METHOD
5 - DETERMINATION OF PARTICULATE MATTER EMISSIONS FROM STATIONARY SOURCES
NOTE: This method does not include all of the
specifications (e.g.,
equipment and supplies) and procedures (e.g., sampling and analytical) essential to its
performance. Some material is incorporated by reference from other methods in
this part. Therefore, to obtain reliable results, persons using this method
should have a thorough knowledge of at least the following additional test
methods: Method 1, Method 2,
Method 3.
6.1.1.4 Differential Pressure Gauge
6.1.3
Gas Density Determination Equipment.
6.2.1
Probe-Liner and Probe-Nozzle Brushes.
6.2.3
Glass Sample Storage Containers.
6.2.5
Graduated Cylinder and/or Balance.
6.2.6
Plastic Storage Containers.
6.2.7
Funnel and Rubber Policeman.
8.0
Sample Collection, Preservation, Storage, and Transport.
8.1.3
Desiccate filters and ambient pressure
8.2
Preliminary Determinations.
8.3
Preparation of Sampling Train.
8.6
Calculation of Percent Isokinetic.
9.1
Miscellaneous Quality Control Measures
9.2
Volume Metering System Checks.
9.2.2 Calibrated Critical Orifice.
10.0
Calibration and Standardization.
10.3.1 Calibration Prior to Use
10.3.3 Acceptable Variation in Calibration.
10.4 Probe Heater Calibration.
12.0 Data Analysis and Calculations.
12.2 Average Dry Gas Meter Temperature and Average Orifice Pressure Drop.
12.4 Volume of Water Vapor Condensed.
12.6 Acetone Blank Concentration.
12.8 Total Particulate Weight.
12.9 Particulate Concentration.
12.12 Stack Gas Velocity and Volumetric Flow Rate
13.0 Method Performance. [Reserved]
14.0 Pollution Prevention. [Reserved]
15.0 Waste Management. [Reserved]
16.1 Dry Gas Meter as a Calibration Standard.
16.2 Critical Orifices As Calibration Standards.
16.2.1 Selection of Critical Orifices.
16.2.2 Critical Orifice Calibration.
16.2.3 Using the Critical Orifices as Calibration Standards.
18.0 Tables, Diagrams, Flowcharts, and Validation Data.
1.0 Scope and Application.
1.1 Analyte. Particulate matter (PM). No CAS number
assigned.
1.2 Applicability.
This method is applicable for the determination of PM emissions from stationary
sources.
1.3 Data Quality
Objectives. Adherence to the requirements of this method will enhance the
quality of the data obtained from air pollutant sampling methods.
2.0 Summary of Method.
Particulate matter is
withdrawn isokinetically from the source and collected on a glass fiber filter
maintained at a temperature of 120 ± 14¡C (248 ± 25¡F) or such other
temperature as specified by an applicable subpart of the standards or approved
by the Administrator for a particular application. The PM mass, which includes
any material that condenses at or above the filtration temperature, is
determined gravimetrically after the removal of uncombined water.
3.0 Definitions. [Reserved]
4.0 Interferences. [Reserved]
5.0 Safety.
5.1 Disclaimer. This
method may involve hazardous materials, operations, and equipment. This test
method may not address all of the safety problems associated with its use. It
is the responsibility of the user of this test method to establish appropriate
safety and health practices and to determine the applicability of regulatory
limitations prior to performing this test method.
6.0 Equipment and Supplies.
6.1 Sample Collection.
The following items
are required for sample collection:
6.1.1 Sampling Train.
A schematic of the
sampling train used in this method is shown in Figure 5-1
in Section 18.0. Complete construction details are given in APTD-0581 (Reference 2 in Section 17.0); commercial models of this
train are also available. For changes from APTD-0581 and for allowable
modifications of the train shown in Figure 5-1, see the following subsections.
NOTE: The operating and maintenance procedures for the
sampling train are described in APTD-0576 (Reference 3
in Section 17.0). Since correct usage is important in obtaining valid results,
all users should read APTD-0576 and adopt the operating and maintenance
procedures outlined in it, unless otherwise specified herein.
6.1.1.1 Probe Nozzle.
Stainless steel (316)
or glass with a sharp, tapered leading edge. The angle of taper shall be ²30¡,
and the taper shall be on the outside to preserve a constant internal diameter.
The probe nozzle shall be of the button-hook or elbow design, unless otherwise
specified by the Administrator. If made of stainless steel, the nozzle shall be
constructed from seamless tubing. Other materials of construction may be used,
subject to the approval of the Administrator. A range of nozzle sizes suitable
for isokinetic sampling should be available. Typical nozzle sizes range from
0.32 to 1.27 cm (1/8 to 1/2 in) inside diameter (ID) in increments of 0.16 cm
(1/16 in). Larger nozzles sizes are also available if higher volume sampling
trains are used. Each nozzle shall be calibrated, according to the procedures
outlined in Section 10.1.
6.1.1.2 Probe Liner.
Borosilicate or
quartz glass tubing with a heating system capable of maintaining a probe gas
temperature during sampling of 120 ± 14 ¡C (248 ± 25 ¡F), or such other
temperature as specified by an applicable subpart of the standards or as
approved by the Administrator for a particular application. Since the actual
temperature at the outlet of the probe is not usually monitored during
sampling, probes constructed according to APTD-0581 and utilizing the
calibration curves of APTD-0576 (or calibrated according to the procedure
outlined in APTD-0576) will be considered acceptable. Either borosilicate or
quartz glass probe liners may be used for stack temperatures up to about 480 ¡C
(900 ¡F); quartz glass liners shall be used for temperatures between 480 and
900 ¡C (900 and 1,650 ¡F). Both types of liners may be used at higher
temperatures than specified for short periods of time, subject to the approval
of the Administrator. The softening temperature for borosilicate glass is 820
¡C (1500¡F), and for quartz glass it is 1500 ¡C (2700 ¡F). Whenever practical,
every effort should be made to use borosilicate or quartz glass probe liners.
Alternatively, metal liners (e.g.,
316 stainless steel, Incoloy 825 or other corrosion resistant metals) made of
seamless tubing may be used, subject to the approval of the Administrator.
6.1.1.3 Pitot Tube.
Type S, as described
in Section 6.1 of Method 2, or other device
approved by the Administrator. The pitot tube shall be attached to the probe
(as shown in Figure 5-1) to allow constant monitoring of the stack gas
velocity. The impact (high pressure) opening plane of the pitot tube shall be
even with or above the nozzle entry plane (see Method
2, Figure 2-7) during sampling. The Type S pitot tube assembly shall have a
known coefficient, determined as outlined in Section
10.0 of Method 2.
6.1.1.4 Differential Pressure Gauge.
Inclined manometer or
equivalent device (two), as described in Section
6.2 of Method 2. One manometer shall be used for velocity head (¥p)
readings, and the other, for orifice differential pressure readings.
6.1.1.5 Filter Holder.
Borosilicate glass,
with a glass frit filter support and a silicone rubber gasket. Other materials
of construction (e.g.,
stainless steel, Teflon, or Viton) may be used, subject to the approval of the
Administrator. The holder design shall provide a positive seal against leakage
from the outside or around the filter. The holder shall be attached immediately
at the outlet of the probe (or cyclone, if used).
6.1.1.6 Filter Heating System.
Any heating system
capable of maintaining a temperature around the filter holder of 120 ± 14 ¡C
(248 ± 25 ¡F) during sampling, or such other temperature as specified by an
applicable subpart of the standards or approved by the Administrator for a
particular application.
6.1.1.7 Temperature Sensor.
A temperature sensor
capable of measuring temperature to within ±3 ¡C (5.4 ¡F) shall be installed so
that the sensing tip of the temperature sensor is in direct contact with the
sample gas, and the temperature around the filter holder can be regulated and
monitored during sampling.
6.1.1.8 Condenser.
The following system
shall be used to determine the stack gas moisture content: Four impingers
connected in series with leak-free ground glass fittings or any similar
leak-free noncontaminating fittings. The first, third, and fourth impingers
shall be of the Greenburg-Smith design, modified by replacing the tip with a
1.3 cm (1/2 in.) ID glass tube extending to about 1.3 cm (1/2 in.) from the
bottom of the flask. The second impinger shall be of the Greenburg-Smith design
with the standard tip. Modifications (e.g., using flexible connections between the impingers, using materials
other than glass, or using flexible vacuum lines to connect the filter holder
to the condenser) may be used, subject to the approval of the Administrator.
The first and second impingers shall contain known quantities of water (Section
8.3.1), the third shall be empty, and the fourth shall contain a known weight
of silica gel, or equivalent desiccant. A temperature sensor, capable of
measuring temperature to within 1 ¡C (2 ¡F) shall be placed at the outlet of
the fourth impinger for monitoring purposes. Alternatively, any system that
cools the sample gas stream and allows measurement of the water condensed and
moisture leaving the condenser, each to within 1 ml or 1 g may be used, subject
to the approval of the Administrator. An acceptable technique involves the
measurement of condensed water either gravimetrically or volumetrically and the
determination of the moisture leaving the condenser by: (1) monitoring the
temperature and pressure at the exit of the condenser and using Dalton's law of
partial pressures; or (2) passing the sample gas stream through a tared silica
gel (or equivalent desiccant) trap with exit gases kept below 20 ¡C (68 ¡F) and
determining the weight gain. If means other than silica gel are used to
determine the amount of moisture leaving the condenser, it is recommended that
silica gel (or equivalent) still be used between the condenser system and pump
to prevent moisture condensation in the pump and metering devices and to avoid
the need to make corrections for moisture in the metered volume.
NOTE: If a determination of the PM collected in the
impingers is desired in addition to moisture content, the impinger system
described above shall be used, without modification. Individual States or
control agencies requiring this information shall be contacted as to the sample
recovery and analysis of the impinger contents.
6.1.1.9 Metering System.
Vacuum gauge,
leak-free pump, temperature sensors capable of measuring temperature to within
3 ¡C (5.4 ¡F), dry gas meter (DGM) capable of measuring volume to within 2
percent, and related equipment, as shown in Figure 5-1. Other metering systems
capable of maintaining sampling rates within 10 percent of isokinetic and of
determining sample volumes to within 2 percent may be used, subject to the
approval of the Administrator. When the metering system is used in conjunction
with a pitot tube, the system shall allow periodic checks of isokinetic rates.
6.1.1.10 Sampling trains
Sampling trains
utilizing metering systems designed for higher flow rates than that described
in APTD- 0581 or APTD-0576 may be used provided that the specifications of this
method are met.
6.1.2 Barometer.
Mercury, aneroid, or
other barometer capable of measuring atmospheric pressure to within 2.5 mm Hg
(0.1 in.).
NOTE: The barometric pressure reading may be obtained
from a nearby National Weather Service station. In this case, the station value
(which is the absolute barometric pressure) shall be requested and an
adjustment for elevation differences between the weather station and sampling
point shall be made at a rate of minus 2.5 mm Hg (0.1 in.) per 30 m (100 ft)
elevation increase or plus 2.5 mm Hg (0.1 in) per 30 m (100 ft) elevation
decrease.
6.1.3 Gas Density Determination Equipment.
Temperature sensor
and pressure gauge, as described in Sections 6.3
and 6.4 of Method 2, and gas analyzer, if necessary, as described in Method
3. The temperature sensor shall, preferably, be permanently attached to the
pitot tube or sampling probe in a fixed configuration, such that the tip of the
sensor extends beyond the leading edge of the probe sheath and does not touch
any metal. Alternatively, the sensor may be attached just prior to use in the
field. Note, however, that if the temperature sensor is attached in the field,
the sensor must be placed in an interference-free arrangement with respect to
the Type S pitot tube openings (see Method 2,
Figure 2-4). As a second alternative, if a difference of not more than 1
percent in the average velocity measurement is to be introduced, the
temperature sensor need not be attached to the probe or pitot tube. (This
alternative is subject to the approval of the Administrator.)
6.2 Sample Recovery.
The following items
are required for sample recovery:
6.2.1 Probe-Liner and Probe-Nozzle Brushes.
Nylon bristle brushes
with stainless steel wire handles. The probe brush shall have extensions (at
least as long as the probe) constructed of stainless steel, Nylon, Teflon, or
similarly inert material. The brushes shall be properly sized and shaped to
brush out the probe liner and nozzle.
6.2.2 Wash Bottles.
Two Glass wash
bottles are recommended. Alternatively, polyethylene wash bottles may be used.
It is recommended that acetone not be stored in polyethylene bottles for longer
than a month.
6.2.3 Glass Sample Storage Containers.
Chemically resistant,
borosilicate glass bottles, for acetone washes, 500 ml or 1000 ml. Screw cap
liners shall either be rubberbacked Teflon or shall be constructed so as to be
leak-free and resistant to chemical attack by acetone. (Narrow mouth glass
bottles have been found to be less prone to leakage.) Alternatively,
polyethylene bottles may be used.
6.2.4 Petri Dishes.
For filter samples;
glass or polyethylene, unless otherwise specified by the Administrator.
6.2.5 Graduated Cylinder and/or Balance.
To measure condensed
water to within 1 ml or 0.5 g. Graduated cylinders shall have subdivisions no
greater than 2 ml.
6.2.6 Plastic Storage Containers.
Air-tight containers
to store silica gel.
6.2.7 Funnel and Rubber Policeman.
To aid in transfer of
silica gel to container; not necessary if silica gel is weighed in the field.
6.2.8 Funnel.
Glass or
polyethylene, to aid in sample recovery.
6.3 Sample Analysis.
The following
equipment is required for sample analysis:
6.3.1 Glass Weighing Dishes.
6.3.2 Desiccator.
6.3.3 Analytical Balance.
To measure to within
0.1 mg.
6.3.4 Balance.
To measure to within
0.5 g.
6.3.5 Beakers.
250 ml.
6.3.6 Hygrometer.
To measure the
relative humidity of the laboratory environment.
6.3.7 Temperature Sensor.
To measure the
temperature of the laboratory environment.
7.0 Reagents and Standards.
7.1 Sample Collection.
The following
reagents are required for sample collection:
7.1.1 Filters.
Glass fiber filters,
without organic binder, exhibiting at least 99.95 percent efficiency (<0.05 percent
penetration) on 0.3 micron dioctyl phthalate smoke particles. The filter
efficiency test shall be conducted in accordance with ASTM Method D 2986-71,
78, or 95a (incorporated by reference - see ¤60.17). Test data from the
supplier's quality control program are sufficient for this purpose. In sources
containing SO2 or SO3, the
filter material must be of a type that is unreactive to SO2 or SO3. Reference 10 in
Section 17.0 may be used to select the appropriate filter.
7.1.2 Silica Gel.
Indicating type, 6 to
16 mesh. If previously used, dry at 175 ¡C (350 ¡F) for 2 hours. New silica gel
may be used as received. Alternatively, other types of desiccants (equivalent
or better) may be used, subject to the approval of the Administrator.
7.1.3 Water.
When analysis of the
material caught in the impingers is required, deionized distilled water [to
conform to ASTM D 1193-77 or 91 Type 3 (incorporated by reference - see
¤60.17)] shall be used. Run blanks prior to field use to eliminate a high blank
on test samples.
7.1.4 Crushed Ice.
7.1.5 Stopcock Grease.
Acetone-insoluble,
heatstable silicone grease. This is not necessary if screw-on connectors with
Teflon sleeves, or similar, are used. Alternatively, other types of stopcock
grease may be used, subject to the approval of the Administrator.
7.2 Sample Recovery.
Acetone, reagent
grade, ²0.001 percent residue, in glass bottles, is required. Acetone from
metal containers generally has a high residue blank and should not be used.
Sometimes, suppliers transfer acetone to glass bottles from metal containers;
thus, acetone blanks shall be run prior to field use and only acetone with low
blank values (²0.001 percent) shall be used. In no case shall a blank value of
greater than 0.001 percent of the weight of acetone used be subtracted from the
sample weight.
7.3 Sample Analysis.
The following
reagents are required for sample analysis:
7.3.1 Acetone.
Same as in Section
7.2.
7.3.2 Desiccant.
Anhydrous calcium
sulfate, indicating type. Alternatively, other types of desiccants may be used,
subject to the approval of the Administrator.
8.1 Pretest Preparation.
It is suggested that sampling
equipment be maintained according to the procedures described in APTD-0576.
8.1.1 Silica Gel
Place 200 to 300 g of
silica gel in each of several air-tight containers. Weigh each container,
including silica gel, to the nearest 0.5 g, and record this weight. As an
alternative, the silica gel need not be preweighed, but may be weighed directly
in its impinger orsampling holder just prior to train assembly.
8.1.2 Check filters
Check filters
visually against light for irregularities, flaws, or pinhole leaks. Label
filters of the proper diameter on the backside near the edge using numbering
machine ink. As an alternative, label the shipping containers (glass or
polyethylene petri dishes), and keep each filter in its identified container at
all times except during sampling.
8.1.3 Desiccate filters and ambient pressure
Desiccate the filters
at 20 ± 5.6 ¡C (68 ± 10 ¡F) and ambient pressure for at least 24 hours. Weigh
each filter (or filter and shipping container) at intervals of at least 6 hours
to a constant weight (i.e.,
²0.5 mg change from previous weighing). Record results to the nearest 0.1 mg.
During each weighing, the period for which the filter is exposed to the
laboratory atmosphere shall be less than 2 minutes. Alternatively (unless
otherwise specified by the Administrator), the filters may be oven dried at 105
¡C (220 ¡F) for 2 to 3 hours, desiccated for 2 hours, and weighed. Procedures
other than those described, which account for relative humidity effects, may be
used, subject to the approval of the Administrator.
8.2 Preliminary Determinations.
8.2.1 Select the
sampling site and the minimum number of sampling points according to Method 1
or as specified by the Administrator. Determine the stack pressure,
temperature, and the range of velocity heads using Method 2; it is recommended
that a leak check of the pitot lines (see Method
2, Section 8.1) be performed. Determine the moisture content using
Approximation Method 4 or its alternatives for the purpose of making isokinetic
sampling rate settings. Determine
the stack gas dry molecular weight, as described in Method 2, Section 8.6; if integrated Method 3
sampling is used for molecular weight determination, the integrated bag sample
shall be taken simultaneously with, and for the same total length of time as,
the particulate sample run.
8.2.2 Select a nozzle
size based on the range of velocity heads, such that it is not necessary to
change the nozzle size in order to maintain isokinetic sampling rates. During
the run, do not change the nozzle size. Ensure that the proper differential
pressure gauge is chosen for the range of velocity heads encountered (see
Section 8.3 of Method 2).
8.2.3 Select a
suitable probe liner and probe length such that all traverse points can be
sampled. For large stacks, consider sampling from opposite sides of the stack
to reduce the required probe length.
8.2.4 Select a total
sampling time greater than or equal to the minimum total sampling time
specified in the test procedures for the specific industry such that (l) the
sampling time per point is not less than 2 minutes (or some greater time
interval as specified by the Administrator), and (2) the sample volume taken
(corrected to standard conditions) will exceed the required minimum total gas
sample volume. The latter is based on an approximate average sampling rate.
8.2.5 The sampling
time at each point shall be the same. It is recommended that the number of
minutes sampled at each point be an integer or an integer plus one-half minute,
in order to avoid timekeeping errors.
8.2.6 In some
circumstances (e.g., batch
cycles) it may be necessary to sample for shorter times at the traverse points
and to obtain smaller gas sample volumes. In these cases, the Administrator's
approval must first be obtained.
8.3 Preparation of Sampling Train.
8.3.1 During
preparation and assembly of the sampling train, keep all openings where contamination
can occur covered until just prior to assembly or until sampling is about to
begin. Place 100 ml of water in each of the first two impingers, leave the
third impinger empty, and transfer approximately 200 to 300 g of preweighed
silica gel from its container to the fourth impinger. More silica gel may be
used, but care should be taken to ensure that it is not entrained and carried
out from the impinger during sampling. Place the container in a clean place for
later use in the sample recovery. Alternatively, the weight of the silica gel
plus impinger may be determined to the nearest 0.5 g and recorded.
8.3.2 Using a tweezer
or clean disposable surgical gloves, place a labeled (identified) and weighed
filter in the filter holder. Be sure that the filter is properly centered and
the gasket properly placed so as to prevent the sample gas stream from
circumventing the filter. Check the filter for tears after assembly is
completed.
8.3.3 When glass
probe liners are used, install the selected nozzle using a Viton A O-ring when
stack temperatures are less than 260 ¡C (500 ¡F) or a heatresistant string
gasket when temperatures are higher. See APTD-0576 for details. Other
connecting systems using either 316 stainless steel or Teflon ferrules may be
used. When metal liners are used,
install the nozzle as discussed above or by a leak-free direct mechanical
connection. Mark the probe with heat resistant tape or by some other method to
denote the proper distance into the stack or duct for each sampling point.
8.3.4 Set up the
train as shown in Figure 5-1, using (if necessary) a very light coat of
silicone grease on all ground glass joints, greasing only the outer portion
(see APTD-0576) to avoid the possibility of contamination by the silicone
grease. Subject to the approval of the Administrator, a glass cyclone may be
used between the probe and filter holder when the total particulate catch is
expected to exceed 100 mg or when water droplets are present in the stack gas.
8.3.5 Place crushed
ice around the impingers.
8.4 Leak-Check Procedures.
8.4.1
Leak Check of Metering System Shown in Figure 5-1. That portion of the sampling
train from the pump to the orifice meter should be leak-checked prior to
initial use and after each shipment. Leakage after the pump will result in less
volume being recorded than is actually sampled. The following procedure is
suggested (see Figure 5-2): Close the main valve on the meter
box. Insert a one-hole rubber stopper with rubber tubing attached into the
orifice exhaust pipe. Disconnect and vent the low side of the orifice
manometer. Close off the low side orifice tap. Pressurize the system to 13 to
18 cm (5 to 7 in.) water column by blowing into the rubber tubing. Pinch off
the tubing, and observe the manometer for one minute. A loss of pressure on the
manometer indicates a leak in the meter box; leaks, if present, must be
corrected.
8.4.2 Pretest Leak
Check. A pretest leak check of the sampling train is recommended, but not
required. If the pretest leak check is conducted, the following procedure
should be used.
8.4.2.1 After the
sampling train has been assembled, turn on and set the filter and probe heating
systems to the desired operating temperatures. Allow time for the temperatures
to stabilize. If a Viton A O-ring or other leak-free connection is used in
assembling the probe nozzle to the probe liner, leak-check the train at the
sampling site by plugging the nozzle and pulling a 380 mm (15 in.) Hg vacuum.
NOTE: A lower vacuum may be used, provided that it is
not exceeded during the test.
8.4.2.2 If a
heat-resistant string is used, do not connect the probe to the train during the
leak check. Instead, leak-check
the train by first plugging the inlet to the filter holder (cyclone, if
applicable) and pulling a 380 mm (15 in.) Hg vacuum (see NOTE in Section 8.4.2.1). Then connect the probe to
the train, and leak-check at approximately 25 mm (1 in.) Hg vacuum;
alternatively, the probe may be leak-checked with the rest of the sampling
train, in one step, at 380 mm (15 in.) Hg vacuum. Leakage rates in excess of 4
percent of the average sampling rate or 0.00057 m3/min
(0.020 cfm), whichever is less, are unacceptable.
8.4.2.3 The following
leak-check instructions for the sampling train described in APTD-0576 and
APTD-0581 may be helpful. Start the pump with the bypass valve fully open and
the coarse adjust valve completely closed. Partially open the coarse adjust
valve, and slowly close the bypass valve until the desired vacuum is reached.
Do not reverse the direction of the bypass valve, as this will cause water to
back up into the filter holder. If the desired vacuum is exceeded, either
leak-check at this higher vacuum, or end the leak check and start over.
8.4.2.4 When the leak
check is completed, first slowly remove the plug from the inlet to the probe,
filter holder, or cyclone (if applicable), and immediately turn off the vacuum
pump. This prevents the water in the impingers from being forced backward into
the filter holder and the silica gel from being entrained backward into the
third impinger.
8.4.3
Leak Checks During Sample Run. If, during the sampling run, a component (e.g., filter assembly or impinger) change becomes necessary,
a leak check shall be conducted immediately before the change is made. The leak
check shall be done according to the procedure outlined in Section 8.4.2 above,
except that it shall be done at a vacuum equal to or greater than the maximum
value recorded up to that point in the test. If the leakage rate is found to be
no greater than 0.00057 m3/min (0.020 cfm) or 4 percent of the average
sampling rate (whichever is less), the results are acceptable, and no
correction will need to be applied to the total volume of dry gas metered; if,
however, a higher leakage rate is obtained, either record the leakage rate and
plan to correct the sample volume as shown in Section 12.3 of this method, or
void the sample run.
NOTE: Immediately after component changes, leak checks
are optional. If such leak checks are done, the procedure outlined in Section
8.4.2 above should be used.
8.4.4 Post-Test Leak
Check. A leak check of the sampling train is mandatory at the conclusion of each
sampling run. The leak check shall be performed in accordance with the
procedures outlined in Section 8.4.2, except that it shall be conducted at a
vacuum equal to or greater than the maximum value reached during the sampling
run. If the leakage rate is found to be no greater than 0.00057 m3/min (0.020 cfm) or 4 percent of the average sampling rate
(whichever is less), the results are acceptable, and no correction need be
applied to the total volume of dry gas metered. If, however, a higher leakage
rate is obtained, either record the leakage rate and correct the sample volume
as shown in Section 12.3 of this method, or void the
sampling run.
8.5 Sampling Train Operation.
During the sampling
run, maintain an isokinetic sampling rate (within 10 percent of true isokinetic
unless otherwise specified by the Administrator) and a temperature around the
filter of 120 ± 14 ¡C (248 ± 25 ¡F), or such other temperature as specified by
an applicable subpart of the standards or approved by the Administrator.
8.5.1 For each run,
record the data required on a data sheet such as the one shown in Figure 5-3. Be sure to record the initial DGM reading.
Record the DGM readings at the beginning and end of each sampling time
increment, when changes in flow rates are made, before and after each leak
check, and when sampling is halted. Take other readings indicated by Figure 5-3
at least once at each sample point during each time increment and additional
readings when significant changes (20 percent variation in velocity head
readings) necessitate additional adjustments in flow rate. Level and zero the
manometer. Because the manometer level and zero may drift due to vibrations and
temperature changes, make periodic checks during the traverse.
8.5.2 Clean the
portholes prior to the test run to minimize the chance of collecting deposited
material. To begin sampling, verify that the filter and probe heating systems
are up to temperature, remove the nozzle cap, verify that the pitot tube and
probe are properly positioned. Position the nozzle at the first traverse point
with the tip pointing directly into the gas stream. Immediately start the pump,
and adjust the flow to isokinetic conditions. Nomographs are available which aid
in the rapid adjustment of the isokinetic sampling rate without excessive
computations. These nomographs are designed for use when the Type S pitot tube
coefficient (Cp) is 0.85 ± 0.02, and the stack gas equivalent
density [dry molecular weight (Md)] is equal to 29 ± 4.
APTD-0576 details the procedure for using the nomographs. If Cp and Md are outside the above stated ranges, do not use
the nomographs unless appropriate steps (see Reference 7 in
Section 17.0) are taken to compensate for the deviations.
8.5.3 When the stack
is under significant negative pressure (i.e., height of impinger stem), take care to close
the coarse adjust valve before inserting the probe into the stack to prevent
water from backing into the filter holder. If necessary, the pump may be turned on with the coarse
adjust valve closed.
8.5.4 When the probe
is in position, block off the openings around the probe and porthole to prevent
unrepresentative dilution of the gas stream.
8.5.5 Traverse the stack
cross-section, as required by Method 1 or as specified by the Administrator,
being careful not to bump the probe nozzle into the stack walls when sampling
near the walls or when removing or inserting the probe through the portholes;
this minimizes the chance of extracting deposited material.
8.5.6 During the test
run, make periodic adjustments to keep the temperature around the filter holder
at the proper level; add more ice and, if necessary, salt to maintain a
temperature of less than 20 ¡C (68 ¡F) at the condenser/silica gel outlet.
Also, periodically check the level and zero of the manometer.
8.5.7 If the pressure
drop across the filter becomes too high, making isokinetic sampling difficult
to maintain, the filter may be replaced in the midst of the sample run. It is recommended that another complete
filter assembly be used rather than attempting to change the filter
itself. Before a new filter
assembly is installed, conduct a leak check (see Section 8.4.3). The total PM
weight shall include the summation of the filter assembly catches.
8.5.8 A single train
shall be used for the entire sample run, except in cases where simultaneous
sampling is required in two or more separate ducts or at two or more different
locations within the same duct, or in cases where equipment failure
necessitates a change of trains. In all other situations, the use of two or
more trains will be subject to the approval of the Administrator.
NOTE: When two or more trains are used, separate
analyses of the front-half and (if applicable) impinger catches from each train
shall be performed, unless identical nozzle sizes were used on all trains, in
which case, the front-half catches from the individual trains may be combined
(as may the impinger catches) and one analysis of front-half catch and one
analysis of impinger catch may be performed. Consult with the Administrator for
details concerning the calculation of results when two or more
trains are used.
8.5.9 At the end of
the sample run, close the coarse adjust valve, remove the probe and nozzle from
the stack, turn off the pump, record the final DGM meter reading, and conduct a
post-test leak check, as outlined in Section 8.4.4. Also, leak-check the pitot
lines as described in Method 2, Section 8.1.
The lines must pass this leak check, in order to validate the velocity head
data.
8.6 Calculation of Percent Isokinetic.
Calculate percent
isokinetic (see Calculations, Section 12.11) to
determine whether the run was valid or another test run should be made. If
there was difficulty in maintaining isokinetic rates because of source
conditions, consult with the Administrator for possible variance on the
isokinetic rates.
8.7 Sample Recovery.
8.7.1
Proper cleanup procedure begins as soon as the probe is removed from the stack
at the end of the sampling period. Allow the probe to cool.
8.7.2 When the probe
can be safely handled, wipe off all external PM near the tip of the probe
nozzle, and place a cap over it to prevent losing or gaining PM. Do not cap off
the probe tip tightly while the sampling train is cooling down. This would
create a vacuum in the filter holder, thereby drawing water from the impingers
into the filter holder.
8.7.3 Before moving
the sample train to the cleanup site, remove the probe from the sample train,
wipe off the silicone grease, and cap the open outlet of the probe. Be careful
not to lose any condensate that might be present. Wipe off the silicone grease from the filter inlet where the
probe was fastened, and cap it. Remove the umbilical cord from the last
impinger, and cap the impinger. If a flexible line is used between the first
impinger or condenser and the filter holder, disconnect the line at the filter
holder, and let any condensed water or liquid drain into the impingers or
condenser. After wiping off the silicone grease, cap off the filter holder
outlet and impinger inlet. Either groundglass stoppers, plastic caps, or serum
caps may be used to close these openings.
8.7.4 Transfer the
probe and filter-impinger assembly to the cleanup area. This area should be
clean and protected from the wind so that the chances of contaminating or
losing the sample will be minimized.
8.7.5 Save a portion
of the acetone used for cleanup as a blank. Take 200 ml of this acetone
directly from the wash bottle being used, and place it in a glass sample
container labeled "acetone blank."
8.7.6 Inspect the
train prior to and during disassembly, and note any abnormal conditions. Treat
the samples as follows:
8.7.6.1 Container No.
1. Carefully remove the filter from the filter holder, and place it in its
identified petri dish container. Use a pair of tweezers and/or clean disposable
surgical gloves to handle the filter. If it is necessary to fold the filter, do
so such that the PM cake is inside the fold. Using a dry Nylon bristle brush
and/or a sharp-edged blade, carefully transfer to the petri dish any PM and/or
filter fibers that adhere to the filter holder gasket. Seal the container.
8.7.6.2
Container No. 2. Taking care to see that dust on the outside of the probe or
other exterior surfaces does not get into the sample, quantitatively recover PM
or any condensate from the probe nozzle, probe fitting, probe liner, and front
half of the filter holder by washing these components with acetone and placing
the wash in a glass container. Deionized distilled water may be used instead of
acetone when approved by the Administrator and shall be used when specified by
the Administrator. In these cases, save a water blank, and follow the
Administrator's directions on analysis. Perform the acetone rinse as follows:
8.7.6.2.1 Carefully
remove the probe nozzle. Clean the inside surface by rinsing with acetone from
a wash bottle and brushing with a Nylon bristle brush. Brush until the acetone
rinse shows no visible particles, after which make a final rinse of the inside
surface with acetone.
8.7.6.2.2 Brush and
rinse the inside parts of the fitting with acetone in a similar way until no visible
particles remain.
8.7.6.2.3 Rinse the
probe liner with acetone by tilting and rotating the probe while squirting
acetone into its upper end so that all inside surfaces will be wetted with
acetone. Let the acetone drain from the lower end into the sample container. A
funnel (glass or polyethylene) may be used to aid in transferring liquid washes
to the container. Follow the acetone rinse with a probe brush. Hold the probe in an inclined position,
squirt acetone into the upper end as the probe brush is being pushed with a
twisting action through the probe; hold a sample container underneath the lower
end of the probe, and catch any acetone and particulate matter that is brushed
from the probe. Run the brush through the probe three times or more until no
visible PM is carried out with the acetone or until none remains in the probe
liner on visual inspection. With stainless steel or other metal probes, run the
brush through in the above-prescribed manner at least six times since metal
probes have small crevices in which particulate matter can be entrapped. Rinse
the brush with acetone, and quantitatively collect these washings in the sample
container. After the brushing, make a final acetone rinse of the probe.
8.7.6.2.4 It is recommended
that two people clean the probe to minimize sample losses. Between sampling
runs, keep brushes clean and protected from contamination.
8.7.6.2.5 After
ensuring that all joints have been wiped clean of silicone grease, clean the
inside of the front half of the filter holder by rubbing the surfaces with a
Nylon bristle brush and rinsing with acetone. Rinse each surface three times or
more if needed to remove visible particulate. Make a final rinse of the brush
and filter holder. Carefully rinse out the glass cyclone, also (if applicable).
After all acetone washings and particulate matter have been collected in the
sample container, tighten the lid on the sample container so that acetone will
not leak out when it is shipped to the laboratory. Mark the height of the fluid
level to allow determination of whether leakage occurred during transport.
Label the container to identify clearly its contents.
8.7.6.3
Container No. 3. Note the color of the indicating silica gel to determine
whether it has been completely spent, and make a notation of its condition.
Transfer the silica gel from the fourth impinger to its original container, and
seal. A funnel may make it easier to pour the silica gel without spilling. A
rubber policeman may be used as an aid in removing the silica gel from the
impinger. It is not necessary to remove the small amount of dust particles that
may adhere to the impinger wall and are difficult to remove. Since the gain in
weight is to be used for moisture calculations, do not use any water or other
liquids to transfer the silica gel. If a balance is available in the field,
follow the procedure for Container No. 3 in Section 11.2.3.
8.7.6.4 Impinger
Water. Treat the impingers as follows: Make a notation of any color or film in
the liquid catch. Measure the liquid that is in the first three impingers to
within 1 ml by using a graduated cylinder or by weighing it to within 0.5 g by
using a balance. Record the volume or weight of liquid present. This information
is required to calculate the moisture content of the effluent gas. Discard the
liquid after measuring and recording the volume or weight, unless analysis of
the impinger catch is required (see NOTE, Section 6.1.1.8). If a different type of condenser is used,
measure the amount of moisture condensed either volumetrically or
gravimetrically.
8.8 Sample Transport.
Whenever possible,
containers should be shipped in such a way that they remain upright at all
times.
9.0 Quality Control.
9.1 Miscellaneous Quality Control Measures
9.2 Volume Metering System Checks.
The following
procedures are suggested to check the volume metering system calibration values
at the field test site prior to sample collection. These procedures are
optional.
9.2.1 Meter Orifice Check.
Using the calibration
data obtained during the calibration procedure described in Section 10.3,
determine the ¥H@ for the metering system orifice. The ¥H@ is the orifice pressure differential in units of in. H20 that correlates to 0.75 cfm of air at
528 ¡R and 29.92 in.
Hg. The ¥H@ is calculated as follows:where:
¥H = Average pressure
differential across the orifice meter, in. H20.
Tm = Absolute average DGM temperature, ¡R.
Pbar = Barometric pressure, in. Hg.
¥ = Total sampling
time, min.
Y = DGM calibration
factor, dimensionless.
Vm = Volume of gas sample as measured by DGM, dcf. 0.0319 = (0.0567
in. Hg/¡R)(0.75 cfm)2
9.2.1.1 Before
beginning the field test (a set of three runs usually constitutes a field test),
operate the metering system (i.e.,
pump, volume meter, and orifice) at the ¥H@ pressure
differential for 10 minutes. Record the volume collected, the DGM temperature,
and the barometric pressure. Calculate a DGM calibration check value, Yc, as follows:
where:
Yc = DGM calibration check value, dimensionless.
10 = Run time, min.
9.2.1.2 Compare the Yc value with the dry gas meter calibration factor Y to determine
that: 0.97Y < Yc
< 1.03Y. If the Yc value is not within this range, the volume metering system should
be investigated before beginning the test.
9.2.2 Calibrated Critical Orifice.
A critical orifice,
calibrated against a wet test meter or spirometer and designed to be inserted
at the inlet of the sampling meter box, may be used as a check by following the
procedure of Section 16.2.
10.0 Calibration and Standardization.
NOTE: Maintain a laboratory log of all calibrations.
10.1 Probe Nozzle.
Probe nozzles shall
be calibrated before their initial use in the field. Using a micrometer,
measure the ID of the nozzle to the nearest 0.025 mm (0.001 in.). Make three
separate measurements using different diameters each time, and obtain the
average of the measurements. The difference between the high and low numbers
shall not exceed 0.1 mm (0.004 in.). When nozzles become nicked, dented, or
corroded, they shall be reshaped, sharpened, and recalibrated before use. Each
nozzle shall be permanently and uniquely identified.
10.2 Pitot Tube Assembly.
The Type S pitot tube
assembly shall be calibrated according to the procedure outlined in Section 10.1 of Method 2.
10.3 Metering System.
10.3.1 Calibration Prior to Use.
Before its initial
use in the field, the metering system shall be calibrated as follows: Connect
the metering system inlet to the outlet of a wet test meter that is accurate to
within 1 percent. Refer to Figure 5-4. The wet test meter
should have a capacity of 30 liters/rev (1 ft3/rev).
A spirometer of 400 liters (14 ft3) or more
capacity, or equivalent, may be used for this calibration, although a wet test
meter is usually more practical. The wet test meter should be periodically
calibrated with a spirometer or a liquid displacement meter to ensure the
accuracy of the wet test meter. Spirometers or wet test meters of other sizes
may be used, provided that the specified accuracies of the procedure are
maintained. Run the metering
system pump for about 15 minutes with the orifice manometer indicating a median
reading as expected in field use to allow the pump to warm up and to permit the
interior surface of the wet test meter to be thoroughly wetted. Then, at each
of a minimum of three orifice manometer settings, pass an exact quantity of gas
through the wet test meter and note the gas volume indicated by the DGM. Also
note the barometric pressure and the temperatures of the wet test meter, the
inlet of the DGM, and the outlet of the DGM. Select the highest and lowest
orifice settings to bracket the expected field operating range of the orifice.
Use a minimum volume of 0.14 m3 (5 ft3) at all orifice settings. Record all the data on a form similar to
Figure 5-5 and calculate Y, the DGM calibration factor,
and ¥H@, the orifice calibration factor, at each
orifice setting as shown on Figure 5-5. Allowable tolerances for individual Y
and ¥H@ values are given in Figure 5-5. Use the average
of the Y values in the calculations in Section 12.0.
10.3.1.1 Before calibrating
the metering system, it is suggested that a leak check be conducted. For
metering systems having diaphragm pumps, the normal leak-check procedure will
not detect leakages within the pump. For these cases the following leak-check
procedure is suggested: make a 10-minute calibration run at 0.00057 m3/min (0.020 cfm). At the end of the run, take the difference of the
measured wet test meter and DGM volumes. Divide the difference by 10 to get the
leak rate. The leak rate should not exceed 0.00057 m3/min (0.020 cfm).
10.3.2 Calibration After Use.
After each field use,
the calibration of the metering system shall be checked by performing three
calibration runs at a single, intermediate orifice setting (based on the
previous field test), with the vacuum set at the maximum value reached during
the test series. To adjust the vacuum, insert a valve between the wet test
meter and the inlet of the metering system. Calculate the average value of the
DGM calibration factor. If the value has changed by more than 5 percent,
recalibrate the meter over the full range of orifice settings, as detailed in
Section 10.3.1.
NOTE: Alternative procedures (e.g., rechecking the orifice meter coefficient) may
be used, subject to the approval of the Administrator.
10.3.3 Acceptable Variation in Calibration.
If the DGM
coefficient values obtained before and after a test series differ by more than
5 percent, the test series shall either be voided, or calculations for the test
series shall be performed using whichever meter coefficient value (i.e., before or after) gives the lower value of
total sample volume.
10.4 Probe Heater Calibration.
Use a heat source to
generate air heated to selected temperatures that approximate those expected to
occur in the sources to be sampled. Pass this air through the probe at a
typical sample flow rate while measuring the probe inlet and outlet
temperatures at various probe heater settings. For each air temperature
generated, construct a graph of probe heating system setting versus probe outlet
temperature. The procedure outlined in APTD-0576 can also be used. Probes
constructed according to APTD-0581 need not be calibrated if the calibration
curves in APTD-0576 are used. Also, probes with outlet temperature monitoring
capabilities do not require calibration.
NOTE: The probe heating system shall be calibrated
before its initial use in the field.
10.5 Temperature Sensors.
Use the procedure in Section 10.3 of Method 2 to calibrate in-stack
temperature sensors. Dial thermometers, such as are used for the DGM and
condenser outlet, shall be calibrated against mercuryin-glass thermometers.
10.6 Barometer.
Calibrate against a
mercury barometer.
11.0 Analytical Procedure.
11.1 Record the data required
on a sheet such as the one shown in Figure 5-6.
11.2 Handle each
sample container as follows:
11.2.1 Container No.
1. Leave the contents in the shipping container or transfer the filter and any
loose PM from the sample container to a tared glass weighing dish. Desiccate
for 24 hours in a desiccator containing anhydrous calcium sulfate. Weigh to a
constant weight, and report the results to the nearest 0.1 mg. For the purposes
of this section, the term "constant weight" means a difference of no
more than 0.5 mg or 1 percent of total weight less tare weight, whichever is
greater, between two consecutive weighings, with no less than 6 hours of
desiccation time between weighings. Alternatively, the sample may be oven dried
at 104 ¡C (220 ¡F) for 2 to 3 hours, cooled in the desiccator, and weighed to a
constant weight, unless otherwise specified by the Administrator. The sample
may be oven dried at 104 ¡C (220 ¡F) for 2 to 3 hours. Once the sample has
cooled, weigh the sample, and use this weight as a final weight.
11.2.2 Container No.
2. Note the level of liquid in the container, and confirm on the analysis sheet
whether leakage occurred during transport. If a noticeable amount of leakage
has occurred, either void the sample or use methods, subject to the approval of
the Administrator, to correct the final results. Measure the liquid in this
container either volumetrically to ± 1 ml or gravimetrically to ± 0.5 g.
Transfer the contents to a tared 250 ml beaker, and evaporate to dryness at
ambient temperature and pressure. Desiccate for 24 hours, and weigh to a
constant weight. Report the results to the nearest 0.1 mg.
11.2.3
Container No. 3. Weigh the spent silica gel (or silica gel plus impinger) to
the nearest 0.5 g using a balance. This step may be conducted in the field.
11.2.4 Acetone Blank
Container. Measure the acetone in this container either volumetrically or
gravimetrically. Transfer the acetone to a tared 250 ml beaker, and evaporate
to dryness at ambient temperature and pressure. Desiccate for 24 hours, and
weigh to a constant weight. Report the results to the nearest 0.1 mg.
NOTE: The contents of Container No. 2 as well as the
acetone blank container may be evaporated at temperatures higher than ambient.
If evaporation is done at an elevated temperature, the temperature must be
below the boiling point of the solvent; also, to prevent "bumping,"
the evaporation process must be closely supervised, and the contents of the
beaker must be swirled occasionally to maintain an even temperature. Use
extreme care, as acetone is highly flammable and has a low flash point.
12.0 Data Analysis and
Calculations.
Carry out
calculations, retaining at least one extra significant figure beyond that of
the acquired data. Round off figures after the final calculation. Other forms
of the equations may be used, provided that they give equivalent results.
12.1 Nomenclature.
An = Cross-sectional area of nozzle, m2 (ft2).
Bws = Water vapor in the gas stream, proportion by
volume.
Ca = Acetone blank residue concentration, mg/mg.
cs = Concentration of particulate matter in stack gas, dry basis,
corrected to standard conditions, g/dscm (gr/dscf).
I = Percent of
isokinetic sampling.
L1 = Individual leakage rate observed during the leak-check conducted
prior to the first component change, m3/min (ft3/min)
La = Maximum acceptable leakage rate for either a pretest leak-check
or for a leak-check following a component change; equal to 0.00057
m3/min (0.020 cfm) or 4 percent of the average sampling rate,
whichever is less.
Li = Individual leakage rate observed during the leak-check conducted
prior to the "ith"
component change (i =
1, 2, 3...n), m3/min (cfm).
Lp = Leakage rate observed during the post-test leak-check, m3/min (cfm).
ma = Mass of residue of acetone after evaporation, mg.
mn = Total amount of particulate matter collected, mg.
Mw = Molecular weight of water, 18.0 g/g-mole (18.0 lb/lb-mole).
Pbar = Barometric pressure at the sampling site, mm
Hg (in. Hg).
Ps = Absolute stack gas pressure, mm Hg (in. Hg).
Pstd = Standard absolute pressure, 760 mm Hg (29.92
in. Hg).
R = Ideal gas
constant, 0.06236 [(mm Hg)(m3)]/[(K)(g-mole)]
{21.85 [(in. Hg)(ft3)]/[(¡R)(lb-mole)]}.
Tm = Absolute average DGM temperature (see Figure 5-3), K (¡R).
Ts = Absolute average stack gas temperature (see Figure 5-3), K (¡R).
Tstd = Standard absolute temperature, 293 K (528 ¡R).
Va = Volume of acetone blank, ml.
Vaw = Volume of acetone used in wash, ml.
Vlc = Total volume of liquid collected in impingers
and silica gel (see Figure 5-6), ml.
Vm = Volume of gas sample as measured by dry gas meter, dcm (dcf).
Vm(std)= Volume of gas sample measured by the dry gas
meter, corrected to standard conditions, dscm (dscf).
Vw(std)= Volume of water vapor in the gas sample,
corrected to standard conditions, scm (scf).
vs = Stack gas velocity, calculated by Method 2, Equation 2-7, using
data obtained from Method 5, m/sec (ft/sec).
Wa = Weight of residue in acetone wash, mg.
Y = Dry gas meter
calibration factor.
¥H = Average pressure
differential across the orifice meter (see Figure 5-4), mm H20 (in. H20).
¥a = Density of acetone, mg/ml (see label on bottle).
¥w = Density of water, 0.9982 g/ml (0.002201 lb/ml).
¥ = Total sampling
time, min.
¥l = Sampling time interval, from the beginning of a run until the
first component change, min.
¥i = Sampling time interval, between two successive component changes,
beginning with the interval between the first and second changes, min.
¥p = Sampling time interval, from the final (nth) component change until the end of the sampling run, min.
13.6 = Specific
gravity of mercury.
60 = Sec/min.
100 = Conversion to
percent.
12.2 Average Dry Gas Meter Temperature and Average Orifice Pressure Drop.
See data sheet (Figure 5-3).
12.3 Dry Gas Volume.
Correct the sample
volume measured by the dry gas meter to standard conditions (20 ¡C, 760 mm Hg or
68 ¡F, 29.92 in. Hg) by using Equation 5-1.
where:
K1 = 0.3858 ¡K/mm Hg for metric units,
= 17.64 ¡R/in. Hg for
English units.
NOTE: Equation 5-1 can be used as written unless the
leakage rate observed during any of the mandatory leak checks (i.e., the
post-test leak check or leak checks conducted prior to component changes)
exceeds La. If Lp or Li exceeds La, Equation 5-1 must be modified as follows: (a)
Case I. No component changes made during sampling run. In this case, replace Vm in Equation 5-1 with the expression:
(b) Case II. One or more component
changes made during the sampling run. In this case, replace Vm in Equation 5-1 by the expression:
and substitute only
for those leakage rates (Li
or Lp)
which exceed La.
12.4 Volume of Water Vapor
Condensed.
where:
K2 = 0.001333 m3/ml for metric units,
= 0.04706 ft3/ml for English units.
12.5 Moisture Content.
NOTE: In saturated or water droplet-laden gas streams,
two calculations of the moisture content of the stack gas shall be made, one
from the impinger analysis (Equation 5-3), and a second from the assumption of
saturated conditions. The lower of the two values of shall be considered
correct. The procedure for determining the moisture content based upon the
assumption of saturated conditions is given in Section 4.0 of Method 4. For the purposes of this method, the average
stack gas temperature from Figure 5-3 may be used to make this determination,
provided that the accuracy of the in-stack temperature sensor is ± 1¡C (2¡F).
12.6 Acetone Blank Concentration.
12.7 Acetone Wash Blank.
Wa = Ca Vaw ¥ a Eq. 5-5
12.8 Total Particulate Weight.
Determine the total
particulate matter catch from the sum of the weights obtained from Containers 1
and 2 less the acetone blank (see Figure 5-6).
NOTE: In no case shall a blank value of greater than
0.001 percent of the weight of acetone used be subtracted from the sample weight.
Refer to Section 8.5.8 to assist in calculation of results involving two or
more filter assemblies or two or more sampling trains.
12.9 Particulate Concentration.
where:
K3 = 0.001 g/mg for metric units.
= 0.0154 gr/mg for
English units.
12.10 Conversion Factors:
12.11 Isokinetic Variation.
12.11.1 Calculation
from Raw Data.
where:
K4 = 0.003454 [(mm Hg)(m3)]/[(ml)(¡K)]
for metric units,
= 0.002669 [(in.
Hg)(ft3)]/[(ml)(¡R)] for English units.
12.11.2 Calculation
from Intermediate Values.
where:
K5 = 4.320 for metric units,
= 0.09450 for English
units.
12.11.3 Acceptable
Results. If 90 percent ² I ² 110
percent, the results are acceptable. If the PM results are low in comparison to
the standard, and "I" is over 110 percent or less than 90 percent,
the Administrator may opt to accept the results. Reference 4 in Section 17.0
may be used to make acceptability judgments. If "I" is judged to be
unacceptable, reject the results, and repeat the sampling run.
12.12 Stack Gas Velocity and Volumetric Flow Rate
Calculate the average
stack gas velocity and volumetric flow rate, if needed, using data obtained in
this method and the equations in Sections 12.3
and 12.4 of Method 2.
13.0 Method Performance. [Reserved]
14.0 Pollution Prevention. [Reserved]
15.0 Waste Management. [Reserved]
16.0 Alternative Procedures.
16.1 Dry Gas Meter as a Calibration Standard.
A DGM may be used as a
calibration standard for volume measurements in place of the wet test meter
specified in Section 10.3, provided that it is calibrated initially and
recalibrated periodically as follows:
16.1.1 Standard Dry
Gas Meter Calibration.
16.1.1.1. The DGM to
be calibrated and used as a secondary reference meter should be of high quality
and have an appropriately sized capacity [e.g., 3 liters/rev (0.1 ft3/rev)]. A spirometer [400 liters (14 ft3) or more capacity], or equivalent, may be used for this
calibration, although a wet test meter is usually more practical. The wet test
meter should have a capacity of 30 liters/rev (1 ft3/rev) and capable of measuring volume to within 1.0 percent. Wet
test meters should be checked against a spirometer or a liquid displacement
meter to ensure the accuracy of the wet test meter. Spirometers or wet test
meters of other sizes may be used, provided that the specified accuracies of
the procedure are maintained.
16.1.1.2 Set up the
components as shown in Figure 5-7. A spirometer, or
equivalent, may be used in place of the wet test meter in the system. Run the
pump for at least 5 minutes at a flow rate of about 10 liters/min (0.35 cfm) to
condition the interior surface of the wet test meter. The pressure drop
indicated by the manometer at the inlet side of the DGM should be minimized [no
greater than 100 mm H2O (4 in. H2O) at a
flow rate of 30 liters/min (1 cfm)]. This can be accomplished by using large
diameter tubing connections and straight pipe fittings.
16.1.1.3 Collect the
data as shown in the example data sheet (see Figure 5-8).
Make triplicate runs at each of the flow rates and at no less than five
different flow rates. The range of flow rates should be between 10 and 34
liters/min (0.35 and 1.2 cfm) or over the expected operating range.
16.1.1.4 Calculate
flow rate, Q, for each run using the wet test meter volume, Vw, and the run time, ¥ . Calculate the DGM coefficient, Yds, for each run. These calculations are as follows:
where:
K1 = 0.3858 ¡C/mm Hg for metric units
= 17.64 ¡F/in. Hg for
English units.
Vw = Wet test meter volume, liter (ft3).
Vds = Dry gas meter volume, liter (ft3).
Tds = Average dry gas meter temperature, ¡C (¡F).
Tadj = 273 ¡C for metric units
= 460 ¡F for
English units.
Tw = Average wet test meter temperature, ¡C (¡F)
Pbar = Barometric pressure, mm Hg (in. Hg).
¥ p = Dry gas meter
inlet differential pressure, mm H2O (in. H2O).
¥ = Run time, min.
16.1.1.5 Compare the
three Yds values at each of the flow rates and determine
the maximum and minimum values. The difference between the maximum and minimum
values at each flow rate should be no greater than 0.030. Extra sets of
triplicate runs may be made in order to complete this requirement. In addition,
the meter coefficients should be between 0.95 and 1.05. If these specifications
cannot be met in three sets of successive triplicate runs, the meter is not
suitable as a calibration standard and should not be used as such. If these
specifications are met, average the three Yds values
at each flow rate resulting in no less than five average meter coefficients, Yds.
16.1.1.6 Prepare a
curve of meter coefficient, Yds, versus flow rate,
Q, for the DGM. This curve shall be used as a reference when the meter is used
to calibrate other DGMs and to determine whether recalibration is required.
16.1.2 Standard Dry
Gas Meter Recalibration.
16.1.2.1 Recalibrate
the standard DGM against a wet test meter or spirometer annually or after every
200 hours of operation, whichever comes first. This requirement is valid
provided the standard DGM is kept in a laboratory and, if transported, cared
for as any other laboratory instrument. Abuse to the standard meter may cause a
change in the calibration and will require more frequent recalibrations.
16.1.2.2 As an
alternative to full recalibration, a two-point calibration check may be made.
Follow the same procedure and equipment arrangement as for a full
recalibration, but run the meter at only two flow rates [suggested rates are 14
and 30 liters/min (0.5 and 1.0 cfm)]. Calculate the meter coefficients for
these two points, and compare the values with the meter calibration curve. If
the two coefficients are within 1.5 percent of the calibration curve values at
the same flow rates, the meter need not be recalibrated until the next date for
a recalibration check.
16.2 Critical Orifices As Calibration Standards.
Critical orifices may
be used as calibration standards in place of the wet test meter specified in
Section 16.1, provided that they are selected, calibrated, and used as follows:
16.2.1 Selection of Critical Orifices.
16.2.1.1 The
procedure that follows describes the use of hypodermic needles or stainless steel
needle tubings which have been found suitable for use as critical orifices.
Other materials and critical orifice designs may be used provided the orifices
act as true critical orifices (i.e.,
a critical vacuum can be obtained, as described in Section 16.2.2.2.3). Select
five critical orifices that are appropriately sized to cover the range of flow
rates between 10 and 34 liters/min (0.35 and 1.2 cfm) or the expected operating
range. Two of the critical orifices should bracket the expected operating range.
A minimum of three critical orifices will be needed to calibrate a Method 5
DGM; the other two critical orifices can serve as spares and provide better
selection for bracketing the range of operating flow rates. The needle sizes
and tubing lengths shown in Table 5-1 in Section 18.0
give the approximate flow rates.
16.2.1.2 These
needles can be adapted to a Method 5 type sampling train as follows: Insert a
serum bottle stopper, 13 by 20 mm sleeve type, into a 1/2-inch Swagelok (or
equivalent) quick connect. Insert the needle into the stopper as shown in Figure 5-9.
16.2.2 Critical Orifice Calibration.
The procedure
described in this section uses the Method 5 meter box configuration with a DGM
as described in Section 6.1.1.9 to calibrate the critical orifices. Other
schemes may be used, subject to the approval of the Administrator.
16.2.2.1 Calibration
of Meter Box. The critical orifices must be calibrated in the same
configuration as they will be used (i.e., there should be no connections to the inlet of the orifice).
16.2.2.1.1 Before
calibrating the meter box, leak check the system as follows: Fully open the
coarse adjust valve, and completely close the by-pass valve. Plug the inlet.
Then turn on the pump, and determine whether there is any leakage. The leakage
rate shall be zero (i.e., no
detectable movement of the DGM dial shall be seen for 1 minute).
16.2.2.1.2 Check also
for leakages in that portion of the sampling train between the pump and the
orifice meter. See Section 8.4.1 for the procedure; make any corrections, if
necessary. If leakage is detected, check for cracked gaskets, loose fittings,
worn O-rings, etc., and make the necessary repairs.
16.2.2.1.3 After
determining that the meter box is leakless, calibrate the meter box according
to the procedure given in Section 10.3. Make sure that the wet test meter meets
the requirements stated in Section 16.1.1.1. Check the water level in the wet
test meter. Record the DGM calibration factor, Y.
16.2.2.2 Calibration
of Critical Orifices. Set up the apparatus as shown in Figure
5-10.
16.2.2.2.1 Allow a
warm-up time of 15 minutes. This step is important to equilibrate the
temperature conditions through the DGM.
16.2.2.2.2 Leak check
the system as in Section
16.2.2.1.1. The
leakage rate shall be zero.
16.2.2.2.3 Before
calibrating the critical orifice, determine its suitability and the appropriate
operating vacuum as follows: Turn on the pump, fully open the coarse adjust
valve, and adjust the by-pass valve to give a vacuum reading corresponding to
about half of atmospheric pressure. Observe the meter box orifice manometer
reading, ¥H. Slowly increase the vacuum reading until a stable reading is
obtained on the meter box orifice manometer. Record the critical vacuum for
each orifice. Orifices that do not reach a critical value shall not be used.
16.2.2.2.4 Obtain the
barometric pressure using a barometer as described in Section 6.1.2. Record the
barometric pressure, Pbar, in mm Hg (in. Hg).
16.2.2.2.5 Conduct
duplicate runs at a vacuum of 25 to 50 mm Hg (1 to 2 in. Hg) above the critical
vacuum. The runs shall be at least 5 minutes each. The DGM volume readings
shall be in increments of complete revolutions of the DGM. As a guideline, the
times should not differ by more than 3.0 seconds (this includes allowance for
changes in the DGM temperatures) to achieve ± 0.5 percent in K' (see Eq. 5-11).
Record the information listed in Figure 5-11.
16.2.2.2.6 Calculate
K' using Equation 5-11.
where:
K' = Critical orifice
coefficient, [m3)(¡K)1/2]/ [(mm
Hg)(min)] {[(ft3)(¡R)1/2)]/[(in.
Hg)(min)]}.
Tamb = Absolute ambient temperature, ¡K (¡R).
Calculate the arithmetic mean of the K' values. The individual K' values should
not differ by more than ±0.5 percent from the mean value.
16.2.3 Using the Critical Orifices as
Calibration Standards.
16.2.3.1 Record the
barometric pressure.
16.2.3.2 Calibrate
the metering system according to the procedure outlined in Section
16.2.2. Record the
information listed in Figure 5-12.
16.2.3.3 Calculate
the standard volumes of air passed through the DGM and the critical orifices,
and calculate the DGM calibration factor, Y, using the equations below:
where:
Vcr(std) = Volume of gas sample passed through the
critical orifice, corrected to standard conditions, dscm (dscf).
K1 = 0.3858 K/mm Hg for metric units
= 17.64 ¡R/in. Hg for
English units.
16.2.3.4 Average the
DGM calibration values for each of the flow rates. The calibration factor, Y,
at each of the flow rates should not differ by more than ± 2 percent from the
average.
16.2.3.5 To determine
the need for recalibrating the critical orifices, compare the DGM Y factors
obtained from two adjacent orifices each time a DGM is calibrated; for example,
when checking orifice 13/2.5, use orifices 12/10.2 and 13/5.1. If any critical
orifice yields a DGM Y factor differing by more than 2 percent from the others,
recalibrate the critical orifice according to Section 16.2.2.
17.0 References.
1. Addendum to
Specifications for Incinerator Testing at Federal Facilities. PHS, NCAPC.
December 6, 1967.
2.
Martin, Robert M. Construction Details of Isokinetic Source-Sampling Equipment.
Environmental Protection Agency. Research Triangle Park, NC. APTD-0581. April
1971.
3.
Rom, Jerome J. Maintenance, Calibration, and Operation of Isokinetic Source
Sampling Equipment. Environmental Protection Agency. Research Triangle Park,
NC. APTD-0576. March 1972.
4. Smith, W.S., R.T.
Shigehara, and W.F. Todd. A Method of Interpreting Stack Sampling Data. Paper
Presented at the 63rd Annual Meeting of the Air Pollution Control Association,
St. Louis, MO. June 14-19, 1970.
5. Smith, W.S., et
al. Stack Gas Sampling Improved and Simplified With New Equipment. APCA Paper
No. 67-119. 1967.
6. Specifications for
Incinerator Testing at Federal Facilities. PHS, NCAPC. 1967.
7.
Shigehara, R.T. Adjustment in the EPA Nomograph for Different Pitot Tube
Coefficients and Dry Molecular Weights. Stack Sampling News 2:4-11. October
1974.
8. Vollaro, R.F. A
Survey of Commercially Available Instrumentation for the Measurement of
Low-Range Gas Velocities. U.S. Environmental Protection Agency, Emission
Measurement Branch. Research Triangle Park, NC. November 1976 (unpublished
paper).
9. Annual Book of
ASTM Standards. Part 26. Gaseous Fuels; Coal and Coke; Atmospheric Analysis.
American Society for Testing and Materials. Philadelphia, PA. 1974. pp.
617-622.
10.
Felix, L.G., G.I. Clinard, G.E. Lacy, and J.D. McCain. Inertial Cascade
Impactor Substrate Media for Flue Gas Sampling. U.S. Environmental Protection
Agency. Research Triangle Park, NC 27711. Publication No. EPA- 600/7-77-060.
June 1977. 83 pp.
11. Westlin, P.R. and
R.T. Shigehara. Procedure for Calibrating and Using Dry Gas Volume Meters as
Calibration Standards. Source Evaluation Society Newsletter. 3(1):17- 30.
February 1978.
12. Lodge, J.P., Jr.,
J.B. Pate, B.E. Ammons, and G.A. Swanson. The Use of Hypodermic Needles as
Critical Orifices in Air Sampling. J. Air Pollution Control Association.
16:197-200. 1966.
18.0 Tables, Diagrams, Flowcharts, and Validation
Data.
Figure
5-1. Particulate Sampling Train.
Figure
5-2. Leak Check of Meter Box.
Figure
5-3. Particulate Field Data.
Figure
5-4. Equipment arrangement for metering system calibration.
Figure
5-5. Example Data Sheet for Calibration of Metering System (English Units).
Figure
5-6. Analytical Data Sheet.
Figure
5-7. Equipment Arrangement for Dry Gas Meter Calibration.
Figure
5-8. Example Data Sheet for Calibration of a Standard Dry Gas Meter for Method
5 Sampling Equipment (English units).
Figure
5-9. Critical Orifice Adaptation to Method 5 Metering System.
Figure
5-11. Data sheet for determining K' factor.
Figure
5-12. Data sheet for determining DGM Y Factor.
