Report - Agence canadienne d'évaluation environnementale

The accident scenarios considered and their consequences
Assessing the risks related to the project
Among the main aspects which governed the route’s development, the proponent
mentioned the intention to avoid as much as possible the high-density population
areas. He detailed the consequences of three possible pipeline accident scenarios,
i.e. the complete rupture of the buried line, a medium leak in the buried line, and the
complete rupture of a line aboveground. Table 11 and Figure 11 detail these
outcomes. Considering the population’s density in certain places along the pipeline’s
retained route, the Panel included the potential consequences associated with
thermal radiation thresholds that are greater than 5 kW/m 2 in its analysis.
Table 11 Consequences of the pipeline’s three accident scenarios
Accident
scenarios
Complete
rupture of the
buried line
Medium leak
of the buried
line
Complete
rupture of a
line
aboveground
Distance to
the 5-kW/m 2
thermal
radiation
threshold
Distance to the 12.5kW/m
2 thermal
radiation threshold
Distance to the
37.5 1 -kW/m 2
thermal radiation
threshold
730 m 522 m 356 m
22 m 11 m A few metres
510 m 430 m 367 m
Distance to the
lower
flammability
limit
141 m
(127 m
aboveground)
8 m
(3 m
aboveground)
353 m
(30 m
aboveground)
1. Threshold value for structural damage to buildings and equipment caused by thermal radiation exposure and
used as a criterion to locate them.
Sources: adapted from PR5.3.2, p. 7 and Appendix H, p. 39 and 40.
The sensitive elements of the host environment
According to the proposed route, several sensitive elements could be inside various
impact areas corresponding to thermal radiation thresholds of 37.5, 12.5 and
5 kW/m 2 , depending on their position with respect to various project pipeline
segments. Table 12 summarizes them.
In light of the summary of sensitive elements identified, the Panel noted the presence
of a campground that could be located in the 5-kW/m 2 impact area should the pipeline
rupture. In answer to a question from the Panel, the proponent also provided an
analysis of sensitive elements in the 1.6-kW/m 2 thermal radiation impact area, which
represents a 1,070-m radius from both sides of the proposed pipeline’s right-of-way.
Rabaska Project – Implementation of an LNG Terminal and Related Infrastructure 155