Hazardanalysisppt 5th sem-aug'24

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Title : Hazard Analysis (HAZAN)

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Un-thoughtful accidents ?Need for Hazard analysis

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What is a hazard?

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Hazard is the potential for harm. A hazard is often associated with a condition or activity that can cause undesired consequences such as injury or illness if left uncontrolled.

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Basically, a hazard can cause harm or adverse health effects to individuals or to organizations as property or equipment losses.

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Types of hazard

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1) Chemical hazardsChemicals can affect skin by contact. Chemicals can also enter our body

either through the inhalation or digestive system if air is contaminated with chemicals, vapor, mist or dust.

The accumulation of chemicals in or on our body will cause acute (immediate) effect or chronic (long-term) effect.

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2) Physical hazards

Physical hazard will cause injury risks on our body.

This category includes the hazards from working in confined spaces, being hit by flying objects, caught in explosions, hurt by collapsing machinery, falling from heights and tripping on obstacles.

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3) Biological hazards (biohazards)Biohazards refer to biological substances

that pose a harm to the health of living organisms.

Sources of biological hazards may include insects, bacteria, fungi, plants, worms, animals and viruses.

These sources can cause a variety of health effects ranging from skin irritation and allergies to infections, cancer and so on.

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4) Ergonomic hazards

Ergonomic hazards refer to workplace conditions that pose the risk of injury to the musculoskeletal system of the worker.

These injuries can be caused by performing repetitive and forceful movements and awkward postures that arise from improper work methods and improperly designed workstations, tools, and equipment.

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5) Noise hazards Excessive noise can disrupt concentration, interfere with communication and

result in loss of hearing.High impact noises are particularly

damaging.Noise can also mask out signals and

affecting communication with others.

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What is Hazard Analysis?

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Hazard Analysis

Analysing their potential causes

First step in a process used to

assess risk

Result of a hazard analysis is the

identification of different type of

hazards

Process of recognizing

hazards that may arise from a system or its environment

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Job Hazard Analysi

s

Technique that focuses on job tasks as a way to identify hazards before they occur

Identify hazards potentially

created by a product, process

or application

Technique to identify the dangers of specific tasks in order to reduce the risk of injury to workers.

Focuses on the relationship between the worker, the task, the tools, and the work environment

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Determine the hazards and hazardous events of the equipment under control and the control system

Analyse the event sequences leading to the hazardous events identified

To analyse the risk associated with the hazardous events

Identify hazards

Identify causes

Determine risks

Hazard Analysis Objective

s

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Why Hazard Analysis is important?

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Importance / Benefit

To train workers

how to do their jobs

safely

Policies and

procedure improved

investigate

accidents Increase quality

Decrease injury rate.

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identify what personal protective equipment

Hearing protection

Body protection

Eye protection

Foot protection

Material handling aids

Hand protection

Respiratory protection

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Hazard Analysis Procedure

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Examine the job and determine the components

Identify tasks likely to present hazards

Identify and assess hazards Determine and devise controls

measures Develop safe work procedures if

hazards cannot be eliminated

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How to identify and analyze hazard?

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Identifying The Hazards Identify the hazards of each step.

For each hazard, ask:What can go wrong?What are the consequences?How could it arise?What are other contributing

factors?How likely is it that the hazard will

occur?

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HAZARD ANALYSIS METHODS

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Hazard may be realized or unrealized Realized hazard – has happened in the

past and can therefore be identified from experience.

Unrealized hazard – is a potential for a hazardous situation that has not happened yet but can be recognized by analyzing the characteristic of an environment or failure modes of equipment item.

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Hazard analysis methods include :

Process Hazard AnalysisEvent Tree AnalysisFailure Modes And Effect Analysis

Fault Tree AnalysisCause-consequence Diagram Hazard And Operability Studies

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1) PROCESS HAZARD ANALYSISA systematic method designed to identify and

analyze hazards associated with the processing or handling of highly hazardous material

PHA analyzes -The potential causes and consequences of

fires, explosions and releases of toxic chemicals

- the equipment, instrumentation, human actions and other factors which might affect the process.

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The Most Hazardous

Processes Are First- Most hazardous processes must be

evaluated first - All PHA must be

completed as soon as possible

- PHA must be updated at least every five years

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2) Event Tree Analysis (ETA)ETA defines the consequential events which flow from the primary ‘initiating’ event.

Event trees are used to investigate the consequences of loss-making events in order to find ways of mitigating rather than preventing losses.

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3) Failure modes and effect analysis (FMEA)To identify which failures in a system can

lead to an undesirable situation.Particularly suited to electrical and

mechanical processes.Result are strongly dependent on analyst’s

understanding of the failure modesEffects of failure modes can be quantified

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4) Fault tree analysis (FTA)To evaluate the economic justification

for carrying out improvement to a system

FTA works back from the undesired or “top event” to the contributing causes(backward reasoning logic techniques)

To identify the causes of top event

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Example of FTA

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5) Cause-Consequence analysis (CCA)

Is proving to be a very useful tool to depict and maintain an up-to date, real-time working risk management system enthralled in daily operations (e.g. operational).

These diagrams combine the inductive and deductive reasoning of logical diagrams (e.g. ETA, FTA) to identify the basic causes and consequences of potential accidents.

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Example of CCA

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6) Hazard and Operability Study (HAZOP)

A structured and systematic method that identifies equipment that is being used in a way that it was not designed to be, and which might create hazards and operational problems.

HAZOPs are usually conducted by multi-skilled team that studies piping and instrument diagrams.

Each pipeline and vessel is evaluated for certain limitations and deviations in flow, temperature, pressure, etc.

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How to control hazard?

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Controlling the Hazards The order of precedence and effectiveness of hazard control is the following:1. Engineering controls.2. Administrative controls.3. Personal protective

equipment.

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1) Engineering ControlsEngineering controls include the

following:Elimination/minimization of the hazardSubstitution of equipment or process to decrease hazard

Isolation of the hazard with interlocks, machine guards, blast shields, or other means; and

Removal or redirection of the hazard such as with local and exhaust ventilation.

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2) Administrative ControlsAdministrative controls include the following:

Written operating procedures, work permits, and safe work practices;Exposure time limitations (used most commonly to control heat stress and ergonomic hazards);

Monitoring the use of highly hazardous materials;

Alarms, signs, and warnings;Buddy system; and training

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3) Personal Protective Equipment (PPE)Personal Protective Equipment is acceptable

as a control method in the following circumstances:When engineering controls are not feasible or do not totally eliminate the hazard;

While engineering controls are being developed;

When safe work practices do not provide sufficient additional protection; and

During emergencies when engineering controls may not be feasible.

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Case Study of Hazard Analysis

Fire at Formosa Plastic Corporation:Evaluating Process Hazard

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INTRODUCTIONThis case study describes a fire and

series of explosions in an olefins production unit located in Point Comfort, Texas due to hydrocarbon release.

16 employees were injured and 1 seriously injured.

The fire lasted for 5 days.

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At 3:05 PM on October 6, 2005, a trailer being towed by a forklift snagged and pulled a small drain valve of a liquid propylene system.

Vaporized propylene forming a large flammable vapor liquid.

Operators began to shut the plant down and attempt to isolate the leak. But, the attempt was failed.

At 3:07 PM, the vapor ignited and created an explosion. As a result, two operators were burned and fire reached more than 500 ft in air as shown in figure 1.

The fires lasted for five days and about 7 million gallons of water were used to cool vessel.

INCIDENT DESCRIPTION

44Figure 1: Propylene Fire

05/02/2023 propylene

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At 9:00 PM, Highway 35 that run adjacent to the Formosa complex and through ‘Point Comfort’ was closed. A shelter-in-place was provided for the Point Comfort community.

It was recorded about 20 local residents need medical evaluation at local hospitals.

Figure 2 shows the view of the damaged plant from Highway 35.

Figure 3 shows the Olefin II unit ( one of the 17 units) where the fire and explosion occurred.

05/02/2023 46Figure 2 : View of the Damaged Plant from Highway 35

05/02/2023 47Figure 3 : Olefin II units

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INCIDENT SEQUENCEA worker driving a forklift towing a trailer under a

pipe rack moving backward between two column to turn around.

When the worker drove forward, the trailer caught on a valve and stick out a strainer in propylene piping system.

The trailer pulled the valve and associated pipe (Figure 4) out of the strainer and leaving 1.9 inch diameter opening.

Pressurized liquid propylene rapidly escaped through the opening and partially vaporized creating both of propylene liquid and rapidly expanding vapor cloud.

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The forklift driver and other contractors saw the release and evacuated.

An operator heard and saw the release and notified the control room.

The operators closed control valves and began to shut down the unit as well as pump from motor control center to slow the leak as he saw the vapor cloud.

The vapor cloud ignited and operators left the unit and declared a site-wide emergency.

A large pool of fire burned under the pipe rack.The Formosa ERT arrived and took command of

the incident response.The fire was extinguished about 5 days.

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CAUSES OF INCIDENTFigure 6 shows the propylene piping

involved in this incident stick out into an open space and no impact protection.

Figure 7 shows passive fire protection was installed on only three of four support column rows and the columns that supported the pressure relief valves and emergency vent piping had no fireproofing.

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PROCESS HAZARD ANALYSIS

Figure 8 shows the protection of fire fighting equipment.

Figure 9 shows the lack of protection where the impact and release occurred.

Remote equipment isolation is done by the operators by isolating minor leaks with local valves.

05/02/2023 55Figure 8 : Protection of Fire Fighting Equipment

05/02/2023 56Figure 9 : Vehicle Impact Point

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LESSONS LEARNEDWhen performing a hazard analysis, facility

sitting analysis or pre-startup safety review, vehicle impact and remote isolation catastrophic releases should be investigated.

The use of flame resistant clothing may limit the severity of injury to employees who work in plants with large inventories of flammable gases and liquids.

Evaluate the applicability and use of current safety standards when designing and constructing a chemical process plant.

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ReferencesFire at Formosa Plastics Corporation:. Case study,

Washington: CSB publications, 2006.Hazard Analysis Methodologies.

https://www.osha.gov/SLTC/etools/safetyhealth/mod4_tools_methodologies.html (accessed March 27, 2015).

Job Hazard Analysis. 2002. https://www.osha.gov/Publications/osha3071.html (accessed March 26, 2015).

Types of Hazards. http://students.fortresslearning.com.au/del301/types-of-hazards/ (accessed March 23, 2015). 

Fire at BHN platform, ONGC-2005, Bombay High