Simultaneous Operations (SIMOPS) refer to the execution of two or more activities by different functional teams within the same operational area at the same time. SIMOPS situations are common in Oil & Gas, Petrochemical, LNG, Power, and Industrial Facilities, particularly when construction, commissioning, start up, maintenance, drilling, and live production activities occur concurrently within an operating plant.
Although each activity may be individually assessed and controlled, performing them simultaneously introduces additional interface risks due to their interaction. These combined risks are often not visible in isolated task-based risk assessments and can significantly increase the likelihood of safety, operational, and environmental incidents.
Such risks may lead to:
A structured SIMOPS study ensures that these interaction risks are properly identified, evaluated, and controlled to enable safe simultaneous execution without compromising personnel, assets, environment, or operational integrity.
SIMOPS Risk Assessment is a structured process used to review simultaneous activities and evaluate hazards created due to their interaction. Unlike traditional risk assessments that evaluate individual tasks, SIMOPS focuses on the combined effect of concurrent activities and the additional risks generated due to their overlap.
The key objectives of SIMOPS Risk Assessment are to:
SIMOPS studies are especially important during brownfield expansions, plant modifications, shutdowns, and multi contractor activities in live operating facilities. These studies apply to both onshore facilities such as refineries and terminals, as well as offshore platforms and subsea production systems.
SIMOPS represents a conflict between activities that may create undesired safety, environmental, operational, or financial consequences. These risks arise not from a single activity, but from the interaction between multiple activities performed simultaneously.
SIMOPS reviews also play an important role in supporting process safety studies such as HAZOP by addressing operational and activity based interaction hazards that are not covered during process design risk assessments.
The SIMOPS workshop is the central element of the SIMOPS risk assessment process. It involves active participation from all relevant stakeholders, including the plant owner, operators, contractors, engineering teams, and safety personnel. The purpose of the workshop is to identify interaction hazards, evaluate risks, and define mitigation measures to ensure safe execution.
The SIMOPS methodology includes the following steps:
The first step is to review all planned activities and identify operations that will occur simultaneously within the same location. This helps define SIMOPS boundaries and overlapping activities.
Typical examples include construction near operating equipment, hot work during plant operation, lifting operations near live systems, and commissioning during ongoing production.
Once simultaneous activities are identified, hazards arising from their interaction are evaluated. These hazards may result from energy sources, equipment movement, or operational interference.
Common hazard categories include:
Both individual activity hazards and interaction hazards are considered.
After identifying activities and hazards, the interaction between activities is evaluated using the SIMOPS Matrix and authorization flowchart. This process determines whether simultaneous operations are allowed, restricted, or prohibited.
Based on this classification:
This step ensures unsafe combinations of activities are prevented.
A detailed risk evaluation is performed using an approved risk matrix to assess the likelihood and consequence of each interaction hazard. Based on this evaluation, risks are classified as high, medium, or low.
High risks are unacceptable and require immediate corrective action. Medium risks are acceptable only with mitigation and must be reduced to ALARP. Low risks are considered acceptable under standard controls.
Existing safeguards such as engineering protections, isolation systems, safety procedures, and permit controls are reviewed to determine their effectiveness. After applying these safeguards, residual risk is evaluated to confirm whether it is within acceptable limits.
If the risk remains high, additional mitigation measures are required.
Additional safety measures may include rescheduling activities, isolating systems, providing physical barriers, or increasing supervision. Clear responsibilities are assigned to ensure all mitigation measures are properly implemented and monitored.
This ensures accountability and effective risk control.
SIMOPS assessment provides critical input to the Permit to Work system by identifying conflicting activities, defining safe work sequences, and establishing isolation requirements.
No high risk simultaneous activity should proceed without SIMOPS review and proper PTW authorization. This integration ensures safe coordination of all work activities.
All SIMOPS findings are documented in structured formats such as worksheets, hazard registers, layout drawings, and mitigation tracking logs. These documents provide a clear record of hazards, risk evaluations, and control measures.
SIMOPS is a dynamic and ongoing process. The assessment must be updated regularly as project conditions change, new activities are introduced, or operational priorities shift. Continuous monitoring ensures all safety measures remain effective during execution.
The objective of SIMOPS is not to prevent simultaneous activities, but to enable them safely through structured planning, hazard identification, risk evaluation, and control implementation.
A properly conducted SIMOPS study ensures safe, efficient, and compliant project execution in operating facilities.
Elixir Engineering provides professional SIMOPS Risk Assessment Services using a structured, workshop-based methodology and practical risk control approach.
We provide:
We support Oil & Gas, Petrochemical, LNG, Power, and Industrial Facilities.
Elixir Engineering provides professional SIMOPS studies to help you identify risks and ensure safe simultaneous operations.
Contact us today to discuss your SIMOPS requirements.
