United States Office of Air Quality EPA-450/3-82-019
Environmental Protection Planning and Standards July 1982
Agency Research Triangle Park NC 27711
Air ~
Guideline Series
Measurement of
Volatile Organic
Compounds -
Supplement 1
-------
EPA-450/3-82-019
Guideline Series
Measurement of
Volatile Organic
Compounds -
Supplement 1
Emission Measurement Branch
Emission Standards and Engineering Divison
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air, Noise, and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
July 1982
-------
OAQPS GUIDELINE SERIES
The guideline series of reports is being issued by the Office of Air Quality Planning and Standards (OAQPS) to provide
information to state and local air pollution control agencies; for example, to provide guidance on the acquisition and
processing of air quality data and on the planning and analysis requisite for the maintenance of air quality Reports
published in this series will be available - as supplies permit - from the Library Services Office (MD35) U S
Environmental Protection Agency, Research Triangle Park, North Carolina 27711; or, for a nominal fee from the
National Technical Information Service, 5285 Port Royal Road, Springfield, Virginia 22161.
-------
PREFACE
Emphasis on the control of volatile organic compounds through
the State Implementation Plans, new source performance standards,
and national emission standards for hazardous air pollutants has
created a need for standardized test procedures. In setting
national performance standards for new sources, and national emission
standards for hazardous air pollutants, the Environmental Protection
Agency has followed a policy of establishing a reference method for
each regulated source category and pollutant. These source specific
test methods generated by the Environmental Protection Agency do not
always provide the type of general application test methods that are
more likely to satisfy the measurement method guidance needed by the
States in their efforts to implement their own regulations for
sources emitting volatile organics.
The purpose of this supplemental document, therefore, is to
continue to provide guidance to the States on the measurement of
volatile organic compounds from a diversity of sources and pollutants
that is consistent with the methodology being applied by the Environmental
Protection Agency as it develops regulations for specific sources and
pollutants.
This document is a supplement to Measurement of Volatile Organic
Compounds, EPA-450/2-78-041, September 1979.
-------
INTRODUCTION.
CONTENTS
Page No.
1
GENERAL MEASUREMENT OF TOTAL GASEOUS ORGANIC COMPOUND
EMISSIONS USING A FLAME IONIZATION ANALYZER 2
1. Applicability and Principle 2
2. Range and Sensitivity 3
3. Interferences •*
4. Apparatus £
5. Reagents °
6. System Performance Specifications -J
7. Procedure ]J|
8. Calculations '°
9. Bibliography iy
DETERMINATION OF SELECTED VOLATILE ORGANIC EMISSIONS BY THE
ADSORPTION COLLECTION TECHNIQUE 21
1. Applicability and Principle 21
2. Range and Sensitivity ^
3. Interferences ix
4. Precision or Reproducibility ^
5. Apparatus 22
6. Reagents fj
7. Procedure ^
8. Quality Assurance 25
9. Calculations 26
10. Bibliography <-5
APPROXIMATE DETERMINATION OF SELECTED VOLATILE ORGANIC
EMISSIONS USING DETECTOR TUBES 29
1. Applicability and Principle 29
2. Concentration Range and Sensitivity 29
3. Interferences 30
4. Apparatus 30
5. Procedure 31
6. Quality Assurance 33
7. Calculations 33
8. Bibliography 33
TECHNICAL REPORT DATA SHEET 34
-------
INTRODUCTION
This document consists of three test methods for the measurement
of volatile organics that the Environmental Protection Agency believes
have a wider range of application than the reference methods promulgated
by the Agency in the course of developing national performance standards
for specific source categories. While these three methods do not contain
source specific application instructions, they can, with proper
consideration as alternate or screening methods, produce results that in
many instances are adequate for determining regulatory compliance.
The first method, "General Measurement of Total Gaseous Organic
Compound Emissions Using a Flame lonization Analyzer," can be applied to
a wide variety of sources in ways that will yield results that are
appropriate to many volatile organic regulations.
The second method, "Determination of Selected Volatile Organic
Emissions by the Adsorption Collection Technique," builds on ambient
air sampling and analysis techniques from the National Institute of
Occupational Safety and Health series of test methods to devise a
similar test method for stationary source conditions.
The third method, "Approximate Determination of Selected Volatile
Organic Emissions Using Detector Tubes," is a general procedure for the
application of detector tubes to stationary sources that recognizes the
possible deficiencies of detector tubes in this application. This method
fits the "screening method" category, which means that while the method
may produce biased or inprecise results, control agencies may, on
occasion, find it adequate for compliance determinations.
-------
GENERAL MEASUREMENT OF TOTAL GASEOUS ORGANIC
COMPOUND EMISSIONS USING A FLAME IONIZATION ANALYZER
1. Applicability and Principle
1.1 Applicability. This method can be used to determine total
gaseous organic compound volume or mass stack gas emission concentration
in terms of carbon, methane, propane, or a source-specific organic
compound.
If the instrument is calibrated with mass concentration standards
prepared with a source-specific organic and then used to measure
emissions of that organic, the results represent actual mass
concentrations of that organic. Since the detector responds to nearly
all organics, a supplemental measurement is necessary if it is desired
to exclude any particular organic(s) from the final result.
Application to sources emitting varying amounts of two or more
organic compounds that have considerably different response factors
will produce ambiguous results. Particular care should be exercised
in the choice of equipment and operation in potentially explosive
atmospheres.
1.2 Principle. The sample is extracted from the source through
a heated (if necessary) sample line and glass fiber filter into a flame
ionization analyzer (FIA). In the FIA, the combustion of a specific
organic compound in a Hg/Og flame forms ions that establish a current
proportional to the mass flow rate of that organic to the flame. The
ions are collected on two polarized electrodes, and the current is
-------
measured on a potentiometric recorder and compared with a calibration
curve based on propane (CgHg), or a source-specific organic, as
appropriate. The results are reported as volume or mass concentration
equivalents of methane (CH4), propane, carbon, or the source-specific
organic.
2. Range and Sensitivity
2.1 Range. Signal amplification and attenuators shall be
available so that a minimum signal response of 10 percent of full
scale can be produced when analyzing calibration gases or samples.
2.2 Sensitivity. The detector sensitivity shall be equal
to or better than 2.0 percent of the full-scale setting, with a
minimum full-scale setting of 10 ppm (methane or carbon equivalent).
3. Interferences
3.1 Inorganic Gases. The FIA does not respond to nitrogen,
carbon monoxide, carbon dioxide, or water vapor, but its response
\
to organics is affected by the composition of the background or
carrier gas'. Therefore, the calibration gases shall be contained
in air if air is the major component of the emission sample.
A mixed fuel (either 40 percent H2/60 percent N2 or 40 percent
H2/60 percent He) may be helpful in reducing response variability
due to changes in the sample or carrier gas composition.
3.2 Organic Compounds. Acetylenic compounds give a slightly
higher response than aliphatic compounds. Carbon atoms bound to
oxygen, nitrogen, or halogens give a reduced or zero response.
Aldehydes produce little, if any, response on a FIA.
-------
Table 1 illustrates these effects in terms of the relative
response of one FIA to various hydrocarbons. The response is
shown as effective carbon number (ECN), as follows:
Instrument response caused
ECN = by atom °f given type
Instrument response caused
by aliphatic carbon atom
These values shall be available for the specific detector used under
"as used" conditions (e.g., mixed H9/H fuel). These numbers can
L. C
vary widely for different operating conditions and for different
detectors. For example, variations of as much as 25 percent have
been observed in studies of the types of organics associated with
automotive emissions (see Citation 9.6 under Bibliography).
Table 1 also illustrates that the accuracy of this method for
a given source is largely dependent on knowledge about the particular
makeup of organic emissions from the source.
When two or more compounds are present in the emissions, it
is advisable to consider whether or not the standards generated
by the procedure described in Section 7.3 provide the compounds in
the same relative proportions (mole fraction) as they exist in the
emissions. If not, or if the relative proportions of each compound
are changing with time in the emissions, then consideration should
be given to the substitution of a gas chromatographic analytical
procedure. Each organic in an air emission contributes to a total
FIA response as follows:
-------
Table 1. APPROXIMATE EFFECTIVE CARBON NUMBERS
(FROM BECKMAN INSTRUMENTS)
Type of atom
Carbon
Carbon
Carbon
Carbon
Carbon
Carbon
Oxygen
Oxygen
Oxygen
Oxygen
Chlorine
Chlorine
Nitrogen
Occurrence
In aliphatic compound
In aromatic compound
In olefinic compound
In acetylenic compound
In carbonyl radical
In nitrile
In ether
In primary alcohol
In secondary alcohol
In tertiary alcohol, ester
As two or more chlorine atoms
on single aliphatic carbon atom
On olefinic carbon atom
In amine
Effective
carbon number
+1.0
+1.0
+0.95
+1.30
0.0
+0.3
-1.0
-0.6
-0.75
-0.25
-0.12 each
+0.05
Value similar to
that for oxygen atom
in corresponding
alcohol
-------
ECNcx
Rcx • mole fcx
Mcx
Where:
R = Response due to the presence of a particular compound.
*•« A
mole f = Fraction of the emissions or calibration standards
CA
contributed by a particular compound (mole basis).
I ECN = Summation of the effective carbon numbers of the atoms
C A
which constitute a molecule of a particular compound.
M = Molecular weight of a particular compound.
GA
By comparing z R for the standards to I R for the emissions, one
^ A
can determine the extent to which ambiguities can be expected in
concentration and mass rate measurements. This comparison should be
made regardless of the number of compounds in the calibration gas. This
information can be obtained through study of comparative analyses with
gas chromatography on a source category basis.
3.3 Other Effects. Significant changes in viscosity of the
.sample gas from that of the calibration gas could change gas volume
flow rate and therefore the mass rate of organics to the detector.
If this phenomenon is expected to occur, make provisions to change the
calibration procedures to identify and correct it.
4. Apparatus
4.1 Flame lonization Analyzer. Adaptable to field use, with
heat traced sample piping. The analyzer shall be demonstrated, preferably
by the manufacturer, to meet or exceed manufacturer's
specifications and those described in Section 6.1 of this method.
-------
The entire sampling and analytical system exposed to gaseous organics
shall be capable of being maintained in a temperature range consistent
with the particular measurement requirements to prevent condensation
and minimize adsorption in sampling lines.
4.2 Sample Conditioning or Interface System. Probe, with
filter, stainless steel or Teflon sample line, three-way valve
for introducing calibration gas, Teflon-coated diaphragm pump or
stainless steel bellows pump, and stainless steel flow control valves,
capable of being maintained in a temperature range consistent with
the particular measurement requirements.
4.3 Barometer and Bubble Tube Flowmeter. To establish volume
flow rate to detector.
4.4 Recorder (optional). Strip chart recorder with a voltage
input compatible with the FIA. Other recording devices may be used
provided that the minimum data-recording rate is one measurement
value per minute.
4.5 Calibration. Sections 4.5.2 through 4.5.6 are for the
optional procedure in Section 7.3.
4.5.1 Tubing. Teflon, 6.4-mm outside diameter, separate pieces
marked for each calibration concentration.
4.5.2 Tedlar or Aluminized Mylar Bags. Fifty-liter capacity, with
valve, separate bag marked for each calibration concentration.
-------
4.5.3 Syringe. 5 yl, individually calibrated to dispense
liquid organic.
4.5.4 Syringe. 25 ul, individually calibrated to dispense
liquid organic.
4.5.5 Dry Gas Meter, with Temperature and Pressure Gauges.
Accurate to +2 percent, to meter nitrogen in preparation of
standard gas mixtures, calibrated at the flow rate used to prepare
standards.
4.5.6 Midget Impinger/Hot Plate Assembly. To vaporize liquid
organic.
5. Reagents
5.1 Fuel. \\2 produced by a H~ generator, or a 40 percent
H2/60 percent He or 40 percent HL/60 percent N2 mixture.
5.2 Combustion Air. High-purity air. Always required if
the emission stream does not contain sufficient oxygen, and may be
required by the analyzer. Supplemental support air may yield
more stable operation of the analyzer.
5.3 Zero Gas. High-purity air with less than 0.1 ppm
organics (methane or carbon equivalent).
5.4 Calibration Gases. Two gas mixture standards with
volume concentrations corresponding to ranges of 5 to 10 ppm
(methane or carbon equivalent) and 1.5 to 2.5 times the expected
stack gas concentration, prepared and certified by direct cylinder
analysis by a gas manufacturer. The latter concentration is hereafter
referred to as the span gas. The standards will normally consist
-------
of propane in air. Other organic(s) may be used, if appropriate.
The gas manufacturer shall recommend a maximum shelf life for each
cylinder so that the concentration does not change by more than
+2 percent from the certified value. The date of gas cylinder
preparation, certified propane concentration, and recommended
maximum shelf life shall be affixed to the cylinder before shipment
from the gas manufacturer to the buyer.
5.5 Low Pressure Propane Cylinder and Dilution System. Alternative
for generating calibration gases. Refer to Section 7.2.
5.6 Source-Specific Organic. Either a sample obtained from
the source, or a sample distilled from paint, ink, etc., in
accordance with ASTM Procedure D3272-73T. Vacuum distillation may
be more appropriate. This item is only required when unaltered
emissions of a specific organic are being measured, and mass
calculations in terms of that organic are necessary.
6. System Performance Specifications
6.1 Linearity. Within +5 percent of the expected
value, up to the maximum percent absolute (methane or carbon equivalent)
calibration point. Each analyzer shall be demonstrated before initial
use to meet this specification using a four-point (minimum) calibration,
with at least one calibration point in each of the following ranges:
5 to 10, 50 to 100, 500 to 1,000, and 5,000 to 10,000 ppm (methane or
carbon equivalent). Certification of such demonstration by the
manufacturer is acceptable. Additional calibration points that encompass
emission values outside of these ranges shall be included, as necessary.
-------
6.2 System Zero Drift. Not to exceed +1 percent full scale
or +5 percent of stack gas reading, whichever is more, per test
period.
6.3 System Span Drift. Not to exceed +3 percent full scale
or +5 percent of stack gas reading, whichever is less, per test
period.
7. Procedure
7.1 Sampling. Locate the FIA in a suitably protected environment.
Assemble the system as shown in Figure 1. Install the sample probe
in the stack with the probe opening(s) centrally located. Maintain a
tight seal around the probe where it enters the stack. An in-stack filter
shall be attached to the probe if any particulate matter is present. A
sample may also be collected according to the procedure described in
Method 23 (45 FR 39776, June 11, 1980) provided it can be demonstrated
that bag wall losses do not exceed 5 percent from the time of
collection to the time of analysis. For operating instructions specific
to the FIA being used, refer to the manufacturer's manual.
Adjust the sample conditioning and analyzer heating systems to
provide a temperature consistent with the measurement requirements,
and allow the systems to warm up.
Before sampling, perform a leak check as follows: Recheck to
confirm that all fittings are tight. With the sample probe plugged,
close the flow control valve and open the excess sample bleed valve.
Use leak detection fluid or immerse the tubing leading from the
bleed valve in a jar of water to check that sample flow has ceased.
-------
Three-way
valve
Flow control
valve
Excess sample
valve
Probe
Heated
sample
line
Particulate
fi1ter
Samole
pump
Calibration
gas
Stack
Flame
ionization
analyzer
and
recorder
Fiqure 1. Flame Ionization Analyzer System.
11
-------
Other leak check procedures can be used provided that they conclusively
establish and demonstrate a no-flow situation. At the conclusion of
sampling, recheck for leaks. If leaks have developed, void the run.
To begin sampling, set the signal attenuation to yield a minimum
response of 10 percent of full scale unless the stack concentration is
less than 1 ppm. Adjust the flow and bleed valves to minimize sample
line residence time. Compare system readings with the calibration line
to obtain emission concentrations based on the calibration gas.
Once each hour, verify that sample is introduced to the FIA under
the same conditions of pressure and flow rates used in calibration by
momentarily connecting the inlet line to the FIA to a bubble tube
Howmeter and noting the flow rate. Use the barometer to observe any
significant changes in barometric pressure between pre-test calibration
and sampling.
System zero and span values will change or drift due to system
temperature and pressure changes, or other factors which can affect the
sample mass flow rate to the detector. Therefore, periodically (at
least once an hour) introduce zero and span gases to the analyzer during
each test period to determine zero and span drifts. If the analyzer has
drifted beyond the allowable performance specification, consider the data
collected since the last zero and span check to be invalid, unless the
drift can be attributed to a quantitatively known change in temperature,
pressure, or sample mass flow rate to the detector. Repeat the zero and
span drift checks at the conclusion of the test period. Make no
adjustment of the zero or span controls without noting the extent of the
drift and the time of adjustment.
12
-------
7.2 Pretest Calibration and Linearity Performance Check.
Within 1 hour before the start of the first test period, construct a
calibration curve as follows: With the signal attenuation at the
most sensitive setting, introduce zero gas and adjust the respective
zeroing controls to indicate a reading of less than 1 percent of full
scale. With the signal attenuation at a sensitive setting, introduce
the 5- to 10-ppm cylinder calibration gas and adjust the span control to
yield a reasonable response value for that concentration on the analyzer
readout. Repeat these two steps until adjustments are no longer
necessary. Calculate a predicted response for the cylinder span gas,
then introduce that gas and note the value obtained on the expected
signal attenuation setting. If the value is not within +5 percent
of its predicted value, then the analyzer may need repairs, or one
or both of the calibration gases may need replacement. In any event,
this linearity performance check specification shall be met before the
analyzer is used for the test. Draw a straight line through the two
calibration gas points and zero as derived by the least squares method.
As an alternative procedure, a low pressure high concentration propane
cylinder standard and a dilution system calibrated with bubble tube
flowmeters may be used to construct a three-point calibration curve.
Start with the cylinder standard and then predict the response values
for the two calculated dilutions. Apply the +5 percent criteria
described above. Draw a straight line through the three calibration gas
points and zero as derived by the least squares method.
7.3 Source-Specific Organic Standard Gas Mixtures. (Optional—see
Sections 1.1 and 5.6). This procedure is applicable only where the
-------
extent of bag wall surface adsorption/condensation of the organic
compound is known.
7.3.1 Preparation of Standards. Assemble the apparatus shown
in Figure 2. Evacuate a 50-liter Tedlar bag that has passed a leak
check (described in Section 7.3.2), and meter in about 50 liters of
air. Measure the barometric pressure, the relative pressure at the
dry gas meter, and the temperature at the dry gas meter. While the
bag is filling, use the 25-ul syringe to inject 10 ul of the liquid
organic through the septum on top of the impinger. First slightly
overfill the syringe, then invert it and depress the plunger to the
10 yl mark to dispel any air bubbles, and then inject. This gives a
concentration somewhat less than 200 yg/liter. In a like manner, use
the 5-yl syringe to prepare dilutions having approximately 40- and
20-yg/liter concentrations. To calculate the specific concentrations,
refer to Section 8.2.
Alternatively, use an analytical balance to weigh the syringe
before and after injecting the organic into the bag.
These gas mixture standards may be used for a few days from the
date of preparation, or less as determined by repetitive analysis
for concentration degradation. Discard the standards when the
degradation exceeds 10 percent. (Caution: Contamination may be a
problem when a bag is reused if the new gas mixture standard is a
lower concentration than the previously contained gas mixture standard.)
7.3.2 Bag Leak Checks. After each use, determine that a bag did
not develop leaks. To leak check, connect a water manometer and
-------
00
HOT PLATE
TEDLAR BAG
Figure 2 . Preparation of standards (optional).
-------
pressurize the bag to 5 to 10 cm H20 (2 to 4 in. H20). Allow to
stand for 10 minutes. Any displacement in the water manometer
indicates a leak. (Note: an alternative leak check method is
to pressurize the bag to 5 to 10 cm H20 or 2 to 4 in. H20 and allow
to stand overnight. A deflated bag indicates a leak.) If the bag
is in a rigid container, place a rotameter in line between the bag
and the pump inlet. Evacuate the bag. Failure of the rotameter to
register zero flow when the bag appears to be empty indicates a leak.
It is advisable that these leak checks also be performed before bag use.
8. Calculations
Correct all measurements or calculations for CH., C^Hg, etc., if
required by the emission regulation, by either assuming ambient values
are present, or by using source category values derived from gas
chromatographic analysis.
8.1 Indicated Carbon or Surrogate Organic Compound Concentration.
The surrogate organic compound will normally represent the average
carbon number (volume basis) of the emissions. These calculations
may assume either a single component organic in the emission, or a
constant ratio in the composition of multi-component systems with
equivalent FIA response factors to all compounds. If different FIA
response factors are known, they can be applied.
8.1.1 Volume Concentration [ppmv]. Results are on a wet gas
basis.
8.1.1.1 Concentration as carbon equivalents.
Cc=NcCr (Eq. 1)
-------
Where:
C = Emission concentration expressed as carbon equivalents.
N = Number of carbon atoms per molecule of calibration gas.
^
c
C = Emission concentration determined by the calibration line.
r
8.1.1.2 Concentration on the basis of the calibration gas.
These values are the Cr values taken from the calibration line.
8.1.1.3 Concentration on the basis of surrogate organic compound.
Cs - Rc Cr (Eq. 2)
Where:
C = Emission concentration expressed as the surrogate organic
compound.
R = Ratio of the number of carbon atoms per molecule of the
c
surrogate organic compound to the number of carbon atoms
per molecule of the calibration gas.
8.1.2 Mass Concentration [mg/m3]. The volume occupied by 1
mg-mole of ideal gas at 760 mm Hg and 20°C is 24.040 cm . One cubic
4
meter at these conditions would at saturation contain 4.16 x 10
•3 -2
mg-moles, so 1 cm of this volume (1 ppmv) would contain 4.16 x 10
mg-moles. Therefore the formula for converting volume concentration
to mass concentration is as follows:
C = 4.16 x 10"2 mg-moles CM (Eq. 3)
m xx
Where:
C = Indicated carbon or surrogate organic compound mass
m
concentration, mg/m .
-------
Cx = Cc> Cr> or GS> depending on how the results are to be
expressed.
MX = Molecular weight of carbon, the calibration gas, or
surrogate organic compound, mg/mg-mole.
8.2 Source-Specific Organic Standards Concentrations (Optional'
see Section 1.1} Use these calculations when the FIA is calibrated
with source-specific organic standards. Calculate each organic
standard concentration prepared in accordance with Section 7.3 as
follows:
B d
Where:
m m
. 4)
_ 760 mm Hg 10 1000 yg
-
m
m
C = Organic standard concentration, yg/1.
B = Volume of liquid organic injected, yl .
d = Density of the organic at 293°K, mg/yl .
« Absolute temperature of the dry gas meter, °K.
= Gas volume measured by dry gas meter, liters.
Y = Dry gas meter calibration factor.
Pm = Absolute pressure of the dry gas meter, mm Hg.
8.3 Source-Specific Organic Emission Concentrations.
8.3.1 Mass Concentration [mg/m ]. The emission values in yg/1
are taken from the source-specific organic standards response curve.
-------
These values are equivalent to mg/m concentrations and are referred
to as Cm values.
Css= (Eq. 5)
ss 4.16 x 10 * mg • moles • M
Where:
C = The emission concentration [ppmv] of the source-specific
organic(s).
M = Molecular weight of the source-specific organic(s). If
the organic emissions consist of two or more compounds,
a mass weighted average molecular weight value should be
calculated.
9. Bibliography
9.1. Intersociety Committee. American Public Health Assn. Tentative
Method for Continuous Analysis of Total Hydrocarbons in the Atmosphere
(Flame lonization Method). Methods of Air Sampling and Analysis.
Method 108, 41301-02-71T. Washington, D.C. 1972.
9.2. Johnson, M. Oxygen Synergism in the Model 400 FIA. Beckman
Instruments, Inc. Fullerton, CA. October 1970.
9.3. Beckman Instruments, Inc. Instruction Manual 82132-A. Model
402 Hydrocarbon Analyzer. Fullerton, CA. February 1971.
9.4. Andreatch, A.J. and R. Feinland. Continuous Trace Hydrocarbon
Analysis by Flame lonization. Anal. Chem. 32:(8):1021-4. July 1960.
9.5. Morris, R.A. and R.L. Chapman. Flame lonization Hydrocarbon
Analyzer. J. APCA. ll(10):467-9. October 1961.
-------
9.6. Black, P.M., I.E. High, and J.E. Sigsby. The Application
of Total Hydrocarbon Flame lonization Detectors to the Analysis
Of Hydrocarbon Mixtures from Motor Vehicles, With and Without
Catalytic Emission Control. Water, Air, Soil Pollut. 5(l):53-62.
October 1975.
9.7. Brown, G.E., D.A. DuBose, W.R. Phillips and G.E. Harris.
Response Factors of VOC Analyzers Calibrated with Methane for Selected
Organic Chemicals. EPA-600/52-81-002. May 1981.
-------
DETERMINATION OF SELECTED VOLATILE ORGANIC
EMISSIONS BY THE ADSORPTION COLLECTION TECHNIQUE
1. Applicability and Principle
1.1 Applicability. This method applies to the determination
of selected organic compounds that are included in the National
Institute for Occupational Safety and Health (NIOSH) Analytical Methods
series (see Citation 10.1 under Bibliography).
1.2 Principle. A gas sample is extracted from the stack
and the volatile organic vapors are collected on suitable adsorption
media. The sample is then analyzed by methods contained in the
NIOSH Analytical Methods series. Results are in ppm by volume, on
a dry gas basis.
2. Range and Sensitivity
The lower limit of detection varies according to the organic
compound being sampled and the total amount of stack gas sampled.
For specific details, refer to the appropriate NIOSH method.
3. Interferences
The chromatographic columns and the corresponding operating
parameters described in NIOSH methods normally provide adequate
resolution. If resolution interferences are encountered on some
sources, the chromatograph operator must select the column and
operating parameters best suited to his particular analytical
requirements. To reduce the chance of a positive bias, it is suggested
that the chromatograph operator use two different columns to confirm his
analysis.
-------
4. Precision or Reproducibility
The precision or reproducibility of analysis is to be determined
for each source and organic(s) application as directed in Section 7.2, and
is to be within +5 percent.
5. Apparatus
Refer to the NIOSH method for the particular organic(s) to be
sampled. In addition, the following items are required.
5.1 Sampling
5.1.1 Probe. (Optional) Borosilicate glass or stainless steel,
approximately 6-mrn ID, with a heating system if water condensation is
a problem, and a filter (either in-stack or out-stack heated to stack
temperature) to remove particulate matter. In most instances, a plug of
glass wool is a satisfactory filter.
5.1.2 Flexible Tubing. To connect probe to adsorption tubes. Use
a material that exhibits minimal sample adsorption.
5.1.3 Leakless Sample Pump. Flow controlled, constant rate pump,
with set of limiting (sonic) orifices to provide pumping rates from
approximately 10 to 100 cc/min.
5.1.4 Bubble-Tube Flowmeter. Volume accuracy within +_! percent,
to calibrate pump.
5.1.5 Stopwatch. To time sampling and pump rate calibration.
5.1.6 Adsorption Tubes. Similar to ones specified by NIOSH, except .
the amounts of adsorbent per primary/backup sections are 800/200 mg for
charcoal tubes and 1040/260 mg for silica gel tubes. As an alternative,
the tubes may contain a porous polymer adsorbent such as Tenax GC or
XAD-2.
-------
5.1.7 Barometer. Accurate to 5 mm Hg, to measure atmospheric
pressure during sampling and pump calibration.
5.1.8 Rotameter. 0 to 100 cc/min, to detect changes in flow
rate during sampling.
5.2 Analysis
5.2.1 Chromatographic Columns. Columns as specified in the
NIOSH method for the particular organic to be sampled. The analyst
may use other columns provided that the precision and accuracy of
the analysis of standards are not impaired, and that the information is
available for review, confirming that there is adequate resolution of
the organic peak(s). (Adequate resolution is defined as an area
overlap of not more than 10 percent of each organic peak by another
peak. Calculation of area overlap is explained in proposed Appendix C,
Supplement A: "Determination of Adequate Chromatographic Peak
Resolution," - 45 FR 26682, April 18, 1980).
6. Reagents
Refer to the NIOSH method for the particular organic to be
sampled. In addition, the following items are required:
6.1 Audit Standards. Two appropriate solution standards with
concentrations unknown to the analyst. The liquid audit samples must
consist of a solution containing the organic compound of interest
in the same solvent that is used to elute the solid adsorbent.
The audit standards must be prepared in the same manner as
standards in the respective NIOSH method. The two liquid audit concen-
trations must be an equivalent gas volume concentration in the range
of 5 to 20 ppm and 100 to 300 ppm. When they are available, the tester
may obtain audits by contacting: U.S. Environmental Protection Agency,
-------
Environmental Monitoring Systems Laboratory, Quality Assurance Division
(MD-77), Research Triangle Park, North Carolina 27711.
7. Procedure
7.1 Sampling. Assemble the sample train as shown in Figure 1.
Follow the sampling portion of the NIOSH method section entitled
"Procedure." Calibrate the pump and limiting orifice flow rate through
adsorption tubes with the bubble tube flowmeter before sampling. The
sample system can be operated as a "recirculating loop" for this operation,
Record the ambient temperature and barometric pressure. Then, during
sampling, use the rotameter to verify that the pump and orifice sampling
rate remains constant.
Use a sample probe, if required. Minimize the length of flexible
tubing between the probe and adsorption tubes. Several adsorption tubes
can be connected in series, if the extra adsorptive capacity is needed.
The gas sample must be provided to the sample system at a pressure sufficient
for the limiting orifice to function as a sonic orifice. Record the total
time and sample flow rate (or the number of pump strokes), the barometric
pressure, and ambient temperature. Obtain a total sample volume commensurate
with the expected concentration(s) of the volatile organic(s)
present, and recommended sample loading factors (weight sample per weight
adsorption media). Laboratory tests prior to actual sampling may be
necessary to predetermine this volume. When more than one organic is
present in the emissions, then relative adsorptive capacity information
must be developed. If water vapor is present in the sample at
concentrations above 2 to 3 percent, the adsorptive capacity may be
severely reduced.
-------
7.2 Sample Analysis. Follow the analysis portion of the NIOSH method
section entitled "Procedure." Operate the gas chromatograph according
to the manufacturer's instructions. After establishing optimum conditions,
verify and document these conditions during all operations. Analyze the
audit samples (see Section 8.3), then the emission samples. Repeat the
analysis of each sample until the relative deviation of two consecutive
injections does not exceed +5 percent.
7.3 Standards and Calibration. Prepare the standards according
to the respective NIOSH method. Use a minimum of three different
standards; select the concentrations to bracket the expected average
sample concentration. Perform the calibration before and after each day's
sample analyses. Prepare the calibration curve using the least
squares method.
8. Quality Assurance
8.1 Determination of Desorption Efficiency. During the testing
program, determine the desorption efficiency in the expected sample
concentration range for each batch of adsorption media to be used
according to the respective NIOSH method. Follow the NIOSH procedure
with an internal standard. A minimum desorption efficiency of 50 percent
must be obtained. Repeat the desorption determination until the
relative deviation of two consecutive determinations does not exceed
+5 percent. Use the average desorption efficiency of these two
consecutive determinations for the correction specified in Section 9.
If the desorption efficiency of the compound(s) of interest is questionable
under actual sampling conditions, use the Method of Standard Additions to
determine this value.
-------
8.2 Determination of Sample Collection Efficiency. For the
source samples, analyze the primary and backup portions of the adsorption
tubes separately. If the backup portion exceeds 10 percent of the total
amount (primary and backup), repeat the sampling with a larger sampling
portion.
8.3 Analysis Audit. Immediately before the sample analyses,
analyze the two audits in accordance with Section 7.2. The analysis
audit must agree with the audit concentration within +10 percent.
8.4 Pump Leak Checks and Volume Flow Rate Checks. Perform both
of these checks immediately after sampling with all sampling train
components in place. Perform all leak checks according to the manufacturer's
instructions, and record the results. Use the bubble-tube flowmeter to
measure the pump volume flow rate with the orifice used in
the test sampling and record the result. If it has changed by more than
+5 but less than +20 percent, calculate an average flow rate for the test.
If the flow rate has changed by more than +20 percent, recalibrate the
pump and repeat the sampling.
9. Calculations
Perform all calculations according to the respective NIOSH
method. Correct all sample volumes to standard conditions. If a sample
dilution system has been used, multiply the results by the appropriate
dilution ratio. Correct all results by dividing by the desorption
efficiency (decimal value). Report results as ppm by volume, dry basis.
10. Bibliography
10.1 NIOSH Manual of Analytical Methods, Volumes 1, 2, 3, 4, 5, 6. 7.,
U.S. Department of Health and Human Services, National Institute for
:5
-------
Occupational Safety and Health, Center for Disease Control, 4676 Columbia
Parkway, Cincinnati, Ohio 45226. April 1977 - August 1981. May be
available from the Superintendent of Documents, Government Printing Office,
Washington, D.C. 20402. Stock Number/Price: Volume 1 - 017-033-00267-3/$13,
Volume 2 - 017-033-00260-6/$ll, Volume 3 - 017-033-00261-4/$l4,
Volume 4 - 017-033-00317-3/$7.25, Volume 5 - 017-033-00349-1/S10,
Volume 6 - 017-033-00369-6/S9, and Volume 7 - 017-033-00396-5/S7. Prices
subject to change. Foreign orders add 25 percent.
-------
Flexible tubing
Probe
Stack
Adsorption tube
I
Note:
•^
It may be necessary to
heat the probe and sample
tubing to prevent sample
condensation.
Supplemental
adsorption tube
(as required)
Rotameter
Bubble tu
flowmete
0
-:aure
28
-------
APPROXIMATE DETERMINATION OF SELECTED VOLATILE
ORGANIC EMISSIONS USING DETECTOR TUBES
1. Applicability and Principle
1.1 Applicability. This method applies to the measurement of
individually selected volatile organics in source gases only when the
extent of detector tube reactions with all other gases present in the
source gas is known. An overall positive bias in the measurements is
acceptable if the emission values thus generated are still acceptable
for the purpose of the sampling. However, biased results must be
protected from improper use.
1.2 Principle. A previously collected or instantaneous sample
of source gas is drawn through a glass tube that contains a chemical
reagent on an adsorbent by a calibrated sampling pump. This chemical
reagent is selected for its colorimetric reaction with the gas in
question. The length of the color change or stain is measured, and is
indicative of the volume concentration. If a desiccating pre-layer
is present in the detector tube, results are on a dry basis.
2. Concentration Range and Sensitivity
The concentration range and sensitivity of this method can be varied
by the amount of sample gas drawn through the tube, or by the chemical
reactions employed. Refer to literature from the detector tube
manufacturer for the particular analysis desired.
-------
3. Interferences
Refer to the manufacturer's instructions furnished with the tubes
employed. The information provided by the detector tube manufacturer
about interfering gases may not be sufficient to determine the applicability
of a given detector tube to a given source gas. Therefore, detector tubes
shall only be used on sources where the relationship between concentrations
reported by detector tube analysis and some other approved analytical
technique has been established through comparative sampling.
4. Apparatus
4.1 Sample Pump. Piston type detector tube pump, 100 cc/stroke,
such as Mine Safety Appliance, Bendix Gastec, Matheson-Kitagawa, Draeger, or
equivalent. Use a pump from the same manufacturer as the detector tubes
used.
4.2 Detector Tubes. Selected for the gas(es) to be measured
and the expected concentration range, with instruction sheets, lot
identification, and expiration dates. Store tubes according to the
manufacturer's instructions.
4.3 Sampling Probe. Glass or stainless steel, heated as required,
of sufficient length that the exit gas temperature will be regulated to
the approximate temperature at which the detector tube was calibrated by
the manufacturer. If studies indicate this temperature is particularly
important, a thermometer in a tee fitting attached to the exit end of
the sampling probe is also required.
4.4 Filter. Required if particulate matter is present that could
clog detector tube inlet.
-------
4.5 Flexible 1 Liter Sample Bag and Inert Leakless Pump. Required
if the pressure of the source differs by more than 3 percent from
atmospheric pressure.
4.6 Condenser. Required if water vapor or other condensible material
is present in the gas to be sampled in quantities sufficient to plug the
filter or detector tube.
4.7 Barometer. Accurate to 5 mm Hg, to measure atmospheric pressure
during all analyses.
4.8 Thermometer. Accurate to 1° Cs to measure atmospheric temperature
during all analyses.
4.9 Audit Cylinder Standard. Appropriate gas mixture standard with
concentration known only to the person supervising the analysis of samples.
It is preferable that the audit cylinder standard be prepared according to
the procedure in proposed Method 23 (45 PR 39776, June 11, 1980). Some
detector tubes respond correctly only in the presence of moisture and oxygen
in which case these gases must be included in the audit standard. The
concentration of the audit cylinder should be within a factor of one-half
to two of the expected stack gas concentration. When it is available, the
tester may obtain an audit cylinder by contacting: U.S. Environmental
Protection Agency, Environmental Monitoring Systems Laboratory, Quality
Assurance Division (MD-77), Research Triangle Park, North Carolina 27711.
5. Procedure
5.1 Sampling and Analysis. Assemble and use the apparatus according
to the manufacturer's instructions. If the source pressure is within
3 percent of atmospheric and no condenser is required, use the piston pump
to purge the probe and then draw sample into the detector tube.
-------
If the source pressure is greater than atmospheric, use a gas tight
probe fitting at the stack and allow the probe to purge. Then attach
and fill the flexible sample bag with source gas. If the source pressure
is less than atmospheric, use an inert leakless pump to purge source gas
through the probe, and then fill the flexible bag. For those instances
where a flexible sample bag is required, withdraw the analysis sample
from the sample bag with the piston pump as soon as possible after the
bag is filled.
Record the expiration date of the tubes, atmospheric temperature and
barometric pressure, and volume sampled.
Note the length of stain or color change produced on each tube,
and the length of time the stain was allowed to develop. Record the
indicated concentration of each tube. Repeat the analysis until either
of two consecutive tubes do not deviate more than +25 percent from their
average. Each average value constitutes one result.
If condensation of water or other material interferes with operation
of the detector tube, a small condenser may be used between the sample
probe and the flexible bag, however, sample loss may occur. Lowering of
the source gas dew point by pumping the source gas into an inert sampling
bag containing a known volume of zero air via an inert, leakless pump may
also be employed. If the manufacturer's instructions for the tubes
employed prescribe a humidity correction, then devise and use some means
of measuring the sample gas relative humidity.
-------
6. Quality Assurance
6.1 Analysis Audit. Immediately before the sample analyses, perform
analyses on the audit cylinder by following the procedure in Section
5.1. The analysis audit results should agree with the cylinder concentration
within +25 percent.
6.2 Flexible Bag Leak Checks, Pump Leak Checks and Pump Volume Checks.
Perform all of these checks immediately after sampling and analysis. Perform
bag leak checks according to Method 23. Perform all pump checks according
to the pump manufacturer's instructions. Record all results.
7. Calculations
Correct each sample concentration result as indicated on the detector
tube according to the detector tube manufacturer's instructions for
temperature, humidity and pressure. Normally, pressure is the only
significant correction required.
8. Bibliography
8.1 Bendix, Inc. Gastec Precision Gas Detector System Manual.
Bendix Environmental and Process Instruments Division, Drawer 83V
Lewisburg, West Virginia 24901.
8.2 Mine Safety Appliance Company. Instructions for Operation
and Maintenance of M.S.A. Universal Sampling Pump. Pittsburgh,
Pennsylvania 15208.
8.3 Method 23. Determination of Halogenated Organics from
Stationary Sources. 45 FR 39776. Proposed June 11, 1980.
-------
TECHNICAL REPORT DATA
1 Please read Instructions on the reverse before completing!
1. REPORT NO. 2.
EPA -450/3-82-019
4. TITLE AND SUBTITLE
Measurement of Volatile Organic Compounds -
Supplement 1
7. AUTHOR(S)
Emission Measurement Branch
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Emission Measurement Branch (MD-13)
Emission Standards and Engineering Division
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
12. SPONSORING AGENCY NAME AND ADDRESS
DAA for Air Quality Planning and Standards (MD-10)
Office of Air, Noise, and Radiation
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
3. RECIPIENT'S ACCESSION NO.
5 REPORT DATE
July 1982
g PERFORMING ORGANIZATION CODS
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA/200/04
15. SUPPLEMENTARY NOTES
6. ABSTRACT
This document consists of three test methods that the Environmental Protection
Agency believes have a wider range of application as written than the reference
methods promulgated by the Agency in the course of developing national performance
standards for specific source categories. While these three methods do not contain
source specific application instructions, they can, with proper consideration as
alternate or screening methods, produce results that in many instances are adequate
for determining compliance. The methods are "General Measurement of Total Gaseous
Organic Compound Emissions Using a Flame lonization Analyzer," "Determination of
Selected Volatile Organic Emissions by the Adsorption Collection Technique," and
"Approximate Determination of Selected Volatile Organic Emissions Using Detector
Tubes."
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Held/Group
Air Pollution
Analyzing
Sampling
Organic Compounds
Gas Sampling
Stationary Sources
Volatile Organic Compouncs
Analytical Strategy
Organic Vapors
Environmental Assessment
13 B
13. DISTRIBUTION STATEMENT
19 SECURITY CLASS (This Report/
Unclassified
21. NO. OF PAGES
40
One .ass-~^ea
EPA Firm 7220-1 'Rev 1-7T\ = = S-C,S S^I-'ON'SISSG-E'E
34
------- |