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Control of Industrial Major Accident Hazards (CIMAH) Report Page 13
Ranhill SAJ Sdn. Bhd. Revision 01
Part D: Information on the Potential Major Accident Date Aug 2019

Kampung Tengah 2 Water Treatment Plant

In this study, four (4) incident scenarios were modelled and considered to be the
event that result in loss of containment of Chlorine to the surrounding environment
leading to major accident hazard / event. Scenarios modelled as follows:

• Scenario 1: Chlorine Drum Catastrophic Failure / Rupture (Scrubber
Failure)
Instantaneous release of Chlorine to the surrounding inside the Chlorine
Room with assumption made that chlorine scrubber system is failed where it
is unable to scrub and contain the chlorine gas inside the building effectively
before releasing to the atmosphere through scrubber stack at 7.5 meter-high
above ground at 1.05 atm. In this study, chlorine scrubber system is working
effectively 80% of the time as a conservative estimation (Chlorine Institute
USA historical data is around 80% effective at any point of time).

• Scenario 2: Chlorine Drum Catastrophic Failure / Rupture (Door Opened)
Instantaneous release of Chlorine during changeover activities where the
Chlorine Room door is opened. Changeover activities are carried out every
week and estimated last for 2 hours as a conservative estimation. Therefore,
the chance of the Chlorine Room door being opened to allow the Chlorine gas
dispersion is 1.19% probability (2 hours a day and 7 days a week per year).

• Scenario 3: Chlorine Drum 50mm Hole Diameter Leak (Door Opened)
Leak on the Chlorine drum shell with 50mm hole diameter during changeover
activities where the Chlorine Room door is opened. Changeover activities
carried out every week and estimated last for 2 hours as a conservative
estimation. Therefore, the chance of the Chlorine Room door being open to
allow the Chlorine gas dispersion is 1.19% probability (2 hours a day and 7
days a week per year).

• Scenario 4: Chlorine Drum 10mm Hole Diameter Leak (Door Opened)
Leak on the Chlorine drum shell with 10mm hole diameter during changeover
activities where the Chlorine Room door is opened. Changeover activities
carried out every week and estimated last for 2 hours as a conservative
estimation. Therefore, the chance of the Chlorine Room door being open to
allow the Chlorine gas dispersion is 1.19% probability (2 hours a day and 7
days a week per year).