&ER&
              United Slates
              Environmental Protection
              Agency
              Office of Radiation Programs
Eastern Environmental
Radiation Facility
1890 Federal Drive
Montgomery, AL 36109
EPA 520/5-87-005
June 1987
              Radiation
              EERF Standard Operating
              Procedures for Rn-222
              Measurement Using Charcoal
              Canisters

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                                    EPA 520/5-87-005
    EERF STANDARD OPERATING PROCEDURES FOR
RADON-222 MEASUREMENT USING CHARCOAL CANISTERS
                 David J.  Gray
                Sam T. Wtndham
                  March 1987
     U.S. Environmental Protection Agency
         Office of Radiation Programs

   Eastern Environmental Radiation Facility
              1890 Federal Drive
          Montgomery, Alabama  36109

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                  EERF Standard Operating Procedures for
              Radon-222 Measurement Using Charcoal Canisters

I.   Introduction

     Activated charcoal has a large affinity for several gases and vapors
including radon-222 (hereafter referred to as radon).  Radon Is sorbed
onto the charcoal grains and decays to several participate decay products:
radium A (polonium-218); radium B (lead-214); radium C (blsmuth-214);
radiunrC1 (polonlum-214); and radium 0 (lead-210).  Radon concentration Is
determined by counting the gamna ray emissions of both lead-214 (295 KeY
and 352 KeY) and bismuth-214 (609 KeY).  This Is possible due to the
relatively short half-life of these progeny.  Within 3 hours the progeny
are In equilibrium with radon-222.

     The passive nature of activated charcoal allows both adsorption and
desorption, and, in addition, the adsorbed radon undergoes radioactive
decay during the exposure period.  Therefore, the canister cannot
uniformly Integrate over the entire exposure period.  However,  the
canisters can be calibrated to yield precise results for radon
concentrations In structures during the deployment period of 48 hours  used
by the U.S. Environmental Protection Agency (EPA).

     The charcoal adsorption method has been reviewed extensively by Cohen
(Co83, Co86), Prichard (Pr85), and George (Ge84).  The EPA's canister  and
analysis technique most closely resemble George's work, differing only In
calibration aspects.

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II.  Materials and Equipment

A.   Charcoal Canister

     The passive radon charcoal canister used by the EPA consists  of  the
following materials: (1) 8 ounce metal  can with I1d (4 Inch diameter  by
1 1/8 Inch deep); (2) 70 ^ 1 grams of 6 X 16 mesh activated charcoal;
(3) metal screen, with an openness of at least 30 to SO percent;
(4) removable, Internally expanding retaining ring; (5) pad material
attached to the Inner surface of the lid; and (6) a 13 Inch strip  of
pliant vinyl tape.  The materials are assembled as seen In Figure  1.

     The activated charcoal must have low radioactivity content.
Specifically, gamma emitters, except for natural potasslum-40,  must be
less than 0.1 plcocurles per gram.

B.   Counting System

     The following components make up the counting system used  by  the
EPA's Eastern Environmental Radiation Facility:  (1) 3' by 3"
sodium-Iodide detector and photomultlpller tube Inside counting shield;
(2) high voltage power supply; (3) pre-amplifier and amplifier; (4) single
channel analyzer and sealer; (5) timer; (6) time of day clock;  and
(7) printer.

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          Pad attached to lid to retain
          screen during shipping
X
  Internal expanding
  stainless steel
  retainer ring
                                                8 ounce metal can
                                                 13" strip of vinyl tape
                 Stainless steel screen,
                 30-50 percent open
70 + 1 grams of 6 i 16 mesh charcoal
                  FIGURE 1
          Charcoal canister assembly

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     Four sodium fodlde detectors are served by a single high voltage
power supply, timer, printer,  and time of day clock.   Each detector has
Its own pre-ampllfler, amplifier-single channel analyzer, and sealer.  The
four detectors are arranged together Inside a shield  that has steel walls
8 Inches thick.  Within the shield the detectors are  separated  from each
other by 4 Inches of lead.  A wooden jig Is used on each detector to
assure consistent counting geometry for the canisters on the detector.
The arrangement of detectors In the shield and the electronics  are shown
In Figures 2 and 3.

     The counting system is operated in the single channel mode with a
lower discriminator setting of 270 KeV and an upper discriminator setting
of 720 KeV.  All counts in this region are summed during the counting
period.  A multi-channel analyzer is used once a week to assure there has
been no shift of the peaks In the region of interest.

C.   Radon Calibration Chamber

     The EERF uses 2 radon calibration chambers to expose charcoal
canisters and* other instruments to known concentrations of radon and radon
decay products in controlled environmental conditions.  Radium-226 sources
are used to provide radon which 1s continuously flowed through  the
chambers.  In the chamber, controlled conditions include relative humidity
(10 to 90 percent), temperature (0* to 40*C), condensation nuclei (10  to
106/ml), radon concentration (10 to 1,000 plcocuries  per liter
(pCI/liter), and radon decay product concentration or working level (WL)
(0.01 to 5 WL).

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           FIGURE  2
Four detectors 1n  counting  shield

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           FIGURE  3
Two shields with electronics

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     The temperature, tumidity,  radon concentration,  radon decay product
concentration, and condensation  nuclei concentration  are monitored
continuously and printed out each hour.  Radon concentrations are
monitored using a 0.5 liter flow through scintillation cell and decay
product concentrations are monitored by counting,  with a surface barrier
detector, the alpha activity from decay products collected on a filter.

     Grab samples in conjunction with the hourly printouts are used to
determine radon and decay product concentrations in the chambers.  The
grab samples, which are done In  conformance with recently published EPA
procedures (EPA86), are used to  calibrate the hourly  printouts.

0.   Standard and Background Canisters

     Counting system performance Is determined daily  by counting standard
canisters containing known radioactivity and background canisters.  The
standard canisters were made by  the quality assurance group at the EERF In
the following manner:  (1) a known activity of about  20.5 nd, liquid
radium-226 was slurried into the 70 grams of charcoal in a canister with
the retainer screen removed; (2) this was heated to dry all liquid from
the charcoal; (3) the canister was sealed by soldering a galvinized metal
disc in the can where the screen normally is located; (4) the lid was
placed on the canister and secured with tape; and  (5) the standard was
stored for thirty days to allow  secular equilibrium to be reached between
the radium, the radon, and the progeny.  Standard  and background canisters
were prepared for each crystal and are counted every  morning to establish

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a dally counting efficiency for each detector systea.  The counting
efficiency Is determined by counting the standard and background canisters
each for 10 minutes.   The background count Is subtracted from the  standard
count to get the net count.  This Is divided by the tine, 10 mfnutes, to
get net counts per minute (CPM).  By dividing the net CPU by the known
activity (pd) of the standard the efficiency (CPM/pCI) of the detector
for that day 1s determined.

E.   Scales

     Digital scales are used to weigh individual  canisters both before
shipment to the user and upon receipt after exposure.  This weight
difference, which relates to moisture gain or humidity, Is an integral
part of the calculation of radon concentration and will be explained In
greater detail in the next section.  Canisters are weighed to 0.1  gram
accuracy.
                                    8

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III. Laboratory Methods

A.   Canister Preparation

     Calibrations are run on representative samples of canisters  from each
new batch from a supplier.  As required by the EPA purchase contract, the
supplier identifies each batch by the color of the vinyl  tape used  to seal
the lid.  Gamma emitter content of the charocal  is also checked for each
batch to make sure no contaminated charcoal 1s being used.

     Each canister Is given an individual  serial  number.  This number Is
printed on the data label attached to the  top of  each canister.   Once this
label is attached, the canister is weighed and the weight 1s written on
the label and is automatically entered into the  EERF computer for that
respective canister serial number.  The canister  Is now ready to  use for
calibration runs or In a home for a radon  measurement.

B.   Calibration

     The response of charcoal canisters depends on the length of  time the
canister is exposed and on the amount of water gained during the  exposure.
This is because the charcoal has a strong  tendency to adsorb water  from
air.  For this reason the canister calibration Is a two step process
designed to adjust for both water gain and exposure time.  The following
steps are used to calibrate canisters:

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     1.   Chamber Preparation

     The charcoal canisters are calibrated to three timidity ranges (low,
medium, and high) over a  period of one to six days.  Low, medium, and high
humidity correspond approximately  to 20,  50,  and 80 percent humidity.  The
radon concentration In the chamber 1s kept as constant as possible during
the three runs.  The first step of this process, therefore, entails
stabilizing the chamber at the desired condition.

     2.   Canister Exposure Sequence

     When the chamber Is  stabilized, a set of 30 canisters Is put Into the
chamber and exposed In the following manner:   a group of five each for 1,
2, 3, 4, 5, and 6 days, respectively.  The canisters are opened Inside the
chamber and the exact start times  are recorded.  This exposure sequence Is
repeated twice more, once at each  of the  other two hualditles, to complete
the calibration run.

     3.   Removal and Counting

     At the end of each 1 day period specified above, a group of 5
canisters 1s removed for  counting.  The lids  are placed on the canister
while still Inside the chamber and the canisters are reooved, taped, and
the exact time Is recorded.  The canisters are allowed to sit for at least
3 hours to allow progeny  to equilibrate with  the radon before counting.
                                    10

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     Each canister 1s counted for ten minutes on a sodium-Iodide  detectors
described previously.  The count time and detector number are  recorded  so
that the efficiency of that detector, from previous counting of standard
and background, can be Incorporated In the calculation of calibration
factors.  After counting, the canisters are weighed and the weight
difference Is recorded.

     4.   Calculation of Calibration Factors

     A calibration factor 1s calculated for each canister using the
following equation:

     CF _          NET CPU	                     (Equation  1)  (Ge84)
             (Ts) (E) (RN) (OF)
where
     CF      = Calibration factor, radon adsorption rate (1/mln),
     NET CPH = Gross CPM for that canister - background CPM for that
               detector for that day,
     T       = Exposure time of the canister (minutes),
     E       = Detector efficiency for the appropriate detector (CPM/pCI),
     RN      = Radon concentration 1n the chamber for the exposure period
               (pCI/llter),
     OF      = Decay factor from the midpoint of exposure to the  time of
               counting, which Is calculated from
                             .693t                     .693t
               DF =  e'  T     »  i«*-\    or   e
                         'w»  R« (min)         c    5501 mln
                          i/t   n
where t   =  time 1n minutes from midpoint of exposure  to the start of
             counting.
                                    11

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     5.    Generation of Calibration Curves

     Calibration factors as derived from the equation above are  used to
generate two tables and two curves.  The first table, Table 1, relates
calibration factor to weight gain (water) for the canisters for  a  2 day
exposure, the time used by EPA for Its surveys (see  IV 0).  Data 1n this
table are plotted to generate Figure 4.   The second  table, Table 2,
relates  exposure time to adjustment factors  for 20,  50, and 80 percent
humidity.  The adjustment factor Is used to  modify the calibration factor
for exposure times different from the desired 2 day  exposure time.  If a
canister Is exposed for exactly 2 days,  the  adjustment factor Is 1.  This
1s explained In more detail In III C 5.   Data In this table are  plotted to
generate Figure 5.

     Figures 4 and 5 are typical calibration data that were developed for
a particular batch of canisters from a supplier.  New calibration  data are
developed and used with each different lot of canisters.

C.   Calculation of Radon 1n an Exposed Canister

     Equation 1 above nay be rearranged to solve for the  radon
concentration If the calibration factor Is known. This equation will be

     RN  ,          MET CPH	                    (Equation 2)
             (Ts) (E) (CF) (DF)
                                    12

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where
     RN      » Radon concentration In pCI/llter,
     NET CPM = Gross CPM for the canister - background CPN for that
               detector for that day,
     T      * = Canister exposure time (minutes),
     E       = Detector efficiency (CPM/pCI),
     CF      = Calibration factor, and
     OF      •= Decay factor from the midpoint of exposure to the start of
               counting.

                                  Table  1
                       Water Gain Versus Calibration
                       Factors For a 2 Day Exposure

Percent Humidity               Water Gain (g)            CF (I1ter/m1n)
20
20
20
20
20
50
50
50
50
50
80
80
80
80
80
0.0
0.0
0.0
0.0
0.0
1.7
1.8
1.9
1.8
1.8
7.7
7.5
7.7
7.9
7.9
0.105
0.101
0.105
0.110
0.107
0.098
0.094
0.097
0.102
0.096
0.077
0.082
0.076
0.076
0.078
                                    13

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                Table 2

Exposure Time Versus Adjustment Factors
  for Low. Medium,  and  High  Humidity
Time of Exposure
(Hours)
24
24
24
24
24
48
48
48
48
48
72
72
72
72
72
96
96
96
96
96
120
120
120
120
120
144
144
144
144
Adjustment Factors
20 Percent
0.137
0.143
0.141
0.135
0.138
0.107
0.110
0.105
0.101
0.105
0.087
0.091
0.088
0.083
0.085
0.074
0.080
0.075
0.074
0.075
0.070
0.073
0.071
0.069
0.071
0.064
0.068
0.064
0.062
50 Percent
0.132
0.137
0.132
0.126
0.127
0.096
0.102
0.097
0.094
0.098
0.075
0.079
0.075
0.073
0.075
0.058
0.062
0.059
0.057
0.060
0.051
0.054
0.051
0.050
0.052
0.045
0.047
0.047
0.044
(llter/mln)
80 Percent
0.116
0.125
0.118
0.117
0.118
0.077
0.082
0.076
0.076
0.078
0.048
0.051
0.051
0.046
0.049
0.035
0.034
0.033
0.033
0.034
0.023
0.025
0.024
0.023
0.023
0.018
0.019
0.016
0.018
                   14

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                                  FIGURE 4.  WATER GAIN VERSUS CALIBRATION FACTORS (CF)
                                                      FOR A TWO DAY EXPOSURE
                                                                     -«-     --•••••••••••••
                                                                     :&::::::»......!  ••
                                                                       *********
                                                       •••••••••••••••••••••••••••••••••••••a***
                                                          --•«••••••••»«••••••••••••*••••••••••*
                                                       »•-_.      -*•••*•«••••••••«••••••••••••
                                                       •••*••••••-.     ^•••••••••••••••••••••
.04-
.02'
I
0
                2.0
4.0
6.0
8.0
 I
10.0
12.0
14.0
160
  1
18.0
                                                                Water Gain (g)

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                   Figure 5. EXPOSURE TIME VERSUS ADJUSTMENT FACTORS (AF)
                             FOR LOW, MEDIUM, AND HIGH HUMIDITY
.14
.12
.10
.06
.06
.04
.02
          10     20     30    40     50    60     70     80     90     100    110    120    130    140    150
                                          Exposure Time  (Hours)

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     The following steps are  taken  to  analyze the canister and calculate
the radon concentration to which a  canister has been exposed:

     1.   Count the standard  canister  on the detector to be used.
Calculate the efficiency (E)  for that  detector 1n CPM/pCI as In section
II-D.  This efficiency Is used for  all  counting done on that detector  for
that day.

     2.   Count the background canister on the detector.  This background
count Is used for all counting done on that detector for that day.

     3.   Weigh the canister  to be  analyzed.   This weight gain In grams of
water during the exposure period Is referred to as (g) In Table 1 and
Figure 4.

     4.   Use the water gain  (g) on the X-axis on Figure 4 to  obtain an
Initial CF from the Y-axis.

     5.   If an exposure period other  than 48 hours was used,  this  Initial
CF must be adjusted to reflect the  actual  exposure time for the canister.
This Is done by using the water gain to select the appropriate humidity
curve on Figure 5.  The correct humidity curve Is selected based on the
following criteria:
              If (g) Is                     Use Curve for
          less than 1.0 g                   20 percent
          1.0 g to 4.0 g                    50 percent
          greater than 4.0 g                80 percent
                                    17

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     Using the correct water gain on the X-axis and relative humidity
curve on Figure 5, an adjustment factor (AF) Is selected from the Y-axis
and used to adjust the Initial CF (obtained In step 4 above) for the
exposure time.  This Is done as follows:

Final CF used in Eq. 2 = Initial CF   X     AF for actual exposure time
                                         AF for 2 day (48 hr) exposure time
     From this it is seen that If the actual exposure time 1s 48 hours the
AF becomes 1.0 and the initial CF Is actually the 'CF used In Equation 2.

     6.   The decay factor (OF) Is used to correct for radiological decay
between exposure and counting.  It Is calculated from the midpoint of
exposure to the start of counting using the formula
                    .693t
     OF
        =  6   ^1/2 ^or rad°n
where t is the tine from midpoint of exposure to the start of counting and
T. iy Is the half-life of radon.

EXAMPLE CALCULATION

     To calculate the concentration of radon in a canister we use
Equation 2,
     RM=          NET CPH
              (Ts) (E) (CF) (OF)
                                    18

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The data gfven for this example calculation are the following:

     Weight Out  •  158.7 g
     Weight In   »  161.1 g
     Exposure Period  =  12-29-86 at 1052 CST to
                         01-01-87 at 0950 CST
     Gross Counts  =  2,942 in 10 minutes
     Background Counts  =  721 in 10 minutes
     Standard Counts  =  58,423 in 10 minutes for a 20,549 pCI source

From these data, we first determine that
     Net CPM =
                          - 721     =  222 CPM
                      10 min.
     T       = 70 hours, 58 minutes = 4258 minutes, and

     E       =       (58.423 - 72D/10 minutes   = 0.281 CPM/pCi.
                            20,549 pCi
To determine the calibration factor (CF), we must refer to the equation
     CF  ,  Initial CF  X      AF for exposure time
                              AF for 2 day (48 hours)
and use the weight gain in our calculations.  In this example, the weight
gain during exposure was 2.4 g (161.1 g - 158.7 g).  From Figure 4, we
find that the initial CF for 2.4 g  -  0.094; and, according to Figure 5,
                                    19

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a 2.4 9 weight gain requires the use of the curve for SO percent
humidity.  Since a 2.4 g weight gain of 50 percent humidity results 1n an
AF for the actual exposure time (~ 71 hours) of 0.080 and an AT for 48
hours of 0.098, the final CF Is 0.077, as calculated by
     final CF  =  0.094  X      °'080     =  0.077 .
                                0.098
     The decay factor for Equation 2 Is calculated by
                    .693t
     DF •  ••  ^
where t   =  midpoint of exposure time to start of counting time,

                  2
             = 6,441 minutes,

and Tj ,2 of radon = 3.82 days or 5,501 minutes.  The decay factor then
Is calculated by

                 (.693) (6,441)
     OF =  e~  	 »
                     5,501

        =  0.444.
                                    20

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     The final radon concentration Is calculated by substituting the above
values Into Equation 2 as follows:
                        222
     RN =  	
            (4258) (0.281) (0.077) (0.444)
        =  5.4 pCi/liter.

     The 2-sigma counting error Is calculated as follows:
     2o.error  =  2   YGross counts * Background Counts
                        Gross counts - Background Counts
     2o error  =  2  V2.942 * 721  §
                       2,942 - 721
               =  .054.

               =  5.4 percent.

Therefore, the radon concentration was 5.4 pC1/liter ^ 5.4 percent.

D.   Calculation of Minimum Detectable Activity

     The minimum detectable activity (MDA) for measuring  radon using
charcoal canisters 1s a function of the background counting rate of the
counter system and the counting time (A163).  The MDA at  the 3-sigma
significance level Is given by
     HDA  .  3  X    V
                    BKG Count Time
                                    21

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where

     MDA  =  MOA as function of counts above background,
     BKG Count = Total background counts, and
     BKG Count Time = Counting time of background.

For the ECRF counting system, this calculates as
                           r750"
     MDA (CPU)  =  3  X  	 ,
                           10
                =  8.2 counts per minute.
This may be converted to activity of radon In pd/llter by  assuming
exposure conditions.  For our desired exposure conditions,  this calculates
as follows:

     Assumed conditions:
          Exposure time = 2 days (48 hours)
          Relative humidity - 50 percent (2 gram water gain)
          Time in shipment = 3 days (4,320 minutes)
          Counter efficiency = 0.28 CPM/pCi
          MDA (CPM) =8.2 (from above)
                        	MDA (CPH)	
     MOA  (pd/llter) =  (Exposure Tfme) (E) (CF)  (DF)
                                    8.2
                        (2.880) (0.28) (.098) (.48)
                     =  0.22 pd/llter

Since assumed conditions are not always met, In EERF data reports the MDA
Is conservatively reported as less than 0.5 pC1/liter.

                                    22

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E.   Quality Assurance Procedures

     The EERF radon calibration chambers are the principal  source  of
quality assurance exposures for charcoal canisters.  After  the  Initial
calibration run on each new batch of canisters from a supplier, periodic
checks are made on randomly selected canisters to assure no deviation.

     Reliability of the EERF calibration chambers Is assured through
several programs.  As described previously, the chamber Is  monitored
continuously while In operation.  Also, dally checks on the radon  and
       t
radon decay product concentrations are made using grab sampling
techniques.  These same techniques are used by the EERF In  national  and
International measurement cross-check programs.  The EERF participates  In
these programs every time they are offered, usually several times  per
year.  The EERF also sends groups of Us canisters to operators of other
radon calibration chambers for blind exposures as verification  checks.

     As part of the EERF's participation 1n the state radon survey
program, we request that the participating states expose duplicate
canisters and return them to the EERF for routine processing.  This Is
usually done In 5 percent of the homes surveyed.  The EERF  also requests
that the states submit blank canisters back to the EERF for analysis.
These are sent In by each state at a rate of approximately  2 canisters
per week.
                                    23

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     The sodium Iodide detectors and counting systems used for the
analysis of canisters are calibrated dally using standard sources
described 1n section II-D.  The standard count for each detector system
each day Is entered Into a computer maintained control chart  (Ro65).   If
the dally standard count exceeds the 2 slgma variation of the average  of
all previous counts for that system, the system Is not used for counting
until the cau'se of the excessive variation Is determined.  The same type
analysis Is also performed dally for a background canister on each system.

     In actual field use the coefficient of variation of a canister should
not exceed 10 percent at a radon concentration of 4 pCI/llter or greater.
This precision Is monitored using duplicate canisters (EPA86).
                                    24

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IY.  Survey Methods

A.   Shipping of Canisters

     Canisters are prepared for use as described In section III-A.  After
preparation they are Individually boxed and the Individual boxes are
packed Into a shipping case, usually 150 canisters per case.  These are
shipped to the users through normal commercial carriers.  An Individual
canister In its box may be mailed to a user.  Prepaid labels are used to
ship the Individual boxes to the user and a prepaid label Is provided to
return the canister from the user to the EERF.  Each Individual box has a
gummed flap for sealing the box prior to shipment.

B.   Deployment

     The charcoal canisters should be used as directed In the Interim
Indoor Radon and Radon Decay Product Measurement Protocols,
EPA 520/1-86-04, April 1986.  The protocols specify house conditions at
the time of measurement, provide Instructions on selecting the location
In the house at which to make the measurement, and suggest how to
interpretation of results.  Copies of the Interim Indoor Radon and Radon
Decay Product Measurement Protocol may be obtained by written request to
either of the following addresses:
     U.S. Environmental  Protection Agency        Eastern Environmental
     Office of Radiation Programs (ANR-458)        Radiation Facility
     401 M Street, S.W.                           1890 Federal  Drive
     Washington, DC  20460                       Montgomery,  AL  36109
                                    25

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Mtknblt drifU of on  open door, vlnden. flrtplKt. etc.  Ao unlitor «ho«U tt ti^ot»d to «1r
•toolo brtttht.   It  thovltf to p1*co« oo  o Ublt or thtlf ot looit t foot  obon ttt  floor MM
itald bt In optfl tfr. not In o clout. o>uor, cupbo*r4, ott.

    The unftttr should be  opened ind eiyoted U  the olr for t full dk/f (41 hours)  «»d the*
returned towdliUljr for procftslng.  foil* the HOCCDUK  btloi for optntng wd nttiMn( Ut
ckircpsl c«Miter.   Do  not  open  the coilstor  to begin  U*  octsvreocnt  If jov annot end the
          to f dfys.
                                       MKIDUU

1.  hone the tept fro* oround U« ceilttcr.  Sin the Upe to retool  the cutster ot the end of
    the BiiBrcotrt.

t.  Hoove OH lid fr» the unlsur.  Piece the lottr holf of the twister, wltt the screen si*
    op  lottft the open  olr,  on  o Uble  or  shelf  to  the  roc* chosen occordlof to the ibOM
    listrvctloM.

L  Mil to the tUrt fete end Hot oo the label on the uoliUr 114.

4.  After 2 foil d»/i (48 Hours), replace the  lid on the unfitcr ind rtMil  It *1U the Upe.

I.  fill In tht step  diU  end tloe on tte libel.  Tkls  Is  tirj totwrUnt.  Mso. pleise fill lo
    V* Inforttttlon requested (To Be tacleud B/ Occvpint) OB the other side of this sheet.

I.  Floce the canlsUr end this sheet  lo tht bo* provided.  Scol the boi is  shorn beloo end plice
    the iddreiwd. posuge-psld libel  « the be*.

I.  Ml the boi «tthlo 1 diy of reieilloi the emitter,  fc poiUoo Is  roojilrod.
                                     FIGURE  6
                               Instruction  sheet

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C.   Forms

     A combination data-Information form 1s shipped with each canister.
The Information side of the form contains detailed Instructions  for use
and return of the canister.  This form 1s shown In Figure 6.   The  other
side of the form consists of blanks to be completed by the homeowner and
the government agencies conducting the study.  This data form Is shown In
Figure 7.  Accurate and complete answers In the blanks are very  Important.

0.   Time Restrictions

     The following time restrictions,  In regard to exposure time and the
time In transit during return of the canister, are used 1n the EERF
programs.  The exposure time for the canister must not be less than 24
hours (1 day) nor longer than 144 hours (6 days).  The desired exposure
time Is 48 hours (2 days).  The time delay In returning the canister to
the EERF for processing should be as short as possible to avoid  excessive
decay.  All canisters received at the EERF are counted, regardless of the
delay time.  If the 3 slgma counting error 1s less than 100 percent, the
results are calculated.  If the 3 slgma counting error Is greater  than 100
percent, the canister Is not calculated.

E.   Reporting

     Usually, all canisters received at the EERF are counted  on  the day
they are received.  The EERF reports results from canisters processed each
two weeks.  The report contains data for the canisters received  during the
                                    27

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                               canna » KOTO?
kit Ml ttM JM lUltH Ml



f Urt *tt   /    /   TIM
IMMt

  HM
  m
                                      U8 teU    /  /
                                                                    Q*
                                                                    M III
1.   JoiUJ tip codt «t locttloa of
t.   T»t of bv1141»t In «ti«di •Nivrioent MS Mdi:  Q |1*«1« fully tarn
    Q HUI-f«
               U; building  Q builntu  Q Khoel  Q othtr
I.  Poor of kwlldlfig i**r* •"wcwnt nt Hdt:  Q biumit  Q ftrtl Hoar
       MC«rv4 floor or tbmt
                                                  fMll/ roM  Q ll»1ng roM
                                                  * othtr
4.  IOCB t* «Meh HiiureHnt Hi Hdt:  Q btdreoB  Q_f
    Q uiffnlihctf tatncnt Q offlci  Q cl»iveo J]

I.  Vert tiUrler doort tnd wtadoas Httljr oota or closttf Airing Ktuirnntt
    Q Hottl/ optn              Q Hoitlj cloud
        intt:
•ouu I.D. Code
ttologk Region Co*
                              FOR GOrUNCn OH

                                        bnliter
                                                        (On unliUr 1tb*l)
kit iKtlvtd
                                  (M HI


                            BlU Counted
Dttector liatar

Mlgkt Ait	



tnUrtd tar	
                                        •     d    jrr

                                        lr«u Ce»»U

                                        thlgkt I»	
                                                                     R
                                        Ckcctod tgr.

                                        fcrtflod tgr
                                 FIGURE  7
                               Data  form
                                   28

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previous two week period.  Summary reports may be provided on request.
The reports contain all  the responses to questions on the data forms.  If
a form was not fully completed, this section will be blank on the report.
Certain omissions, such  as a start or stop date/time, make It Impossible
to calculate a radon value.  The canister, however, Is counted and the
count data filed by canister serial number.  If the missing data are
supplied at a later date, the results will be calculated and reported on
the next repqrt.  If any Irregularities are noted In a canister, such as
the top not taped properly, this will be noted in the comment section of
the report.  The responsible agency conducting the survey will be notified
       i
by telephone if any canister result Is greater than 100 pCI/Hter.

     Agencies conducting surveys with the EERF canisters who have the
appropriate computer equipment may access their data directly in the CERF
computer.  They will be  given access only to their own data and will only
be able to receive data  from the EERF system.  The EERF also can arrange
to send data directly to agencies who have access to electronic mall.
Interested persons should contact the EERF to arrange to get computer
access or electronic mail.

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                                REFERENCES

A163     Altshuler, B. and Paste mack, B., Statistical Measures of the
         Lower Limit of Detection of a Radioactivity Counter, Health
         Physics, Vol. 9, pp. 293-298.

Co83     Cohen, B.L. and Cohen, E.S., Theory and Practice of Radon
         Monitoring by Adsorption In Charcoal, Health Physics, Vol. 45,
         No. 50, 1983.

Co86     Cohen, B.L. and Nason, R., A Diffusion Barrier Charcoal
         Adsorption Collector for Measuring Radon Concentration In Indoor
         Air, Health Physics, Vol. 50, No. 4, 1986.

EPA86    Environmental Protection Agency, Interim Indoor Radon and Radon
         Decay Product Measurement Protocols, EPA 520/1-86-04.

Ge84     George, A.C., Passive, Integrated Measurement of Indoor Air Using
         Activated Carbon, Health Physics, Vol. 46. No. 4. 1984.

Pr85     Prkhard, H.M. and Marlon, K., A Passive Diffusion Rn-222 Sampler
         Based on Activated Carbon Adsorption, Health Physics, Vol. 48,
         No. 6, 1985.

Ro65     Rosensteln, M. and Goldln, A.S., Statistical Techniques for
         Quality Control of Environmental Radloassay, Health Laboratory
         Science, Vol. 2, pp. 93-102.
                                    30

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     EWIROWEMM. RADIATION DMA  (ERD)  is  published   quarterly
(January,   April, July,  CctoEerT  by  the  0*   S.   Environmental
Protection Agency's Office of Radiation Programs.

     Requests for information concerning  publication and distribution
of ERD should be directed to:

                         Charles  H.  Petto
                     Technical  Support Branch
              Eastern Environmental Radiation Facility
                        1890 Federal Drive
                     Montgomery, Alabama  36109

     Requests for information   concerning  the  operation  of  ERAMS
should be directed to:

                     Charles  R.  Phillips, Chief
              Monitoring and  Analytical Services Branch
              Eastern Environmental Radiation Facility
                        1890 Federal Drive
                     Montgomery, Alabama  36109
                              or  to:
                      James H. Gunter, Chief
                Environmental Studies  and Statistics
               Analysis and Support Division (ANR-461)
                U.  S. Environmental Protection Agency
                        Waterside Mall East
                         401 H Street, SW
                      Washington, DC   20460
                                 ***

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