Biomedical Engineering Reference
In-Depth Information
Small spills
Large spills
ID
Name
Isolate
Protect
Isolate
Protect
Day
Night
Day
Night
0.5 mi
1.9 mi
200 ft
0.2 mi
0.5 mi
600 ft
1017 Chlorine
Figure 8.1
Isolation and protection distances.
3. On a map of the incident area, draw (to scale)
a circle with the radius of the initial
isolate
distance, with its center at the center of the
incident site. Mark which way the wind is
blowing at the site. Then, through the center of
this circle, place the upwind edge of a square
box which is the
protect
distance on each side.
This edge is perpendicular to the wind direc-
tion. For practical purposes, you have defined
the potential hazard area. The toxic plume
should pass somewhere within this area. If you
know the approximate wind speed, you can
also have an idea of where the leading edge
of the cloud might be wind speed
Zone), the next is the Warm Zone (or Yellow Zone)
and last is the Cold Zone (or Green Zone).
The significance of the zones is as follows:
The
Hot Zone
(also called the exclusion zone or
inner zone, or red zone) is the area that the inci-
dent occurred in and that contamination exists in.
All individuals entering the hot zone must wear
the appropriate levels of personal protective equip-
ment (PPE) and be decontaminated before leaving.
Entry and exit points will be established at the
outer boundary of the hot zone to regulate the entry
and exit of personnel and equipment into and out
of the hot zone. The outer boundary of the hot
zone is initially established by visually surveying
the immediate area and determining where the
hazardous materials involved are located. Moni-
toring equipment may also be used to define this
area. The North American Emergency Response
Guidebook (NAERG) is also useful in establishing
this area, using the isolate and protect guides in
the green pages.
The
Warm Zone
(also called the contamination
reduction zone, or yellow zone, or middle zone) is
the transitional are between the hot zone and the
cold zone. This zone usually contains the decon-
tamination area and access control points through
which personnel enter and exit the hot zone. This
zone is less dangerous than the hot zone and
personnel can wear lower levels of PPE than those
in the hot zone.
The
Cold Zone
is the outermost part of the
scene and is considered to be not contaminated.
This is where the command post is located along
with support equipment, including ambulances
and EMS providers. Normal work clothes are
×
time
=
distance (Figure 8.2).
Once the area of the perimeter is established,
EMS providers can assist with the formation of
zones. There are three zones for WMD scene
management. The first is the Hot Zone (or Red
Draw circle with radius of
isolation distance
r
Mark the wind direction
Draw a box size of protect
distance, place upwind edge
over center of circle, towards
downwind
r
Figure 8.2
Isolation and protection zones.
