burns can also occur to a person within a hot environment in a situation where this is exposure or contact with a heat source such as a flames (Di Corleto 2012).

 

The Underpinning Science

One of the most important scientific concepts involved with understanding people’s reaction to heat is the concept of homoeostasis. This is a process in the body where the body responds to changes in order to maintain stability within the internal environment of the body. By the human body being able to respond to situations such as heat, the body can control temperature, water balance of blood, blood sugar levels and so forth. The body responds to heat by trying to cool down the body, which is the reason humans perspire. In a situation where the external environment is more than the body can handle, issues such as heat stress occurs. This is especially the case when someone does not stay hydrated and therefore the body cannot perspire as it should when someone is hydrated (Di Corleto 2012).

The transfer of heat is also an important concept in understand how heat energy can cause danger. As Figure 1 shows, there are three ways in which heat can be transferred which are through convection, conduction and radiation. In particular, conduction and radiation are the largest threats to the well-being of people. Conduction involves the transfer of heat through contact, where moving particles of warm materials increase the energy of the molecules on a cooler material. This explain why if someone is to touch a hot surface with their hand of a significantly lower temperature, they will get burned. Radiation on the other hand involves the heat felt off hot objects such as an oven or the sun. Heat waves radiate out from hot objects in all directions and is absorbed by other objects, such as people. This explains why people can overheat by being exposed to hot temperatures, as well as why people can be be burnt by the sun (Science Learning 2009).

Figure 1: Types of heat transfer

(Swan 2014)

Hazardous Situations

There are many situations where the hazards and risks involved with thermal energy are present. These include:

• Cooking – the use of ovens can cause burns and can cause heat stress in some circumstances
• Outdoor activities – possibility of sun burns and overheating
• Farming activities (shearing) – occurrence of heat stress, heat stroke and heat rash from working in uninsulated iron sheds and no air circulation

(Di Corleto 2012)

In terms of hazardous situations involving fire as a source of heat, one of most appropriate examples is the occupation of fire fighting, whereby there is not only a source of heat from the fire itself but also heat from the sun if a fire is outdoors. Along with the type of gear worn by fire fighters, they are at high risk of being burned by fire and/or experiencing heat-related illnesses such as heat stroke.

(Di Corleto 2012)

 

Measurements and Evaluation

Burns are a very common injury obtained as a result of contact with heat sources, however there a three degrees in which a burn can be classified according to the seriousness of a burn, which is illustrated in Figure 2. The least serious burns than can be received are first-degree burns (superficial burns) that do no penetrate the outer layer of skin or epidermis but tend to cause redness and swelling. Worse than this are second-degree burns (partial-thickens burns) which do penetrate the outer layer of skin but not the inner layer of skin or dermis, causing redness or mottling, swelling and blisters. The worst burn a person can receive are third-degree burns (full-thickness burns) where the inner layer of skin is penetrated and nerve ending destroyed, leaving a white or charred appearance. (McDougal 2005; Di Corleto 2012). Although contact with heat sources can cause terrible outcomes, there are limits in which a body can withstand heat before becoming injured. This is dependant on the temperature of a source as well as the amount of time in contact with the heat source. In particular, for something that is 44 ˚C, 6 hours of exposure/contact will cause injury. For 47 ˚C, 45 minutes of exposure/contact will cause injury, while for 70 ˚C, it takes on 2 seconds to receive a burn (McDougal 2005).

In terms of the health effects caused by exposure to heat such as outcomes of heat stress, a body’s threshold for heat depends on air temperature, humidity levels, the presence of hot objects, the presence of air movement, the type and amount of physical activity someone is doing, the clothing being worn, as well as personal experience with hot environments. For example, someone from Australia will cope much better with heat than someone from a cold climate such as Canada. Ultimately, if someone is doing labour intensive work outdoors in thick, long clothing on a particularly hot and humid day with little breeze, they are at high risk of heat stress (Canadian Centre for Occupational Health and Safety 2016). As someone’s internal core body temperature is usually somewhere between 36.8°C and 37.2°C, exceeding this temperature is when harm can occur. A body temperature of 40°C can cause heat stroke, while a body temperature of 42°C or higher can cause death (Di Corleto 2012).

Figure 2: Types of burns

(Burn Recovery n.d.)

Safety Strategies

Legislation and Standards

• Work Health and Safety Regulations s 3.1 – requires that workers exposed to extreme heat or cold are able to work without having any risk to their health or safety
• Occupational Health and Safety Regulation 2001 clause 47 and 48 – requires that shelter, ventilation and consideration of work rest regimes are the responsibility employers to ensure a work environment that is safe and healthy

Control Measures

• Scheduling work to avoid hottest part of the day
• Access to cool drinking water
• Personal protect equipment to prevent burns from fires, and light material clothing for working in hot environments
• Sufficient air circulation in buildings

 

References

Burn Recovery n.d., Diagnosing a burn injury, viewed 9 June 2016, http://www.burn-recovery.org/injuries.htm

Canadian Centre for Occupational Health and Safety 2016, Hot environments – Control measures, viewed June 9 2016, https://www.ccohs.ca/oshanswers/phys_agents/heat_control.html

Di Corleto, R 2012, ‘Physical hazards: Thermal environment’, OHS Body of Knowledge, April, pp. 1-29, viewed 8 June 2016, http://www.ohsbok.org.au/wp-content/uploads/2013/12/26-Hazard-Thermal-environment.pdf?ce18fc

McDougal, H 2005, Laboratory manager’s professional reference, Holt, Rinehart and Winston Inc., Austin.

Science Learning 2009, Heat energy, viewed 9 June 2016, http://sciencelearn.org.nz/Contexts/Fire/Science-Ideas-and-Concepts/Heat-energy

Swan, B 2014, Ignition and spread of fire, viewed 9 June 2016, http://www.evacconnect.com/blog/2014/07/ignition-and-spread-of-fire/

Chemical Energy – Corrosive Substances

The Problem

There are many ways in which chemicals can cause a threat to someone’s health and safety. In particular, chemical energy is described as the energy stored in the bonds of chemical compounds. Chemical reactions are a common process were chemical energy is released, often in the form of heat (Encyclopaedia Britannica 2016). Corrosive substances contain chemicals that have the potential to cause visible destruction or irreversible damage to living tissue cells at an area of contact with chemicals, whether the chemical is liquid, solid, or a gas. The harmful reaction related to corrosive chemicals may include mild to highly severe irritations to someone’s eyes, skin, respiratory tract, and/or gastrointestinal tract (Cornell University 2016). In Australia from 2006 – 2007, a total of 1350 claims for chemical exposures were made, where three of these were fatalities as result of a single encounter with chemicals, while 58 of the reports were from long-term contact. The main claims made related to skin/dermatitis conditions and respiratory conditions (Pisaniello & Tepe 2012).

 

The Underpinning Science

In terms of corrosive chemicals, most are either acids or bases. Some of the most common acids include hydrochloric, chromic, acetic, sulfuric nitric, and hydrofluoric acid, while some common bases are potassium hydroxide, ammonium hydroxide, and sodium hydroxide (Canadian Centre for Occupational Health and Safety 2007a). To explain how chemical energy relating to corrosive chemicals causes harm, the outcome of dermatitis on the surface of someone’s skin from contact with a corrosive chemical can be used. As Figure 1 shows, dermatitis is the inflammation of skin which occurs as a result of the body attempting to react to damaged tissue cells. Some chemicals have stronger reactions, however the process of damage to the skin regardless of the type of corrosive chemical involves chemicals reacting in a way which changes properties of the outer layer of skin that protects against substances. Due to this protective layer being compromised, the ability of irritants from chemicals to infiltrate the skin increases. Following infiltration, chemical substances can come in contact with cells and tissues which causes skin damage, indicated by redness, swelling and painful sensations. The damage caused by the reaction is ultimately dependant on the properties of a chemical substance, the concentration, and the length and frequency of exposure to the chemical (Canadian Centre for Occupational Health and Safety 2007b).

Figure 1: Dermatitis caused by chemical irritations

(Edit This 2011)

Hazardous Situations

Hazardous chemicals can either be classed as a physical hazard or a health hazard. Physical chemical hazards include chemicals that are explosive, flammable or reactive, while chemicals which are health hazard include corrosive chemicals and toxic chemicals (Lehigh University 2016).

• Explosive – has the ability to suddenly release pressure (eg. Working with oxidising agents)
• Flammable – has the ability to easily catch fire (Working with chemicals near a source of heat such as a naked flame or spark)
• Reactive – when exposed to other chemicals, heat, air, water, etc. it has the ability to burn, explode, or release vapour which may be toxic in some cases (eg. Working with multiple chemicals in one area)
• Toxic – Has the ability to cause illness or possible fatal damage to someone depending on exposure/contact (eg. Working with pesticides)

(Lehigh University 2016)

In terms of corrosive chemical hazards, it has been explained that they have the ability to cause irritation to contacted body parts or possibly permanent damage. Corrosive chemicals as a hazard exist in workplaces and also in everyday products used at home for cleaning, such as bleach. Bleach is a chlorine-based corrosive substance, whereby both the breathing in of fumes or physical contact with the substance can cause irritation to the nose, lungs, eyes, and skin. In more serious situations, harm from the substance may include burns, damage to the respiratory and nervous systems, asthma flares and much more (Institute for Vibrant Living 2016).

 

Measurements and Evaluation

In understanding the damage a corrosive chemical can have on a person, the pH of a substance is important to know. The measurements of strength and concentration of a substance determines the pH, where strength is the percent of ionisation that occurs when an acid or base is mixed with water, while concentration refers to ratio of the acid or base substance to water. The pH of a substance is ranked on a scale of 1 to 14, where 1 is strongly acidic, 7 neutral, and 14 strongly basic (University of Nebraska Lincoln 2016). For the case of the example of bleach as a commonly used corrosive substance, it would rank as a highly basic (alkaline) substance with its pH generally being around 13.   As it can be seen in Figure 2, the further away a substance is from the neutral ranking of 7, the more risk of harm the substance contains (Pure H2O Technology 2012).

While the pH of a substance is a large factor behind the possible harm that can be obtained from a corrosive substance, the amount of contact with a substance is an influencing result of the harm inflicted. For the case of a highly acid or basic substance, momentary contact can cause major damage to the contacted area. Substances with pH rankings that are not extreme can also produce serve corrosion if there is an extended period of contact with a substance (University of Nebraska Lincoln 2016).

Figure 2: pH rankings

(University of Nebraska Lincoln 2016)

Safety Strategies

Legislation and Standards

• Model Work Health and Safety Act (WHSA ss 22–25)  and Model Work Health and Safety Regulations – requires designers, manufactures, importers and suppliers of chemical substances for use in workplaces to (according to their role) apply necessary calculations, analysis, testing and examining, as well as to provide adequate information about chemicals
• WHSA s 19 – requires chemical containers to be labelled (as according to the Globally Harmonised System of Classification and Labelling of Chemicals shown Figure 3) , the providing of safety data sheets, and the use and display of hazardous chemicals registers

(Pisaniello & Tepe 2012)

Control Measures

• Use of personal protective equipment such as gloves (including gloves specifically for stronger chemicals), face masks, eye protection, face shields, lab coats, aprons, etc.
• Housekeeping – correct storage of chemicals, labelled containers, access to emergency equipment such as emergency showers, immediate cleaning of surfaces that have come into contact with chemicals
• Restrictions on eating, drinking and smoking in chemical storage or use areas

(Worcester Polysynthetic Institute 2004)

Figure 3: Globally Harmonised System of Classification and Labelling of Chemicals

(Pisaniello & Tepe 2012)

References

Canadian Centre for Occupational Health and Safety 2007a, Corrosive materials – Hazards, viewed June 7 2016, https://www.ccohs.ca/oshanswers/chemicals/corrosive/corrosiv.html

Canadian Centre for Occupational Health and Safety 2007b, Dermatitis, irritant contact, viewed 7 June 2016, https://www.ccohs.ca/oshanswers/diseases/dermatitis.html

Cornell University 2016, Chapter 8 – Chemical hazards, viewed 7 June 2016, https://sp.ehs.cornell.edu/lab-research-safety/laboratory-safety-manual/pages/ch8.aspx#8.9

Edit This 2011, Dermatology – Blistering dermatoses, viewed 8 June 2016, http://editthis.info/iusmicm/Dermatology_-_Blistering_Dermatoses 

Encyclopaedia Britannica 2016, Chemical energy, viewed 7 June 2016, http://www.britannica.com/science/chemical-energy

Institute for Vibrant Living 2016, The dangers of bleach, viewed June 8 2016, http://www.ivlproducts.com/Health-Library/Health-Concerns/Healthy-Living/The-Dangers-of-Bleach/

Lehigh University 2016, Hazard communication (right-to-know), viewed 8 June 2016, https://www.lehigh.edu/~inehs/hazcom.html

Pisaniello, D & Tepe, S 2012, ‘Chemical hazards’, OHS Body of Knowledge, April, pp. 1-39, viewed 7 July 2016, http://www.ohsbok.org.au/wp-content/uploads/2013/12/17-Hazard-Chemical.pdf?d06074

Pure H2O Technology 2012, pH factor, viewed 8 June 2016, http://2behealthynow.com/Living_Waters_System/Ph_Factor.html

University of Nebraska Lincoln 2016, Corrosive chemical hazards & risk minimization, viewed 8 July 2016, http://ehs.unl.edu/sop/s-corrosive_chem_haz_risk_min.pdf

Worcester Polysynthetic Institute 2004, Chemical hygiene plan, viewed 8 June 2016, http://www.wpi.edu/offices/safety/hygiene.html

 

 

Gravitational Potential Energy – Falls from Heights

The Problem

Gravitational potential energy is a problem that poses a risk to everyone’s well being for the entirety of their lives. From the beginning of life all the way until the last stages of life, gravity continues to constantly exist and create potentially harmful or life threatening risks. Gravitational energy is the concept of the force of attraction by which bodies and inanimate objects fall towards the centre of the earth as a result of loss of balance or lack of security (Adams & Breslin 2012).

Gravitational energy can be found in in any situation where objects have the potential to fall from a height or where someone could possibly slip or trip (Safetyline Institute 2005). Undoubtedly the most consequential hazard related to gravitational energy are falls from heights.The dangers involved with gravitational energy, falls in particular, are quite clear. In Australia from July 2002 to June 2005, a national average of 343 deaths occurred from falls within buildings, while an average of almost 106,000 hospitalisations per year were to blame from falls as well. In contrast to this, the average number of deaths caused by fires per year equated to a significantly lower figure of 110 deaths and 3,300 injuries (Adams & Breslin 2012). The consequences of falling even from very small heights can be serious, with spinal cord injuries, bone fractures, concussion, brain damage, and of course death all being possible outcomes from a fall (Work Safe 2016). In terms of the seriousness of gravitational energy causing falls from heights, the only types of accidents that cause more deaths and injuries than falls on a global scale are car accidents (Adams & Breslin 2012).

Table 1 below shows the number of occupational injury claims made between 2001 and 2007 in Australia, as well as the cause of injury. Claims caused by falls, trips and slips unsurprisingly take up a large portion of the claims in the table. Being hit by moving objects also takes up a large portion as well, however this number would include being hit by objects that were not influenced by gravity as such (Adams & Breslin 2012).

(Adams & Breslin 2012)

The Underpinning Science

To understand the science behind gravitational potential energy and how it actually has the potential to cause harm, it is important to understand that it is not the gravitational energy that causes harm in the case of a trip, slip, fall and so forth, but the effect of kinetic energy.  Gravitational potential energy involves the factors which lead to a situation where an object has the potential of gaining kinetic energy through falling, as shown in Figure 1 below. In other words, an object must be subject to a gravitational field to have gravitational potential energy (Skwirk n.d.). The level of gravitational potential energy an object or person is subject to is dependant on mass and height. In a situation where a human who weighs 75kg is at an elevation of one metre, they will have a greater gravitational potential energy than someone else who is elevated at the same height but who has a smaller mass with a weight of 60kg. This is also the same for height, where two people could weigh the same, but the person who is elevated higher will have the greater potential energy among the two due to being subject to a larger gravitational field (Skwirk n.d.).

As mentioned before, kinetic energy plays a factor in the outcome of gravitational potential energy. Velocity is included in kinetic energy, which is the rate of change in the position of a body or object. By using object mass (m) and velocity (v), kinetic energy can be determined by the rule ½ mv² (Adams & Breslin 2012). During a fall, velocity energy continues to increase due to acceleration, where velocity will reach a maximum point at the moment of impact. At this point in time, kinetic energy is then transferred to the body of a person (Kiran Kumar & Srivastava 2013).

Figure 1: Visual explanation of gravitational potential energy

(Flickr 2014)

Hazardous Situations

Gravitational potential energy can cause harm in just about any situation, and this is because the effects of gravity occur everywhere on earth. There are four main hazards which exist from gravitational potential energy. The first three include:

1. Slips – Caused by loss of traction on a ground surface or slippery surfaces. This hazard exists in many occupations, however one where slipping has a higher chance of occurring is work within kitchens from spilled liquids/food or wet cleaning practices such as mopping (Safe Work Australia 2012).
2. Trips – Caused by the unexpected catchment of a body part on an object, causing loss of balance. This hazard is also existent among many occupations, however this hazard may occur in a simple workplace setting such as an office, where cords on the ground can cause people to trip if gone unnoticed (Safe Work Australia 2012).
3. Falling objects – Caused by an object’s loss of balance on an elevated surface. Many workplace accidents caused by a fallen object are in manufacturing and construction, where objects such as tools may fall from heights and hit a person working below (Adams & Breslin 2012).

The fourth hazard has already been discussed in some depth, which is the hazard of falls from heights. Just like the other hazards mentioned, falls from heights can occur in a number of ways. This includes hazards included with working on ladders, working on suspended structures and platforms, riding in crane-suspended loads, and so forth. Overall, it is occupations in construction where this hazard is most common. In particular, the risk involved with the hazard is highly dependant on the safety procedures involved.  Especially for working with heights, harnesses, the quality of the equipment used and personal experience are important factors (Union Safe 2013).

 

Measurements and Evaluation

The result of falling from a height can have many results, ranging from minor or no injuries, to major injuries or death. As it has been established, there are many factors which can determine the result of a fall. Measurements of these factors are crucial in understanding the impact a fall can have on a person. These measurements include the height in which a fall occurs, a person’s body weight, the velocity (as determined by the height and weight), the type of surface impacted upon, the location in which impact occurs on the body, and the elasticity and viscosity of the tissue surrounding the impacted body region. For example, if a young adult was to fall from two metres and land on their feet, the outcome will be a lot less serious than if an elderly person fell two meters and landed on their back (Kiran Kumar & Srivastava 2013).

Although speed increases during a fall, there is a point where acceleration will cancel out and a person or object will fall at a constant rate. This concept is known as terminal velocity.  In a scenario where a women who weighs 54kg reaches a terminal velocity speed of 38 metres per second (136km per hour), it would only take seven seconds to reach 95% of that speed for a fall that equates to about 170 metres (Sample 2004). In terms of more common situations of falls of less than 5 metres where terminal velocity is not reached, statistics show that more than half of falls that occur from 3.35 feet are fatal. This indicates that in a situation where someone is to fall from a height exceeding 3.35 metres, the damage threshold will in the majority of cases exceed to the point where fatal injuries occur from the body’s inability to absorb the impact of the fall (Skegg 2015).

 

Safety Strategies

Legislation and Standards:

• Model Work Health and Safety Act (WHSA) – provides the general responsibilities for safety in workplaces as well as requirements for managing, designing, manufacturing and installing structures/buildings
• WHSR – provides obligations related to gravitational hazards whereby a workplace layout should allow for work to be carried out without risk to people’s health and safety
• Code of Practice – How to Prevent Falls at Workplaces – outlines that where there is risk of injury from a fall, control measures are required

(Adams & Breslin 2012).

Control Measures:

• Ensuring working area is free of trip hazards (move anything that could cause someone to trip/fall)
• Implement use of slip-resistant flooring that takes into consideration the characteristics of specific work places (such as the occurrence of spilled grease in a car garage)
• Use of warning signs such as “caution: wet floor” to notify people of a potential hazard for slipping and falling
• Mark edges of steps or areas where there are unexpected drops where people walk in a bright colour as a warninProvide and use personal protective equipment such as hard hats, harnesses, steel cap boots with gg
• ood grip, etc.

(Adams & Breslin 2012).

 

References

Adams, N, Breslin, P 2012, ‘Physical hazards: Gravity’, OHS Body of Knowledge, April, pp. 1-31, viewed 27 May 2016, http://www.ohsbok.org.au/wp-content/uploads/2013/12/27-Hazard-Gravitational.pdf?4ddbe2

Flickr 2014, Gravitational potential energy, viewed 6 June 2016, https://www.flickr.com/photos/121935927@N06/13580583833

Kiran Kumar, JV & Srivastava, AK 2013, ‘Pattern of injuries in fall from height’, Journal of Indian Academy of Forensic Medicine, January – March, pp. 47-50, viewed 7 June 2016, http://iafmonline.in/data/publications/2013/JIAFM-35(4).pdf 

Sample, I 2004, How big a fall can a person survive?, viewed 7 June 2014, https://www.theguardian.com/science/2004/may/20/thisweekssciencequestions2

Safe Work Australia 2012, Slips and trips at the workplace fact sheet, viewed 6 June 2016, http://www.safeworkaustralia.gov.au/sites/swa/about/publications/Documents/659/Slips%20and%20Trips%20Fact%20Sheet.pdf

Safetyline Institute 2005, Hazard, energy and damage, viewed 5 June 2016, http://www.hs.edu.au/businessedition/kaleidoscope-html/Readings%20OHS%20Cert%20IV/Introduction__Resour.pdf

Skegg, D 2015, Term 1 week 6 risk management, PowerPoint presentation, OCHS11025: Health and Safety Risk Management, CQUniversity e-courses, http://moodle.cqu.edu.au/

Skwirk n.d., Gravitational potential energy, viewed 5 June 2016, http://www.skwirk.com/p-c_s-4_u-308_t-756_c-2844/potential-energy/nsw/potential-energy/force-and-motion/energy

Union Safe 2013, Information sheet: Working at heights, viewed 6 June 2016, http://unionsafe.org.au/wp-content/uploads/2013/04/Working-at-Heights.pdf

Work Safe 2016, What injuries can falls cause?, viewed 5 June 2016, http://www.worksafe.vic.gov.au/safety-and-prevention/health-and-safety-topics/falls-prevention/about-the-problem/what-injuries-can-falls-cause