ASTM F1398-93(2020)

Standard Test Method for Determination of Total Hydrocarbon Contribution by Gas Distribution System Components (Withdrawn 2023)

SIGNIFICANCE AND USE
3.1 The purpose of this test method is to define a procedure for testing components being considered for installation into a high-purity gas distribution system. Application of this test method is expected to yield comparable data among components tested for purposes of qualification for this installation.
SCOPE
1.1 This test method covers the testing of components for total hydrocarbons (THC) contribution to a gas distribution system at ambient temperature. In addition, this test method allows testing of the component at elevated ambient temperatures as high as 70°C.  
1.2 This test method applies to in-line components containing electronics grade materials in the gaseous form, such as those used in semiconductor gas distribution systems.  
1.3 Limitations:  
1.3.1 This test method is limited by the sensitivity of current instrumentation, as well as by the response time of the instrumentation. This test method is not intended to be used for components larger than 12.7-mm (1/2-in.) outside diameter nominal size. This test method could be applied to larger components; however, the stated volumetric flow rate may not provide adequate mixing to ensure a representative sample. Higher flow rates may improve the mixing but excessively dilute the sample.  
1.3.2 Different instrumental methods (such as flame ionization detector (FID), mass spectrometer (MS)) will yield total hydrocarbon (THC) levels that are not comparable due to different sensitivities to different molecular species. Hydrocarbon contaminants of high-purity gas distribution systems can be subdivided into two general categories: (1) noncondensable hydrocarbons (4), that are present due to difficulty of removal and relative atmospheric abundance, and (2) condensable hydrocarbons, that are often left behind on component surfaces as residues. Condensable hydrocarbons include pump oils, degreasing agents, and polishing compound vehicles.  
1.3.3 Because of the tremendous disparity of hydrocarbon species, it is suggested that direct comparisons be made only among data gathered using the same detection method.  
1.3.4 This test method is intended for use by operators who understand the use of the apparatus at a level equivalent to six months of experience.  
1.4 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 5.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
WITHDRAWN RATIONALE
This test method covers the testing of components for total hydrocarbons (THC) contribution to a gas distribution system at ambient temperature. In addition, this test method allows testing of the component at elevated ambient temperatures as high as 70°C.
Formerly under the jurisdiction of Committee F01 on Electronics, this test method was withdrawn in November 2023. This standard is being withdrawn without replacement because Committee F01 was disbanded.

General Information

• Status: Withdrawn
• Publication Date: 14-Apr-2020
• Withdrawal Date: 28-Nov-2023
• ICS: 23.040.01 - Pipeline components and pipelines in general
• Technical Committee: F01 - Electronics
• Drafting Committee: F01.10 - Contamination Control

Relations

• Replaces: ASTM F1398-93(2012) - Standard Test Method for Determination of Total Hydrocarbon Contribution by Gas Distribution System Components
• Effective Date: 15-Apr-2020

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F1398 − 93 (Reapproved 2020)
Standard Test Method for
Determination of Total Hydrocarbon Contribution by Gas
Distribution System Components
This standard is issued under the fixed designation F1398; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Semiconductor clean rooms are serviced by high-purity gas distribution systems. This test method
presents a procedure that may be applied for the evaluation of one or more components considered for
use in such systems.
1. Scope 1.3.3 Because of the tremendous disparity of hydrocarbon
species, it is suggested that direct comparisons be made only
1.1 This test method covers the testing of components for
among data gathered using the same detection method.
total hydrocarbons (THC) contribution to a gas distribution
1.3.4 This test method is intended for use by operators who
system at ambient temperature. In addition, this test method
understand the use of the apparatus at a level equivalent to six
allows testing of the component at elevated ambient tempera-
months of experience.
tures as high as 70°C.
1.4 The values stated in SI units are to be regarded as the
1.2 This test method applies to in-line components contain-
standard. The inch-pound units given in parentheses are for
ing electronics grade materials in the gaseous form, such as
information only.
those used in semiconductor gas distribution systems.
1.5 This standard does not purport to address all of the
1.3 Limitations:
safety concerns, if any, associated with its use. It is the
1.3.1 Thistestmethodislimitedbythesensitivityofcurrent
responsibility of the user of this standard to establish appro-
instrumentation, as well as by the response time of the
priate safety, health, and environmental practices and deter-
instrumentation.This test method is not intended to be used for
mine the applicability of regulatory limitations prior to use.
components larger than 12.7-mm ( ⁄2-in.) outside diameter
Specific hazard statements are given in Section 5.
nominal size. This test method could be applied to larger
1.6 This international standard was developed in accor-
components; however, the stated volumetric flow rate may not
dance with internationally recognized principles on standard-
provide adequate mixing to ensure a representative sample.
ization established in the Decision on Principles for the
Higher flow rates may improve the mixing but excessively
Development of International Standards, Guides and Recom-
dilute the sample.
mendations issued by the World Trade Organization Technical
1.3.2 Different instrumental methods (such as flame ioniza-
Barriers to Trade (TBT) Committee.
tion detector (FID), mass spectrometer (MS)) will yield total
hydrocarbon (THC) levels that are not comparable due to
2. Terminology
different sensitivities to different molecular species. Hydrocar-
bon contaminants of high-purity gas distribution systems can 2.1 Definitions:
be subdivided into two general categories: (1) noncondensable
2.1.1 baseline—the instrument response under steady state
hydrocarbons ( conditions.
removal and relative atmospheric abundance, and (2) condens-
2.1.2 glove bag—an enclosure that contains a controlled
able hydrocarbons, that are often left behind on component
atmosphere. A glove box could also be used for this test
surfaces as residues. Condensable hydrocarbons include pump
method.
oils, degreasing agents, and polishing compound vehicles.
2.1.3 heat trace—heatingofcomponent,spoolpiece,ortest
stand by a uniform and complete wrapping of the item with
This test method is under the jurisdiction of ASTM Committee F01 on
resistant heat tape.
Electronics and is the direct responsibility of Subcommittee F01.10 on Contamina-
tion Control.
2.1.4 methane (CH ) equivalent—that concentration of CH
4 4
Current edition approved April 15, 2020. Published May 2020. Originally
that causes the same instrument response as the sample.
approved in 1992. Last previous edition approved in 2012 as F1398 – 93(2012).
DOI: 10.1520/F1398-93R20. 2.1.4.1 Discussion—The calibration gas contains a known
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1398 − 93 (2020)
concentration of methane (CH ). Instrument response to zero 2.3.5 Q = the flow through the spool piece or component.
4 s
gas and span gas defines the calibration curve for the analyzer. 2.3.6 T = the temperature of the air discharged by the
a
Instrument response to the sample is the summation of the analyzer’s cooling exhaust.
response for each hydrocarbon reaching the detector. The 2.3.7 T = the temperature of the spool piece or component.
s
concentration reported is the methane concentration, from the 2.3.7.1 Discussion—The thermocouple must be located in
calibrationcurvethatcorrespondstotheinstrumentresponseto contact with the outside wall of the component or spool piece.
the sample. The sample’s concentration is equivalent to the 2.3.8 V-1, V-2 = inlet and outlet valves of bypass loop,
methaneconcentrationthatwouldproducethesameinstrument respectively.
response. 2.3.9 V-3, V-4 = inlet and outlet valves of test loop, respec-
tively.
2.1.5 minimumdetectionlimit(MDL)oftheinstrument—the
lowest instrument response above zero detectable that is
3. Significance and Use
readable by the instrument and at least two times the amplitude
of the noise. 3.1 The purpose of this test method is to define a procedure
for testing components being considered for installation into a
2.1.6 response time—the time required for the system to
high-purity gas distribution system. Application of this test
reach steady state after a measurable change in concentration.
method is expected to yield comparable data among compo-
2.1.7 spoolpiece—anullcomponent,consistingofastraight
nents tested for purposes of qualification for this installation.
piece of electropolished tubing and appropriate fittings, used in
place of the test component to establish the baseline.
4. Apparatus
2.1.8 standard conditions—101.3 kPa, 0.0°C (14.73 psia,
4.1 Materials:
32°F).
4.1.1 Test Gas, purified nitrogen or argon with a maximum
2.1.9 test component—any device being tested, such as a
THC concentration not exceeding the manufacturer’s stated
valve, regulator, or filter.
minimum detection limit of the instrument (MDL). Particulate
filtration of the test gas to 0.02 µm or finer is required, using a
2.1.10 test stand—the physical test system used to measure
typical electronics grade filter. The filter must be compatible
impurity levels.
with the 94°C (200°F) bake-out.
2.1.11 zero gas—a gas that has a THC concentration below
4.1.2 Spool Piece, that can be installed in place of the test
the MDLof the analytical instrument. This purified gas is used
component is required. This piece is to be a straight section of
for both instrument calibration and component testing.
316Lelectropolished stainless steel tubing with no restrictions.
2.2 Abbreviations:
Thelengthofthespoolpieceshallbe200mm.Thespoolpiece
2.2.1 FID—flame ionization detector.
shall have the same end connections as the test component.
2.2.2 MFC—mass flow controller. 4.1.2.1 Components with Stub Ends—Use compression fit-
tings with nylon or teflon ferrules to connect the spool piece
2.2.3 MS—mass spectrometer.
and test component to the test loop. Keep the purged glove bag
2.2.4 ppbv—parts per billion by volume assuming ideal gas
around each component for the duration of the test. In the case
behavior, equivalent to nmole/mole (such as nL/L).
of long pieces of electropolished tubing, use two glove bags,
2.2.4.1 Discussion—The same as molar parts per billion
one at each end.
(ppb).
4.1.3 Tubing, used downstream of the purifier shall be 316L
2.2.5 ppbw—parts per billion by weight (such as ng/g).
electropolishedstainlesssteelseamlesstubing.Thediameterof
the sample line to the analyzer shall not be larger than 6.4 mm
2.2.6 ppmv—parts per million by volume assuming ideal
( ⁄4 in.). The length of the sample line from the tee (installed
gas behavior, equivalent to µmole/mole (such as µL/L).
upstream of the pressure gage P ) to the analyzer shall not be
2.2.6.1 Discussion—The same as molar parts per million
more than 600 mm to minimize the effect (adsorption/
(ppm).
desorption) of the sample line on the result. The sample line
2.2.7 ppmw—parts per million by weight (such as µg/g).
shall have no more than two mechanical joints.
2.2.8 slpm—standard liters per minute. The gas volumetric
4.1.4 Valves, diaphragm or bellows type and must be ca-
flow rate measured in liters per minute at 0.0°C (32°F) and
pable of unimpaired operation at 94°C (200°F). The use of
101.3 kPa (1 atm).
all-welded, all-metal valves is preferred.
2.2.9 THC—total hydrocarbon.
4.2 Instrumentation:
2.3 Symbols:
4.2.1 THC Analyzer—The THC analyzer is to be placed
2.3.1 P —the inlet pressure measured upstream of the
downstream of the test component.Accurate baseline readings
purifier and filter in the test apparatus. must be obtained prior to and subsequent to each of the tests.
2.3.2 P —the outlet measured downstream of the analyzer
The baseline must return to levels <100 ppbv, before and after
in the test apparatus. the tests. Deviations greater than this require that all results be
2.3.3 Q = the bypass sample flow not going through the
rejectedandanewtestcomponentbetested.Theanalyzermust
analytical system. be capable of accurately recording changes in THC concentra-
2.3.4 Q = the total sample flow through the analytical tions on a real-time basis, within the constraints of the data
system. acquisition system.
F1398 − 93 (2020)
4.2.2 THC analyzer calibration—Two-point calibration, 5. Hazards
zero and span, is to be performed regularly. Zero gas is defined
5.1 Precautions:
as below the manufacturer’s stated MDL of the instrument,
5.1.1 It is required that the user have a working knowledge
supplied by purified gas, with the purifier in close proximity to
of the respective instrumentation and that the user practice
the analyzer. Span gas is analyzed at the lowest possible
proper handling of test components for trace organic analysis.
detectionrange,whichmaynotbeatthelowestdetectionrange
Good laboratory practices must also be understood.
oftheinstrument.Spangasis5–10ppmvmethane, 620 %for
5.1.2 It is required that the user be familiar with proper
FID. Calibration is based on traceable methane concentration
component installation and that the test components be in-
in the base gas (nitrogen or argon).
stalled on the test stand in accordance with manufacturer’s
4.2.3 Flame Ionization Detector (FID)—The FID detects
instructions.
hydrocarbon species by ionizing the organic material in a
5.1.3 Do not exceed ratings (such as pressure, temperature,
flame. Ions produced in the hydrogen flame yield a measurable
and flow) of the component.
current, directly related to the quantity of hydrocarbons intro-
5.1.4 Gloves are to be worn for all steps.
duced to the flame. Burner gases, hydrogen, and air are not to
5.1.5 Limit exposure of the instrument and test component
containmeasurableamountsofTHC.Purifiersareavailablefor
to atmospheric and hydrocarbon contamination before and
this purpose (especially to remove methane). Burner gases
during the test.
must be maintained at a temperature between 18 and 26°C (64
5.1.6 Precautions must be taken to insure that the tempera-
and 78°F).
ture measured by the thermocouple is as close as possible to
4.2.3.1 The THC data are referred to as ppmv quantity of
that of the spool piece or the test component. Use appropriate
CH equivalents, corresponding to the sum of the number of
insulation and conductive shield to achieve as uniform a
equivalent carbons. Simple, low molecular weight hydrocar-
temperature as possible.
bons are readily detected and quantified as total THC. Higher
5.1.7 Ensure that adequate mixing of the test gas is attained.
molecular weight hydrocarbons and more substituted hydro-
carbons may not be detected well. The FID is, therefore, a
6. Preparation of Apparatus
specific group detector that yields quantification of total
6.1 A schematic drawing of a recommended test apparatus
hydrocarbons for a specific detectable group.
located inside a clean laboratory is shown in Fig. 1. Deviations
4.3 Pressure and Flow Control—Upstream pressure is to be
from this design are acceptable as long as baseline levels
controlled with a regulator upstream of the test component.
consistent with 4.2.1 can be maintained. Nitrogen or argon gas
Flow is to be controlled at a point downstream of the sampling
is purified to remove water and hydrocarbons. The base gas is
port and monitored at that point. A mass flow controller is
then filtered by an electronics grade, high purity, point of use
preferred for maintaining the flow as described in 8.3.
gas filter (pore size rating ≤0.02 µm) before it is delivered to
However, a variable area flowmeter plus a back pressure
the test component.
regulator may be used instead. Sampling is to be performed via
6.2 A bypass loop may be used to divert gas flow through
a tee in the line, with a run of straight tubing before the mass
the test stand and the analyzer whenever the spool piece or a
flow controller. All lines must conform to 4.1.3. Inlet pressure
testcomponentisinstalledorremovedfromtheteststand.This
is monitored by P . Test flow is the sum of Q and Q . Q is
1 1 2 1
prevents the ambient air from contaminating the test apparatus
directly controlled, and Q is the total flow through the
and the hydrocarbon analyzer; thus, the analyzer baseline
analyzer (refer to Fig. 1).
remains the same. A glove bag is used to enclose test
4.4 Bypass Loop—The design of the bypass loop is not
component lines of the test apparatus during the installation
restrictedtoanyonedesign.Itcouldbe,forexample,a3.2-mm
and removal of the spool piece and the test piece.
( ⁄8-in.) 316Lstainless steel coil or a flexible tube section. This
6.3 A total hydrocarbon analyzer capable of detecting hy-
allows the flexibility necessary to install test components of
drocarbon concentration levels down to <50 ppb is connected
different lengths.
to the test stand to sample the gas flowing through the test
piece.TheTHC analyzer uses hydrogen fuel for the generation
oftheflamerequiredfortheFIDintheinstrument.Thepurified
and filt
...

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: F1398 − 93 (Reapproved 2020)
Standard Test Method for
Determination of Total Hydrocarbon Contribution by Gas
Distribution System Components
This standard is issued under the fixed designation F1398; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Semiconductor clean rooms are serviced by high-purity gas distribution systems. This test method
presents a procedure that may be applied for the evaluation of one or more components considered for
use in such systems.
1. Scope 1.3.3 Because of the tremendous disparity of hydrocarbon
species, it is suggested that direct comparisons be made only
1.1 This test method covers the testing of components for
among data gathered using the same detection method.
total hydrocarbons (THC) contribution to a gas distribution
1.3.4 This test method is intended for use by operators who
system at ambient temperature. In addition, this test method
understand the use of the apparatus at a level equivalent to six
allows testing of the component at elevated ambient tempera-
months of experience.
tures as high as 70°C.
1.4 The values stated in SI units are to be regarded as the
1.2 This test method applies to in-line components contain-
standard. The inch-pound units given in parentheses are for
ing electronics grade materials in the gaseous form, such as
information only.
those used in semiconductor gas distribution systems.
1.5 This standard does not purport to address all of the
1.3 Limitations:
safety concerns, if any, associated with its use. It is the
1.3.1 This test method is limited by the sensitivity of current
responsibility of the user of this standard to establish appro-
instrumentation, as well as by the response time of the
priate safety, health, and environmental practices and deter-
instrumentation. This test method is not intended to be used for
mine the applicability of regulatory limitations prior to use.
components larger than 12.7-mm ( ⁄2-in.) outside diameter
Specific hazard statements are given in Section 5.
nominal size. This test method could be applied to larger
1.6 This international standard was developed in accor-
components; however, the stated volumetric flow rate may not
dance with internationally recognized principles on standard-
provide adequate mixing to ensure a representative sample.
ization established in the Decision on Principles for the
Higher flow rates may improve the mixing but excessively
Development of International Standards, Guides and Recom-
dilute the sample.
mendations issued by the World Trade Organization Technical
1.3.2 Different instrumental methods (such as flame ioniza-
Barriers to Trade (TBT) Committee.
tion detector (FID), mass spectrometer (MS)) will yield total
hydrocarbon (THC) levels that are not comparable due to
2. Terminology
different sensitivities to different molecular species. Hydrocar-
bon contaminants of high-purity gas distribution systems can
2.1 Definitions:
be subdivided into two general categories: (1) noncondensable
2.1.1 baseline—the instrument response under steady state
hydrocarbons ( conditions.
removal and relative atmospheric abundance, and (2) condens-
2.1.2 glove bag—an enclosure that contains a controlled
able hydrocarbons, that are often left behind on component
atmosphere. A glove box could also be used for this test
surfaces as residues. Condensable hydrocarbons include pump
method.
oils, degreasing agents, and polishing compound vehicles.
2.1.3 heat trace— heating of component, spool piece, or test
stand by a uniform and complete wrapping of the item with
This test method is under the jurisdiction of ASTM Committee F01 on
resistant heat tape.
Electronics and is the direct responsibility of Subcommittee F01.10 on Contamina-
tion Control.
2.1.4 methane (CH ) equivalent—that concentration of CH
4 4
Current edition approved April 15, 2020. Published May 2020. Originally
that causes the same instrument response as the sample.
approved in 1992. Last previous edition approved in 2012 as F1398 – 93(2012).
DOI: 10.1520/F1398-93R20. 2.1.4.1 Discussion—The calibration gas contains a known
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1398 − 93 (2020)
concentration of methane (CH ). Instrument response to zero 2.3.5 Q = the flow through the spool piece or component.
4 s
gas and span gas defines the calibration curve for the analyzer. 2.3.6 T = the temperature of the air discharged by the
a
Instrument response to the sample is the summation of the analyzer’s cooling exhaust.
response for each hydrocarbon reaching the detector. The 2.3.7 T = the temperature of the spool piece or component.
s
concentration reported is the methane concentration, from the 2.3.7.1 Discussion—The thermocouple must be located in
calibration curve that corresponds to the instrument response to contact with the outside wall of the component or spool piece.
the sample. The sample’s concentration is equivalent to the 2.3.8 V-1, V-2 = inlet and outlet valves of bypass loop,
methane concentration that would produce the same instrument respectively.
response. 2.3.9 V-3, V-4 = inlet and outlet valves of test loop, respec-
tively.
2.1.5 minimum detection limit (MDL) of the instrument—the
lowest instrument response above zero detectable that is
3. Significance and Use
readable by the instrument and at least two times the amplitude
3.1 The purpose of this test method is to define a procedure
of the noise.
for testing components being considered for installation into a
2.1.6 response time—the time required for the system to
high-purity gas distribution system. Application of this test
reach steady state after a measurable change in concentration.
method is expected to yield comparable data among compo-
2.1.7 spool piece—a null component, consisting of a straight
nents tested for purposes of qualification for this installation.
piece of electropolished tubing and appropriate fittings, used in
place of the test component to establish the baseline.
4. Apparatus
2.1.8 standard conditions—101.3 kPa, 0.0°C (14.73 psia,
4.1 Materials:
32°F).
4.1.1 Test Gas, purified nitrogen or argon with a maximum
2.1.9 test component—any device being tested, such as a
THC concentration not exceeding the manufacturer’s stated
valve, regulator, or filter.
minimum detection limit of the instrument (MDL). Particulate
filtration of the test gas to 0.02 µm or finer is required, using a
2.1.10 test stand—the physical test system used to measure
typical electronics grade filter. The filter must be compatible
impurity levels.
with the 94°C (200°F) bake-out.
2.1.11 zero gas—a gas that has a THC concentration below
4.1.2 Spool Piece, that can be installed in place of the test
the MDL of the analytical instrument. This purified gas is used
component is required. This piece is to be a straight section of
for both instrument calibration and component testing.
316L electropolished stainless steel tubing with no restrictions.
2.2 Abbreviations:
The length of the spool piece shall be 200 mm. The spool piece
2.2.1 FID—flame ionization detector.
shall have the same end connections as the test component.
2.2.2 MFC—mass flow controller. 4.1.2.1 Components with Stub Ends—Use compression fit-
tings with nylon or teflon ferrules to connect the spool piece
2.2.3 MS—mass spectrometer.
and test component to the test loop. Keep the purged glove bag
2.2.4 ppbv—parts per billion by volume assuming ideal gas
around each component for the duration of the test. In the case
behavior, equivalent to nmole/mole (such as nL/L).
of long pieces of electropolished tubing, use two glove bags,
2.2.4.1 Discussion—The same as molar parts per billion
one at each end.
(ppb).
4.1.3 Tubing, used downstream of the purifier shall be 316L
2.2.5 ppbw—parts per billion by weight (such as ng/g).
electropolished stainless steel seamless tubing. The diameter of
the sample line to the analyzer shall not be larger than 6.4 mm
2.2.6 ppmv—parts per million by volume assuming ideal
( ⁄4 in.). The length of the sample line from the tee (installed
gas behavior, equivalent to µmole/mole (such as µL/L).
upstream of the pressure gage P ) to the analyzer shall not be
2.2.6.1 Discussion—The same as molar parts per million
more than 600 mm to minimize the effect (adsorption/
(ppm).
desorption) of the sample line on the result. The sample line
2.2.7 ppmw—parts per million by weight (such as µg/g).
shall have no more than two mechanical joints.
2.2.8 slpm—standard liters per minute. The gas volumetric
4.1.4 Valves, diaphragm or bellows type and must be ca-
flow rate measured in liters per minute at 0.0°C (32°F) and
pable of unimpaired operation at 94°C (200°F). The use of
101.3 kPa (1 atm).
all-welded, all-metal valves is preferred.
2.2.9 THC—total hydrocarbon.
4.2 Instrumentation:
2.3 Symbols:
4.2.1 THC Analyzer—The THC analyzer is to be placed
2.3.1 P —the inlet pressure measured upstream of the downstream of the test component. Accurate baseline readings
purifier and filter in the test apparatus.
must be obtained prior to and subsequent to each of the tests.
2.3.2 P —the outlet measured downstream of the analyzer The baseline must return to levels <100 ppbv, before and after
in the test apparatus.
the tests. Deviations greater than this require that all results be
2.3.3 Q = the bypass sample flow not going through the rejected and a new test component be tested. The analyzer must
analytical system.
be capable of accurately recording changes in THC concentra-
2.3.4 Q = the total sample flow through the analytical tions on a real-time basis, within the constraints of the data
system. acquisition system.
F1398 − 93 (2020)
4.2.2 THC analyzer calibration—Two-point calibration, 5. Hazards
zero and span, is to be performed regularly. Zero gas is defined
5.1 Precautions:
as below the manufacturer’s stated MDL of the instrument,
5.1.1 It is required that the user have a working knowledge
supplied by purified gas, with the purifier in close proximity to
of the respective instrumentation and that the user practice
the analyzer. Span gas is analyzed at the lowest possible
proper handling of test components for trace organic analysis.
detection range, which may not be at the lowest detection range
Good laboratory practices must also be understood.
of the instrument. Span gas is 5–10 ppmv methane, 6 20 % for
5.1.2 It is required that the user be familiar with proper
FID. Calibration is based on traceable methane concentration
component installation and that the test components be in-
in the base gas (nitrogen or argon).
stalled on the test stand in accordance with manufacturer’s
4.2.3 Flame Ionization Detector (FID)—The FID detects
instructions.
hydrocarbon species by ionizing the organic material in a
5.1.3 Do not exceed ratings (such as pressure, temperature,
flame. Ions produced in the hydrogen flame yield a measurable
and flow) of the component.
current, directly related to the quantity of hydrocarbons intro-
5.1.4 Gloves are to be worn for all steps.
duced to the flame. Burner gases, hydrogen, and air are not to
5.1.5 Limit exposure of the instrument and test component
contain measurable amounts of THC. Purifiers are available for
to atmospheric and hydrocarbon contamination before and
this purpose (especially to remove methane). Burner gases
during the test.
must be maintained at a temperature between 18 and 26°C (64
5.1.6 Precautions must be taken to insure that the tempera-
and 78°F).
ture measured by the thermocouple is as close as possible to
4.2.3.1 The THC data are referred to as ppmv quantity of
that of the spool piece or the test component. Use appropriate
CH equivalents, corresponding to the sum of the number of
insulation and conductive shield to achieve as uniform a
equivalent carbons. Simple, low molecular weight hydrocar-
temperature as possible.
bons are readily detected and quantified as total THC. Higher
5.1.7 Ensure that adequate mixing of the test gas is attained.
molecular weight hydrocarbons and more substituted hydro-
carbons may not be detected well. The FID is, therefore, a
6. Preparation of Apparatus
specific group detector that yields quantification of total
6.1 A schematic drawing of a recommended test apparatus
hydrocarbons for a specific detectable group.
located inside a clean laboratory is shown in Fig. 1. Deviations
4.3 Pressure and Flow Control—Upstream pressure is to be
from this design are acceptable as long as baseline levels
controlled with a regulator upstream of the test component.
consistent with 4.2.1 can be maintained. Nitrogen or argon gas
Flow is to be controlled at a point downstream of the sampling
is purified to remove water and hydrocarbons. The base gas is
port and monitored at that point. A mass flow controller is
then filtered by an electronics grade, high purity, point of use
preferred for maintaining the flow as described in 8.3.
gas filter (pore size rating ≤0.02 µm) before it is delivered to
However, a variable area flowmeter plus a back pressure
the test component.
regulator may be used instead. Sampling is to be performed via
6.2 A bypass loop may be used to divert gas flow through
a tee in the line, with a run of straight tubing before the mass
the test stand and the analyzer whenever the spool piece or a
flow controller. All lines must conform to 4.1.3. Inlet pressure
test component is installed or removed from the test stand. This
is monitored by P . Test flow is the sum of Q and Q . Q is
1 1 2 1
prevents the ambient air from contaminating the test apparatus
directly controlled, and Q is the total flow through the
and the hydrocarbon analyzer; thus, the analyzer baseline
analyzer (refer to Fig. 1).
remains the same. A glove bag is used to enclose test
4.4 Bypass Loop—The design of the bypass loop is not
component lines of the test apparatus during the installation
restricted to any one design. It could be, for example, a 3.2-mm
and removal of the spool piece and the test piece.
( ⁄8-in.) 316L stainless steel coil or a flexible tube section. This
6.3 A total hydrocarbon analyzer capable of detecting hy-
allows the flexibility necessary to install test components of
drocarbon concentration levels down to <50 ppb is connected
different lengths.
to the test stand to sample the gas flowing through the test
piece. The THC analyzer uses hydrogen fuel for the generation
of the flame required for the FID
...