ETL 1110-3-498
24 Feb 99
means is time dependent. To provide collective protection for a facility that requires continuous
operation either closing of the outside air intakes during the release, or protecting the air intakes
with a CBR filtration system is required.
B-2. Facility Collective Protection Classification.
Existing and new facilities designated to provide collective protection (CP) can be separated into
the three major classes of protection described below.
a. Class I - Filtration with Pressurization. This class of protection is applicable against
wartime military threats that produce a large-scale release of agents over an extended period of
time. Effective protection requires a CBR filtration and overpressure system that resists a
continual large-scale threat in a 40-km/hr (25-mph) wind. The filtration and pressurization system
may be operated continuously or maintained in a standby mode; i.e., energized only when there is a
known threat of attack. An internal or external CCA and an ingress and egress airlock are
required.
b. Class II - Filtration with Little or No Pressurization. This class of protection is
applicable to a terrorist attack with little or no warning that produces a short duration small-scale
release of agent. Outside air intakes will be protected by continuously operating CBR filtration
units. The filtration system will be sized for the normal facility air intake requirements and need
provide little or no facility overpressure. An airlock is not required, but a vestibule that acts as an
airlock is desirable.
c. Class III - Passive Protection. This class of protection is applicable to a short duration
release such as an industrial accident. Protection is achieved by closing building openings and
turning off ventilation systems. The release must be detected and adequate warning must be issued
before protective measures can be applied.
B-3. Guidance.
a. Designation of CBR Protected Facilities. The commander or authority having
jurisdiction determines if facilities are susceptible to a CBR threat and which facilities require
collective protection.
b. Existing Facilities. Existing facilities designated to have a Class I CP overpressure
system will be modified in accordance with Appendix C. Existing facilities designated to have a
Class II CP system with little or no pressurization will be modified in accordance with Appendix D.
Expedient passive protection CP sealing measures for existing Class III facilities will be based on
the recommendations in ERDEC-TR-336.
c. New Facilities. New facilities designated as a Class I CP overpressure system, or required
to incorporate design features that ease future installation of a CP system, will incorporate the
B-2
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