THE UK Health & Safety Laboratory conducted research HSL0609 into ‘Unidentified Ignition Sources of Unplanned Flammable Releases‘ and found that ” … following investigations into major accidents that had a release and an ignition, about 60% of those incidents did not have an ignition source identified by the investigation” – so if you don’t know what caused it, how can you prevent it from happening (again) ?
BS EN 1127-1 “Explosive atmospheres – explosion prevention and protection. Basic concepts and methodology” lists 13 possible sources of ignition – many familiar, some less common (but credible).
We’ve visualised these sources on our Ignition Sources cards to help increase the awareness of all stakeholders (inc Employees, Contractors, Suppliers & Visitors):
Cards can be attached to Hot Work Permits to remind personnel of the potential ignition sources they may encounter while carrying out the identified & assessed work. They can also be used to tag/label locations where known ignition sources exist.
Regulations associated with flammable/explosive atmospheres (gases, mists, or dusts) require risk assessments to be conducted and regularly reviewed – particularly if there is a reason to suspect that the risk assessment is no longer valid or there has been a significant change.
Like many analyses (PHA, DHA, LOPA, FMEA etc) these risk assessments are often carried out by consultants/contractors and may be done for, rather than with, frontline personnel. Conventional worksheet or tabular outputs may lie dormant until the next scheduled review, a major change, or an incident. These may be difficult to operationalise and have limited potential for ongoing assurance of the control of flammable atmospheres and ignition sources.
Bowties offer a clear, consistent, concise representation of the uncontrolled ignition of flammable atmospheres by a competent ignitor (i.e. one with sufficient energy) and the associated effects on people & assets.
VESTA (Visualising Explosive atmosphere Scenarios & Tracking barrier Assurance) – named after the Roman Goddess of the hearth (fireplace) – is the application of CGE Risk BowTieXP to evaluate & communicate primary ignition threats and their potential consequences – which may include secondary ignition (represented by bowtie chaining & relationship diagrams) of flammable atmospheres in connected systems.
For more information on VESTA, please contact us.
The potential harm and asset damage from a dust explosion have been known for many centuries. A wide variety of materials that can be explosive in dust form exist in many industries, however knowing about an issue is not the same as properly understanding and adequately addressing the challenges.
Michelle Murphy (Mica) & David Hatch (Process Safety Integrity) & draw on their complementary experience in Dust Hazard Analysis (DHA) application 1 and BowTie implementation 2 to present a novel approach to scenario visualisation and asset management using bowties.
Just as a conventional HAZOP or Process Hazard Analysis (PHA) subdivides the process into nodes, the DHA breaks the plant into sections which are systematically challenged to determine if explosion or fire hazards exist. For dusts, this includes identification of competent ignition threats. Subsequent evaluation is conducted to determine which are prevented and/or mitigated by safeguards specific to each threat and consequence.
Risks are assigned and actions issued as per a normal hazard analysis, however the graphical presentation of the ignition scenarios and safeguards and the illustration of potential ignited particles which can travel and ignite within downstream equipment offers significant communication benefits.
This can be particularly helpful in facilities or countries where English and/or Risk are not the primary language or familiar terminology. This paper will show how BowTies are an effective tool to engage less technical stakeholders and offer a robust framework to assure the health (presence and performance) of the assumed or planned human and hardware controls which must be sustained to provide the necessary risk reduction.
In summary, this novel approach evolves analysis into an operational framework to ensure that the ignition risks are better understood, and the controls are properly implemented, operated and maintained.
Click on the icons below to download the papers/presentations:
We believe this approach is equally applicable to Explosive Gas Atmospheres (e.g. EN 60079-10-1) as well as Combustible Dust Atmospheres (e.g. EN 60079-10-2).
For more information on Visual DHA, please contact us.