Key takeaways
- A BowTie shows one hazard and top event, the threats that can cause it, the consequences that can follow, and the barriers on each side.
- CCPS and the Energy Institute set the rule that a barrier must be effective, independent and auditable.
- A diagram shows which barriers exist; barrier management shows whether they are working today, using maintenance, inspection and operations data.
- When choosing software, check the barrier library, live barrier status, links to incident investigations, permissions, Arabic support and on-premise hosting.
What a BowTie is
A BowTie diagram puts one top event, such as a loss of containment, at the center. Threats that could cause it sit on the left, with preventive barriers between each threat and the top event. Consequences sit on the right, with mitigative barriers between the top event and each consequence. Escalation factors that could weaken a barrier, and the controls that manage them, hang below.
Bow ties first appeared in ICI literature in the 1980s and spread widely through Shell in the 1990s. In 2018 the Center for Chemical Process Safety (CCPS) and the Energy Institute published Bow Ties in Risk Management, a concept book that standardized the terms and rules.
What makes a barrier valid
Under the CCPS and Energy Institute rules, a barrier must be:
- Effective: able on its own to stop the threat from reaching the top event, or to stop or significantly reduce a consequence.
- Independent: free of failure modes shared with the threat or with other barriers on the same path.
- Auditable: there is a way to check that it works on demand.
Measures that do not meet all three, such as training or supervision, are degradation controls. They keep a barrier working, but they are not barriers themselves. Mixing the two is the most common BowTie error.
From diagrams to barrier management
A BowTie on a slide shows which barriers should exist. Barrier management asks whether they are working right now. That means connecting each barrier to the data that shows its condition:
- Overdue inspections, tests and maintenance on safety-critical equipment.
- Bypasses, inhibits and overrides on safety systems.
- Open deviations and temporary operating changes.
- Findings from audits and incident investigations.
When a barrier degrades, the site can run an operational risk assessment, add temporary measures and escalate before the gap leads to an incident.
What to look for in BowTie software
| Capability | Why it matters |
|---|---|
| Diagram builder with templates | Consistent BowTies across sites, built faster in workshops. |
| Shared barrier library | The same barrier is defined once and reused, with one owner. |
| Barrier rules and ratings | Checks against effective, independent and auditable, with effectiveness ratings. |
| Live barrier status | Barrier health from maintenance, inspection and operations systems, not from memory. |
| Operational risk assessment | A structured way to decide what to do when a barrier is impaired. |
| Links to incident investigations | Root causes found in investigations update the barriers they point to. |
| Dashboards and reports | Barrier health by site, unit and hazard for managers and regulators. |
| Permissions, approvals and audit trail | Controlled changes to safety-critical information. |
| Arabic and English | Front-line teams work in their own language. |
| On-premise or private cloud | Operational risk data stays inside your network. |
The software landscape
Established BowTie tools include BowTieXP from CGE Risk and THESIS from ABS Group, which focus on building and analysing diagrams. Some organizations pair a diagram tool with separate systems for maintenance and investigations. Others choose a platform that keeps diagrams, live barrier status and investigations together. The right choice depends on whether you mainly need diagrams for studies, or a view of barrier health that operations teams use every day.
How to get started
Start with major accident hazards
Pick the few top events that matter most at each site.
Build BowTies in workshops
Bring operations, maintenance and process safety together, and apply the barrier rules strictly.
Name owners and performance standards
Give each barrier an owner and a measurable standard.
Connect the data
Link barriers to maintenance, inspection and operations systems so their status updates itself.
Review regularly
Review barrier health at a set cadence, and after every significant incident.
Where Basira fits
Basira (بصيرة) is Birbal AI’s process safety platform. Basira Barrier builds BowTies, keeps a shared barrier library and shows live barrier status with operational risk assessments. Basira RCA handles investigations, so findings flow back to the barriers they affect. It runs in Arabic and English, on your own servers or in a private cloud.
Questions and answers
What is a BowTie diagram?
A diagram that shows a hazard and its top event at the center, the threats that can cause it on the left, the consequences on the right, and the barriers that prevent or mitigate each path.
What is the difference between preventive and mitigative barriers?
Preventive barriers sit between threats and the top event and stop it from happening. Mitigative barriers sit between the top event and its consequences and limit the harm once it has happened.
What makes a barrier valid?
Under the CCPS and Energy Institute rules, a barrier must be effective, independent and auditable. Measures that fail these tests are degradation controls, not barriers.
What is barrier management?
The ongoing work of keeping barriers effective: tracking their condition with maintenance, inspection and operations data, and acting when one degrades.
Can BowTie software show live barrier status?
Yes, when it is connected to maintenance, inspection and operations systems. Basira Barrier does this.
Is there BowTie software in Arabic?
Yes. Basira runs in Arabic and English.
Sources
- IChemE Hazards 28: Bow Ties in Risk Management, using the CCPS-EI book (2018)
- IChemE Hazards 27: background to bow ties and the CCPS/EI book (2017)
- US OSHA: Process Safety Management
Birbal AI is an independent company based in Abu Dhabi. Facts about third parties come from the sources above; check them for the latest position.