Loss of Containment

Memorable images representing typical LoC events are employed to improve the awareness of a broad range of personnel to potential Loss of (Primary) Containment (LoC) scenarios and increase their vigilance to such events & their potential causes so they can be promptly addressed.

Users or ‘Players’ are encouraged & helped to learn & apply the principles using this simple mnemonic:

  • REMEMBER Events
  • RECOGNISE Threats
  • RESPECT Barriers
  • REPORT Concerns

Thereafter, there is an obligation on the duty-holder to:

  • RESPOND to Feedback
  • RECOVER Protection

Visualization is used to get and keep the workforce onboard with the process safety mission by challenging them with these simple questions:

  1. Do you UNDERSTAND what can wrong i.e. HAZARDS & LoC Events?
  2. Do you KNOW what the systems are to prevent this from happening i.e. BARRIERS?

Cards

A pack of cards has 52 scenarios which are divided into the following LoC ‘suits’:

♥ DISCHARGE
♣ DAMAGE
♦ DEVIATION
♠ DEGRADATION

Open route to atmosphere
External impact
Failure beyond design conditions/envelope (over-stress)
Failure within design conditions/envelope (under-strength)

These provide simple visual prompts to remind or inform “players” of the potential for LoC:

Although the cards are designed to be intuitive, they are annotated with LoC Event types which can be supplied in different languages or alternative terminologies.

Scenarios

Scenario summaries are presented as separate pages with one LoC on each sheet. They include typical (suggested) Causes for the loss and visual representations of the scenarios in bowtie format, for example:

Visualisation aims to help ‘Players’ recognise Threats and respect Barriers e.g. ensure their actions or inactions do not disable, degrade or delete prevention measures associated with each LoC event.

Risks

The relative risk for each scenario is derived from the Threat & Release potentials.

Release Potential

To help inform plant/field & 3rd party personnel (who typically do not have access to failure databases) on the relative likelihood of the LoC occurring, a scale based on the anticipated occurrence is suggested using the following simple ranking system in descending order of frequency i.e. most likely at top of list:

◙ Human Factors
◙ Control Malfunction
◙ Equipment Failure
◙ Environmental or External Influences

In addition, the potential is influence by relative frequency of each LoC scenario is based on the occurrences of incidents investigated by the US Chemical Safety Board (CSB).

The UK HSE conducted analysis (HSL/2003/07) into Loss of Containment incidents which is summarised as follows:

Specific cause contributions are broken down as follows:

Likelihoods are subjective and must be taken as indicative only. Each user (site or company) should provide context to their own operations with respect to, for example, maintenance strategies, competence etc

Potential Release

Similarly, the relative scale of release (based on the anticipated opening or breach e.g. cracks vs. guillotine) resulting from a LoC is summarised using a 3-tier system.

The relative release (impact) of each LoC scenario is based on the onsite & offsite fatalities & injuries resulting from the event investigated by the CSB.

 Releases are subjective and must be taken as indicative only. Each user (site or company) should provide context to their own operations with respect to, for example, material properties, operating conditions etc.

The relative risk for each scenario is derived from the following matrix based on the potential for or likelihood of release (Release Potential) and the scale of release (Potential Release):


Details of scenario components are provided on the Bowties page.

Suggested uses are provided on the Ideas page.

We invite Users to share their experiences with the Cards & Summaries so that others may be inspired to use these tools in novel & productive ways – this is available on the Feedback page.

For more information on LoC cards, options & pricing, please contact us.