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CDOIF
Chemical and Downstream Oil
Industries Forum
CDOIF is a collaborative venture formed to agree strategic areas for
joint industry / trade union / regulator action aimed at delivering
health, safety and environmental improvements with cross-sector
benefits.
In each of the examples below, the first step is to identify the credible scenarios that
could cause a MATTE to the receptor being assessed (note that this could be credible
scenarios from a single tank, multiple tank or facility based on the grouping of
substances and compartmentalisation).
Once the credible scenarios have been identified, these should then each be categorised
using the MATTE tolerability matrix (refer to Appendix 4) to give a consequence level of
either A, B, C or D - this in turn provides the frequency per receptor per establishment
per year and thus the thresholds for broadly acceptable and intolerable.
When aggregating the risk to a receptor from all credible scenarios, the following text can
be used as a guide:
Tolerability of risk to the receptor, from the establishment as a whole, will depend on the
aggregate predicted frequency of all independent accident scenarios which could impact
a given receptor at or above the respective consequence level. Thus to confirm
tolerability at level D then all independent level D predicted incident frequencies should
be aggregated. To confirm tolerability at level A, all independent level A, B, C and D
predicted incident frequencies should be aggregated.
Refer also to section 6.2.1.5 on interdependent scenarios.
Guideline – Environmental Risk Tolerability for COMAH Establishments v1.0
Page 35 of 88