Transcript Element 2: Hydrocarbon process safety 1

NEBOSH International Technical
Certificate in Oil and Gas
Operational Safety
2
Hydrocarbon process
safety 1
Learning outcomes
2.1 Explain the principles of assessing and managing contractors, including the roles
of parties involved
2.2 Outline the tools, standards, measurement, competency requirements and controls
applicable to Process Safety Management (PSM) in the oil and gas industries
2.3 Explain the role and purpose of a permit-to-work system
2.4 Explain the key principles of safe shift handover
2.5 Explain the importance of safe plant operation and maintenance of hydrocarbon
containing equipment and processes
2.6 Outline the hazards, risks and controls to ensure safe start up and shut down of
hydrocarbon containing equipment and processes
Content
2.1 Contractor management
2.2 Process safety management (PSM)
2.3 Role and purpose of a permit-to-work system
2.4 Key principles of safe shift handover
2.5 Plant operations and maintenance
2.6 Start up and shut down
Introduction
•
A contractor is anyone who is called into work for your company but is
not an employee
•
Many accidents involve contractors working on a site due to a number of
factors:
-
Activities can be risky due to the type of work
-
Poor communication
-
Unfamiliar with the site
-
Poor selection processes, training and competency
Scale of contractor use
•
Many companies turn to contractors to supplement their engineering staff
•
They are also used for specialist tasks, often involving hazardous activities
•
This could involve working on critical process plant and equipment or carrying
out non-routine activities
•
It is important to ensure that contractors are properly briefed on and understand,
the major hazard risks associated with the activities
•
It is often a legal requirement
Contractor management, ownership
and representation
•
There are five basic steps involved in managing contractors:
Step 1: Planning
Step 2: Choosing a contractor
Step 3: Contractors working on site
Step 4: Keeping a check
Step 5: Reviewing the work
Content
2.1
Contractor management
2.2 Process safety management (PSM)
2.3 Role and purpose of a permit-to-work system
2.4 Key principles of safe shift handover
2.5 Plant operations and maintenance
2.6 Start up and shut down
Introduction
• PSM involves managing a number of technical,
managerial and human factors activities which, if not
managed effectively, may lead to a major incident
• High profile incidents such as Buncefield have
highlighted the need for high risk installations to have
effective systems in place to prevent, or limit the effects
of, such incidents
The OSHA process safety
management standard
•
Employee participation
•
Process safety information (PSI)
•
Process hazards analysis (PHA)
•
Operating procedures
•
Training
•
Contractors
•
Pre-startup safety review (PSSR)
•
Mechanical integrity
•
Hot work permits
The OSHA process safety
management standard
• Management of change (MOC)
• Incident investigation
• Emergency planning and response
• Compliance audits
• Trade secrets
• The spacing of operating plant
• Control rooms, temporary refuge and critical associated safety
systems
Management of change controls
• The failure to manage change has been a critical
factor in several major accident incident scenarios
• The destruction of the Nypro UK site (1974) at
Flixborough, was a prime example of a lack of
effective management of change
Management of change controls
Risk assessment and authorisation
•
The UK Chemical Industries Association Safety Advisory Group
outlines the following good practice related to plant modification/change
procedures:
-
Members of staff must be aware of the hazards associated with the
work they carry out
-
Risk assessment must be carried out to determine the possibility and
consequence of the hazards being realised
-
All modifications should be subject to formal management
procedures
Management of change controls
Risk assessment and authorisation
• Good industry practice requires that process and plant
modifications should not be undertaken without having
undertaken a safety, engineering and technical review
• This review should be traceable and identify changes proposed to
the following factors: process conditions; operating methods;
engineering methods; safety; environmental conditions;
engineering hardware and design
Content
2.1
Contractor management
2.2 Process safety management (PSM)
2.3 Role and purpose of a permit-to-work system
2.4 Key principles of safe shift handover
2.5 Plant operations and maintenance
2.6 Start up and shut down
Introduction
• An integral part of a safe system of work
• A permit-to-work system is a formal, recorded process used to
control work which is identified as potentially hazardous
• Such work is generally “non-routine and high risk”
• A permit-to-work system should ensure that authorised and
competent people have thought about foreseeable risks and that
such risk are avoided by using suitable precautions
The key features of a permit-towork system
• A permit-to-work system should be fully documented, and
include:
- How the system works
- The jobs it is to be used for
- The responsibilities and training of those involved
- The arrangements for checking its operation
The key features of a permit-to-work system
• Essential features of permit-to-work systems are:
- Clear identification of the tasks requiring a permit to work
- Responsibilities of issuing/authorising and
recipient/performing authorities (and any limits to their
authority)
- Training requirements for the authorising and performing
authorities
- Details of monitoring and auditing requirements to ensure
that the system works as intended
The key features of a permit-to-work system
• An effective permit-to-work form should:
- Clearly describe the task to be performed
- Indicate the date/location/equipment to be worked on
- Identify the permit validity time
- Identify any isolations that may be required
- Identify any residual hazards
- Cross reference any other activities or isolations
- Make provision for permit extensions
- Incorporate provision for permit hand back and cancellation
Interfaces with adjacent plant
• Important to make sure that one activity under a permit-to-work
does not create danger for another
• Those involved with the issue of permits-to-work should be
aware of potential interaction
• Ensure that when a permit is prepared, the work to be carried out
takes account of the other activity currently planned or underway
• It may be that the interacting activities are covered by separate
responsible authorities therefore close liaison will be necessary
Interfaces with contractors
•
The client company is responsible for operational health and safety
•
Irrespective of where its resources come from i.e. its own staff, contract,
subcontract or agency staff or self-employed workers
•
The client should ensure that contractors:
-
Understand the permit-to-work systems and particular locations at
which they or their employees are to work
-
Are properly trained
Interfaces with contractors
Types of permit (used for the following activities):
• Hot work
• Work on electrical systems
• Work on machinery
• Excavation work
• Work over water
• Diving work
• Confined space entry work
• Work with ionising radiation
• Work with asbestos
Interfaces with contractors
There are typically 3 copies of a permit to work issued:
• One to be kept at the work site, or with the performing
authority
• A copy to be kept on display in the control room
• A copy to be kept with the Issuing authority
Interfaces with contractors
Electronic permits
• Permits can be produced electronically and a
number of companies are using this type of system
• There may be advantages in reducing the amount of
paperwork associated with the permit process
Lock out, tag out and isolation
procedures
•
Lock out, tag out often known as LOTO in the oil and gas sectors is a
safety procedure
•
It ensures that any piece of equipment being worked on cannot be
inadvertently powered up or started in any way while workers are
repairing it
•
LOTO involves the isolation of all energy sources
•
A means of ensuring inadvertent re-energisation; and an adequate means
of warning (usually in the form of a tag or label)
Lock out, tag out and isolation
procedures
• LOTO is concerned with the
isolation of all types of
energy source, including:
- Electrical supplies
- Pneumatics
- Hydraulics
- Steam
Lock out, tag out and isolation procedures
Ensuring safe isolation, lock out and tag out
Isolation steps can be summarized as follows:
• Shutdown the machinery or equipment to be worked upon
• Isolate the equipment from its energy source
• Dissipate any stored energy
• Lockout and tag out the energy isolating devices with assigned
locks and tags
• Confirm that the isolation is effective
Lock out, tag out and isolation procedures
Ensuring safe isolation, lock out and tag out
Removing locks and tags
• Before returning the equipment to service; checks should be made
to ensure that all tools, spare parts, etc have been removed
• Ensure that all safety guards are in place, that all workers are
notified and clear of the equipment
• Only then should the locks be removed, power restored and
checks to confirm that the equipment is functioning correctly
Lock out, tag out and isolation procedures
Ensuring safe isolation, lock out and tag out
Removing locks and tags
•
It is important to remember that only the person locking equipment out has the
key to unlock it
•
If that person is not available (perhaps because of a shift change), for an oil rig,
the key should be left with the Rig Manager and the relief supervisor and the
relieving driller notified of the work that is being performed
•
No equipment should be unlocked without these basic procedures being
followed
Lock out, tag out and isolation procedures
Forms of mechanical isolation
Valves
• The simplest form of isolation device, standard use for process plant
and pipelines suitable for all fluids at all pressure ranges
• Valves may not give tight shut-off due to seal damage, and require
locking off to prevent inadvertent operation
Lock out, tag out and isolation procedures
Forms of mechanical isolation
Valves
• Locking-out equipment is not
always a straight-forward procedure
and at times requires careful analysis
and consideration
Lock out, tag out and isolation procedures
Spades and spectacle plates
• A solid plate inserted between flanges, standard use for process
plant and pipelines
• Suitable for all fluids over a range of pressure ratings
Lock out, tag out and isolation procedures
Specialist isolation techniques
•
Squeeze off
•
Foam bagging
•
Pipe stoppers
•
Pipe plugs
•
Inflatable bags
•
Pipe freezing
•
Hot tapping and stopping
•
Pigs
Lock out, tag out and isolation procedures
Pipe line plug
Lock out, tag out and isolation procedures
Pipe line freezing
Content
2.1
Contractor management
2.2
Process safety management (PSM)
2.3
Role and purpose of a permit-to-work system
2.4
Key principles of safe shift handover
2.5
Plant operations and maintenance
2.6
Start up and shut down
Introduction
•
Effective communication is important in all organisations
•
Oil and Gas exploration and production are continuous 24-hour operations
•
Personnel typically reside on the offshore installation for 2-4 week periods,
working alternating 12-hour shifts
•
Poor communications and handover have been a factor in many major accidents
(for example, Piper Alpha)
•
The objective of handover is the accurate reliable communication of taskrelevant information across shift changes or between teams
Introduction
Effective handover consists of three elements:
1) A period of preparation by out-going personnel
2) Handover where out-going and in-coming personnel communicate to exchange taskrelevant information
3) Cross-checking of information by in-coming personnel as they assume responsibility for
the task
Shift handover
•
The Cullen Report concluded that one of the many factors which contributed to the
Piper Alpha disaster was failure of transmission of information at shift handover
•
Knowledge that a pressure safety valve had been removed and replaced by a blind
flange was not communicated between shifts
•
Clarification of issues not adequately recorded or communicated at shift handover is
therefore potentially problematic
Two-way with both participants
taking joint responsibility
•
Give effective shift handover communication a high priority
•
Pay particular attention to handovers which occur when staff have returned
following a lengthy absence from work
•
Specify key information needed by the incoming operator to update their mental
model of plant status
•
Use operator support (logs, displays etc)
•
Include communication skills in their selection criteria for shift-workers
•
Develop the communication skills of existing staff
Key principles in handover
•
Ensure that the incoming shift is aware of any outstanding permit-controlled jobs, the
status of those jobs, and the status of the plant
•
Work-in-progress should be left in a condition that can be reliably communicated to, and
understood by, the oncoming shift
•
A permit log, permit file or display boards are ways of recording on-going permits
•
It is essential that there is good communication between incoming and outgoing issuing
and performing authorities
•
It is recommended that the incoming issuing authority signs to allow the continuation of
a permit
Key principles in handover
Formal handover check sheet
•
Key communication of operational plant status should not rely solely on the memory of
the parties involved in the handover process
•
For example, the outgoing person to recall plant ‘status information’ or the incoming
person ‘to ask specific questions’
•
A check sheet should be used at handover and the completed sheet should be retained to
evidence that a structured handover procedure has been carried out
Content
2.1
Contractor management
2.2 Process safety management (PSM)
2.3 Role and purpose of a permit-to-work system
2.4 Key principles of safe shift handover
2.5 Plant operations and maintenance
2.6 Start up and shut down
Asset integrity
•
Asset Integrity can be defined as the ability of an asset to perform its required function
effectively and efficiently whilst protecting health, safety and the environment
•
Asset integrity management is the means of ensuring that the people, systems,
processes and resources that deliver integrity are in place, in use and will perform
when required over the whole lifecycle of the asset
•
Essential for the integrity of any installation are the safety-critical elements (SCEs)
Asset integrity
Barriers
• The SCEs represent the barriers which prevent, control
or mitigate the major accident scenarios
• In the Swiss Cheese Model (see next slide), an
organisation's defences against failure are modelled as
a series of barriers, represented as slices of swiss
cheese
• The holes in the cheese slices represent individual
weaknesses in individual parts of the system, and are
continually varying in size and position in all slices
Asset integrity
Swiss cheese model
Maintenance, inspection and testing
Maintenance
•
Factors that may help to determine the frequency and nature of maintenance includes:
-
The manufacturer's recommendations
-
The intensity of use
-
Operating environment
-
The risk to health and safety from any foreseeable failure or malfunction
Maintenance, inspection and testing
Maintenance strategies
•
Corrective
- Refers to action only taken when a system or component failure
has occurred
•
Preventive
- Equipment is repaired and serviced before failures occur
Maintenance, inspection and testing
Maintenance strategies
•
Predictive
-
•
Refers to maintenance based on the actual condition of a component
Reliability centred maintenance
-
RCM involves the establishment or improvement of a maintenance
program in the most cost-effective and technically feasible manner
Maintenance, inspection and testing
Inspection
•
Factors influencing inspection frequency include:
- Where required by national regulations
- After damage, major modification or repair
- Equipment operating in extreme weather or harsh environments
Maintenance, inspection and testing
Testing
• Required to ensure that SCE continues to meet the required
performance standard
• Functionality testing may be required following maintenance
• Testing of certain equipment may be required under national
regulations
Maintenance, inspection and testing
Corrosion prevention
•
Corrosion is the deterioration of materials by chemical interaction with
their environment
•
The term corrosion is sometimes also applied to the degradation of
plastics, concrete and wood, but generally refers to metals
•
The rusting of ordinary steel is the most common form of corrosion
Maintenance, inspection and testing
Corrosion prevention
Some of the major harmful effects of corrosion include:
•
Structural failure or breakdown of equipment
•
Failure of vessels and pipes
•
Mechanical damage to valves, pumps, etc, or blockage of pipes by solid
corrosion products
Maintenance, inspection and testing
Corrosion prevention
Corrosion allowance
•
Metal added to the design thickness against general corrosion loss
Coatings
•
The choice of coating is related to its intended function
Cathodic and anodic protection
•
This is the control of metal potentials to reduce the corrosion rate
Maintenance, inspection and testing
Corrosion prevention
Inhibitors
•
These are substances added in small concentrations to reduce the corrosion rate
Corrosion control and system history
•
Repairs or local changes in a system may alter the requirements for corrosion
inhibitors or chemicals required for process control
•
Time-related corrosion changes in a system must also be accounted for
Maintenance, inspection and testing
Corrosion prevention
Quality control
•
Confusion of materials must be avoided
•
Where resistance to corrosion depends on correctly applied welding
technology, it should be carried out to appropriately designed and
qualified welding procedures
Maintenance, inspection and testing
Corrosion prevention
Corrosion awareness
•
When corrosion reaches a critical level, it can lead to an expensive or catastrophic
situation
•
It is important that even those not involved in corrosion control or maintenance should
have an understanding of the application, effects and benefits of a corrosion control
programme and how their work may impact upon its efficiency
Maintenance, inspection and testing
Corrosion prevention
•
This plant was only about 5 years old,
but due to poor maintenance was
stained in many locations from acid
seepage
•
This made it hard to inspect and to
know how it was ageing
Maintenance, inspection and testing
Corrosion prevention
• These pre 1940’s
riveted pressure vessels
remained in good
condition and
successfully operated
in service until the
1990’s
Maintenance, inspection and testing
Corrosion prevention
Competency and training
•
Asset integrity management needs a high level of competency
•
It is essential that staff involved not only have the skills, knowledge and
competence to carry out their tasks, but also understand the performance
standards required for the equipment (SCE’s) on which they are working
Risk based maintenance and
inspection strategy
•
The Accident Prevention Institute (API) Publication 581 - Base Resource
Document: Risk Based Inspection (RBI); is an industry specific document
designed to be applied to the petroleum and chemical process areas
Risk based maintenance and
inspection strategy
•
The approach recognises that a RBI programme aims to:
- Define and measure the level of risk associated with an item
- Evaluate safety, environmental and business interruption risks
- Reduce risk of failure by the effective use of inspection resources
Risk based maintenance and
inspection strategy
•
The likelihood of failure is determined from the sum of six weighted factors:
-
Amount of equipment within item
-
Damage mechanism
-
Usefulness of inspection
-
Current equipment condition
-
Nature of process
-
Safety design and mechanisms
Risk based maintenance and
inspection strategy
•
The consequence of failure is divided into only two factors:
- Fire/explosion
- Toxicity
Risk based maintenance and
inspection strategy
•
The inspection programme is developed to reduce the risk by
determining:
- The type of damage to look for
- How to look for damage
- Where to look for damage
- When to look for damage
Techniques, principles and importance of safe operation,
standard operation procedures and maintenance
•
In the major hazard industries, procedures are essential for safe operation:
-
To minimise errors/failures
-
To protect against loss of operating knowledge
-
To standardise working practices for safe operation
-
To ensure maintenance and return of equipment back is carried out correctly
-
To provide a basis for training
-
To meet statutory requirements
Techniques, principles and importance of safe operation,
standard operation procedures and maintenance
•
Typical procedures may include:
-
Standard operating procedures/operating philosophy
-
Abnormal operating procedures
-
Temporary operating procedures
-
Plant trials
-
Emergency operating procedures
Control of ignition sources during
maintenance and operations
•
Hazardous areas on an oil and gas installation (concerning the presence of flammable
materials) are “zoned”
•
Fixed sources of equipment are designed to prevent “sparking” during their operation
•
Should they come into contact with a flammable material, they cannot ignite the material
•
Maintenance work is periodically undertaken on or around, live process plant
•
Such work must be strictly controlled, to avoid the possibility of fire and explosion
Cleaning and gas freeing of plant and
equipment
•
The operation of gas-freeing should be distinguished from that of cleaning
•
Gas-freeing (or purging) means the removal of flammable gas or vapour from a tank
•
Cleaning refers to the removal of solid and liquid residues
•
Cleaning and gas freeing are processes that are applied to tanks, vessels or other
equipment in order to prepare them for maintenance activities such as hotwork,
confined space entry and inspection
Cleaning and gas freeing of plant
and equipment
•
Purging
•
Venting
•
Draining of water, product
•
Oxygen
•
Non-condensables (NCD’s)
•
Inerting
Content
2.1 Contractor
management
2.2
Process safety management (PSM)
2.3
Role and purpose of a permit-to-work system
2.4
Key principles of safe shift handover
2.5
Plant operations and maintenance
2.6
Start up and shut down
Associated hazards and controls
Hazards
Start-up and shut-down
•
The release of stored energy
•
Flammable hydrocarbon release, leading to fires, explosion
•
Toxic gas release
•
Overpressure of plant and equipment
•
Thermal shock
•
Inadvertent starting of machinery
Maintenance, inspection and testing
Hazards
Shut-down controls
•
Use of permit-to-work
•
Isolation of equipment (electrical, mechanical etc) and LOTO
•
Venting, draining, removal of materials from equipment
•
Purging, cleaning of equipment
•
Spading or blanking of equipment
•
Ensuring that equipment is “gas free”
Associated hazards and controls
Hazards
Start-up controls
•
All Permits closed out
•
Spades, blanks removed
•
De-isolation of equipment
•
Instruments calibrated
•
Alarms, gas detection systems functional
•
ESD’s, flares, relief valves, deluge systems functional
•
Pressure, leak, integrity testing
•
Emergency plans in place
Associated hazards and controls
Kick formation
•
The downhole fluid pressures are controlled through the
balancing of the hydrostatic pressure provided by the
drilling mud used
•
Should the mud pressure fall below the pore pressure of
the formation fluids they will flow into the wellbore and up
the annulus
•
This is commonly called a ‘kick’
•
Can quickly escalate into a blowout (Gusher)
Associated hazards and controls
Water and hydrates presence and removal
•
In drilling, record water depths are continuously being set by oil companies in the
search of hydrocarbon reserves in deep waters
•
Due to environmental concerns and restrictions, water based drilling fluids are
often more desirable than oil based fluids, especially in offshore exploration
•
A well recognised hazard in deep water offshore drilling, using water based fluids,
is the formation of gas hydrates in the event of a gas kick
Associated hazards and controls
Water and hydrates presence and removal
• In deep-water drilling, the hydrostatic pressure of the column
of drilling fluid and the relatively low seabed temperature,
could provide suitable conditions for the formation of
hydrates in the event of a gas kick
• This can cause serious well safety and control problems
during the containment of the kick
Associated hazards and controls
A large gas hydrate plug formed in a subsea hydrocarbon pipeline
Source: Petrobras (Brazil)
Associated hazards and controls
Dehydration system
Associated hazards and controls
Testing, commissioning and hook up
Testing
•
Clear demarcation of where limits of intervention cease and reliance upon the
control systems interface begins is a critical step in defining the operating
procedures for a given plant or process
•
The justification of reliance upon human intervention rather than automated
systems should be established
Associated hazards and controls
Testing, commissioning and hook up
Controls
•
The principle controls for start-up and shut-down are the safe working
procedures
•
The procedures should be ordered and phased so that interlinked plant
operations can resume or cease in a safe and controlled manner
Associated hazards and controls
Testing, commissioning and hook up
Commissioning
•
Commissioning of process plant is the practical test of the adequacy of prior
preparations, including training of operating personnel and provision of adequate
operating instructions
•
Commissioning procedures document a logical progression of steps necessary to
verify that installed plant is fully functional and fit for purpose
Associated hazards and controls
Testing, commissioning and hook up
Commissioning
•
A general sequence of steps in commissioning may typically include:
-
System configuration check
-
Instrumentation system check - verification of alarms and trips
-
Flushing and cleaning of lines and vessels with water
-
Assessment of ancillary equipment
-
Calibration of vessels and instrumentation
Learning outcomes
2.1 Explain the principles of assessing and managing contractors, including the roles
of parties involved
2.2 Outline the tools, standards, measurement, competency requirements and controls
applicable to Process Safety Management (PSM) in the oil and gas industries
2.3 Explain the role and purpose of a permit-to-work system
2.4 Explain the key principles of safe shift handover
2.5 Explain the importance of safe plant operation and maintenance of hydrocarbon
containing equipment and processes
2.6 Outline the hazards, risks and controls to ensure safe start up and shut down of
hydrocarbon containing equipment and processes
2
Hydrocarbon process
safety 1