Vehicle impact assessment of critical pipelines is a crucial process to evaluate the potential damage caused by vehicle collisions with pipelines carrying hazardous materials. This assessment helps in identifying and mitigating potential risks to ensure the safety of the pipeline, surrounding environment, and public.
The objective of the vehicle impact assessment of critical pipelines includes,
To assess the vehicle impact on critical pipe lines as major societal risk contributors in the Critical Pipelines and Wellhead Operations QRA.
- To evaluate the design factors and adequacy of existing crash barriers, corrugated barriers, restraint systems, distance between vehicle crash barriers from pipeline etc.
- Identify specific gaps, if any based on the detailed analysis.
- Recommendation of the spacing requirements in the pipeline corridor(s) so as to facilitate hassle free inspection, maintenance, lifting activities and emergency response
- Identify any inadequacies and propose recommendations for remedial action and thus assist in the demonstration of ALARP for a vehicle collision event.
The Assessment of Vehicle impact on critical pipelines shall be done based on the following criteria,
- Technical site survey (A comprehensive check sheet will be used)
- Data Analysis
- Vehicle impact study
- Interact with Drivers/Operators of internal and external.
Based on the outcome of the technical survey and data analysis,
The following shall be developed:
- Develop a Finite Element (FE) based vehicle impact model which analyze
- Collision impact of vehicle(s) with the pipelines on vulnerable locations.
- Dropped impact from vehicle(s) falling off from bridges and culverts onto critical pipelines, wherever applicable.
- Other causal factors that pose risks of vehicle contact or impact, such as vehicles passing over pipelines / legal crossing.
- Spacing requirements in the pipeline corridor(s) so as to facilitate hassle free inspection, maintenance, lifting activities and emergency response.
Relevant Process and Engineering documents shall be collected which is required for
- Identification of critical Pipelines at site
- Type / classes of road
- Type of vehicles (Internal vehicle movements within the site or from external vehicles)
- Vehicle size
- Speed of the vehicle
- Vehicle Movement
- Historical data (Previous failures and incidents)
- Pipeline Details (Size, Thickness, Diameter, type of fluids , Routing)
The selected Pipelines are assessed in vehicle impact Major Accident Hazard assessment. The necessary data required for the assessment are collected through interactive observations, examination of documents, discussions, focused questions and by site survey.
The Vehicle Impact assessment shall be conducted to present and discuss the draft findings for each of the pipelines.
- Risk-based analysis shall be performed for identified impact scenarios incorporating statistical attributes after taking due consideration of the existing safeguards. Detailed analysis shall be done for identified gaps and it will be discussed in vehicle impact assessment.
- The vehicle impact model shall reflect the SITE specific data related to type / classes of road, type of vehicles, vehicle size and speed with which it is plying along the pipeline route, various impact angles, the pipeline wall thickness, diameter and strength of the pipeline to assess its resistance to failure, the energy absorbed by pipeline displacement, fracture mechanics aspects like dent assessment and mechanical damage assessment, method of pipeline support and the spacing between supports, associated impact consequences etc. A comprehensive checklist shall be used to register all the requirements / check points and related inputs.
The ALARP demonstration shall be done for all recommendations from Vehicle Impact Assessment. For recommendation from workshop which does not fall under broadly acceptable region of the risk tolerability criteria or ALARP (As low as reasonably practicable) region will follow below hierarchical approach for the identification of additional risk reduction measures where required as part of the ALARP demonstration.
The ALARP demonstration process shall follow requirements of ALARP Demonstration Standard:
- Eliminate, to physically remove the hazard
- The implementation of substitution strategy involves the replacement of a hazardous substance or process with a less hazardous alternative.
- One approach to mitigating hazards is to implement segregation through distance or isolation.
- Prevention by engineering e.g. process detection, ESD depressurization
- Mitigation by engineering e.g. fire and gas detection, active/passive fire protection
- Prevention/mitigation by organization e.g. manning, training, procedures
- Mitigation by intervention e.g. emergency response, maintenance
- Personal protective equipment.
Hierarchy of control
This Cost-benefit analysis (CBA) demonstration study for identified recommendations for Dukhan facilities, Stations and Operating Units. Here, the cost and benefit of select recommendations from the Vehicle impact assessment shall be enclosed in order to aid decision-makers to execute the recommendation.
The cost elements and boundary conditions for cost-benefit analysis will be mutually agreed depending on the nature of the recommendation, contractual scope and protocol for Cost-Benefit analysis. The proposed cost benefit analysis will be duly submitted in the workshop for discussion and approval. It shall be agreed on a case-to-case basis after discussion.
The Cost Benefit Analysis is performed for all recommendations taken from Vehicle impact assessment, except for the recommendations that meet the below mentioned criteria.
- A fundamental understanding of engineering principles is necessary to determine the bill of materials, which is subsequently utilized to conduct a cost-benefit analysis.
- The implementation of high/low deviation alarms in the current distributed control system (DCS) and modifications to the control logic without the incorporation of supplementary instrumentation are proposed.
- The logical modification of electrostatic discharge (ESD) interlocks can be achieved without the need for any additional instrumentation.
- Designating existing alarm as critical alarm
- The proposed measures include updating the standard operating procedure, incorporating dead zones for corrosion monitoring, and enhancing the frequency of preventive maintenance.
- P&ID and other document corrections
- Studies including alarm audits
- Low-cost recommendations, such as the provision of non-reflective vests and blinds, are suggested.
The Vehicle Impact Assessment Report shall, as a minimum, contain
- Critical pipeline and route details.
- Technical survey results.
- Statistical data pertaining to vehicles analyzed as part of study. Comprehensive checklist shall be used to register all the requirements / check points and related inputs.
- Finite Element (FE) based vehicle impact model or equivalent approach with sufficient rigour which analyze:
- Collision of vehicle(s) with the pipelines on vulnerable locations.
- Dropped impact from vehicle(s) falling off from bridges and culverts onto critical pipelines, wherever applicable.
- All other causal factors having vehicle contact / impact risks e.g. vehicles passing over pipelines / legal crossing.
- Design adequacy of existing crash barriers, corrugated barriers, restraint systems.
- Risk-based analysis of various vehicle impact scenarios
- Detailed gap analysis exercise with respect to spacing requirements in the pipeline corridor(s) and separation / spacing requirements.
- Detailed review of the ASME compliance requirements with regards to existing location class suitability of the pipelines.
- Review of adequacy of administrative control measures for preventing vehicle impact.
- Provide detailed individual CBA and ALARP demonstration studies for all the recommendations coming out of study with suggested execution strategy.
- Perform criticality ranking of all generated actions from a risk-based perspective.
- Include mapping of recommendations against the relevant CCPS PSM elements
CCPS process safety management system
The findings of Vehicle impact assessment study shall be prepared as a detailed draft report for review and approval. Final report shall be submitted upon incorporation of all comments.
Separate meeting shall be conducted for action prioritization, assignment of action party, target date finalization and mapping of actions against CCPS PSM elements. The discussions shall be recorded in the minutes of the workshop, which shall be finalized and signed by all parties.