off-site chlorine risk assessment from shum shui kwok dock to
TRANSCRIPT
Appendix 12.11
Off-site Chlorine Risk
Assessment from Shum
Shui Kwok Dock to
STWTW
ERM-HONG KONG, LTD WSD
A12.11-1
A12.11-1 INTRODUCTION
This Appendix provides supplementary information to Section 12.25 of the
Main Report. The total risk associated with transport of chlorine from Shum
Shui Dock to STWTW has been assessed as a reference and the results are
compared to the Hong Kong Risk Guidelines (HKRG), which applies to fixed
installation in general. The assessment methodology and assumptions are
provided in the Main Report and will not be repeated in this Appendix.
A12.11-1.1 OFF-SITE TRANSPORT RISK RESULTS FOR CHLORINE DELIVERY FROM SHUM SHUI
KWOK DOCK TO STWTW
FN curves for off-site chlorine transport risk during the Construction and
Operational Phases of are shown in Figure 1.1. The off-site chlorine transport
risk is higher during the Operational Phase compared to that during the
Construction Phase. It is mainly due to the higher chlorine delivery quantities
(761 tonnes versus 642 tonnes). The FN curves are in the upper ALARP region.
The fatalities at frequency of 10-9 per year are about 900 for both Construction
and Operational Phases. This is lower than the 1000 fatality criterion as per
HKRG.
It should be noted that transport societal risk is generally presented as per one
kilometre. Summation of societal risk along the route could result in over-
estimation of risk. Nevertheless, the current risk level remains within the
ALARP region.
ERM-HONG KONG, LTD WSD
A12.11-2
Figure 1.1 FN Curves for Off-site Chlorine Transport from SSK Dock to STWTW
ERM-HONG KONG, LTD WSD
A12.11-3
The individual risk (IR) from SSK Dock to STWTW is shown in Figure 1.2.
Only the Operational Phase IR is shown as this is the worst case due to higher
quantity of chlorine delivery. As can be seen, the individual risk levels are
well below the Hong Kong Risk Guidelines criterion of 10-5 per year. The IR
spreads along both sides of the routes and reduces rapidly to below the 10-7
per year.
Figure 1.2 Individual Risk for Off-site Chlorine Transport from SSK Dock to STWTW
10-7
per year