Excavation - Common Program Practices | AIChE

Excavation - Common Program Practices

Last updated May 30, 2019 | Element: Common Program Practices

  • Non-routine work increases process risk and can directly lead to conditions that make a catastrophic accident much more likely.
  • Safe work practices are critical elements in the management of non-routine work.
  • Safe work practices include an integrated management system of policies, procedures and permits that help protect workers from hazards and prevent the sudden release of process materials or energy during non-routine work activities.
  • Safe work procedures and permits help ensure that workers understand the hazards and take appropriate actions to manage risk when performing non-routine work activities.

Policies – govern the safe work practices and state the scope of activities that require a permit provided by the safe work practice. 

Procedures – provide details on how the work is to be executed.

Permits – describe job-specific hazards and specify safeguards for a finite period of time as documented on the permit.


Element Detail


1. Documented Standard

  • The procedures and supporting documents and forms associated with the Safe Work Practices program should be fully documented, authorized, version controlled and subject to periodic review.
  • These documents should be available to all personnel involved in the practices both staff and contractors.

2.  Accountabilities

  • A Senior Manager should be the single point of accountability for the system managing Safe Work, including the Permit to Work system.
  • Roles should be specified for all people involved in the planning, approval, and execution of the work practices. These should include a description of all responsibilities and the necessary competence needed to fulfill these roles. 

3. Training and Competency

  • All individuals involved in Safe Work Practices should be trained and certified for all roles they fulfill in the system. This training should include complete understanding of the planning, approval and execution of the practices and intent of the system.
  • This should include both plant staff and contractors.
  • The training should include competency assessment and documenting of the outcome. Refresher training should be an integral part of the program.
  • A register of all certified individuals and the roles they are certified to fulfill should be maintained.

4. Planning and Scheduling

  • The task objective, method and tools should be specified along with the specific location and equipment to be worked upon.
  • The worksite should be visited to identify relevant equipment and to identify all task hazards and process safety hazards.
  • The need for special provisions should be identified such as Energy Isolation (Lock Out / Tag Out), confined spaces, lifting, scaffolding / mobile platform, hazardous materials handling, skills / competency, noise, temperature, etc.
  • The condition of ongoing plant processes and other nearby activities should be considered when scheduling the work. Good practice is to have a matrix of allowable simultaneous operations or “SimOps” and those which are prohibited.

5. Risk Assess Hazards

  • With an understanding of the work method, tools to be used, work party skills/ competence and process status, the hazards should be identified and risk assessed. When the risk is unacceptable, barriers should be specified to control the hazards to an extent where the residual risk is acceptable.
  • If the risk is still unacceptable, alternative approaches to the work method, tools, people, timing or location should be determined.

6. Permit Control Process

  • Hazardous work should be controlled by a permitted process (i.e., a defined process with various levels of authorization from plant staff).
  • The permit should specify all of the safeguard barriers to be in place to carry out the task. This will include energy isolations, gas testing, protective equipment, scaffolding, etc.
  • Issuing of the permit is an important control gate and should not be carried out unless all necessary conditions are met.
  • Typically Permits are valid for a single shift and should be returned to the Permit office once complete or suspended at the end of the shift. Any work continuing through the shift handover should be approved anew by the oncoming Shift Supervisor.
  • There should be a single location point for permit issuance where contractors go to collect permits issued to them and where they return them at the end of a shift.
  • The control process should include a register of all permits issued, the work task(s) being carried out and to who the permit was issued. Copies of each permit should held in the same area so people can readily see all ongoing work. 

7. Communicate (Scope, Hazards, Controls, and Mitigations)

  • It is the role of the Supervisor or Area Authority to communicate all hazards in the work area to the person receiving the permit.
  • When energy isolations are required, it is good practice for the Supervisor or Area Operator to identify the isolations and demonstrate their energy free status.
  • Where gas testing is required before work commences, the Authorized Gas Tester should communicate the status to the work party, alerting them if the test does not meet standards.                                                                 
  • The Performing Authority or person raising the permit has a responsibility to communicate all hazards and controls to the work party before the task commences. This is normally carried out during a “tailgate/toolbox” or briefing meeting where the work scope is outlined, hazards and barrier identified, specific responsibilities defined and members sign up to the work sheet.
  • Good practice has that the permit and all associated documentation be posted at the work site for all to see and access.

8. Monitor and Manage Ongoing Work

  • Once a permit has been issued, the plant staff should monitor progress to some extent. Typically, the more hazardous the task, the higher the level of surveillance necessary.
  • Where specific hazards are present permanent monitoring may be necessary such as “fire watcher” for Excavation or “Entry Attendant” for Confined Space Work
  • Permanent or periodic gas testing maybe appropriate
  • When a shift ends, the Supervisor should be responsible for ensuring all copies of the permit have been returned and that work has ceased in the area.

9. Work Left In Safe Condition Upon Completion or Interruption

  • When a task is complete, the work area should be cleared of all tools, equipment and materials and all surfaces cleaned remove any tripping or slipping hazards.
  • If it is necessary to interrupt work, either due to a natural break or in an emergency situation, all work should immediately cease and the work area returned to a safe condition. If an emergency is sounded then the work party should cease work, the work area then proceed to their muster point and await further instructions. Once the emergency has cleared, work should not commence without the permission from the Supervisor through reissuance of the permit.

10. Verification and Assurance

  • Verification or Compliance Audits and spot checks should be car-ried out regularly to ensure that the Permit to Work system is functioning correctly. These checks should include:

o  Whether the permit has been correctly completed

o  If the task method described is being carried out and whether it is understood by the entire work party.

o  Whether all specified barriers and isolations are in place

o Test the understanding of the hazards and controls by the work party members 


11. Capture, Incorporate and Share Lessons Learned

  • Most safe systems of work include a process for capturing and sharing lessons learned. These include lessons on the task carried out, the risk assessment, the approvals process and the work preparation.
  • When a lesson is learned, the need for modifying procedures, to incorporate the lessons learned, should always be considered.

12. Communicates Obligation and Authority to Stop Unsafe Work

  • It should be recognized that all staff and contractors on the plant site have the Authority and Obligation to stop work when an unsafe condition or act is observed that could affect the safety of personnel and/or the environment.
  • This expectation should be routinely communicated to all people on the plant.
  • Ensure that no repercussions are directed towards personnel who use stop work authority.