Consider a site where maintenance work is taking place on live equipment while contractors are carrying out hot work nearby and lifting operations are underway in the same area. Each activity may be safe when planned in isolation, but when carried out at the same time, the interaction between them introduces additional hazards. These combined risks are not always obvious, yet they can significantly increase the likelihood of an incident if not properly managed.
This is a typical example of a SIMOP.
SIMOP stands for Simultaneous Operations. It refers to situations where two or more work activities take place at the same time and in the same area, creating the potential for interaction between tasks, people, equipment or energy sources.
Understanding what SIMOPS are and how to manage them is critical in complex operational environments where work cannot simply be sequenced one task at a time. We'll also discuss how a Permit to Work system is key to effectively managing SIMOPS.
Understanding Simultaneous Operations
Simultaneous operations occur when activities overlap in time and space. The risk does not come from the individual tasks alone, but from how those tasks interact with each other.
For example, a lifting operation may introduce suspended loads above another work area. Hot work may introduce ignition sources near flammable substances released by maintenance activities. Vehicle movements may intersect with pedestrian access routes used by contractors.
In SIMOP scenarios, the combined risk is often greater than the sum of the individual risks. This makes SIMOPS a distinct hazard that requires specific consideration and control.
Where SIMOPS Commonly Occur
SIMOPS are common in industries where space is constrained and operational demands are high. This includes offshore installations, construction sites, manufacturing plants, utilities, energy facilities and large infrastructure projects.
They often arise during shutdowns, turnarounds or periods of intense activity, when multiple teams are working to tight schedules. In these environments, it is rarely practical to stop all other work to allow one task to proceed in isolation.
As a result, SIMOPS become a normal part of operations rather than an exception.
Why SIMOPS Increase Risk
The primary reason SIMOPS increase risk is that interactions between activities can create new hazards that are not captured when tasks are assessed individually.
These interactions may involve shared spaces, shared equipment, shared energy sources or competing priorities. Communication breakdowns, unclear responsibilities and changes in conditions can further amplify risk.
Without structured management, SIMOPS can lead to conflicting controls, unsafe assumptions and gaps in supervision.
Identifying SIMOP Scenarios
Identifying SIMOPS requires looking beyond individual task risk assessments. It involves understanding what other work is taking place nearby, who else is affected and how activities might interact.
This includes considering physical proximity, timing, access routes, environmental conditions and shared resources. Effective identification relies on good planning, visibility of work activities and communication between teams.
SIMOPS are often missed when work is planned in isolation or when visibility across activities is limited.
Managing SIMOPS Effectively
Managing SIMOPS does not necessarily mean preventing work from happening at the same time. Instead, it involves understanding the interactions and applying additional controls to manage the combined risk.
Controls may include sequencing certain high-risk activities, establishing exclusion zones, increasing supervision, adjusting permit conditions or introducing additional communication requirements.
In many cases, SIMOPS management requires coordination across teams rather than individual task-level control.
The Role of Permit to Work Systems in SIMOPS
Permit to Work systems play a central role in managing SIMOPS. By providing visibility of active and planned work, PTW systems help identify overlapping activities before they begin.
Permits can be used to highlight potential conflicts, trigger additional controls and ensure that supervisors are aware of what other work is taking place in the same area. When permits are managed centrally, SIMOPS can be assessed proactively rather than reactively.
Without this visibility, SIMOPS are often discovered too late, during execution rather than planning.
Communication and Coordination
Clear communication is essential in SIMOP environments. Everyone involved needs to understand not only their own task, but how it fits into the wider picture.
This includes knowing what other activities are underway, who is responsible for coordination and how changes should be communicated. Regular coordination meetings, clear handovers and defined escalation routes help reduce the risk of misunderstanding.
SIMOPS require shared situational awareness, not just individual competence.
Dynamic Risk and Change Management
SIMOPS are dynamic by nature. Activities start and finish, conditions change and priorities shift. What was safe earlier in the day may no longer be safe later on.
Effective SIMOPS management includes monitoring changes and reassessing risk as work progresses. If new activities are introduced or conditions change significantly, controls may need to be reviewed and updated.
Structured processes for suspending or modifying work are essential to managing this dynamic risk.
Common SIMOPS Pitfalls
SIMOPS often don't get managed effectively due to assumptions that tasks are independent, overreliance on individual risk assessments, or lack of clear ownership for coordination.
Other common issues include poor visibility of work, inadequate communication between teams and pressure to maintain schedules at the expense of safety.
Recognising these pitfalls is the first step towards addressing them.
Summary
Simultaneous operations are a reality in many high-risk environments. They are not inherently unsafe, but they do require deliberate management.
Understanding what SIMOPS are, recognising where they occur and applying structured controls helps organisations reduce risk and maintain safe operations even when multiple activities must take place at the same time.
When SIMOPS are managed proactively, with clear visibility, coordination and accountability; organisations can balance operational demands with effective risk control rather than being forced to choose between them.
