Current through September 16, 2024
1. The owner or
operator shall identify and analyze at least one alternative release scenario
for each toxic highly hazardous substance that is used in a process and at
least one alternative release scenario to represent all flammable highly
hazardous substances or explosives that are used in processes.
2. The facility may use the R.M.P.
Guidance for Off-Site Consequence Analysis, which is adopted by
reference pursuant to NAC 459.95528, to calculate any of the values required in
this section.
3. For each scenario
required pursuant to subsection 1, the owner or operator shall select a
scenario that:
(a) Is more likely to occur
than the worst-case release scenario developed pursuant to NAC 459.95366;
and
(b) Will reach an endpoint
off-site. If no alternate release scenario will reach an endpoint off-site,
then the owner or operator shall select the alternate release scenario with the
most significant on-site impact.
4. The owner or operator shall consider,
without limitation and where applicable, scenarios in which:
(a) A transfer hose releases because of
splits or sudden uncoupling of the hose;
(b) Process piping releases because of a
failure at a flange, joint, weld, valve and valve seal, drain or
bleed;
(c) A process vessel or pump
releases because of a crack or a failure of a seal, drain, bleed or
plug;
(d) A vessel overfills and
spills, or overpressurizes and vents through a relief valve or rupture disc;
and
(e) A shipping container is
mishandled and thereby breaks or is punctured leading to a spill.
5. The owner or operator:
(a) Shall use the appropriate parameters set
forth in NAC 459.95364 to determine the distance to the endpoints;
(b) May use:
(1) The methodology provided in the
R.M.P. Guidance for Off-Site Consequence Analysis, which is
adopted by reference pursuant to NAC 459.95528; or
(2) A commercially or publicly available
technique for air dispersion modeling, if the technique accounts for the
specified modeling conditions and is recognized in the industry as a current
practice; and
(c) May
use a proprietary model that accounts for the modeling conditions if the owner
or operator allows the Division access to the model and describes to local
emergency planners, upon request, the features of the model and any differences
from publicly available models.
6. The owner or operator may consider active
and passive mitigation systems for an alternative release scenario if the
mitigation systems are capable of withstanding the event that triggered the
release and still function as intended.
7. When selecting the alternative release
scenarios, the owner or operator shall consider, without limitation:
(a) Any accidental release and any incident
that was investigated pursuant to NAC 459.95429; and
(b) The analyses performed pursuant to NAC
459.95414.
Added to NAC by Environmental
Comm'n by R121-98, eff. 5-27-99; A by R137-04,
2-15-2005
NRS
459.3818,
459.3833
