4.1 INTRODUCTION
Environmental and safety are the aspects that need to be considered in any production plant as these aspects could affect the production process, human health, and environment. Raw materials, product, by-product, and equipment are the most important elements included in safety measurement of production plant. In this chapter, every element that could be hazard to human and environment are discussed for example how raw materials and equipment could be a threat to human and how by-product could be a threat to environment. This chapter will be discussed on how to apply and implement Hazard Identification, Risk Assessment and Risk Control (HIRARC) according to designated plant. Enforcing the law of Occupational Safety and Health, HIRARC are greatest important.
4.2 SAFETY CONSIDERATION
In order to maintain optimum productivity of plant production, employee and employers have to work together to ensure a safe work place for manpower activities. Plus, the need of safe work place environment and safety consideration to protect people from any hazard are utmost important. Efficient method to identify the risk involving process and implement the most practical and applicable measure to reduce and manage the risk is by implementing Hazard Identification, Risk Assessment and Risk Control (HIRARC).
4.2.1 Objective of Hazard Identification, Risk Assessment and Risk Control (HIRARC)
HIRARC is a fundamental of basic risk management in management, operation, and practice of planning of a business. The purposes of HIRARC are as follows
- To identify any element that could be hazard to employee and others
- To consider the chances of any harms to be hazard in the circumstances of a particular case and possible severity obtained from those harms
- To enable employee planning an optimum safety measures to ensure the risks are controlled all the time
4.2.2.1 Material Safety Data Sheet (MSDS)
MSDS is list of information on the hazards, safety and emergency measures related to specific products. All the information about the product and by product will be list in this sheet and the hazard of the product will also be identified.
4.2.2.2 Hazard Identifications
Hazard identification means the identification of unwanted events that brings to materialisation of the hazard and the mechanism by which those unwanted events could occur. In other word, to identify hazard that can cause injury exist around the plant which can be separate into three main groups, health hazards, safety hazards, and environmental hazards. Therefore, it can be simplified that there are three types of common accident based on the past study. The utmost accident that happened in chemical plants is fire, followed by explosions and toxic release.
4.2.3 Chemical Hazard and Risks in the Workplace
In chemical safety term, “hazard” refers to the inherent hazardous properties of a chemical or chemical operation, while “risk” generally means the likelihood of the hazardous properties of a chemical that may cause harm to the people surrounding and the severity of that harm. The risk dealing with chemical or in a chemical operation depends on the inherent hazard, the working environment, physical form of the chemical involved and the method of handling and lastly the operating procedures.
4.2.4 Chemical Hazards of Vinyl Acetate Monomer (VAM)
VAM is a flammable, reactive, colourless liquid that is partly soluble in water. At higher levels, VAM odour could be sharp and irritating while it has fruity smell when at lower levels.
- Flammability
VAM is a flammable liquid with flash point is below 37°C. It form flammable vapour when mix with air at room temperature. Plus, its vapours are heavier than air and may travel a long distance to an ignition source such as a flame or electric spark and then flash back.
- Reactivity
VAM is a reactive molecule and it could polymerize uncontrollably if did not handled or stored properly. Prolonged or intense exposure to heat, sunlight, ultraviolet light or x-rays may result in polymerization. Furthermore, spontaneous polymerization may also result from exposure to amines, strong acids, alkalis, silica, alumina, oxidizing agents. However, hydrolysation in water not considered as hazardous reaction.
- Health Effects
VAM is irritating to the upper respiratory tract, skin and eyes. Potential hazard to eyes are irritation, redness and swelling but cause a low acute toxicity by all routes of exposure. Report based on lab experiment stated that high level inhalation exposure to VAM in animal results in deaths from pulmonary edema. Moreover, lifetime drinking water or inhalation exposure to VAM shown cancer effects in laboratory animals which tumor reported localize directly to attached part with VAM. Tumor observed at high exposure concentrations are not considered to be relevant to humans exposed to low concentrations under typical use conditions.
- Environmental Effects
VAM tends to stay in the air where it is rapidly degraded by photochemical pathways. It has 0.6 days atmospheric half-life and 7 days hydrolytic half-life at pH 7 and 25°C. Volatilization of VAM could occur once it is released to soil or water. In case of effect of VAM to water, VAM partitions mostly to the water where it undergoes hydrolysis and it is readily biodegraded by either anaerobic or aerobic mechanisms. Plus, VAM is considered to be moderately toxic to aquatic organisms. In conclusion, VAM considered non-harmful to environment.
4.2.5 Chemical Hazards of Acetic Acid
At temperature above 16.7 °C, acetic acid is described as clear, colourless, combustible liquid with a pungent odour which is smell like vinegar.
- Flammability
Acetic acid has a flash point of 39 °C. Autoignition’s temperature of acetic acid is at 427 °C and dilute acetic acid solutions are not combustible. Fire involving acetic acid should be fought upwind and from the maximum distance possible. Moreover, vapour explosion of acetic acid may occur indoors, outdoors, or maybe in sewer. Vapour travel to a source of ignition and flash back.
- Reactivity
Overall, acetic acid is unstable at heating and freezing temperature. The vapour of acetic acid will form explosive mixtures with air. Plus, reaction of acetic acid with chromic acid, ammonium nitrate, sodium peroxide, nitric acid, phosphorus trichloride, or other oxidizers could cause fires or explosions. In case of hazardous decomposition, toxic gases like carbon dioxide and carbon monoxide may be released as acetic acid heated to decomposition. In concentrated form, acetid acid is highly corrosives.
- Health Effects
Exposure to acetic acid may occur through inhalation, ingestion, skin contact and absorption through the skin. Based on lab experiment, glacial acetic acid is corrosive to tissues while concentrated acetic acid can cause moderate to severe burns. In addition, vapour acetic acid also can cause eye, skin, mucous membrane, and upper respiratory tract irritation upon exposure. In case of effect on humans, acetic acid may irritate eyes, mucous membrane, upper respiratory tract and skin.
- Environmental Effects
Acetic acid environmental effects depend on the concentration and duration of exposure. It can be a threat to plants, animals, and aquatic as it comes in high concentration. Acetic acid exposed to environment as a vapour and it also soluble in water but it degrades rapidly into harmless substance once releases to environment.
4.2.6 Chemical Hazard of Ethylene
Ethylene is a gaseous with boiling point of -104 °C at atmospheric pressure and it is stored in the liquid state under high pressure or at low temperature. Plus, it has solubility in water of 131 mg/l at 20 °C.
- Flammability
Ethylene gas is highly flammable and explosive.
- Reactivity
Ethylene is reactive substances because of double bond structure present in the alkenes. Due to its high reactivity, ethylene may undergo a lot different reactions such as oxidation, halogenation, alkylation, hydration, and polymerisation.
- Human Health
Ethylene has low toxic level and risk to human health is minimal. It is identified from occupational exposure, general public exposure, and directly or indirectly exposure to environment but exposure to the gas can cause dizziness, lightheaded, and perhaps pass out. However lab experiment stated that ethylene is metabolised to ethylene oxide which can cause cancer from carcinogenic and mutagenic effect.
- Environmental Effect
Due to its physical and chemical properties, ethylene is released mainly into the atmospheric compartment. About three quarters of atmospheric ethylene originates from natural sources, while one quarter is from anthropogenic sources. The main anthropogenic release is from burning of hydrocarbons and biomass.
4.2.7 Chemical Hazard of Oxygen
Oxygen is an odourless, colourless, non-flammable gas. It is an oxidizing gas and could accelerates combustion. Oxygen is stored in cylinders at high pressure.
- Flammability
Oxygen is a non-flammable gas
- Reactivity
Oxygen vigorously accelerates combustion. Some non-combustible materials could burn with presence of an oxygen enrich atmosphere which is greater than 23%. Oxygen may form explosive compounds as exposed to combustible materials such as oil, grease, and other hydrocarbon material. Plus, heat applied on a container with oxygen can cause pressure increase hence cause container rupture.
- Human Health
If oxygen is inhaled as much as 80% or above at atmospheric pressure for more than a few hours, it may cause nasal stuffiness, cough, sore throat, chest pain, and breathing difficulty. Moreover, breathing pure oxygen under pressure may cause lung damage and also central nervous system effects which cause dizziness, poor coordination, tingling sensation, visual and hearing disturbances, muscular twitching, unconsciousness and convulsions.
- Environmental Effect
Highly concentrated sources of oxygen promote rapid combustion and therefore are fire and explosion hazards in the presence of fuels.
4.2.9 Personal Protective Equipment
PPE is equipment that will protect the user against safety at work. By this, that person will be protected against one or more risks arising from chemical or chemical operation to the person’s health or safety. OSHA 1910.132 requires employers to determine the proper personal protective equipment for each hazard and to train any employees the guidelines how and when to wear safety protective equipment. Example of personal protective equipment listed for the use of handling of chemicals can be classified into following categories such as protective clothing, hand and foot protective gears, eye and face protective equipment and last but not least the respiratory protective equipment. This protective equipment may save your life in any danger situation.
4.2.9.1 Protective Clothing
Protective clothing may refer which gear that literally can protect body or personal clothing from contact with dangerous chemical or any spread of contamination in workplace. This may include gowns, aprons and overalls. This chemical resistance that may affect the quality of the protective clothing are the resistance to degradation of the chemical due to the spread of chemical and the permeability of the chemical.
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Proper selection of protective clothing may result in a better in safety and health such as any dangerous chemical operations depends on the risks involved. Suitable material of protective clothing should be in good quality and appropriate form in order to provide protective if any danger occurred. Handling of chemical is a risk that may happen if not handled it properly, protection can be achieved by the personal clothing such as gowns and overalls made of synthetic material based of terylene or nylon with a water repellent finish.
4.2.9.2 Hand Protective Gears
Hand protective gears may protect the hand and arm from any spills of the chemical and by prevent the spread of contamination. Generally gears are gloves used in industry. The selection of gloves usually must be based on the hazard occurred in the industry. In production of plant typically involved dangerous chemical when operating the process. In consideration, reference should be considered in order to categorise based on the chemical resistance properties and physical characteristic of the glove. The Chemical resistance, thermal protection and mechanical strength should be considered when in any different path of industry. Chemical resistance of the protection level depends on the glove material itself, the method of construction and thickness of the gloves. It should be aware that chemical resistance property of gloves may be adversely affected by abrasion and heat. For thermal protection gloves may made from neoprene which can be used for handling oils at low temperatures and cotton gloves can operate against moderate heat level.
4.2.9.3 Foot Protection Gears
Foot protective gears protect the foot and leg from any dangerous chemical and to prevent the spread of contamination. Foot protection gears are shoes or boots. The footwear is selected based on the hazard involved and from the working environment. Mostly in plant, it is best to wear a safety boots, in order to prevent any unsafe accident occur. The type of injury should be related to the risk of the injury, the foot should at least be protected by well-made shoes. In cases it depends on the risk of the parts of the body being injured as example of ankle, knee or thigh.
4.2.9.4 Eyes and Face Protection Equipment
In process of chemical operation, eye or face might be need a protective equipment in order to prevent any hazard of splashes of hot or any dangerous liquid chemicals, flying object as example of bursting containers, any dust or vapour that might be harmful to eye and face and lastly the intense light from the radiation emitted to the chemical process. By that, safety goggles should be wearing during the process operation. Other than that, face shield with adjustable head harness that may protect the face but not fully at the ayes area. Besides, eye and face protective equipment is also available in tints and shades for the protection of radiation or intense light from the chemical operation.
4.2.9.5 Respiratory Protective Equipment
The potential of exposure in MEK plant may achieve 200 ppm, therefore the use of respiratory protective equipment is important in order to prevent the harmful of gas through the respiratory system. Respiratory protective system equipment also used to provide breathing air when working in any dangerous chemical environment where the presence of chemicals in air at high concentration. Be sure to consider all potential exposures when working in place where dangerous chemical exposure occurred. Combination of filters, prefilters or cartridges to protect against different types of form such as mist, vapour, dust and other chemical mixtures must be relates. Exposure of 3000 ppm and above, the situation is absolutely dangerous to life and health. The range of exposure must be less than 3000 ppm and if possible use a NIOSH approved self-contained breathing apparatus just to make sure the better quality and protection approved by the NIOSH.
4.3 RISK ASSESSMENT
Risk analysis that is most effective is one that uses likelihood and severity in qualitative method. The result are present in a risk matrix is very effective method of communicating the distribution of the risk at the plant area workplace. The likelihood of an event occurring range from “most likely” to “inconceivable” are where the value came from. As shown in the table below of likelihood using the following values:
Table 4.1: Likelihood
LIKELIHOOD |
EXAMPLE |
RATING |
Most likely |
The most likely result of the hazard/event being realized |
5 |
Possible |
Has a good chance of occurring and is not unusual |
4 |
Conceivable |
Might be occur at some time in future |
3 |
Remote |
Has not been known to occur after many years |
2 |
Inconceivable |
Is practically impossible and has never occurred |
1 |
Source: DOSH HIRARC Guideline
The severity is categories into five elements. The increasing level of severity to an individual’s health, property and environment that is present in the table below:
Table 4.2: Severity
SEVERITY (S) |
EXAMPLE |
RATING |
Catastrophic |
Numerous fatalities, irrecoverable property damage and productivity |
5 |
Fatal |
Approximately one single fatality major property damage if hazard is realized |
4 |
Serious |
Non-fatal injury, permanent disability |
3 |
Minor |
Disabling but not permanent injury |
2 |
Negligible |
Minor abrasions, bruises, cuts, first aid type injury |
1 |
Source: DOSH HIRARC Guideline
Table 4.3: Likelihood vs Severity
Severity (S) |
|||||
Likelihood(L) |
1 |
2 |
3 |
4 |
5 |
5 |
5 |
10 |
15 |
20 |
25 |
4 |
4 |
8 |
12 |
16 |
20 |
3 |
3 |
6 |
9 |
12 |
15 |
2 |
2 |
4 |
6 |
8 |
10 |
1 |
1 |
2 |
3 |
4 |
5 |
Source: DOSH HIRARC Guideline
The priority is determined based on the following risk category for necessary actions
. Table 4.4: Risk Category
RISK |
DESCRIPTION |
ACTION |
15-25 |
HIGH |
A HIGH risk requires immediate action to control the hazard as detailed in the hierarchy of control. Actions taken must be documented on the risk assessment form including date for completion. |
5-12 |
MEDIUM |
A MEDIUM risk requires a planned approach to controlling the hazard and applies temporary measure if required. Actions taken must be documented on the risk assessment from including date for completion. |
1-4 |
LOW |
A risk identified as LOW may be considered as acceptable and further reduction may not be necessary. However, if the risk can be resolved quickly and efficiently, control measure should be implemented and recorded. |
Source: DOSH HIRARC Guideline
4.4 RISK CONTROL & PREVENTIVE MEASURE
HIRARC last step process is risk control. The assessed hazard will be assigned by risk control step for every control needed. Suitable control requires proper evaluating and selecting long and short term controls. The short-term measures to protect workers are implementing and the long term controls can be put in place when reasonably applicable. The five type of control started from elimination, substitution, engineering control, administrative control and last defences is personal protective equipment (PPE) which used when controls measure practicable and where additional protection is needed. The hierarchy of control to be applied is shown below.
Figure 4.1: Hierarchy of Control (Source: DOSH HIRARC Guideline)
4.4.1 Elimination
Elimination is the most effective hazard control which the step is by eliminating the hazard or in other words, physically removing it. Taking example when an employee is doing a job high above the ground, the hazard can be eliminatedby moving the piece they are working on to ground level to eliminate the need to work at heights.
4.4.2 Substitution
Substitution is a preventive step involves replacing some task that might produces hazard with something that might not. This step quite similar to elimination but it required replaced task for the eliminated task. Taking example of process of replacing lead based paint with acrylic paint.
4.4.3 Engineering Controls
The main objective of engineering controls is rather isolates people from hazards than eliminate the hazards. Capital costs of engineered controls tend to be higher than less effective controls in the hierarchy. However they may reduce future costs. For example, building a work platform is a chosen step rather than purchase, replace, and maintain fall arrest equipment. Plus, isolation could create a physical barrier between person and hazard. For example, using a remote control is much safer than manually control.
4.4.4 Administrative Controls
Definition of administration controls is changing the way people work. This control types need an organization that could handle all the employees. The examples of its steps are including procedure changes, employee training, and installation of signs and warning labels. Administrative controls do not remove hazards, but limit or prevent people’s exposure to the hazards, such as completing road construction at night when fewer people are driving.
4.4.5Personal Protective Equipment
Personal protective equipment (PPE) includes gloves, respirators, hard hats, safety glasses, high-visibility clothing, and safety footwear. PPE is the least effective means of controlling hazards because of the high potential for damage to render PPE ineffective. Moreover, some PPE, such as respirators, increase physiological effort to complete a task and, therefore, may require medical examinations to ensure workers can use the PPE without risking their health
4.5 RELEVANT OSH LEGISLATION AND REGULATION
The legislation and regulation for occupational, safety and health need to be obey for every processing plant. The act and regulations ensuring both employer and employees to take safety and health issue in working area seriously. Safety and health objective is to provide a good safe working condition and to control plant or factory operation with respect to the safety, health and welfare of the employer and employee. The regulations need to be follow which is The Factory Act 1948 and Control of Industrial Major Accident Hazard (CIMA) 1996. Manufacture, Storage and Import of Hazardous Chemicals Rules, 1989. As stated under OSHA 1994 regulation is Employer’s Safety and Health General Policy Statement 1995, Control of Industrial Major Accidents Hazards 1996, Safety and Health Committee 1996, Classification, Packaging and Labelling of Hazardous Chemical 1997, Safety and Health Officer 1997 and Use and Standards of Exposure of Chemical Hazardous to Health 2000. Duty to implement safety and health act are under responsible of both employer and employees and Occupational Safety and Health Act OSHA 1994 summarized the duties of employer and employees as below.
Duties of Employer:
- Provide and maintain safe plant and system of work
- Make arrangement for safe use operation, handling, storage, and transportation of plant and substances.
- Provide instruction, information, training and supervision.
- Provide and maintain safe pace of work and means of access to and egress from any place of work.
- Provide and maintain safe and Healthy working environment and adequate welfare facilities.
Duties of Employees:
- Reasonable care for safety and health him/herself and others.
- Co-operate with employer and others.
- Wear and use PPE.
4.6 MAJOR EQUIPMENT AND POTENTIAL INCIDENT IN PROCESS PLANT
Table 4.5: HIRARC Major Equipment in Process Plant
Hazard Identification |
Risk Analysis |
Risk Control |
|||||||
No. |
Equipment |
Hazard Identifies |
Potential Accident |
Types of injury |
Likelihood |
Severity |
Risk (Likelihood x Severity) |
Recommend Control Measure |
Person In Charge |
1 |
Reactor |
Leaking |
Explosion |
Fatalities |
4 |
4 |
16 (High) |
Use Detector & Preventive Maintenance |
Design Project Coordinator |
2 |
Heat Exchanger |
Rupture |
Explosion |
Fatalities |
3 |
4 |
12 (Medium) |
Use Detector & Preventive Maintenance |
Installation, Operation and Maintenance |
3 |
Decanter |
Leaking |
Fire |
Injury |
3 |
3 |
9 (Medium) |
Safe Operation procedure |
Operator |
4 |
Vaporizer |
Over temperature |
Fire |
Injury |
3 |
3 |
9 (Medium) |
Use Detector & Proper Maintenance and Schedule |
Installation, Operation and Maintenance |
5 |
Distillation Column |
Overpressure, Over temperature |
Spillage, Backflow, Fire |
Injury |
3 |
3 |
9 (Medium) |
Use Detector & Safe Operation procedure |
Operator |
6 |
Absorber |
Crack |
Spillage |
Injury |
3 |
2 |
6 (Medium) |
Proper Maintenance and Schedule |
Installation, Operation and Maintenance |
7 |
Separator |
Leaking, Crack |
Explosion |
Injury |
3 |
3 |
9 (Medium) |
Proper Maintenance and Schedule |
Installation, Operation and Maintenance |
Table 4.6: HIRARC Potential Incident in Process Plant
Hazard Identification |
Risk Analysis |
Risk Control |
|||||||
No |
Hazard Identifies |
Potential Accident |
Accident Consequent |
Types of injury |
Likelihood |
Severity |
Risk (Likelihood x Severity) |
Preventive Control measure |
Person in charge |
1 |
Piping |
Leakage, Rupture |
Explosion |
Fatalities |
4 |
4 |
16 (High) |
Detector & Preventive Maintenance |
Installation, Operation and Maintenance |