Draft EPA Firewater Retention Guidance Published March 2018 – What Does it Mean for Your Site?
The revised Firewater Retention Guidelines from the Environmental Protection Agency (Agency) were made available in draft format in March 2018.
The release of these new draft guidelines may not mean that you will be required to install firewater retention or upgrade your existing firewater retention. However there are some key changes that may need consideration when determining your required course of action:
a) The qualifying criteria for firewater retention have changed slightly – the revised criteria are:
1. Environmentally hazardous substance storage thresholds
Substance storage thresholds are now based on hazard statements instead of risk phases.
2. Environmental receptor criteria
Whilst consideration of environmental receptors has always been required in firewater retention risk assessments, this is now an explicitly stated qualifying criteria.
b) The new risk assessment outlined in the Draft Guidelines is focused on consequence rather than likelihood.
The risk assessment is used to determine whether firewater retention is required for a facility that does not necessarily fall within the two qualifying criteria noted above. Whilst the previous Agency guidance required an assessment of the likelihood of the fire incident versus the environmental impact of the contamination, the new Draft Guidance requires a consideration of the significance of the fire event (S) versus the environmental hazard potential (H). A prescriptive risk assessment formula is set out in the new Guidance.
c) There have been changes to the way firewater retention capacity is calculated. The main changes of note include:
1. Changes to the methods for calculating the firewater from each different site area or 'type' of area including a new FWRA tool (excel spreadsheet) that is required to be completed.
2. A change in the rainfall contribution (from a 1 in 20-year rainfall event to a 1 in 10-year rainfall event).
d) The types of containment that may be used for holding contaminated firewater have changed slightly.
The most significant change is the inclusion of a restriction on the use of bunds. Bunds cannot be used to provide firewater retention unless the contents of the bunds are directly involved in the fire event.
It is recommended that you complete a risk assessment for your facility in accordance with the new guidance in order to assess whether any changes will be required for your facility.
Please contact one of our risk assessment specialists if you require any further information or assistance.