GAIL Vijaipur which has been accredited with ISO-9001:2015, ISO 14001:2015, ISO 45001:2018 and ISO 50001:2018 standards has awarded iFluids Engineering to carry out Quantitative Risk Assessment (QRA) study for Diesel Tank at HVJ Compressor Station of GAIL India Limited, Vijaipur in the state of Madhya Pradesh.
The Main Objective of this study is to evaluate the potential risk levels for personnel due to accidental release of hazardous materials from loss of containment scenarios from the facilities and to demonstrate that individual risks are within the broadly acceptable regions. Given below are the Objectives of QRA:
- Hazards Identification and Events with Major Loss of Containment (LOC)
- Calculation of physical effects of failure case scenarios which include Estimation of Jet Fire, Pool Fire heat radiation distances, Flammable gas dispersion distances, and overpressure explosion distances
- Evaluation of Failure Frequency
- Societal risk quantification and Potential Loss of Life estimation
- Perform a risk assessment to confirm that risk can be reduced consistent with the ALARP principle according to the UK HSE risk acceptance criteria
- Recommend risk reducing measures to ensure that all risks are in ALARP or in Acceptable region.
A diesel tank of capacity 50 KL is placed inside Vijaipur Compressor station for storage of diesel which is used for internal usage. A motor operated pump is installed for unloading of diesel from tanker and transferring it to day tanks of HVJ DEG and VDPL DEG through a dedicated pipe.
Findings from the QRA study are mentioned below
Location Specific Individual Risk
It is the probability of a person in an year becoming a victim to an accident if the person remains permanently and unprotected in a certain location. Moreover Individual risks at different locations of a particular plant varies.
Among the Risk ranking locations considered, all risk ranking vulnerable areas lie in the ACCEPTABLE Region.
Individual Risk for the people
The Individual Risk (IR) gives a measure of the risk that will apply to each location (in this case, each area, generally), independent of the population.
The Individual risk results for the people concerned is the individual contour of 1E-06/Avg.Year, 1E-07/Avg.Year, 1E-08/Avg.Year and 1E-09/Avg.Year extends up to 18.53m, 36.51m, 45.49m, 49.37m in radius from the centre of the Diesel Tank, respectively.
The Individual Risk Per Annum for the People at the risk ranking locations considered for the study lies in the ACCEPTABLE region.
Societal Risk
The Societal Risk gives the relationship between frequency and the number of people suffering from a specific level of harm in a given population from the realization of specific hazards. It is evident that the societal risk for overall population considered for the study falls broadly in the ACCEPTABLE region.
Based on the observations and conclusions few generic recommendations are provided for further safety
- Personnel entering the hazardous area shall be ensured not carrying any ignition sources like Mobile phone, lighter, smoking or inflammable materials etc. at entry gates as per prevailing practices to avoid presence of any unidentified source of ignition.
- Mock drills to be organized at plant level to ensure preparation of the personnel’s working for handling any hazardous situation.
- Ensure early detection of an undesirable event (HC leak, Flame etc.) by deploying suitable detectors and development of subsequent isolation mechanism shall be ensured in the stations.
- Ensure gas detectors are provided within the site in order to facilitate manual gas leak monitoring and regular leakage checks.
- A detailed preventive maintenance plan and “Work Permit” procedures to be followed by maintenance personnel for protection of property from damage and fire etc.
- Ensure arrangements and procedures for periodic proof testing of storage tank overfill prevention systems are in place to minimize the likelihood of any failure that could result in loss of containment. A detailed preventive maintenance plan should be followed.
- Ensure Standard operating procedures are being followed in operation of tank drain, dyke drain and other critical valves with supervisory control and mechanically locking option.
- In case of any leakage, evacuate staffs at the leakage affected area and guide them to a safe place; prevent entry of unnecessary personnel into the affected area; and isolate ignition source. Personnel for emergency treatment should stop leakage in a safe manner