Fundamental Intent | AIChE

Fundamental Intent

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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SWP Element 

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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SWP Element 

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: 

  1. Designing a scaffold
  2. Erecting a scaffold                                                                                
  3. Inspecting a scaffold
  4. Use of a scaffold as a work platform
  5. Alteration of a scaffold
  6. Erecting of a scaffold in a confined space                                                                       
  7. Use of mobile scaffolds
  8. Use of underhung scaffolds (overwater)
  9. 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:

  • Approved fall protection measures (e.g., safety harnesses) should be used if the working height is greater than 1.8 m (6 ft.) from floor or platform level.
  • A fall protection plan for external access to the vessel/confined space should be developed by the person-in-charge if the entry point exceeds 1.8 m (6 ft.) vertically (e.g., proper harnesses or scaffolding).
  • A fall protection plan for internal access to the vessel/confined space should also be developed when confined space entry requires internal work heights exceeding 1.8 m (6 ft.) vertically.
  • Scaffolding activities will normally require a safe work permit or, if inside a confined space, an additional confined space entry certificate/entry permit.
  • Scaffold design, erection, inspection, use, alteration, and dismantling should meet the regulations of the country where it is being used.
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SWP Element 

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: 

  1. Loading and unloading operations                                                                        
  2. Chemical disposal or draining                 
  3. Batch reaction operations
  4. Chemical dosing / charging
  5. Leak repair / Online sealing
  6. Laboratory chemicals handling
  7. Chemical cleaning
  8. Hazardous waste segregation
  9. Storage/warehouse

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SWP Element 

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: 

  1. Inter-process connection/line breaking activities
  2. Hot work activities
  3. Confined space entry activities
  4. Interlock bypassing activities
  5. Multiple permit to work (PTW) related activities in the same area (SIMOPS)   
  6. Unplanned releases/impact assessments after incidents
  7. Inspection/maintenance activities


  • A permit-to-work 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.
  • Permits whether on paper/or digital are the communication protocol when signed acknowledging the contract between two parties. This contract if not managed properly could lead to fatalities, if not given the attention to hazards present at the worksite. 
  • The importance of a structured field review of the safe control of work process - with resulting KPI’s to inform management of the strengths and weaknesses in the system and where to place resources to improve the process - cannot be understated.
  • Operating the business safely is not just not a choice but has become a highest priority for the organizations having aspirations to continuously grow. Top-performing organizations and their leadership genuinely care about the health and safety of their employees and contractors who undertake maintenance and refurbishment task at their worksites.
  • Growing organizations face bigger challenges at workplace as they continue making modifications to achieve stringent targets to sustain in the market.
  • It is imperative to recognize that completion of the tasks in a safe, timely and quality manner is the foundation for ensuring that the organizations continues to generate profits and improve share values and shareholders confidence, safely, reliably and economically. To achieve this, organization needs a rigorous management system to ensure tasks are done consistently and reliably is called Permit to work.
  • Effective safe work permits include job planning, hazard identification and Risk Assessment (RA), scheduling, Isolation Management (IM), and issuance of a Permit to Work (PTW). It is a formal system stating the WHAT, WHEN, WHERE, WHO and HOW these activities are performed in the facility.
  • Task risk assessment is at the heart of safe work permits include job planning.  Risk assessment 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.
  • 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 be the same at all times. They can vary to the extent that, the risk assessment team or the permit issuers may decide not to go ahead with the job.
  • Investigation reports of high potential consequence incidents identifies that the associated permits do not identify situational specific hazards (for example - hazards of process fluids, number of people around the job location, prevailing abnormal conditions around job location) and/or human factors.  It has been observed during major incident investigations that permit issuers are not sufficiently sensitized to potential worst-case scenarios during their training on PTW, and therefore, rarely consider situational factors and Human factors while preparing the permits. Their focus remains on identifying job specific hazards which – if left unmitigated - could lead to minor to medium injuries of the workers engaged in the job. However, history taught us that missing process specific or situation specific hazards if not controlled properly can lead to major injuries and multiple fatalities.
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SWP Element 

Hot Tapping - Fundamental Intent

To identify and manage risks associated with welding and drilling on live equipment and pipelines, to prevent fires or explosions that could result in personal injuries, property damage, community impacts, environmental impacts, or business impacts.


Considerations during the development of a Hot Tapping SWP include:

  • Although hot tapping on live equipment and pipelines is practiced widely across the industries, and enough experience has been obtained, the risks remain the same every time the activity is performed. 
  • No two activities involving welding on live systems are identical. The risks differ for each case and extreme caution has to be exercised from the task design stage to completion of execution.


Hot tapping refers to a two-step process. 

  1. The first step to weld a branch nozzle on the live operating equipment or pipeline. 
  2. 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 to be done. For the purpose of clarity of 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:

  • Metallurgy of the parent equipment / pipeline
  • Operating pressure
  • Operating temperature
  • Chemistry and physical properties (hazardous properties) of the operating fluid
  • Condition of the equipment / pipeline on which the activity has to 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 work place can also occur, dependent on location and process chemicals within.


Potential incidents can occur if:

  • The pipeline or equipment on which the hot tapping is to be done is not inspected and certified fit for hot tapping.
  • The metallurgy of the pipeline or equipment is not fit for hot tapping.
  • The fluid flow is not maintained as required to adequately cool the weld metal.
  • The welding is done by untrained personnel with the possibility of not controlling the heat input.
  • The hot tap connection is inadequately designed.
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SWP Element 

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: 

  1. Entry to clean, internally inspect or repair a storage tank
  2. Entry to clean, internally inspect or repair of a process vessel
  3. Entry into a silo
  4. Entry into a column or a silo skirt with restricted openings
  5. Entry to clean or change filter elements in bag houses
  6. Entry into dryers or ball mills
  7. Entry to Inspect or repair boilers
  8. Entry to underground utility tunnels
  9. Entry into exhaust ducts or ventilation systems
  10. Entry into sewer pits and sewers
  11. Entry to clean rail cars or tank trucks
  12. Entry to clean ships or barges
  13. Entry into open top spaces more than 4 ft deep such as dikes, excavations and cooling towers
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SWP Element 

Temporary Instrumentation and Controls Bypass - Fundamental Intent

To identify and manage bypassing of instrumented safeguards on process equipment, 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 “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

  1. Bypassing low flow pump safeguard     
  2. Bypassing low level safeguards on tank inlet valves     

Automation Asset Integrity Activities

  1. Bypassing safeguard device to investigate poor performance and repair if necessary
  2. Bypassing safeguard device for scheduled testing

Other Bypassing Activities

  1. Any other bypassing of safeguard functions or devices while protected equipment is not in an inherently safe state

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SWP Element 

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
  • Kinetic energy – energy of moving objects (i.e. gears or saw blades)
  • Potential energy – stored energy (i.e. object that may fall due to gravity if not controlled, hydraulic 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

Examples activities that would require use of an Energy Isolation (Lock-Out/Tag-Out) SWP: 

Working on Rotating Equipment

  1. Pumps
  2. Agitators
  3. Compressors
  4. Turbines
  5. Conveyors
  6. Blowers
  7. Star valves
  8. Extruders
  9. Cutters
  10. Rollers

Working on Powered Equipment

  1. Electrical switchgear
  2. Electrical circuits

Working on Pneumatically-Operated Equipment

  1. Conveying systems
  2. Pneumatically operated machinery

Working on Hydraulically-Operated Equipment

  1. Filter presses
  2. Molding presses
  3. Automated packaging equipment

During Line or Equipment Opening Activities

  • Refer to Line/Equipment Opening SWP for additional details

During Confined Space Entry Activities

  • Refer to Confined Space Entry SWP for additional details
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SWP Element 

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:


  1. Removing process pump for maintenance activities
  2. Replacing a pump seal or packing
  3. Replacing a valve
  4. Replacing process instrumentation
  5. Replacing process piping
  6. Modifying process piping
  7. Opening equipment for cleaning
  8. Opening equipment for inspection
  9. Removing process instrumentation for shop calibration
  10. Installing isolation blinds
  11. Installing new piece of equipment
  12. Replacing valve packing
  13. Replacing agitator seal or packing
  14. Removing pressure relief device for maintenance
  15. Replacing gaskets in piping and equipment
  16. Unplugging lines
  17. Removing a blind flange on the end of a line
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SWP Element 

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

  1. Gas cutting and welding      
  2. Electric arc welding      
  3. Open flame boilers / space heaters
  4. Brazing
  5. Soldering
  6. Stress relief and heat treatment
  7. Use of explosives
  8. Exposure of pyrophoric scale

“Spark Potential” Activities

  1. Cutting and grinding
  2. Needle  guns
  3. Sand blasting / abrasive blasting
  4. Internal combustion engines (e.g., trucks, forklifts, etc.)
  5. Use of non-intrinsically safe electrical equipment
  6. Stress relief and heat treatment
  7. Opening sealed and/or pressurized electrical equipment (e.g., junction boxes, switches, light fixtures, etc.)
  8. Electrostatic discharge / static electricity
  9. Jackhammers / chippers
  10. Hammering / impact tools
  11. Opening/operating equipment that could create a flammable source in the presence of existing ignition sources (e.g., process heater fireboxes)
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SWP Element 

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