Hazop Study
Hazop is a structured and systematic way to identify possible hazard in process, activity, product, facility or logical system.
Every variation in work parameter is consideration for each step to see or check what could go wrong.
Hazop often used as a technique for identifying potential hazard in system and identifying operability problems.
Hazop is a qualitative assessment of a hazard or an operating problem occurring in a process plant while risk Analysis is a quantitative assessment of the consequences of a hazard.
Hazop is a brainstorming technique :
Hazop is the best suited for assessing hazard in facilities, equipment and processes and is capable of assessing systems from multiple perspective.
- Design assessing system design capability to meet user specification, safety standard to identifying weakness in systems, physical and operational environment, assessing environment to ensure system is appropriately situated, supported, serviced, contained.
- Operational and procedural control, assessing engineered control, sequences operations, procedural control.
- Assessing different operational mode startup, stand by, normal operation, steady and unsteady states, normal shut-down, emergency shut-down.
When to do Hazop :
- Design Stage
- Design freeze stage
- plant start-up stage
- operation stage
Requirement For Hazop :
- Flow Diagram
- Process description with interlock description
- Operating manual
- Equipment layout and specification sheet
- piping specification
- MSDS ( material safety data sheet)
- unit plot plan
- vendor information
- provisional operating instruction and emergency shut-down procedure.
- Any report of safety review
Which department are involves in Hazop study :
- Mechanical engineer
- chemical engineer
- R & D Department
- instrument engineer
- electrical engineer
- civil engineer
The team headed by experience specialist from work management or trained consultant.
Guide word use in Hazop study :
- NO or not
- More
- Less
- As well AS
- Part Of
- Reverse
- Other than
Guide Word May be apply In Hazop study :
Process condition :- Flow, Temperature, Pressure, Concentration
Activities :- Transfer, Mixing, Heating etc
Substances :- Except ” REVERSE FLOW “
Time :- Duration, Frequency, Absolute time & Sequence
Place :- Position, Source, Destination
Hazop worksheet : create a process node
- Guide words :- Guide words provides the team with starting point to identify issue. Guide word is important to achieve maximum benefit from Hazop.
- Parameters :- Parameter Describe physically, chemical changes.
- deviations :- unreasonable / undesired change in the parameter. Deviation is formed by a
combination of the parameter and guideword.
- Causes :- Each hazard, the root cause is determined, such that the appropriate safeguards for the causal
events are determined.
- Consequences :- Hazop team took into consideration the following factors:
• The present design status of the safeguards and controls
• Physical and working environment conditions
• Levels of training, experience, skills, education etc of the facilities personnel
- Safeguards :- Preventive safeguards, which aim to prevent the event cause from occurring.
- Detective safeguards, which aim to improve the response time to an event.
- Protective safeguards, which aim to protect from the escalation consequences and are always
used regardless of whether the event has occurred. - Mitigation safeguards, which aim to reduce the severity of the escalation consequences and are
activated once the event cause and escalation consequences have occurred.
- Recommendation :- Safeguards are not adequate, further recommendations are proposed.
Hazop study methodology :
Step 01 : Defination
- Define scope and objectives
- Define responsibilities
- Select team
Step 02 : Preparation
- plant the study
- collect data
- Agree style of recording
- Estimate the time
- Arrange a schedule
Step 03 : Examination
- Divide the system into parts
- Select a part and define design intent
- Identify deviation by using guide words on each element
- Identify consequences and cause
- Identify whether a significant problem exists
- identify protection, detection and indicating mechanism
- Identify possible remedial / mitigating measures
- Agree actions
- Repeat for each element and then each part
Step 04 : Documentation and follow-up
- record the examination
- Sign off the documentation
- Produce the report of the study
- Follow up that actions are implemented
- Re-study any parts of system if necessary
- produce final output report
Important Factors For success Of the Hazop :
- Should have clearly defines objective
- Study leader should be experiences in the Hazop
- The team should contain people from design and other operations
- The team size should be kept fairly small
- The preparative work should be done carefully so that necessary document are to hand are accurate and up-to-date
Hazop Advantage :
- Powerful and flexible technique
- Useful for large and small organizations
- Can be applied for new as well as existing operations
- Based on the principle of total loss control
Hazop study limitations :
- Can not replace hazard analysis
- Require considerable manpower
Read More : Hazard Types
Q & A :
1. What is Hazop ?
Ans. Hazard and operability, systematic approach and to determine potential problems.
2. What purpose of Hazop ?
Ans. Identify, evaluate and control hazard and risk in complex processes &Address potential hazards
3. What industries use Hazop ?
Ans. Chemical, pharmaceutical, oil and gas, nuclear and mining industries used Hazop.
4. What are the guide word use in Hazop ?
Ans. Identify scenarios and NO, MORE, LESS, AS WELL AS, PART OF, REVERSE, and OTHER THAN.
5. What is difference between Hazop and risk assessment ?
Ans. Both aim cover potential risk, Hazop is mor time consuming, Hazop is more rigorous.
