DSHW-1993-002466 - 0901a0688013c026

/-I I at-LLT'L
HERCULES
DSHW TN
1993.11251
Vlwk clJx^^^S
Hercules Aerospace Company
Space/Strategic Propulsion
Bacchus Works
Magna, Utah 84044-0098
[phone]
10 June 1993
F. Bumell Cordner
Division of Air Quality
Department of Environmental Quality
1950 West North Temple
Salt Lake City, Utah 84114-4820
\ RECEIVED
pm 0 5 mi
4ir Quality
Subject: SCREEN Modeling for Remediation of Fluorine Cylinders at Hercules Plant 1
Dear Mr. Cordner:
In the 1970's Hercules used gaseous fluorine in the synthesis of numerous
propellant ingredients. A number of fluorine cylinders left over from this program remain at
our facility. Shipment of these cylinders offsite for disposal is difficult as the pressiu^ rating
for each of the cylinders has expired. After careful consideration of different options,
Hercules believes that the safest and most expedient method of remediating these cylinders is
to vent them one at a time at their current location. Venting would be accomplished by
means of a small explosive charge placed on the valve of each cylinder.
Fluorine is considered an airbome toxic. As such the concentration of fluorine at
our fenceline during remediation cannot exceed the TLV/100, which in this case is 0.016
mg/m\ Lynn Menlove indicated that the DAQ would review this issue for approval provided
that Hercules used the SCREEN model to determine fenceline concentrations averaged over 8
hours.
Attached is a report providing additional information on the fluorine cylinders and
results of the modeling effon. The SCREEN model predicted that the fenceline concentration
for fluorine would not exceed 0.016 mg/m^ when the procedures proposed by Hercules are
followed. If you develop any further questions during review of this issue, please contact me
at 251-3574 or Chris Falkenberg of my staff at 251-5313.
Sincerely,
E. Richard Anderson, Manager
Enviromnental Engineering and
Hygiene
ERA/CDFalkenberg/
SCREEN Modeling for Remediation of Fluorine Transfer Station
SUMMARY AND CONCLUSIONS
Hercules proposes to remediate 54 fluorine and 10 tetrafluorohydrazine (N2F4) cylinders
at our Plant 1 facility. The cylinders would be vented one at a time to the open atmosphere by
means of an explosive charge attached to each cylinder valve. The operation would be conducted
in an open field some 1265 meters north of the closest Hercules property fenceline.
The SCREEN model was used to estimate pollutant concentrations at various distances
downwind from the operation. SCREEN predicts that fluorine concentrations at the Hercules
fenceline would not exceed Threshold Limit Value/safety factor concentrations set by the Utah
Division of Air Quality. These results are quite conservative. Actual fluorine concentrations
would be smaller as a significant amount of the fluorine would react before it reached the
fenceline.
Teti-afluorohydrazine cylinders are less of a concem because individual N2F4 cylinders
contain less gas than the fluorine cylinders. Because of the similarity with which the SCREEN
model would analyze both situations, any operation approved for the fluorine cylinders should
also be approved for the tetrafluorohydrazine cylinders.
INTRODUCTION
In the 1970's, Hercules used gaseous fluorine in the synthesis of numerous propellant
ingredients. Tetrafluorohydrazine (N2F4) was also used as a raw ingredient during this same time
frame. Towards the end of the program, liquid fluorine was brought on plant and transferred into
compressed gas cylinders at an area known as the fluorine transfer station, Facility 9005. The
cylinders were then shuttied back and forth between the transfer station and the operating facility
for production of the propellant ingredients.
When the program ended in 1978, a number of cylinders were left behind at the transfer
station and have remained ever since. The following table shows the quantity and type of
cylinders involved with this effort.
Compound
Fluorine
Number of
Cylinders
54
N2F4
(Tetrafluorohydrazine)
10
Tvpe of Cvlinder
ICC - 3AA 1000, Normally rated to 1000
psi, 400 psig max for fluorine service.
Approximately 11" in diameter, 50" tall and
when full contain 7.9 pounds of fluorine.
DOT - 3AA 2015, Each bottle is 7" in
diameter, 30" tall, pressvuized to 120 psig,
and contains 1.25 pounds of N2F4. One of
the ten cylinders is substantially larger than
the others, but is believed to be empty.
SCREEN Modeling for Remediation of Page 2
the Fluorine Transfer Station
By design, the fluorine station is situated in an open field some 750 feet away from the
nearest building. See the attached map for the location of the fluorine station with respect to the
rest of Hercules' Plant 1 facilities. The station itself is very simple, it consists merely of a single
sided steel barricade designed to protect operators during the fluorine transfer process. As such,
the station doesn't provide any protection from the elements. The compressed gas cylinders at
the station have been exposed to wind, rain, and snow conditions for several years. Rust and
other corrosion has appeared on some of the cylinders.
Hercules has examined several different disposal options for the cylinders in the past few
years. Disposal offsite is difficult as the pressure rating for the cylinders has expired. Public
transport of such cylinders is illegal without special exemption and coordination with the DoT.
Stress caused to the cylinders during offsite transportation is thought to be an additional safety
risk when considering the age and reactive nature of the tank contents.
Of the onsite disposal options evaluated, venting the cylinders in place is the safest and
requires the least handling of the cylinders. Most of the cylinders will not have to be moved
until after they are empty. The open area of the transfer station also allows for dispersion of the
fluorine before it reaches other facilities on plant. Small explosive charges will be used to knock
the valve off of cylinders one at a time. Hercules, as a manufacturer of explosives, is very
familiar with this technology.
PROPOSED PROCEDURE
The primary consideration for this entire effort is to assiu"e that Hercules personnel and
the general poptilace are not exposed to unacceptable levels of fluorine gas. An area of sufficient
size to protect plant personnel will be cordoned off during the operation. All personnel entering
this area will be required to wear the proper personal protective equipment. Test equipment will
also be used when in tiiis area to assure that fluorine concentrations are within safe levels.
Once the area is secured, an explosives team will enter the area. They will secure a small
explosive charge to the valve of a single cylinder. After setting the charge, the team will retire
to a safe drawback site and detonate the explosive charge remotely. The type and nature of each
resultant plume will be recorded. Unless it can be demonstrated that a number of cylinders are
already empty, the cylinders will be vented one at a time. Empty cylinders may be vented
several at a time to allow for subsequent washout.
Calculations show that the fluorine cylinders will take approximately 25 seconds to vent
across the valve orifice. After an appropriate dispersal period (estimated to be a half hour)
operators would cautiously reenter the area and determine the airbome fluorine concentration.
Once it is fotmd that the fluorine has dispersed, the charge for the next cylinder can be set.
Using this procedure it is estimated that twelve cylinders could be vented in a day. The total
daily fluorine load would therefore be 12 cylinders/day x 8 lbs/cylinder or 96 pounds/day. The
entire operation would take between 5 and 6 days at a total fluorine load of 432 pounds.
SCREEN Modeling for Remediation of Page 3
the Fluorine Transfer Station
Tedrafluorohydrazine is an extremely sensitive material, these cylinders are expected to
detonate under the impetus of the explosive charge. Shrapnel from the these cylinders will be
controlled by placing the cylinders either in a hole or in some sort of portable enclosure.
Detonation products would include nitrogen dioxide (NO2) and hydrogen fluoride (HF) gases.
Mass balance calculations show that a total of 9.6 pounds of hydrogen fluoride and 11.04 pounds
of nidrogen dioxide would be produced from remediating the N2F4 cylinders.
Once the cylinders have all been vented they will be washed out in a light caustic solution and
then sent to an appropriate disposal facility.
SCREEN MODELLING
The SCREEN model was developed by the EPA to model the air quality impacts of
stationary sources. Documentation for the model implies that the model was primarily developed
for smokestacks and flares. These situations involve relatively constant emissions from elevated
sources which differs somewhat from the intermittent emissions expected from the fluorine
station. Fluorine concentrations will be relatively high immediately after a cylinder is vented,
but will then decrease as die fluorine disperses. Assumptions and inputs used for the model must
therefore be selected very carefully in order to make the model results relevant.
SCREEN Model Procedure
The SCREEN model calculates maximum 1 hour pollutant concentrations at various
distances for a given set of input conditions. The SCREEN model results will be compared to
industrial hygiene Threshold Limit Values (TLV) for fluorine to determine whether the fluorine
release is acceptable or not. TLV values for fluorine are expressed for 8 hour averaging times.
According to the SCREEN model documentation, the SCREEN 1 hour maximum concentration
may be converted to an 8 hour maximum concentration by multiplying die 1 hour value by a
factor of 0.7.
The industrial hygiene TLV value for fluorine is 1.6 mg/m^ as set by the American
Conference of Govemmental Industrial Hygienists (ACGIH). As an added safety precaution,
OSHA has reduced this exposure limit by a factor of 10 which results in a workplace exposure
limit of 0.16 mg/m^. Furthermore, the Utah Division of Air Quality (DAQ) has recognized that
TLV values are designed to protect workers in the workplace. To protect the general populace
which may be more susceptible, the DAQ uses a safety factor of 100 for airborne toxics such as
fluorine. Fenceline concentrations where the general public could encounter the fluorine plume
must therefore meet the TLV/100 criteria of 0.016 mg/m\
To summarize the above discussion, the following steps will be used witii the SCREEN
model to detennine the suitability of venting the fluorine cylinders to the atmosphere:
SCREEN Modeling for Remediation of Page 4
the Fluorine Transfer Station
1. Gather physical data conceming the effort. These data include the mass flow rate
from the cylinders, the release height from the ground, distance to the plant
fenceline boundaries, etc.
2. Evaluate assumptions required for the model. Several conversations with the
DAQ have helped determine some of these assumptions.
3. Run the SCREEN model using the above information to obtain 1 hour maximum
fluorine concentrations for various weather conditions and distances. Weather
conditions used are the standard stability classes (Stability Classes A, B, C, Etc.)
used by most dispersion models.
4. Multiply the one hour maximum concentrations produced by SCREEN by 0.7 to
obtain 8 hour maximum concentrations.
5. Compare the SCREEN 8 hour concentrations to the onplant exposure limit of 0.16
mg/m^. Determine the necessary distance to meet this concentration level.
Unprotected Hercules personnel must be at least this far from the fluorine station
during the operation.
6. Compare the SCREEN 8 hour concentrations to the general populace exposure
limit of 0.016 mg/m^ at the Hercules fenceline. SCREEN results less than this
value are suitable for submission to the DAQ for review and approval.
Phvsical Data and Assumptions
Conversations with the DAQ have set some of the inputs to die model. Mr. Bob Swart
of the DAQ indicated tiiat the fluorine emissions should be modeled as a point source with the
emission rates set at the hourly flow rates for fluorine. Under these conditions, the SCREEN
model treats the fluorine emissions as emissions from a smokestack. The table on the following
page shows the SCREEN model inputs required for a point source along with the values used
and the conesponding rationale. In most cases, values were selected to assure conservative
model results.
The SCREEN model can perfonn calculations to compensate for elevated tenain near a
source. The resultant plume could impact the elevated tenain and result in higher pollutant
concentrations than for flat tenain. The fluorine station is at an elevation of 4,782 feet. The
closest Hercules property line to the fluorine station is approximately 1265 meters straight north
as shown on the attached map. The elevation at this point is 4,555 feet, which is 227 feet lower
in elevation than the fluorine station. Complex and simple tenain adjustment calculations were
not used as the closest Hercules fenceline is at a lower elevation than the fluorine station.
SCREEN Modeling for Remediation of
the Fluorine Transfer Station
Page 5
MODEL INPUT
Source Type
(Point, Flare, or Area)
Emission Rate
Stack Height
Stack Diameter
Gas Exit Velocity
Gas Exit Temp
1 Ambient Air Temp
Receptor height above
1 ground
Rural/Uitan Option
Building Down Wash
VALUE USED
Point
1.513 gram/second
1.0 meter
1.0 meter
1.0 meter/second
293°K
293'K
0 Meter
Urban
No
RATIONALE
As indicated by DAQ (Bob Swart)
With half hour dispersion times, maximum
achievable rate is 12 cylinders vented over an
8 hour period or 1.513 grams/second. |
Average height of the cylinders atiove ground.
Wide variations in stack diameter and stack
gas exit velocity have a minor effect on the
SCREEN model results, see the results section
of this report. These two parameters have
been set at conservative values of 1.0 meter
and 1.0 meters/second. |
See above, the fluorine cylinders will be
horizontal when vented. The exit gas will only
have a small vertical component when vented.
Hot gases tend to rise. Exit gas temperatures
less than or near ambient air temperatures are
Ignored by the SCREEN model. Setting the
exit gas temperature near ambient
temperatures results In conservative SCREEN
results.
Default recommended by SCREEN model
As indicated by DAQ (Bob Swart)
Fluorine cylinders are in an empty field, but are
surrounded by over 500 buildings on Hercules
Plant 1 facility.
The closest building to the fluorine cylinders is
750 feet away, the SCREEN model predicts
that the plume will already have risen to its
fullest height by then.
SCREEN Modeling for Remediation of
the Fluorine Transfer Station
Page 6
SCREEN MODEL RESULTS
SCREEN model printouts for each weather condition evaluated are attached to this report.
Of the six possible weather conditions, only Stability classes A, B, C, and D were evaluated.
Stability Classes E and F were not evaluated as they apply to night time conditions. The
following table summarizes the results:
SCREEN MODEL RESULTS
stability
Class
A
B
C
D
Fenceline Boundary Standard
TLV/100
0.016 mg/m^
0.016 mg/m^
0.016 mg/m''
0.016 mglrrp
SCREEN Prediction
8 Hour Fenceline Concentration
0.004 mg/m^
0.004 mg/m^
0.06fLmg/fn^ • -^ '
0.014 mg/m^
Onplant Exposure Limit
Distance to 0.16 mglrrP
193 meters
193 meters
269 meters
391 meters
The left side of the table compares the 8 hour fenceline concentration calculated by
SCREEN to tiie TLV/100 standard for fluorine (0.016 mg/m^). All of the predicted fluorine
concentrations are less than the fenceline standard. Thus SCREEN predicts that the general
populace will not be exposed to unacceptable levels of fluorine.
The right side of the table shows the downwind distance before the fluorine concentration
falls below 0.16 mg/m'. Unprotected Hercules personnel must be at least this far from fluorine
station during a venting operation. Hercules will enforce these distances during the operation.
The attached map shows isopleth circles that detail how far such personnel must be from the site
under the various weather conditions evaluated.
SCREEN predicts that higher fluorine concentirations will be encountered on unstable days
with elevated wind speeds (Stability Classes C and D). The elevated winds will likely keep the
plume closer to the ground and allow it to travel faster downwind before dispersal.
It is believed that these SCREEN results are extremely conservative. Besides the
conservative inputs used for the model, fluorine is an extremely reactive gas that will not stay
in its elemental state for long. Hercules believes that a majority of the fluorine will react with
the fresh steel surfaces exposed on the gas cylinders during venting. Fluorine remaining after
venting will quickly react with water in the air to form hydrogen fluoride. Hydrogen fluoride
has a 60% higher TLV in comparison to fluorine (2.6 mg/m' versus 1.6 mg/m'). In addition, the
wind must be blowing directiy to the nouth to approach the shortest fenceline distance. Other
wind directions result in longer fenceline distances and smaller fluorine concentrations at the
fenceline. All of these factors will combine to result in smaller actual fluorine fenceline
concentirations than acmally predicted by the SCREEN model.
Smokestack Concems
The SCREEN model treats the fluorine emission as an emission from a smokestack with
a given height, diameter, gas velocity, and temperatvu-e inside the stack. Since tiie fluorine
emissions are vented directly to the atmosphere, a number of runs were made with SCREEN to
determine the effect of these parameters on SCREEN results. The study assumed a hypothetical
set of conditions as detailed in the table below. SCREEN predicted that the downwind
concentration of pollutants for this baseline situation would be 67.54 mg/m' at 1000 meters
downwind. The next table shows the results of varying a number of the input conditions and the
resulting effect on the SCREEN predictions.
BASELINE PARAMETERS
Source
Type
Point
Emission
1 gram/s
Stack
Height
1.0 M
Stack
Diameter
l.OM
Stack
Exit
Velocity
l.OM
Stack
Gas
Temper.
293°K
Ambient
Temper.
293°K
Receptor
Height
OM
Urban
or
Rural
Urban
MODIFICATIONS TO BASELINE PARAMETERS
Parameter to Vary
Stack Height
Stack Inside
Diameter
Stack Gas Exit
Velocity
Stack Gas Exit
Temperature
Baseline Value
1 Meter
.. .
1 Meter
1.0 Meter/Sec
293°K
Modifications
0.1 Meter
0.5 Meter
2.0 Meter
5.0 Meter
10.0 Meter
20.0 Meter
0.1 Meter
0.4 Meter
0.8 Meter
1.2 Meter
2.0 Meter
3.0 Meter
0.5 Meter/sec
0.8 Meter/sec
1.2 Meter/sec
2.0 Meter/sec
3.0 Meter/sec
5.0 Meter/sec
100«K
200°K
300<'K
400°K
500°K
1000°K
Screen Result at
1000 M. Downwind
67.54 mg/m'
67.54 mg/m'
67.45 mg/m'
67.02 mg/m'
65.79 mg/m'
50.40 mg/m'
67.65 mg/m'
67.63 mg/m'
67.57 mg/m'
67.49 mg/m'
67.31 mg/m'
67.05 mg/m'
67.64 mg/m'
67.59 mg/m'
67.45 mg/m'
67.14 mg/m'
66.81 mg/m'
66.03 mg/m'
67.54 mg/m'
67.54 mg/m'
65.79 mg/m'
58.76 mg/m'
56.09 mg/m'
51.91 mg/m'
Trend
No effect until
stack height
exceeds 1 meter.
Only minor effect
until stack height
reaches 5 meters.
Minor effect, less
than 1% variation
in result over
the entire range.
Minor effect.
around 2.4%
variation over the
entire range.
No effect until gas
exit temperature
exceeds ambient,
then hot exit
gases reduce
downwind
concentrations.
SCREEN Modeling for Remediation of Page 8
the Fluorine Transfer Station
The above analysis shows that smokestack parameters such as stack diameter and gas exit
velocity do not have much effect on the ultimate SCREEN model results. For the ptuposes of
the fluorine analysis, it doesn't really matter how close the fluorine plume approximates a
smokestack emission as these parameters have a negligible result on the SCREEN results. The
other two parameters of stack height and gas exit temperature can have a moderate effect on
SCREEN results. For the fluorine analysis, these two values were set at conservative values to
assiure that SCREEN predictions were conservative.
Tetrafluorohydrazine Modelling
SCREEN modelling results for detonating the tetrafluorohydrazine cylinders will always
result in more acceptable fenceline pollutant concentrations in comparison to the fluorine
cylinders. Three separate factors combine to support this conclusion. First, the amount of gas
released from detonating a teti:afluorohydrazine cylinder will be six times less than released from
a fluorine cylinder (8 pounds versus 1.25 pounds). Since SCREEN predictions are directiy
proportional to mass flow rates, tedrafluorohydrazine downwind concentrations will always be
smaller.
Secondly, SCREEN model results are independent of chemical species, i.e. SCREEN
doesn't use physical property data for the pollutants being modelled. Different transport rates
between fluorine and tetrafluorohydrazine will not be a factor in the SCREEN results. Finally,
the MSDS for tetrafluorohydrazine indicates that it rapidly decomposes into NOj and HF gases
upon contact with moist air. It is assumed that these same constituents are produced under
detonation situations. The TLVs for NO2 and HF are both higher than the TLV for fluorine.
Thus, higher concentrations of these gases could be present at the fenceline and still be within
acceptable levels.
The end result is tiiat SCREEN modelling does not need to be done for the
tetrafluorohydrazine cylinders. The above factors show that SCREEN results for
tetrafluorohydrazine will always be less of a concem than emissions from the fluorine cylinders.
As SCREEN predicts acceptable fluorine concentrations, by analogy the SCREEN model will
also predict acceptable downwind concentrations from detonating the^ tedrafluorohydrazine
cylinders.
SCREEN MODEL RUNS
STABILITY CLASSES A, B, C, & D
05-10-93
16:21:57
*** SCREEN-1.1 MODEL RUN ***
*** VERSION DATED 88300 ***
Fluorine Station, Stability Class A, 12 Cylinders/day
SIMPLE TERRAIN INPUTS:
SOURCE TYPE = POINT
EMISSION RATE (G/S) = 1.513
STACK HEIGHT (M) = 1.00
STK INSIDE DIAM (M) = 1,00
STK EXIT VELOCITY (M/S)= 1.00
STK GAS EXIT TEMP (K) = 293.00
AMBIENT AIR TEMP (K) = 293.00
RECEPTOR HEIGHT (M) = .00
lOPT (1=URB,2=RUR) = 1
BUILDING HEIGHT (M) = .00
MIN HORIZ BLDG DIM (M) = .00
MAX HORIZ BLDG DIM (M) = .00
BUOY. FLUX = .00 M**4/S**3/ MOM. FLUX
*** STABILITY CLASS 1 ONLY ***
•k-k-k-kic-lf-k^ickif-k-k-k-k-k-k-k-k-k-ick-kicie-k-k-k-k-k-k-k-k-k
*** SCREEN AUTOMATED DISTANCES ***
*>c** ********************* *********
25 M**4/S**2
*** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES ***
DIST
(M)
100.
200.
300.
400.
500.
500.
700.
800.
900.
1000.
lioo.
1200.
1300.
MAXIMUM
100.
CONC
(UG/M**3)
504.9
148.5
64.62
35.55
22.43
15.40
11.41
9.157
7.851
7.029
6.441
5.978
5.590
STAB
1
1
1
1
1
1
1
1
1
1
1
1
1
1-HR CONCENTRATION
504.9 1
UIOM
(M/S)
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
AT OR
1.0
USTK
(M/S)
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
BEYOND
1.0
MIX HT
(M)
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
100. M;
320.0
PLUME
HT (M)
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
SIGMA
Y (M)
31.4
61.6
90.7
118.8
146.1
172.4
198.0
222.8
247.0
270.5
293.3
315.6
337.4
31.4
SIGMA
Z (M)
25.2
52.6
82.1
113.6
147.0
182.1
219.0
257.6
297.7
339.4
382.6
427.2
473.2
25.2
DWASH
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
DWASH= MEANS NO CALC MADE (CONC =0.0)
DWASH=NO MEANS NO BUILDING DOWNWASH USED
DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED
DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED
DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB
*********************************
*** SCREEN DISCRETE DISTANCES ***
r*** ************************ -kit *******
*** TERRAIN HEIGHT OF O.M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES ***
DIST CONC UIOM USTK MIX HT PLUME SIGMA SIGMA
(M) (UG/M**3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH
1265. 5.719 1 1.0 1.0 320.0 3.0 329.9 456.9 NO
DWASH= MEANS NO CALC MADE (CONC =0.0)
DWASH=NO MEANS NO BUILDING DOWNWASH USED
DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED
DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED
DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB
***************************************
*** SUMMARY OF SCREEN MODEL RESULTS ***
***************************************
CALCULATION MAX CONC DIST TO TERRAIN
PROCEDURE (UG/M**3) MAX (M) HT (M)
SIMPLE TERRAIN 604.9 100. 0
***************************************************
** REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS **
***************************************************
*** SCREEN-1.1 MODEL RUN ***
*** VERSION DATED 88300 ***
Fluorine Station, Stability Class B, 12 Cylinders/day
SIMPLE TERRAIN INPUTS:
SOURCE TYPE = POINT
EMISSION RATE (G/S) = 1.513
STACK HEIGHT (M) = 1.00
STK INSIDE DIAM (M) = 1.00
STK EXIT VELOCITY (M/S)= 1.00
STK GAS EXIT TEMP (K) = 293.00
AMBIENT AIR TEMP (K) = 293.00
RECEPTOR HEIGHT (M) = .00
lOPT (1=URB,2=RUR) = 1
BUILDING HEIGHT (M) = .00
MIN HORIZ BLDG DIM (M) = .00
MAX HORIZ BLDG DIM (M) = .00
05-18-^-
16:23 59
BUOY. FLUX = .00 M**4/S**3; MOM. FLUX
*** STABILITY CLASS 2 ONLY ***
**********************************
*** SCREEN AUTOMATED DISTANCES ***
**********************************
25 M**4/S**2
*** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES ***
DIST
(M)
100.
200.
300.
400.
500.
600.
700.
8 00.
900.
1000.
1100.
1200.
1300.
MAXIMUM
100.
CONC
(UG/M**3)
604.9
148.5
54.62
35.65
22.43
15.40
11.41
9.157
7.851
7.029
6.441
5.978
5.590
STAB
2
2
2
2
2
2
2
2
2
2
2
2
2
1-HR CONCENTRATION
604.9 2
UIOM
(M/S)
1.0
. 1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
AT OR
1.0
USTK
(M/S)
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
BEYOND
1.0
MIX HT
(M)
320.0
- 320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
100. M:
320.0
PLUME
HT (M)
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
SIGMA
Y (M)
31.4
61.6
90.7
118.8
146.1
172.4
198.0
222.8
247.0
270.5
293.3
315.6
337.4
31.4
SIGMA
Z (M)
25.2
52.6
82.1
113.6
147.0
182.1
219.0
257.6
297.7
339.4
382.6
427.2
473.2
25.2
DWASH
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
DWASH= MEANS NO CALC MADE (CONC =0.0)
DWASH=NO MEANS NO BUILDING DOWNWASH USED
DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED
DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED
DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB
*********************************
*** SCREEN DISCRETE DISTANCES ***
*********************************
*** TERRAIN HEIGHT OF O.M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES ***
DIST CONC UIOM USTK MIX HT PLUME SIGMA SIGMA
(M) (UG/M**3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH
1265. 5.719 2 1.0 1.0 320.0 3.0 329.9 456.9 NO
DWASH= MEANS NO CALC MADE (CONC =0.0)
DWASH=NO MEANS NO BUILDING DOWNWASH USED
DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED
DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED
DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB
***************************************
*** SUMMARY OF SCREEN MODEL RESULTS ***
***************************************
CALCULATION MAX CONC DIST TO TERRAIN
PROCEDURE (UG/M**3) MAX (M) HT (M)
SIMPLE TERRAIN 604.9 100. 0.
***************************************************
** REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS **
***************************************************
05-18-93
16:24:30
*** SCREEN-1.1 MODEL RUN ***
*** VERSION DATED 88300 ***
Fluorine Station, Stability Class C, 12 Cylinders/day
SIMPLE TERRAIN INPUTS:
SOURCE TYPE
EMISSION RATE (G/S)
STACK HEIGHT (M)
STK INSIDE DIAM (M)
STK EXIT VELOCITY (M/S)=
STK GAS EXIT TEMP (K)
AMBIENT AIR TEMP (K)
RECEPTOR HEIGHT (M)
lOPT (1=URB,2=RUR)
BUILDING HEIGHT (M)
MIN HORIZ BLDG DIM (M) =
MAX HORIZ BLDG DIM (M) =
POINT
1.513
00
00
00
293.00
293.00
.00
1
.00
.00
.00
BUOY. FLUX = .00 M**4/S**3/ MOM. FLUX
*** STABILITY CLASS 3 ONLY ***
**********************************
*** SCREEN AUTOMATED DISTANCES ***
**********************************
,25 M**4/S**2.
*** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES ***
DIST
(M)
100.
200.
300.
400.
500.
600.
700.
800.
900.
1000.
1100.
1200.
1300.
CONC
(UG/M**3)
1102.
283.5
128.5
73.62
47.94
33.84
25.27
19.66
15.81
13.10
11.17
9.775
8.757
STAB
3
3
3
3
3
3
3
3
3
3
3
3
3
UIOM USTK MIX HT PLUME
(M/S) (M/S) (M) HT (M)
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1,
1,
1
1
MAXIMUM 1-HR CONCENTRATION AT OR BEYOND
100. 1102. 3 1.0 1.0
320.0
320.0-
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
100. M:
320.0
DWASH= MEANS NO CALC MADE (CONC =0.0)
DWASH=NO MEANS NO BUILDING DOWNWASH USED
DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED
DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED
DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB
*********************************
*** SCREEN DISCRETE DISTANCES ***
3
3
3
3
3
3
3
3
3,
3,
3,
3
3,
3.0
SIGMA
Y (M)
.6
,3
.4
21
42
62
81.7
100.4
118.5
136.1
153.2
169.8
185.9
201.7
217.0
232.0
21.6
SIGMA
Z (M)
20.0
. 40.0
60.0
80.0
100.0
120.0
140.0
160.0
180.0
200.0
220.0
240.0
260.0
20.0
DWASH
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
inTit ************************ *ir* ******
*** TERRAIN HEIGHT OF O.M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES ***
DIST CONC UIOM USTK MIX HT PLUME SIGMA SIGMA
(M) (UG/M**3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH
1255. 9.078 3 1.0 1.0 320.0 3.0 226.8 253.0 NO
DWASH= MEANS NO CALC MADE (CONC = 0.0)
DWASH=NO MEANS NO BUILDING DOWNWASH USED
DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED
DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED
DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB
***************************************
*** SUMMARY OF SCREEN MODEL RESULTS ***
***************************************
CALCULATION MAX CONC DIST TO TERRAIN
PROCEDURE (UG/M**3) MAX (M) HT (M)
SIMPLE TERRAIN 1102. --100 . 0.
***************************************************
** REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS **
***************************************************
05-18-93
16:25:17
*** SCREEN-1.1 MODEL RUN ***
*** VERSION DATED 88300 ***
Fluorine Station, Stability Class D, 12 Cylinders/day
SIMPLE TERRAIN INPUTS:
SOURCE TYPE = POINT
EMISSION RATE (G/S) = 1.513
STACK HEIGHT (M) = 1.00
STK INSIDE DIAM (M) = 1.00
STK EXIT VELOCITY (M/S)= 1.00
STK GAS EXIT TEMP (K) = 293.00
AMBIENT AIR TEMP (K) = 293.00
RECEPTOR HEIGHT (M) = .00
lOPT (1=URB,2=RUR) = 1
BUILDING HEIGHT (M) = .00
MIN HORIZ BLDG DIM (M) = .00
MAX HORIZ BLDG DIM (M) = .00
BUOY. FLUX = .00 M**4/S**3/ MOM. FLUX
*** STABILITY CLASS 4 ONLY ***
**********************************
*** SCREEN AUTOMATED DISTANCES ***
**********************************
.25 M**4/S**2
*** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES ***
DIST
(M)
100.
200.
300.
400.
500.
600.
700.
800.
900.
1000.
1100.
1200.
1300.
CONC
(UG/M**3)
2166.
571.1
263.1
152.9
100.9
72.18
54.57
42.96
34.87
29.00
24.58
21.18
18.49
STAB
4
4
4
4
4
4
4
4
4
4
4
4
4
UIOM
(M/S)
USTK
(M/S)
0
0
0
0
0
1.0
0
0
0
0
0
0
.0
0
0.
0
0
0
0
0
0
0
0
0
0
0
MAXIMUM 1-HR CONCENTRATION AT OR BEYOND
100. 2156. 4 1.0 1.0
MIX HT PLUME
(M) HT (M)
0
0
0
.0
320
320
320
320
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
100. M:
320.0
DWASH= MEANS NO CALC MADE (CONC =0.0)
DWASH=NO MEANS NO BUILDING DOWNWASH USED
DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED
DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED
DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB
*********************************
*** SCREEN DISCRETE DISTANCES ***
3
3
3
3
3
3.0
3
3
3
3,
3
3
3
3.0
SIGMA
Y (M)
15
30
45
59
73
85
99.0
111.4
123.5
135.2
146.7
157.8
168.7
15.7
SIGMA
Z (M)
13.8
27.2
,2
,9
,3
,3
,1
,6
40,
52,
65,
77
89,
100,
111.8
122.8
133.5
144.1
154.4
13.8
DWASH
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
************************ iWr* ****** ^^
*** TERRAIN HEIGHT OF O.M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES ***
DIST CONC UIOM USTK MIX HT PLUME SIGMA SIGMA
(M) (UG/M**3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH
1265. 19.37 4 1.0 1.0 320.0 3.0 164.9 150.8 NO
DWASH= MEANS NO CALC MADE (CONC =0.0)
DWASH=NO MEANS NO BUILDING DOWNWASH USED
DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED
DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED
DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB
***************************************
*** SUMMARY OF SCREEN MODEL RESULTS ***
***************************************
CALCULATION MAX CONC DIST TO TERRAIN
PROCEDURE (UG/M**3) MAX (M) HT (M)
SIMPLE TERRAIN 2166. 100. 0
***************************************************
** REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS **
***************************************************
^^G^
r.} UEDf^l 11 EC Hercules Aerospace Company
I'P ••crfcwUl-C^ Space/Strategic Propulsion
-^•^^^""•^^^•^~" Bacchus Works
^<\ Magna, Utah 84044-0098
^WyC^ [phone]
X^^ ^ 30 July 1993
Nando Meli K^ ^^
Division of Air Quality »
Department of Environmental Quality
1950 West North Temple
Salt Lake City, Utah 84114-4820
Subject: Data Collection During Fluorine Transfer Station Remediation
Dear Mr. Meli:
During a phone conversation on the 27* of July, you requested the type of data that
Hercules plans to collect during remediation of the Fluorine Transfer Station. Previous
conespondence with the DAQ on this issue has made significant use of the SCREEN model
to predict airbome concentrations of fluorine under various weather conditions. In evaluating
this model, Hercules maintained that the SCREEN predictions should be very conservative
because of the reactive nature of fluorine. Most of the fluorine is expected to react before it
traveled a significant distance downwind.
Attached is a product description sheet for a gas analyzer specifically designed to
monitor airbome fluorine concentrations. Hercules will use this device on selected shots to
compare predicted SCREEN model results to actual downwind concentrations. The device
has a recorder output so we can leave it unattended fairly close to the fluorine station without
undue risk of personnel exposure to fluorine. At the conclusion of the effort, Hercules will
prepare a report for the DAQ discussing the measured fluorine concentrations and the
implications to the SCREEN model. If you develop any further questions during review of
this issue, please contact me at 251-3574 or Chris Falkenberg of my staff at 251-5313.
Sincerely,
^JC^u.^^2^^^.^
E. Richard Anderson, Manager
Environmental Engineering and
Hygiene
Attachment
ERA/CDFalkenberg/
. -.- -^ -•'-V, i 3 "^ ..>-^.
* • -.J •! -.^i r-^ ;VJ:
;^Bra»ii#.Tra
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3 WW2 «
" i i %^ 'i ii 4''.>-^li'^ k iu .^ in ;•
3
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I «o 1?«^' '
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-w=iiJ a^ ":»i'3l2 •^>^>-^9 3 BJ ;.' s 53 a in^pa 2 sw'a n a ad 2^a 83
..--i:o:fl- L"'!!'^ ^in,-k^;« ^-^*
1 iWs Asr I ij«<B
8 jn
H2 3O2 HCl HCN
ryi r*i pn M PM"-
i'7 ^\B^'3i (t,_«j 'W-3 2 w^»-i?2 " *2 " * '3
.i ; ;'^ •-»• il s s ^J
31
HON HF NHa^SO. F
r^ AsHa^^Ha SIH4 CI2 CO^Si^^ JHCI HCr
Ck CO2 H2 SOJ HC! HON HF NH3 SO^^lBrgAsH
PH, SiH4 CI2 CO^; H2 PH3 HCI HGNS HF NHp^Oa F
Bfj ASH3 PHr SiHi5^^;ui4^5&IHGllHiisii^feN
SO2 t, Br^ AsHa mslWjf^l^^HpNHlH
UiTS.? *W'
a •
IT
Br^ AsH, PH3 SJH4 CL CO, H^ SG^ HGl HCN HllNH
OUo To PHo SiH.i CL CO' i BO NH, HCl*He^
SS2000
800-451-9444
1- r-a uv^ r-- vfn wrrinrrtfiir—l]r'n---i>^M'"-Bt''fa'TMri iTn
Applications for Hz, HF, HCl, CI2, SO2,
HCIV, CO2, NH3, F2, BT2
Features:
(1) High Specificity
Sensidyne's diffusion t\pe electrochemical sensors are based
upon unique electroKtes, specifically designed for each gas
to he deteaed. Characterized by fast response and high
accuracy, these sensors have minimal interference from wind
speed, moisture or co-existing gases.
(2) RFI/EMI Shielding
False alarms are a continuous problem with other portables.
Every Sensid>Tie SS2000 is designed to prevent radio fre-
quency inferference and elearomagnetic interference (RFI/
EMI). This shield prevents false alarms caused by electrical
noise.
(3) Low Maintenance
Construaed of high impaa corrosion resistant plastic, the
SS2000 is built for rugged corrosive environments that often
attack hot wire, thermistor and solid state metal oxide sensors.
Incorporating common electronics, these instruments make
training and repair simple while holding down inventory^
spare parts costs. Designed for maintenance free operation,
the SS2000 femily of portables does not require pumps,
reagents or mechanical moving parts. All of these portables
are designed to withstand a wide range of temperatures. Ease
of maintenance and instrument life are further enhanced by
lengthy bum in time, rigorous testing before shipment and
conformal coated PC boards with gold contacts.
(4) Continuous Monitoring
SensidvTie's Portable SS2G00 ean be hand carried for contin-
uous monitoring of gas leaks. When combined with the
batterv' charger and optional wall mounting bracket, a contin-
uous fixed monitoring system is created. In a fixed wall
mount configuration, ifyou temporarily lose power, an inter-
nal battery takes over to safeguard your personnel. An
optional independent Class "C" contaa, single fxjle, double
throw, relay switch seleaable for latching and non-latching
is also available.
(5) Easy Calibration
Sensidyne offers various inexpensive, direct calibration kits
for flexible and economical calibration. It is not necessar\'to
open the instrument and no special tools are required for
performing a calibration. Sensidyne's sensors are not suscep-
tible to the excessive drift that plagues other sensors. This
means you have fewer calibrations, increased accuracy and
long term unattended operation.
(6) Long Life Sensors
These reliable diffusion-type electrochemical sensors are de-
signed for a specific gas to be detected. Sensidyne's durable
field proven sensors are ideal for corrosive.environments,
unlike solid state or hot wire sensors which are attacked by
corrosive gases. The sensor has an expected life of three years.
(7) Rechargeable Batteries
With rechargeable Nicad batteries the SS2000 will provide in
excess of 20 hours of continuous monitoring under normal
conditions. A battery charger is available with the SS2000
Portable.
(8) Intrinsically Safe
The SS2000 can operate safely in hazardous areas. It is intrisi-
cally safe for use in NEC Class 1, Division 1, Groups B, C and D
areas unless unit is used while charger is installed or when
used with relay switch option.
(9) Triple Alarm System
A loud (90 DBA) audible alarm and red LED alarm are acti-
vated when an alarm condition exists. The field adjustable
alarm set point can be conveniently set at the left side panel of
the SS2000, allowing you to change the setting without open-
ing the instrument. An additional alarm (LED) light comes on
automaucally when a low battery condition exists.
(10) Operates in O2 Free Environment
These elearochemical sensors can operate in an oxygen free
environment and are ideal when inen gas blankets are
required.
Other Features:
• A 1-5 Vdc recorder output • Optional contaa closure
• Alarm reset button • Optional wall mounting
• Adjustable alarm set button bracket
• Power "ON" light
Carrying Handle-
,Au^.. :•.;..;•
. 'Span, Zero A Alarm
Set (On Side Of Unit)-
•~JS.-
^-<-,(R««r Of UnH)
.iA^ Recorder Outpm • f
.•MUi."'..;-^.:':*V-rr^'r'.".i:?^^^.r;.:
-'^Alarm Sec. : (Depressing Button
Will DispUy Alarm
,Set Point On Meter)
AMMONIA
AURM
JJT
•1
<^
\^.-;• Tsr^ •/>7^:ii^-^:ji:
::;^^^.^:^,i-
•':-'.-^:'-'t:^'f*^y^'^;^^\'-:-',-'--
-Visual Alarm
^XS^^^iJ^JiSfffr^^- ^ •:.
".——Analog Meter •<irV':
-Alarm Reset / "'•
si^ (Shuts Off Active nv^Alarm)/:;;.v^,-;;iV;:
-Power Indicator
-Low Battery Alarm
-On ' Off Swtodi "
0%e] Specifications and ufdering Infonnation 800-451-9444
'•f T'f^ •'r.---{t'--'--"^-'- •^'•^'^ --—*-'if --••'TffM''"' •tiiBr*rrtTriiftM^i*Uingi'
Specifications
Detection
Principle
Measuring
Range
(PPM)
Adjustable
Alarm Point'
(PPM)
(Factory Set)
Response Time
To Alarm Point
(Time (sec.)/Exposed
to PPM)
Accuracy
Repeatability
Minimum
Readable
Concentration
Change (PPM)'
Temperature
Range
Humidity
Range
Sampling
Rate
Sensor
Life (In Years)
Battery
Life'
Dimensions
Weight
SS2000
H, Cl, F. Br, HCl HF SO,
Amperometric
Electrochemical
Diffusion-Type
0-4%
2%
Vol
<18/4%
0-3
0-10
0-100
0.5
1.0
10.0
< 5/2.5
<5/5
<5/50
0-10
1.0
<6/5
0-10
1.0
<6/5
0-10
5.0
<20/10
0-10
0-100
3.0
10.0
<15/10
<10/50
0-10
2.0
<10/10
= 10%
±10%
±0.2%
to 40° C
32° F
to 104° F
±0.15
=0.5
±5
±0.5
-5°Ct0 45°C 23°Ft0l13°F
±0.5
±5
=0.5
-5°Cto40°C
23°FtOl04°F
CO, NH, HCN
Potentiometric Electrochemical
Diffusion
1.000-
10,000
5,000
<30/
10,000
1-100
5-500
25
25
< 45/100
<35/125
.3-30
10.0
<30/30
= 10%
= 10%
= 150 = 0.5
±2.5
±0.15
-5°Ct0 45°C
23°Fto113°F
20% to 90% Relative Humidity/Non-Condensing
N/A
3 5 5 5 5 5 5 3 3 5
20 Hours (Rectiargeable)
8.5" H X 4.3" W X 6.8" D
216 mm H x 109 mm W x 173 mm D
3.4 Ibs
1.5 kg
SS4000
SiH. AsH, PH,
Controlled Potential
Electrolysis
Method
0-10
0-30
2.0
<10/10
0-1.0
0-5
0.2
<10/1
=8%
±5%
0.5
2
0.05
0.2
0°Cto40°C
32° Fto 104° F
20% to 90%
200 ml/min.
1 Year
Over 35 Hours
5.9-X 4.1-X 2.8"
148 mm X 104 mm X 70 mm
3.4 Ibs
1.5 kg
'Other alarm set points are available.
^The least concentration increment that can be read above the units' minimum read out indication.
'Expected battery life for nonalarm conditions.
Ordering Infomiation
SS2000-7011834( )
NH, (-1)
CI, (- 2 ) Speciiy Range
HCN (-3)
CO. (-5) F, (-15)
HF (-7) Speciiy Range SO, (-18)
HCI (-8) Br, (-22)
H, (-10)
SS4000
PH, 7010900-1
AsH, 7010901-1
SiH, 7010902-1
This brochure includes general specifications which are sub|ca to change without notice. Read and understand all applicable Federal, stale and local health and safetv laws and regulations
including OSHA and ensure TOU arc in complete compliance with said laws and reguladons before using these products. Read and understand all instructions before using these products.
^® 16333 Bay Vista Drive
B Clearwater, R 34620 USA.
800-451-9444
In norida(813) 530-3602
Telex 756223
Fax [phone]
CopvTight 1989 ©Sensidsne. Inc.
Rev. 9/92
HERCULES RECEIVED
m. 0 1 1993
Air Quality
\.
Hercules Aerospace Company
Space/Strategic Propulsion
Bacchus Works
Magna, Utah 84044-0098
[phone]
30 June 1993
F. Bumell Cordner
Division of Air Quality
Department of Environmental Quality
1950 West North Temple
Salt Lake City, Utah 84114-4820
Subject: Addendum to SCREEN Mcxleling for Remediation of Fluorine Cylinders at
Hercules Plant 1
Dear Mr. Cordner:
On June 10, 1993 Hercules delivered a report to the DAQ conceming SCREEN
modeling for remediation of fluorine cylinders at our Plant 1 facilities. Hercules wishes to
remediate these cylinders by venting them to the atmosphere. Venting would be
accomplished by means of a small explosive charge placed on the valve of each cylinder.
SCREEN modellmg included in the repon delivered June 10* indicated that the fenceline
concentration of fluorine would not exceed the TLV/100 value of 0.016 mg/m^
After preliminary review of this report, Mr. Bob Swart of your department
indicated that Hercules should consider two additional issues. First, the modeling conducted
to date considered oniy Stability Classes A through D. Mr. Swart indicated that we shouid
consider Stability Classes E and F even though .they are primarily considered night time
conditions. Secondly, the one scenario already presented considered only the closest
fenceline distance from the fluorine area which happened to be at a lower elevation. Mr.
Swart suggested that Hercules consider additionai fenceline locations that might actually be
farther away but at a higher elevation.
Stability Classes E and F
Modeling conducted on this effort to date only considered Stability classes A
through D as these are generally accepted daytime conditions. Stability classes E and F are
primarily night time conditions when positive vertical thermal gradients and calm conditions
lead to poor pollutant dispersion. These conditions can occur during the daytime, however,
under inversion circumstances.
For simple terrain, the SCREEN model considers only Stability classes A through
E, Stability class F is not included. The only time SCREEN considers Stability Class F is for
the single situation of complex terrain and rural conditions. Accordingly, only Stability class
E has been considered for additional modeling. The next table shows the Stability class E
m(xiel results in comparison to the modeling results previously presented:
Addendum to SCREEN Modeling for Remediation
of the Fluorine Transfer Station
Page 2
SCREEN MODEL RESULTS
Stability
Class
A
B
1 ^
D
jllig^^^^^
Fenceline Boundary Standard
TLV/100
0.016 mg/m^
0.016 mg/m^
0.016 mg/m'
0.016 mg/m' IIP^^^^^^^^^
SCREEN Prediction
8 Hour Fenceline Concentration
0.004 mg/m'
0.004 mg/m'
0.064 mg/m'
0.014 mg/m'
Onplant Exposure Limit
Distance to 0.16 mg/m'
193 meters
193 meters
269 meters
391 meters
The modelling shows that the 8 hour fenceline concentration for fluorine under
Stability class E conditions is 0.049 mg/m\ This value exceeds the applicable fenceline
standard of 0.016 mg/m\ Since the predicted fluorine concentration is more than three times
the limit, it is concluded that the fluorine cylinders cannot be remediated under Stability class
E conditions.
As mentioned above. Stability class E conditions occur mostly at night, but can
occur during the day depending on the season. Winter inversion conditions in the Salt Lake
valley can arguably be considered Stability class E or F conditions irregardless of the time of
day because of the opaque cloud cover and cold air drapped undemeath warm air. A daytime
Stability class E conditions would be considered rare in the summer or early fall because of
the high incidence of solar radiation and winds that accompany weather fronts.
There is no one to one correspondence between Stability class and clearing index.
According to the National Weather Service, the clearing index is a function of daily high
temperatures and wind speeds at the mixing height. Higher temperatures and higher elevated
wind speeds result in higher clearing indexes. It is arguable that a daytime clearing index
greater than 500 excludes Stability class E conditions. Solar radiation necessary to raise
temperatures and elevated wind speeds are botii factors typical of high clearing index days but
atypical of Stability class E and F conditions. Because of this, Hercules proposes that
fluorine remediation operations occtu- only on days where the clearing index exceeds 500.
This provision should assure that operations will not occur on days with Stability class E or F
conditions.
Elevated Terrain
The SCREEN model considers elevated terrain above stack height as "complex
terrain." The complex teirain portion of SCREEN uses a separate modeling routine known as
the VALLEY model. It produces 24 hour average pollutant concentrations. These
concentrations have to be mathematically adjusted to obtain 8 hour concentrations which can
Addendum to SCREEN Modeling for Remediation
of the Fluorine Transfer Station
Page 3
then be compared to TLV values. Using the SCREEN model documentation, it is clear that
the 24 hour pollutant concentrations must be multiplied by a factor of 1.75 in order to obtain
8 hoiu" concentrations.
The attached map shows the two additional locations considered. These points
were chosen as worst case situations because of their proximity to and elevation above the
fluorine station. Point A on the map is the location previously considered. Point B is
directly west of the fluorine area and is some 8.5 meters higher in elevation. Point C is to
the southwest and is 51 meters higher. For comparison purposes. Points B and C were
modelled assuming both simple terrain (no elevation change) and complex terrain features.
Inputs to the model (mass flow rate, stack height, etc.) were the same as used before. The
following table presents the results of the SCREEN modeling for these points:
SCREEN MODEL RESULTS
Stability
Class
D
E
Fenceline Boundary
Standard
(TLV/100)
0.016 mg/m'
0.016 mg/m'
Point A SCREEN
Prediction
(8 Hour)
0.014 mg/m'
-
Point B SCREEN
Prediction
(8 Hour)
0.012 mg/m'
(simple terrain)
0.0064 mg/m'
(complex terrain)
Point C SCREEN
Prediction
(8 Hour)
0.012 mg/m'
(simple terrain)
0.0064 mg/m'
(complex terrain)
NOTE: SCREEN model documentation states that complex terrain calculations consider only
Stability Class E conditions for urban settings
Point A is 1265 meters north and 69.2 meters lower than the fluorine station, this is the
fenceline location previously considered in the original memo.
Point B is 1341 meters west and 8.5 meters higher than the fluorine station.
Point C is 1337 meters southwest and 51.2 meters higher than the fluorine station.
Actual SCREEN printouts are attached as an addendum to this letter. It is apparent
that the two different models used by SCREEN for simple and complex terrain calculations
give significantiy different results. Surprisingly, the simple terrain model predicted nearly
twice the levels of pollutant concentration as predicted by the complex terrain model. In this
situation the simple terrain model appears to be more conservative. All of the predicted
fluorine concentrations are less than the fenceline standard (0.016 mg/m^). Thus the SCREEN
model predicts that the general populace will not be exposed to unacceptable levels of
fluorine at these other locations.
Addendum to SCREEN Modeling for Remediation
of the Fluorine Transfer Station
Page 4
This letter is considered an addendum to the report akeady submitted on 10 June of
this year. Please consult this original report for complete details on the assumptions and
procedures used for applying the SCREEN model to this situation. The original report also
contains additional background information on the fluorine station itself. If you develop any
further questions during review of tiiis issue, please contact me at 251-3574 or Chris
Falkenberg of my staff at 251-5313.
Sincerely,
~:Sji£^jL^
E. Richard Anderson, Manager
Environmental Engineering and
Hygiene
ERA/CDFalkenberg/
Attachments
SCREEN MODELING FOR STABILITY CLASS E
06-23--33
08:51:55
*** SCREEN-1.1 MODEL RUN ***
*** VERSION DATED 88300 ***
Fluorine Transfer Station, E Stability Class
SIMPLE TERRAIN INPUTS:
SOURCE TYPE
EMISSION RATE (G/S)
STACK HEIGHT (M)
STK INSIDE DIAM (M)
STK EXIT VELOCITY (M/Sl
STK GAS EXIT TEMP (K)
AMBIENT AIR TEMP (K)
RECEPTOR HEIGHT (M)
lOPT (1=URB,2=RUR)
BUILDING HEIGHT (M)
MIN HORIZ BLDG DIM (M)
MAX HORIZ BLDG DIM (M)
POINT
1.513
1
1
1
293
293
,00
00
00
00
00
,00
00
00
00
BUOY. FLUX = .00 M**4/S**3/ MOM. FLUX
*** STABILITY CLASS 5 ONLY ***
**********************************
*** SCREEN AUTOMATED DISTANCES ***
**********************************
25 M**4/S**2
*** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES >^**
DIST
(M)
100.
200.
300.
400.
500.
600.
700.
800.
900.
1000.
1100.
1200.
1300.
CONC
(UG/M**3)
5486.
1582.
765.5
462.5
315.6
232.4
180.4
145.3
120.5
102.2
88.21
77.25
68.48
STAB
5
5
5
5
5
5
5
5
5
5
5
5
5
UIOM
(M/S)
USTK
(M/S)
1
1
1
1
1,
1,
1,
1,
1.
1,
1,
1,
1,
,0
,0
0
0
0
0
0
0
0
0
0
0
0
MAXIMUM 1-HR CONCENTRATION AT OR BEYOND
100. 5486. 5 1.0 1.0
MIX HT PLUME
(M) HT (M)
5000.0
5000.0
5000.0
5000.0
5000.0
5000.0
5000.0
5000.0
5000.0
5000.0
5000.0
5000.0
5000.0
100. M:
5000.0
DWASH= MEANS NO CALC MADE (CONC =0.0)
DWASH=NO MEANS NO BUILDING DOWNWASH USED
DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED
DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED
DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB
*********************************
*** SCREEN DISCRETE DISTANCES ***
3
3,
3,
3,
3,
3,
3,
3,
3.
3,
3,
3,
3,
3.0
SIGMA
Y (M)
,2
2
,9
2
3
1
10
21
31
40
50
59
68
7 6v6
84.9
93.0
100.8
108.5
116.0
10.8
SIGMA
Z (M)
7
14
19
25
30
43
47
50
54
57
60
,5
,1
9
,3
2
34.8
39.1
7.5
DWASH
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
*********************************
*** TERRAIN HEIGHT OF M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES
DIST CONC UIOM USTK MIX HT PLUME SIGMA SIGMA
(M) (UG/M**3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DvTASH
1265 71.34 1.0 1.0 5000.0 3.0 113.4 59.5 NO
DWASH= MEANS NO CALC MADE (CONC = 0.0)
DWASH=NO MEANS NO BUILDING DOWNWASH USED
DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED
DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED
DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB
***************************************
*** SUMMARY OF SCREEN MODEL RESULTS ***
***************************************
CALCULATION
PROCEDURE
SIMPLE TERRAIN
MAX CONC
(UG/M**3)
5486.
DIST TO
MAX (M)
100.
TERRAIN
HT (M)
0.
***************************************************
** REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS **
***************************************************
SCREEN MODELING FOR ELEVATED TERRAIN
06-1
16:2
*** SCREEN-1.1 MODEL RUN ***
*** VERSION DATED 88300 ***
Complex Terrain Calculations, Fluorine Transfer Station
COMPLEX TERRAIN INPUTS:
SOURCE TYPE• = POINT
EMISSION RATE (G/S) = 1.513
STACK HT (M) = 1
STACK DIAMETER (M) = 1
STACK VELOCITY (M/S)= 1
STACK GAS TEMP (K) = 2 93.00
AMBIENT AIR TEMP (K)= 293.00
RECEPTOR HEIGHT (M) = .00
lOPT (1=URB,2=RUR) = 1
00
00
00
BUOY. FLUX = .00 M**4/S**3; MOM. FLUX 25 M**4/S**2
FINAL STABLE PLUME HEIGHT (M) = 1.2
DISTANCE TO FINAL RISE (M) = 200.2
TERR MAX 24-HR
HT DIST CONC
(M) (M) (UG/M**3)
*VALLEY 2 4-HR CALCS*
PLUME HT
CONC ABOVE STK
(UG/M**3) BASE (M)
**SIMPLE TERRAIN 24-HR CALCS**
PLUME HT
CONC ABOVE STK UIOM USTK
(UG/M**3) HGT (M) SC (M/S)
51.
9.
1337
1341
3
3
678
660
3.678
3.660
1.1
1.1
OOOO
OOOO
0 0 .0 .0
0 0 .0 .0
06-15-93
16:27:02
*** SCREEN-1.1 MODEL RUN ***
*** VERSION DATED 88300 ***
Complex Terrain Calculations, Fluorine Transfer Station
SIMPLE TERRAIN INPUTS:
SOURCE TYPE = POINT
EMISSION RATE (G/S) = 1.513
STACK HEIGHT (M) = 1.00
STK INSIDE-DIAM (M) = 1.00
STK EXIT VELOCITY (M/S)= 1.00
STK GAS EXIT TEMP (K) = 293.00
AMBIENT AIR TEMP (K) = 293.00
RECEPTOR HEIGHT (M) = .00
lOPT (1=URB,2=RUR) = 1
BUILDING HEIGHT (M) = .00
MIN HORIZ BLDG DIM (M) = .00
MAX HORIZ BLDG DIM (M) = .00
BUOY. FLUX = .00 M**4/S**3; MOM. FLUX
*** STABILITY CLASS 4 ONLY ***
**********************************
*** SCREEN AUTOMATED DISTANCES ***
,25 M**4/S**2
**********************************
*** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCI
DIST
(M)
100.
200.
300.
400.
500.
600.
700.
800.
900.
1000.
1100.
1200.
1300.
1400.
XIMUM
100.
CONC
(UG/M**3)
2166.
571.1
263.1
152.9
100.9
72.18
54.57
42.96
34.87
29.00
24.58
21.18
18.49
16.34
STAB
4
4
4
4
4
4
4
4
4
4
4
4
4
4
1-HR CONCENTRATION
2166. 4
UIOM
(M/S)
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
AT OR
1.0
USTK
(M/S)
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
BEYOND
1.0
MIX HT
(M)
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
320.0
100. M;
320.0
PLUME
HT (M)
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
SIGMA
Y (M)
15.7
30.8
45.4
59.4
73.0
86.2
99.0
111.4
123.5
135.2
146.7
157.8
168.7
179.3
15.7
SIGMA
Z (M)
13.8
27.2
40.2
52.9
65.3
77.3
89.1
100.6
111.8
122.8
133.5
144.1
154.4
164.5
13.8
r-,T '•,,-."
^". ^-z
-•0
WO
uo
wo
NO
1^!0
NO
NO
NO
NO
MO
NO
MO
NO
DWASH= MEANS NO CALC MADE (CONC = 0.0)
DWASH=NO MEANS NO BUILDING DOWNWASH USED
DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED
SCHULMAN-SCIRE DOWNWASH USED
DOWNWASH NOT APPLICABLE, X<3*LB
DWASH=SS MEANS
DWASH=NA MEANS
*********************************
*** SCREEN DISCRETE DISTANCES ***
*********************************
*** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES ***
DIST CONC UrOM USTK MIX HT PLUME SIGMA SIGMA
(M) (UG/M**3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH
1337
1341
17.64
17.56
4 1.0 1.0 320.0 3.0 172.7 158.1 NO
4 1.0 1.0 320.0 3.0 173.1 158.5 NO
DWASH= MEANS NO CALC MADE (CONC = 0.0)
DWASH=NO MEANS NO BUILDING DOWNWASH USED
DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED
DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED
DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB
***************************************
*** SUMMARY OF SCREEN MODEL RESULTS ***
***************************************
CALCULATION
PROCEDURE
SIMPLE TERRAIN
COMPLEX TERRAIN
MAX CONC
(UG/M**3)
2166.
3.678
DIST TO
MAX (M)
100.
1337.
TERRAIN
HT (M)
0.
51. [24-HR CONC)