Temporary Instrumentation and Controls Bypass - Fundamental Intent
To identify and manage bypassing of instrumented safeguards on process equipment, which are designed to pre-vent fires, explosions, or toxic releases that could result in personal injuries, property damage, community impacts, environmental impacts, or business impacts.
Instrumented safeguards execute many types of functions, such as reactive or permissive inter-locks, operator response to alarms, fire and gas systems, and safety instrumented functions. Bypassing (also referred to as “impairing”, “suppression” in the case of alarms, or “jumpering” for electronic circuit bypassing of field devices) the safeguard’s function or a device used by the safeguard may impair or eliminate the safeguard’s ability to prevent or mitigate the hazardous event.
Example activities that might require use of a Temporary Bypass or Jumpering of Instrument-ed Safeguard SWP, a pre-authorized bypass procedure, or a temporary MOC:
Process Start-up Activities
- Bypassing low flow pump safeguard
- Bypassing low level safeguards on tank inlet valves
Automation Asset Integrity Activities
- Bypassing safeguard device to investigate poor performance and repair if necessary
- Bypassing safeguard device for scheduled testing
Other Bypassing Activities
- Any other bypassing of safeguard functions or devices while protected equipment is not in an inherently safe state
- Operating with a failed instrument
- Operating with degraded functionality
Scaffolding - Fundamental Intent
To identify and manage hazards in areas where Scaffolding is being performed and/or used as a work-platform; to prevent falls, collapses or dropped objects that could result in personal injuries, property damage, community impacts, environmental impacts, or business impacts.
Examples activities that would require use of a Scaffolding SWP:
- Designing a scaffold
- Erecting a scaffold
- Inspecting a scaffold
- Use of a scaffold as a work platform
- Alteration of a scaffold
- Erecting of a scaffold in a confined space
- Use of mobile scaffolds
- Use of underhung scaffolds (overwater)
- Dismantling scaffolds
What Is a Scaffold?
A scaffold is an elevated, temporary work platform. There are two basic types of scaffolds:
- Supported scaffolds – which consist of one or more platforms supported by rigid, load- bearing members, such as poles, legs, frames, outriggers, etc.
- Suspended scaffolds – which are one or more platforms suspended by ropes or other non-rigid, overhead support.
Other types of equipment, principally scissor lifts and aerial lifts, can be regarded as specific types of supported scaffolds.
Key Aspects of Hazard Management of Scaffolding:
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Prepare a risk assessment before starting any work at height. If the assessment confirms that there is no alternative to working at height, then suitable work equipment should be selected, considering the nature of the work.
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Approved fall protection measures (e.g. safety harnesses) should be used if the working height is greater than 1.8 m (6 ft.) above the floor or platform level. A fall protection plan for external access to a vessel/confined space should be developed by the person-in-charge if the entry point exceeds approximately 1.8 m (6 ft.) vertically (e.g., proper harnesses or scaffolding; actual requirement varies by jurisdiction). For example, in the US, 29 CFR 1910.146(k)(3)(ii) requires mechanical retrieval devices for vertical entries of 5 feet (1.5 m) or greater.
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A fall protection plan for internal access to a vessel/confined space should also be developed when confined space entry requires internal work heights exceeding approximately 1.8 m (6 ft.) vertically (actual requirement varies by jurisdiction).
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Scaffolding activities will normally require a safe work permit and, if inside a confined space, an additional confined space entry certificate/entry permit.
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Scaffold design, erection, inspection, use, alteration, and dismantling should meet the regulations of the country where it is being used and be performed only by those holding the appropriate certifications or qualifications required.
Field Review of Permits - Fundamental Intent
To improve awareness among permit to work roles of the importance of field visits for identifying situational and human factors which might otherwise be missed during task risk assessments. Not recognizing these factors before issuing permit might pose significant hazards during performing the planned tasks.
Examples of activities that would require a Field Review of Permit SWP:
- Inter-process connection/line breaking activities
- Hot work activities
- Confined space entry activities
- Interlock bypassing activities
- Multiple permit to work (PTW) related activities in the same area (SIMOPS)
- PTW Activities that span multiple work shifts
- Unplanned releases/impact assessments after incidents
- Inspection/maintenance activities
Background
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It is imperative to recognize that completion of tasks in an operating plant in a safe, timely and quality manner is the foundation for ensuring that the organization will retain its operating license and continue to meet the requirements of shareholders.
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To achieve these goals, an organization needs a rigorous management system to ensure that tasks are done consistently and reliably. This system is called Permit to Work (PTW). Safe Work Permits (SWP) are used to implement the PTW system.
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A PTW system is an integral part of a safe system of work and can help to properly manage the wide range of activities which can take place close together in a small space, such as in a storage area or process plant.
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Permits are the communication protocol, which when signed, acknowledge the contract between two parties. Permits may be on paper or electronic and typically focus attention on hazards present at the work site. This permit or contract, if not managed properly, could lead to injuries or fatalities.
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A structured field review of permits (that is, the safe control of the PTW process) is necessary to ensure that the PTW system provides the required risk reduction. Field reviews can be used to develop Key Performance Indicators (KPIs) to identify and inform management of the strengths and weaknesses in the system and where to place resources to improve the process.
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Safe operation of plants and facilities must be the highest priority for an operating organization. Top-performing organizations and their leadership genuinely care about the health and safety of their employees and contractors who undertake maintenance and refurbishment tasks at their worksites.
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Effective SWPs have many steps which include job planning, Hazard Identification and Risk Assessment (HIRA), scheduling, and mitigation/control measures for the hazards. The completion of these steps results in the issuance of a Permit to Work (PTW). This is a formal system stating the Who, What, Where, When and How these activities are performed in the facility.
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HIRA of the tasks to be performed is at the heart of the SWP system. HIRA is a continuous process which helps assess hazards and identify controls from planning the jobs through safe execution to the closure of the Permit to Work. Task risk assessments should address situational factors and human factors.
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Task-based hazards and risks can be standardized and should be the same every time the same task is performed. Situational factors and human factors cannot always be the same. They can vary to the extent that, the risk assessment team or the permit issuers may decide not to go ahead with the job.
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When incidents with high potential consequence have been investigated, the investigators have concluded that the associated permits did not identify situational specific hazards (for example - number of people in the vicinity of the job location, prevailing abnormal conditions at the job location) and/or human factors. Failure to recognize and mitigate situational factors and/or human factors can result in incidents with higher consequences.
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Equipment Identification - Fundamental Intent
To identify and manage situations where incorrect Equipment Identification may pose significant hazards during performance any job or during any incident in plant areas. Such hazardous situations may result in fires or explosions that could result in personal injuries, property damage, community impacts, environmental impacts, or business impacts.
Example activities that would require use of an Equipment Identification SWP:
1. Day-to-day plant operations
2. Inter-process connection
3. Line break activities
4. Hot work activities
5. Activities inside confined space
6. Interlock or safety system bypassing activities
7. Other Permit-to-Work (PTW) related activities
8. Unplanned release response
9. Impact assessments after incidents
10. Inspection Activities
11. Maintenance Activities
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Line Opening - Fundamental Intent
To identify and manage loss of containment of hazardous materials during activities that require opening process lines or process equipment that could result in personal injuries, property damage, community impacts, environmental impacts, or business impacts.
Examples activities that would require use of a Line/Equipment Opening SWP:
- Removing process pump for maintenance activities
- Replacing a pump seal or packing
- Replacing a valve
- Replacing process instrumentation
- Replacing process piping
- Modifying process piping
- Opening equipment for cleaning
- Opening equipment for inspection
- Removing process instrumentation for shop calibration
- Installing isolation blinds
- Installing new piece of equipment
- Replacing valve packing
- Replacing agitator seal or packing
- Removing pressure relief device for maintenance
- Replacing gaskets in piping and equipment
- Unplugging lines
- Removing a blind flange on the end of a line
Hot Tapping - Fundamental Intent
To identify and manage risks associated with welding, cutting drilling and other process boundary-penetration on live equipment and pipelines, so that fires or explosions that could result in personal injuries, property damage, community impacts, environmental impacts, or business impacts are prevented.
Considerations during the development of a Hot Tapping SWP include:
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Hot Tapping is an inherently hazardous process, as it always results in the penetration of an operating process boundary—in effect, Hot Tapping is a controlled loss-of-containment (LOC) event. The first step in any hot tap SWP is a mandatory evaluation to ensure that the operation cannot be performed under normal maintenance conditions; i.e., a “cold tap”, where equipment is de-energized, empty, at ambient temperature conditions, and cleaned prior to the procedure.
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If a routine maintenance operation cannot be performed, strong consideration should be given to a “warm tap” process; i.e., one where the equipment is not out of service and cleaned, but where enough isolation has been performed so as to limit any release of material should the tap fail.
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Although hot tapping on live equipment and pipelines is practiced widely across the process industries, and even though sufficient experience has been obtained, the risks remain the same every time the activity is performed.
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No two activities involving welding on live systems are identical. The risks differ for each case and extreme caution must be exercised from the task design stage to completion of execution.
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Strong consideration should be given during procedural development to circumstances where hot tapping should be absolutely forbidden. These situations might include
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Equipment containing highly toxic materials
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Equipment containing heat transfer fluid (HTF), either vapor or liquid, above 250 C
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Steam above 600 psig
Background
Hot tapping refers to a two-step process.
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The first step is to weld a branch nozzle on the live operating equipment or pipeline.
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During the second step, after welding the branch nozzle, the nozzle coupon is drilled and removed by a specially-designed drilling machine.
The combined activity of welding and drilling to create a new nozzle on live systems is termed as hot tapping. There are also instances when only welding is carried out on live systems with no drilling required. For clarity, in this document the term “hot tapping” to refers to all types of welding on live equipment (with or without drilling).
Hot tapping on live equipment depends on the following characteristics of the system:
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Metallurgy of the parent equipment / pipeline
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Operating pressure
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Operating temperature
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Chemistry and physical properties (hazardous properties) of the operating fluid
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Condition of the equipment / pipeline on which the activity will be performed.
Hot tapping on live systems containing pressurized fluids is one of the most hazardous activities in an operating unit. A loss of containment during welding or drilling on live equipment or pipeline can cause serious damage to the personnel involved in the welding jobs. The consequences can include serious injuries with a potential leading to fatalities. Damage to the assets near the workplace can also occur, dependent on location and process chemicals within.
Potential incidents can occur if:
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The pipeline or equipment on which the hot tapping is to be done is not inspected and certified fit for hot tapping. A common situation that can disqualify equipment for hot tapping is wall thinning.
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The metallurgy of the pipeline or equipment is not fit for hot tapping.
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The fluid flow is not maintained as required to adequately cool the weld metal.
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The procedure is done by untrained personnel with the possibility of not controlling the heat input for welding.
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The hot tap connection is inadequately or improperly designed.
Energy Isolation - Fundamental Intent
To identify and manage release of hazardous energy that could result in personal injuries, property damage, community impacts, environmental impacts, or business impacts. This includes inadvertent start-up of de-energized equipment, release of stored energy and release of hazardous materials during maintenance or operations activities. Types of hazardous energy releases that should be controlled include:
- Electricity – energized circuits still connected to the equipment(including stored electrical energy such as capacitors or battery backups)
- Kinetic energy – energy of moving objects (i.e. gears, fan blades, or saw blades)
- Potential energy – stored energy (i.e. object that may fall due to gravity if not controlled, hydraulic or pneumatic systems under pressure)
- Pressurized liquids and gases (including air and nitrogen)
- Chemical energy – hazardous material releases
- Thermal energy – such as steam or hot water releases
- Communications (that is, Remote starting equipment)
- Radiation – X-rays, laser, or radioactive sources
Lockout/Tagout/Try
Refers to the placement of a lock and isolation tag on an isolating device indicating that the isolating device and its system shall not be operated or removed until the lock and isolation tags are removed. Then Try to start the equipment (for electrical isolations) or Try to find residual pressure, chemicals, or energy in the process by checking bleed valves or other sources. The Try step is mandatory. The Try step confirms that the isolation and lock work as planned.
Examples activities that would require use of an Energy Isolation (Lock-Out/Tag-Out) SWP:
Rotating Equipment
- Pumps
- Agitators
- Compressors
- Turbines
- Conveyors
- Blowers
- Star valves
- Extruders
- Cutters
- Rollers
Power Equipment
- Electrical switchgear
- Electrical circuits
Pneumatically-Operated Equipment
- Conveying systems
- Pneumatically operated machinery
Hydraulically-Operated Equipment
- Filter presses
- Molding presses
- Automated packaging equipment
Line or Equipment Opening Activities
- Refer to Line/Equipment Opening SWP for additional details
Confined Space Entry Activities
- Refer to Confined Space Entry SWP for additional details
Hot Work Activities
- Refer to Hot Work SWP for additional details
Excavation - Fundamental Intent
To identify and manage hazards in areas where excavation work is being performed to pre-vent collapses that could result in personal injuries, property damage, community impacts, environmental impacts, or business impacts.
Considerations when developing an Excavation SWP:
1. Excavation is necessary in construction and in running industrial facilities. Excavations and trenches are unstable by nature, and many types of serious hazards exist when do-ing this type of work, such as hitting underground services. In addition, hazards associ-ated with working within trench exist, including cave-ins from collapse of shor-ing/trench materials, confined space entry incidents, and hazardous fluid collecting at low points in areas where workers will be positioned.
2. Excavations may also be required to access existing underground services, piping, duct-ing and cables, or install new/additional services. While excavations are being per-formed it is paramount to install controls to prevent incidents that could result in per-sonal injuries, property damage, community impacts, environmental impacts, or busi-ness impacts.
3. Regulations require many of us to prevent danger to workers in or near excavations. To maintain the required precautions, a competent person must inspect excavation sup-ports, sloping or shoring at the start of the working shift and at other specified times. No work should take place until the excavation is proven safe.
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Equipment Filling and Mixing - Fundamental Intent
To identify and manage situations of loss of containment - toxic release or/and explosion - due to filling and inadvertent mixing of incompatible fluids, which might pose significant hazards in and outside the plant areas.
Examples activities that would require use of Equipment Filling and Mixing SWP:
- Loading and unloading operations
- Chemical disposal or draining
- Batch reaction operations
- Chemical dosing / charging
- Leak repair / Online sealing
- Laboratory chemicals handling
- Chemical cleaning
- Hazardous waste segregation
- Storage/warehouse
Confined Space Entry - Fundamental Intent
To identify and manage hazards associated with entering equipment and spaces that have limited openings for worker entry and exit, could have unacceptable air quality such as toxics or irritants present or lack of oxygen, or present a risk of engulfment by loose particle or bulk material.
Examples activities that would require use of a Confined Space Entry SWP:
- Entry to clean, internally inspect or repair a storage tank
- Entry to clean, internally inspect or repair of a process vessel
- Entry into a silo
- Entry into a column or a silo skirt with restricted openings
- Entry to clean or change filter elements in bag houses
- Entry into dryers or ball mills
- Entry to Inspect or repair boilers
- Entry to underground utility tunnels
- Entry into exhaust ducts or ventilation systems
- Entry into sewer pits and sewers
- Entry to clean rail cars or tank trucks
- Entry to clean ships or barges
- Entry into open top spaces more than 4 ft deep such as dikes, excavations and cooling towers
Hot Work - Fundamental Intent
To identify and manage fire and explosion hazards in areas where hot work is being performed, to prevent fires or explosions that could result in personal injuries, property damage, communi-ty impacts, environmental impacts, or business impacts.
Examples activities that would require use of a Hot Work SWP:
“Naked Flame” Activities
- Gas cutting and welding
- Electric arc welding
- Open flame boilers / space heaters
- Brazing
- Soldering
- Stress relief and heat treatment
- Use of explosives
- Exposure of pyrophoric scale
“Spark Potential” Activities
- Cutting and grinding
- Needle guns
- Sand blasting / abrasive blasting
- Internal combustion engines (e.g., trucks, forklifts, etc.)
- Use of non-intrinsically safe electrical equipment
- Stress relief and heat treatment
- Opening sealed and/or pressurized electrical equipment (e.g., junction boxes, switches, light fixtures, etc.)
- Electrostatic discharge / static electricity
- Jackhammers / chippers
- Hammering / impact tools
- Opening/operating equipment that could create a flammable source in the presence of existing ignition sources (e.g., process heater fireboxes)
