August
1,
2003
1
Attachment
3
Occupational
Exposure
Assessment
for
HFE­
7000
1.
Introduction/
Exposure
Setting
HFE­
7000,
a
refrigerant
used
as
an
alternative
to
ozone
depleting
substance
(
ODS)
HCFC­
123,
can
also
function
as
an
aerosol
solvent
cleanser.
However,
in
animal
studies,
HFE­
7000
has
been
shown
to
exhibit
toxicity
following
inhalation
exposure.
For
example,
inhalation
exposure
to
10,000
ppm
and
higher
for
approximately
30
days
in
rats
resulted
in
decreased
body
weights,
changes
in
clinical
chemistry,
changes
in
liver
weights,
and
increased
urinary
fluoride.
While
some
of
these
effects
may
be
related
to
specific
responses
of
the
rat
that
are
not
applicable
to
humans
(
e.
g.,
peroxisomal
proliferation),
other
effects
may
not
be
species­
specific
and
are
relevant
to
human
health.
While
HFE­
7000
can
also
be
used
in
fuel
cells
as
well
as
electronics
and
semiconductor
applications,
this
document
attempts
to
provide
a
brief
assessment
of
exposures
in
only
the
aerosol
solvent
end
use.

In
order
to
assess
exposures
for
the
aerosol
solvent
end
use,
several
scenarios
have
been
developed.
For
example,
HFE­
7000
could
be
used
in
a
well­
ventilated
factory
as
the
cleaner
for
a
product
such
as
a
Printed
Circuit
(
PC)
board.
Most
likely,
the
aerosol
would
be
used
in
an
open,
ventilated
room
along
an
assembly
line.
However,
under
more
controlled
circumstances,
the
chemical
could
be
sprayed
in
a
hood.
In
an
assembly
setting,
a
worker
would
spray
HFE­
7000
in
short
bursts
over
an
8­
hour
workday.

Alternatively,
HFE­
7000
could
be
used
in
a
poorly
ventilated
mechanic's
shop
with
or
without
a
large,
open
garage
door.
The
mechanic
worker
would
be
working
in
a
small
area
and
spraying
HFE­
7000
only
periodically.

Exposure
levels
depend
on
multiple
factors
including
the
ventilation
in
the
room,
the
size
of
the
room,
the
amount
of
HFE­
7000
being
used,
and
the
proximity
of
the
spray
gun
to
the
user.
Aerosol
mist
from
spraying
would
be
present
in
the
work
area
throughout
the
production
process.
Since
workers
would
frequently
spray
the
chemical
over
an
8­
hour
workday,
this
assessment
focuses
on
the
long­
term
term
occupational
exposure
to
HFE­
7000
as
a
result
of
inhalation.
Potential
impacts
from
higher
exposure
levels,
such
as
those
that
could
occur
from
an
accident
or
spill,
are
not
assessed
in
this
study.

Section
2
discusses
the
source
of
the
monitoring
data
and
the
approach
used
to
effectively
model
exposure
scenarios;
Section
3
presents
the
results
of
the
analysis;
and
Section
4
lists
references
used
to
create
this
analysis.

2.
Approach
The
approach
for
assessing
occupational
exposure
to
HFE­
7000
was
to
model
the
use
of
an
aerosol
solvent.
The
model
was
based
upon
spray
tests
performed
by
aerosol
solvent
August
1,
2003
2
manufacturing
companies.
In
this
section
the
monitoring
data
reported
by
the
aerosol
solvent
manufacturing
companies,
as
well
as
the
assumptions
and
application
scenarios
used
to
create
the
exposure
model
are
described.

Monitoring
Data:

Simulations
of
an
industrial
environment
in
which
an
aerosol
solvent
would
be
sprayed
are
sometimes
performed
by
facilities
to
test
if,
and
to
what
extent,
a
worker
is
exposed.
It
is
important
to
note,
however,
that
the
data
reflect
the
workplace
conditions
in
which
the
simulations
occur
and
are
not
representative
of
conditions
at
all
facilities.
Such
simulations
have
been
performed
by
3M
 
in
which
exposure
concentrations
of
HFE­
7100
and
7200
sprayed
in
a
factory
setting
were
measured.
Similar
simulations
have
also
been
performed
by
DuPont
Fluoroproducts.
The
testing
conditions
presented
in
these
two
reports
were
used
to
determine
the
parameters
for
the
HFE­
7000
model
(
3M
 
1997
and
DuPont
Fluoroproducts
2002).

Testing
was
done
in
a
room
with
the
dimensions
24
x
24
x
10
feet.
The
aerosol
was
sprayed
on
a
circuit
board
12­
18
inches
from
the
spray
tip
at
a
rate
of
15­
second
discharges
per
minute
for
10
minutes.
3M
 
reports
that
greatest
rate
of
use
by
an
industry
is
approximately
1
lb
per
day
(
454
g/
day)
and
that
[
]
percent
of
their
aerosol
solvent
formulations
consist
of
propellant.
(
3M
 
1997).

DuPont
Fluoroproducts
tested
aerosol­
cleaning
agents
in
a
room
with
the
dimensions
14
x
14
x
8
feet.
The
aerosol
was
sprayed
at
a
rate
of
5­
second
sprays
every
10
minutes
(
equivalent
to
spraying
three
12­
oz
cans
over
an
8­
hour
workday)
(
DuPont
Fluoroproducts
2002).

Using
these
reports
to
create
three
occupational
exposure
scenarios,
this
assessment
provided
here
models
the
use
of
HFE­
7000
in
both
a
factory
assembly
line
and
a
small
mechanic's
shop.
Listed
below
are
the
assumptions
and
application
scenarios
used
to
model
the
use
of
HFE­
7000.

Assumptions:

°
The
highest
industrial
usage
of
HFE
is
454
g/
day
(
3M
 
1997);
°
The
area
of
exposure
is
18
inches
in
equidistant
directions
(
3
x
3
sq
feet);
°
The
minimum
face
velocity
recommended
for
a
small
bench
top
application
was
used:
150
ft/
min,
which
over
9
square
feet,
is
equivalent
to
1350
ft3/
min
or
0.64
m3/
sec
(
ACGIH
1982);
°
No
ventilation
is
present:
50
ft/
min1
over
9
square
feet
is
equivalent
to
450
ft3/
min
or
0.21
m3/
sec
(
U.
S.
EPA
1994);
and
°
Aerosol
spray
formula
consists
of
[
]
percent
HFE­
7000
and
[
]
percent
propellant
(
3M
 
1997).

Application
Scenarios:

Each
of
the
following
exposure
scenarios
was
modeled
for
both
average
and
poor
ventilation.
Exposure
concentrations
for
each
scenario
are
presented
in
Tables
1
and
2.

1
Local
air
currents
is
defined
as
50
ft/
minute.
August
1,
2003
3
Scenario
1
 
This
scenario
represents
the
use
of
HFE­
7000
on
a
factory
assembly
line
sprayed
in
short
bursts
for
an
8­
hour
workday.

 
454
g/
day
of
HFE­
7000
is
used
over
a
period
of
8
hours.

 
The
spray
is
applied
in
5­
second
sprays,
every
5
minutes,
@
0.95
g/
sec.

8­
hour
average
application
rate:

454
grams
used
in
8­
hour
period
=
0.0158
g/
sec
28800
seconds
(
in
8
hours)

15­
minute
average
application
rate:

15
minutes
=
3
sprays
1
spray
every
5
minutes
3
sprays
x
5
seconds
=
15
seconds
of
spraying
time
1
spray
15
seconds
of
spray
x
0.95
grams
=
14.3
grams
sprayed
in
first
15
minutes
1
second
14.3
grams
used
in
first
15
minutes
of
spraying
=
0.0158
g/
sec
900
seconds
(
in
15
minutes)

Scenario
2
 
This
scenario
represents
the
use
of
HFE­
7000
on
a
factory
assembly
line
over
a
portion
of
the
workday.

 
454
g/
day
of
HFE­
7000
is
used
over
a
period
of
1.5
hours.

 
The
spray
is
applied
in
5
second
sprays
every
1
minute,
@
1.0
g/
second.

8­
hour
average
application
rate:

454
grams
used
in
8­
hour
period
=
0.0158
g/
sec
28800
seconds
(
in
8
hours)

15­
minute
average
application
rate:

15
minutes
=
15
sprays
1
spray
every
1
minute
August
1,
2003
4
15
sprays
x
5
seconds
=
75
seconds
of
spraying
time
1
spray
75
seconds
of
spray
x
1.0
grams
=
75
grams
sprayed
in
first
15
minutes
1
second
75
grams
used
in
first
15
minutes
of
spraying
=
0.0833
g/
sec
900
seconds
(
in
15
minutes)

Scenario
3
 
This
scenario
represents
the
use
of
HFE­
7000
in
a
mechanic's
shop
where
HFE­
7000
is
only
used
periodically.

 
454
g/
day
of
HFE­
7000
is
used
over
a
period
of
0.30
hours
 
The
spray
is
applied
in
5­
second
sprays
every
1
minute
@
5
g/
second.

8­
hour
average
application
rate:

454
grams
used
in
8­
hour
period
=
0.0158
g/
sec
28800
seconds
(
in
8
hours)

15­
minute
average
application
rate:

15
minutes
=
15
sprays
1
spray
every
1
minute
15
sprays
x
5
seconds
=
75
seconds
of
spraying
time
1
spray
75
seconds
of
spray
x
5.0
grams
=
375
g
1
second
375
grams
=
0.417
g/
sec
900
seconds
(
in
15
minutes)

3.
Results
The
three
exposure
scenarios
were
modeled
in
both
average
and
poor
ventilation
settings.
The
results
of
the
analysis
are
outlined
in
Tables
1
and
2.
August
1,
2003
5
Table
1.
Eight­
Hour
and
Fifteen­
Minute
Exposure
Concentrations
(
ppm)
to
HFE­
7000
in
Facilities
with
Average
Ventilation
8­
hour
application
rate
8­
hour
concentration
AEL
15­
minute
application
rate
15­
minute
concentration
STEL
Scenario
1
0.0158
g/
sec
2.7
ppm
0.0158
g/
sec
2.7
ppm
Scenario
2
0.0158
g/
sec
2.7
ppm
0.0833
g/
sec
14.4
ppm
Scenario
3
0.0158
g/
sec
2.7
ppm
75
ppm
0.417
g/
sec
71.6ppm
3,000
ppm
Table
2.
Eight­
Hour
and
Fifteen­
Minute
Exposure
Concentrations
(
ppm)
to
HFE­
7000
in
Facilities
with
Poor
Ventilation
8­
hour
application
rate
8­
hour
concentration
AEL
15­
minute
application
rate
15­
minute
concentration
STEL
Scenario
1
0.0158
g/
sec
8.2
ppm
0.0158
g/
sec
8.2ppm
Scenario
2
0.0158
g/
sec
8.2
ppm
0.0833
g/
sec
43.1
ppm
Scenario
3
0.0158
g/
sec
8.2
ppm
75
ppm
0.417
g/
sec
218.2ppm
3,000
ppm
The
exposure
concentration
for
each
of
the
scenarios
modeled
is
significantly
lower
than
the
recommended
8­
hour
AEL
of
75
ppm.
Even
in
settings
with
poor
ventilation,
the
modeled
8­
hour
concentration
is
approximately
10
times
less
than
the
recommended
AEL.
Therefore,
modeling
results
suggest
that
occupational
exposure
to
HFE­
7000
does
not
pose
a
threat
to
workers'
health.

4.
References
3M
 
,
1997.
End
User
Aerosol
3MTM
Hydrofluorether
(
HFE)
Exposure,
May
22,
1997.
Performed
by
Shawn
Kruse.
Contact
Chuan­
Chi
(
Henry)
Chang
of
3M
 
Specialty
Chemicals
Division.

ACGIH.
1982.
Industrial
Ventilation:
A
Manual
of
Recommended
Practice,
17th
Edition.
Chapter
4.
Cited
in
U.
S.
EPA.
1994.
SNAP
Technical
Background
Document:
Risk
Screen
on
the
Use
of
Substitutes
for
Class
I
Ozone­
depleting
Substances:
Aerosols.

DuPont
Fluoroproducts,
2002.
Aerosol
Test
Protocol.
Received
from
Owen
Blake,
October
11,
2002.

U.
S.
EPA.
1994.
SNAP
Technical
Background
Document:
Risk
Screen
on
the
Use
of
Substitutes
for
Class
I
Ozone­
depleting
Substances:
Aerosols.
August
1,
2003
6
