Report - Agence canadienne d'évaluation environnementale

Assessing the risks related to the project
to protect the public, and consequently, emergency measures (DA63; Mr. Glenn Kelly,
DT8, p. 36). In his opinion, this is justified by the longer stability of a steady-state spill
pool fire, which would result in the longer exposure of the neighbouring public. In this
respect, the MDDEP informed the Panel that the proponent’s description of the pool fire
phenomenon was satisfactory:
Considering the very short time span of an LNG initial spill pool and the conditions
required for it to be created, the steady-state pool appears to be a more adequate
choice than the initial spill pool to assess the consequences and risks associated
with a pool fire over water, using the 5-kW/m 2 threshold.
(Ms. Marie-Claude Théberge, DB96)
The CERL also found that the approach used by the proponent was acceptable in
establishing the consequence distances for a 5-kW/m 2 thermal radiation limit on the
basis of a steady-state spill pool, given its longer duration and the potentially greater
exposure that would ensue for the population. It also mentioned that the proponent
took into account both types of spill pools to assess the individual risk isocontours.
However, for a 12.5-kW/m 2 thermal radiation level, the Laboratory believed that the
initial spill pool should be taken into account to assess the consequences of
potentially exposing the population for a short duration (DQ87.1).
The Sandia Laboratory report has also used reference values to analyze risks
associated with LNG facilities. In this respect, the Panel is of the view that the
conditions and values used by Sandia in order to assess the distances associated
with various levels of thermal radiation emitted from a pool fire correspond to a
steady-state pool (Sandia National Laboratories, 2004, p. 143).
♦ Finding — The Panel takes note of the fact that the Canadian Explosives Research
Laboratory of Natural Resources Canada, and the ministère du Développement
durable, de l’Environnement et des Parcs deemed acceptable the approach followed
in regard to the dimension of the liquefied natural gas pool, and used to assess the
consequences arising from accident scenarios with LNG tankers. It also note that the
method used is similar to the one used by Sandia National Laboratories.
The Panel will also consider the distances used by the proponent for a steady-state
spill pool in order to assess the population’s potential exposure to the consequences
of a pool fire, because of the short duration of the initial spill pool and considering the
time required for the possible intervention of emergency services.
The effect thresholds associated with thermal radiation
During a fire, the intensity of the thermal radiation emitted diminishes in proportion to
the distance with the fire source, and individuals exposed to such radiation are
126 Rabaska Project – Implementation of an LNG Terminal and Related Infrastructure