“Technical risk involves SynergenoG employing a wide suite of modelling and risk quantification techniques aimed at identiftying key risk reduction areas and provide client with invaluable insight into potential incidents before they can occur.”
During technical risk assessment, a specialised team visits the client premises and draws up a comprehensive list of all the risks associated with operations to help the clients see potential red flags before an actual incident takes place.
In this respect, SynergenOG has helped numerous customers from all over the world avert unfortunate incidents.
A Fire and Explosion Risk Analysis is to be conducted to identify credible fire scenarios that could result in a major process loss of containment and to determine their impact on personnel and the Main Safety Functions. This analysis mainly consists of two (2) parts: Consequence modelling associated with various process inventories, and frequency assessment.
The consequence modelling will be conducted using DNV Process Hazard Analysis Software Tools (PHAST) V7.11 to evaluate the fire sizes and extent of the associated thermal loads, the extent of flammable gas clouds and explosion overpressures for the respective release scenarios identified. Parallel to the consequence modelling, a detailed frequency assessment will be performed, taking into account the potential sources of leaks associated with the design by utilising historical data from sources such as OGP and UK HSE database.
An Event Tree Analysis (ETA) will then be conducted using in-house customised spreadsheets, which involves SOG’s very own Event Tree generator. A customised Event Tree that reflects the safety barriers incorporated into the process design will be developed and presented to the Project Team to make sure it accurately reflects the safety systems provided and allows evaluation of any design issue that the team may have. The Event Tree will help determine the end event frequencies for various scenarios, taking into consideration the impact of isolation, blowdown, ignition probability, main safety functions and the like. Based on the rendered end event frequencies, a probabilistic analysis involving escalation potential and main safety functions impairment frequencies will be conducted to further assess the design requirements.
Hydrocarbon hazards are typically inherent within the environment where people work, and are also associated with performing specific tasks already recognised as causing a number of the offshore accidents. Non-hydrocarbon risks is normally identified through the HAZID Review and would typically made up of the following:
Refined Hydrocarbons — A hydrocarbon release from the use of marine gas oil or helifuel.
Structural Failure — Failure of the vessel and topsides structures due to fatigue, defective maintenance, design fault or extreme weather, but excluding escalation.
Ship Collision — Collision to any part of the facility by marine vessels, including, passing merchant vessels, visiting offloading vessels and in-field vessels.
Dropped Object — The Dropped Object Assessment assess the vulnerability of the facilities to dropped loads during lifting. Lifting activities pose a potential risk from dropped objects due to mechanical handling equipment failure, lifting of incorrectly secured loads, and/or human error. Dropping an object with sufficient kinetic energy can compromise the integrity of the impacted equipment and have the potential to cause injuries and/or fatalities within the facility. In addition, there is a concern of impacts with equipment from moving loads either through an incorrect lifting path or swinging due to an uncontrolled lifting movement.
The study will address all potential lifts carried out by cranes, which will likely occur on the facility in term of sizes of the load, frequency of occurrence and lifting path, that is over live pipework and other plant equipment.
Transportation — Accidents associated with transport of personnel to/from the facility, including fixed wing and helicopters transfers.
Occupational Accident — Accidents that in most cases do not cause more than a single fatality and has no potential to cause further fatalities outside the immediate area of the incident, for example slips, trips, falls, man overboard, burns, electrocution and other causes.
An Escape, Evacuation and Rescue Analysis (EERA) is to be undertaken to demonstrate the adequacy of the escape, muster areas, means of evacuation and rescue arrangements provided. The EERA will adopt a goal setting approach whereby a series of goals are set which need to be fulfilled to help ensure that personnel can safely leave the facilities in the case of a Major Accident Hazard being realised. The analysis will assess:
• The effects of accidental events on the provision, adequacy and availability of such systems to perform their intended functions on the facilities;
• Determine the required evacuation time considering all activities required to transfer personnel to a place of safety and subsequent rescue;
• Consider personnel ability to be alerted to the incident;
• Assess the ease of escape through sufficient number and diversity of escape routes, provision of a Primary Muster Area (PMA) as well as Secondary or Alternative Muster Area for personnel who are not able to muster in the PMA;
• Examine the availability of evacuation facilities as well as the rescue arrangements for personnel evacuated from the facility.
The EERA will estimate the minimum endurance time required for the safety systems to be available by calculating the time required for personnel to leave their work area, escape to the Muster Area, the situation to be analysed and any personnel involved in the initial event to be rescued and treated and then for all personnel to be able to safely leave the facilities. This will then be used as design criteria for systems related to personnel safety to remain available and functioning. A report detailing the findings and potential improvements in the design and provision of Escape, Evacuation and Rescue (EER) systems will be produced
Assess adequacy of the TR to support escape, muster, evacuation and rescue in the event of a major accident hazard (MAH). The analysis will determine the potential TR impairment mechanism (such as smoke and gas ingress, heat build-up from personnel, depletion of oxygen and build-up of carbon monoxide within the blood stream, fire impingement, and explosion overpressure).
Acoustic Induced Vibration (AIV) due to significant drops in pressure can cause resonant piping vibration and ultimately result in fatigue failures. Customised Acoustic Induced Vibration (AIV) software developed in excel, in accordance to NORSOK Standard ‘L-002 Piping system layout, design and structural analysis’ requirement will be utilised to perform this study The Flow Induced Vibration (FIV) Analysis aims to assess the Likelihood of Failure (LOF) of the process pipework due to vibration caused by flow induced turbulence. The FIV assessment carried out is in line with Energy Institute guidelines. Qualitative assessment is conducted initially to screen the respective process systems and units according to their potential for FIV (based on their individual flow characteristics such as excitation mechanisms, velocity, and the like). Detailed quantitative analysis is then conducted on potential high FIV risk systems identified in the qualitative assessment. LOF for main pipelines is then derived based on the respective pipe diameter, wall thickness, fluid velocity, viscosity and density.
Quantitative Risk Assessment (QRA) is a careful toil to benchmark the risk posed by a particular facility compared to other process facilities. Whilst the QRA risk numbers carry with them a great deal of uncertainty, using a standard approach allows the risks to be benchmarked against other installations, risk ranked using established risk criteria and the key risk drivers established. This final point is critical in allowing safety engineer to focus on analysing the main hazards and evaluating the effectiveness of safety barriers. QRA allows for the comparison of risk reduction options for a particular hazard on an equivalent basis, as well as allowing for the comparison of risks that are generated from separate and unique events (i.e. fire versus explosion events). The personnel impact criteria are defined based on their exposure to various flammability limits, thermal radiation and overpressure levels. Based on the combination of results from Event Tree Analysis and the impact areas for the associated consequence, the risk to personnel is then quantified in terms of the following:
• Location Specific Individual Risk (LSIR) — The risk a hypothetical individual would experience if they were present at a location at all times and indicates the relative risk for a specific area. The LSIR is presented in terms of iso-risk contours on the plant layout
• Individual Risk Per Annum (IRPA) — Indicates the individual risk levels for various worker group based on the manning distribution
• Potential Loss of Life (PLL) — A group risk measure that indicates the maximum number of fatalities in a single accident. The PLL is also expressed as the societal risk and presented in terms of F-N curves. The personnel risk will be assessed using the latest version of RISKCURVES supplied by TNO. RISKCURVES is a fully-featured computer programme to perform QRA. It is capable of plotting iso-risk contours of individual risk, F-N curves of societal or group risk, and the computation of the PLL.
The top risk contributors, with respect to release scenarios, will be determined and appropriate risk reduction measures will be identified as appropriate, to ensure the overall risks of the facility is As Low As Reasonably Practicable (ALARP) in accordance to applicable risk tolerability criteria.
This assessment looks at dispersion of smoke generated by fire events and unignited flammable/ toxic gas due to loss of containment/ leak incidents. Such incident may create a hazardous situation where personnel safety is compromised if exposed to a toxic gas cloud or plumes of smoke obscure their vision. When a gas or vapour is released into the atmosphere, it disperses in the atmosphere. This is a process whereby the original vapour cloud is diluted with the surrounding air as time passes. As wind is defined as the movement of air from one point to another, any vapour released into the air will naturally travel with the wind, that is, it is advected by the wind. These scenarios can be modelled using industrial recognised software (2D or 3D approach) to estimate the extent gas cloud based on its release characteristic, location of release, wind condition and the like.
Noise Study will be undertaken using the Cadna-A Noise Software to evaluate the personnel noise exposure. The assessment will evaluate significant potential airborne noise sources within the facility which are rotating equipment (such as pumps, compressors, generators, coolers) and flare.
The assessment will determine the noise level throughout the whole facility, comprising accommodation and exterior areas (including topsides and machinery spaces) under normal and emergency scenarios, as well as providing recommendation to mitigate the noise hazard. This analysis will provide a noise contour map highlighting noise ‘hotspots’ and aiding in defining facility noise restriction areas and PA/GA system design suitable for the facility. A report detailing this analysis results will be produced.
A Flare and Radiation Study will be conducted to assess the impact of flaring scenario and flame-out scenarios covering emergency and operational flaring. FLARESIM, a specialist software specifically designed to determine the thermal loads associated with a flare system will be utilised to perform the study. The first case considers the maximum flaring rate including depressurisation with the process shutdown and personnel moving to the Muster Area. The second case considers partial topsides shutdown with gas being continually flared with personnel remaining on the topsides for maintenance work. The extent of the thermal radiation under ignited conditions and the flammable cloud dispersion under unignited conditions for both scenarios will be assessed. In the case of emergency flaring it will be to ensure personnel can safely escape from their workplace to the Muster Area and that any gas cloud resulting from flame out will not reach potential ignition sources or manned areas. In the second scenario the thermal radiation will be assessed against conditions to make sure it does not unduly impact on personnel and their ability to undertake normal process and maintenance operations and that any gas resulting from flame out will not reach potential ignition sources or manned areas.