Federal Breath Test Devices Calibrating
Regs (1997)
[Federal Register: August 13, 1997 (Volume
62, Number 156)]
[Notices]
[Page 43416-43425]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr13au97-129]
-----------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
[Docket No. 94-068; Notice 2]
Highway Safety Programs; Model Specifications for Calibrating
Units for Breath Alcohol Testers; Conforming Products List
of
Calibrating Units
AGENCY: National Highway Traffic Safety Administration
(NHTSA), DOT.
ACTION: Notice; request for comments.
-----------------------------------------------------------------------
SUMMARY: This notice amends the Model Specifications for
Calibrating
Units for Breath Alcohol Testers by incorporating an alternative
testing procedure using National Institute for Standards
and Technology
(NIST) Reference Gas Mixtures (RGMs) for the evaluation
of dry gaseous
ethanol calibrating devices and making other changes that
were
previously proposed to simplify the Model Specifications
and to make
them easier to read. This notice also proposes and seeks
comment on a
new alternate procedure for evaluating the accuracy of both
wet bath
and dry gas breath alcohol calibrating units using infra-red
spectroscopy. Published with this notice is an amended Conforming
Products List (CPL) of calibrating units that meet the Model
Specifications. This amended list includes five new listings,
one wet
bath unit and four dry gas units.
DATES: The amendments to the Model Specifications and the
issuance of the Conforming Products List of calibrating
units meeting the Model
Specifications become effective on August 13, 1997. Comments
on the
alternate testing procedure using infra-red spectroscopy
proposed as an
amendment to the Model Specifications published herein must
be received by October 14, 1997.
ADDRESSES: Comments regarding the alternate testing procedure
should
refer to the docket number and the number of this notice
and be
submitted (preferably in ten copies) to the NHTSA Docket
Section, Rm.
5109, 400 Seventh St., S.W. Washington, D.C. 20590 (Docket
hours are
from 9:30 a.m. to 4 p.m.).
FOR FURTHER INFORMATION CONTACT: Dr. James F. Frank, Impaired
Driving Division, Office of Traffic Injury Control Programs
(OTICP), NTS-11, 400 Seventh St., SW, Washington, DC 20590.
Telephone (202) 366-5593.
SUPPLEMENTAL INFORMATION: On August 18, 1975 (40 FR 36167),
NHTSA published a standard for Calibrating Units for Breath
Alcohol Testers. A Qualified Products List of calibrating
units for breath alcohol
testers, of devices which met the standard, was
[[Page 43417]]
first issued on November 30, 1976 (41 FR 53389).
On December 14, 1984, NHTSA issued a notice to convert the
mandatory standards for evidential breath testers and calibrating
units
for breath alcohol testers to Model Specifications for such
devices (49
FR 48855 and 49 FR 48865, respectively) and to establish
a Conforming
Products List (CPL) of evidential breath testers and calibrating
units
meeting the Model Specifications. Amendments to the CPL
have been
published in the Federal Register since that time. Evidential
breath
testers are instruments that measure the alcohol content
of deep lung
breath samples with sufficient accuracy for evidential purposes.
Calibrating units provide known concentrations of ethanol
vapor for the
calibration or calibration checks of instruments which measure
breath
alcohol.
NHTSA published a notice in the Federal Register (59 FR
67377) on
December 29, 1994, amending the Model Specifications for
calibrating
units for breath alcohol testers and updating the CPL for
calibrating
units. The notice also proposed and sought comments about
providing an alternate testing procedure for evaluating
the accuracy and precision
of dry-gas ethanol calibrating units.
Officials who use breath alcohol testers must verify their
accuracy
at appropriate intervals during use. The traditional means
for ensuring
accuracy has been by checking the breath tester calibration
by use of a
``wet bath'' calibrator, a device which provides moist alcohol
in air
samples at accurately known concentrations. Dry gas calibrating
units
have become available as an alternate means for calibration
checking.
A dry gas calibrator produces alcohol-in-inert gas samples
(e.g.,
nitrogen or argon) at accurately known concentrations from
a compressed gas cylinder. Dry gas calibrators, like wet
bath calibrators, can be used to calibrate certain types
of breath testers, but an evaluation of their precision
and accuracy requires alternate procedures. Today's notice
amends the Model Specifications for Calibrating Units for
Breath
Alcohol Testers by incorporating an alternative testing
procedure using
National Institute for Standards and Technology Reference
Gas Mixtures
for the evaluation of dry gaseous ethanol calibrating devices
and
making other changes that were previously proposed to simplify
the
Model Specifications and to make them easier to read. Additional
minor
changes were made to ensure accuracy and improve clarity
of the
document. Also, the term BrAC has replaced the term BAC
throughout the model specifications to ensure consistency
with usage recommended in the Uniform Vehicle Code.
Today's notice also proposes an additional new alternate
procedure
for evaluating wet bath and dry gas calibrating units using
infra-red
spectroscopy. The agency believes that use of infra-red
spectroscopy
will offer several important advantages in the evaluation
of both wet
bath and dry gas calibrating units. Comments are sought
regarding the
agency's proposal.
A. Comments Received
1. Overview
The agency received two comments in response to the notice
of
December 29, 1994: one from Scott Specialty Gas Co. (Scott
Gas), a
manufacturer of a dry gas calibrating unit, and one from
U.S. Alcohol
Testing (USAT), a manufacturer of an evidential breath test
device and
a wet bath calibrating unit that is currently listed on
the NHTSA CPL.
Scott Gas was generally supportive of the proposed revisions
to the
Model Specifications. USAT stated that it would favor the
use of dry
gaseous ethanol calibrating devices when ``it has been adequately
demonstrated that dry-EtOH [calibration units] give results
comparable
to those obtained with conventional wet bath simulator calibration
units.''
Neither of the respondents specifically commented on the
proposed
revisions to simplify the Model Specifications. As stated
in the
notice, these proposed revisions did ``not represent substantive
alterations in the procedures followed or in the criteria
used to
determine whether devices meet these model specifications.''
The
proposed revisions have been adopted without change.
Both Scott Gas and USAT raised questions in their comments
about
those aspects of the Model Specifications relating to the
proposed new
alternate testing procedure for evaluating the accuracy
and precision
of dry gas calibrating units. The comments addressed a number
of key
issues, including the comparability of wet bath and dry
gas calibrating
units and certain specific conditions affecting dry gas
calibrating
units. The issues that were contained in the comments are
summarized
and discussed below.
2. Comparability Between Wet Bath and Dry Gas Calibrating
Units
USAT commented that ``[T]he use of a dry gas EtOH standard
makes no physical sense until it can be demonstrated that
the presence of water vapor in the breath samples analyzed
has no effect on the analytical outcome on the ethanol concentration
of the breath samples analyzed by the [evidential breath
tester].''
While it is true that dry gas and human breath differ in
moisture
content, NHTSA has found no reason to exclude the use of
dry gas
calibrating units solely on this basis. If a calibrating
unit (either
wet bath or dry gas) meets the precision and accuracy criteria
of the
Model Specifications, the calibrating unit should be considered
acceptable for general use.
Independent research has confirmed the comparability of
dry gas and
wet bath calibrating units and the accuracy of dry gas calibrating
units. Kurt M. Dubowski and Natalie A. Essary studied the
performance
of dry gas calibrating units and concluded that ``dry gas
vapor-alcohol
control [VAC] samples conformed to established formal specifications
and * * * compared favorably with simulator effluents for
control tests
of breath alcohol analyzers which are capable of adjusting
VAC results
for ambient atmospheric pressure.''
Lance D. Silverman, et al. reported on the comparability
of wet bath and dry gas calibrating units. These researchers
determined that there was substantial equivalence between
both types of calibrating units. Their data ``based on collection
of ethanol in an impinger and titration using a modified
California Department of Health method * * * confirm[ed]
the alcohol content of EBS compressed gases standards by
an absolute, wet chemical method.''
---------------------------------------------------------------------------
\1\ Dubowski, K. and N.A. Essary ``Vapor-Alcohol Control
Tests
with Compressed Ethanol-Gas Mixtures: Scientific Basis and
Actual
Performance.'' Journal of Analytical Toxicology (1996)20,
484.
\2\ Silverman, L.D., Wong, K. and Miller, S. ``Confirmation
of
Ethanol Compressed-Gas Standard Concentrations by a NIST-traceable,
absolute chemical method and comparison to wet breath alcohol
simulators.'' Accepted for Publication in the Journal of
Analytical
Toxicology, 1997.
---------------------------------------------------------------------------
3. Should the Model Specifications Be Expanded To Address
Unique
Conditions Affecting Dry Gas Calibrating Units?
USAT challenged the use of dry gas calibrating units based
on the
following factors: (a) condensation in the cylinder as a
consequence of
low temperatures during shipment; (b) the need to make corrections
due
to changes in atmospheric pressure; and (c) the performance
of dry gas
calibrators over a range of temperatures and concentrations.
NHTSA has considered these comments carefully and has concluded
that dry gas calibrating units are suitable for evaluation
according to
the Model
[[Page 43418]]
Specifications and believes that the Model Specifications
are
sufficient to ensure the accuracy and precision of dry gas
calibrating
units. However, in light of the concerns raised by USAT,
the agency has
amended the procedures for submitting a product for certification.
When
a manufacturer submits a product to the agency for testing,
it now must
submit also a set of the instructions that are provided
to end users.
The instructions must sufficiently describe the procedures
to be
followed to protect against condensation in dry gas cylinders
that
might occur as a result of freezing during shipment and
to correct for
atmospheric pressure.
(a) Condensation in Dry Gas Cylinders as the Result of
Freezing
USAT commented that dry gas calibrating units were previously
shown
to have a ``memory effect when transported or stored at
temperatures
somewhat below room temperature.'' NHTSA acknowledges that
dry gas
calibrators could freeze during shipment and this could
affect test
results. As a result of freezing, alcohol could condense
in the inside
surface of the cylinder. If this were to happen, re-equilibration
of
the alcohol with the nitrogen after warming to room temperature
could
take a long time. It is possible that the gas in such cylinders
might
be used before re-equilibration occurred with the result
that samples
would be obtained at incorrect concentrations.
Manufacturers of dry gas calibrating units recommend that,
after
receiving the dry gas cylinders, users should warm the cylinders
to
room temperature, then lay them down on a flat surface and
physically
roll them back and forth for a period of ten minutes to
ensure
equilibration of the contents. To test whether this procedure
would
ensure that the dry gas calibrators remained accurate, several
cylinders of Lion Laboratories AlcoCal dry gas calibrators
were placed
in the freezer compartment of a refrigerator overnight at
a temperature
of -15 deg.C, then taken out of the freezer, warmed to room
temperature and rolled on a table top for ten minutes. Data
was collected confirming that tanks that were rolled after
freezing gave accurate results.
---------------------------------------------------------------------------
\3\ Flores, Arthur, ``Dry Gas Calibration Units Report''
U.S.
Department of Transportation Volpe National Transportation
Systems
Center, Cambridge MA, September 1996.
---------------------------------------------------------------------------
As described in the section on procedures for product
submission
included at the end of this notice, when manufacturers submit
their
instruments for testing, they are required to submit copies
of the
instructions they provide to end users. NHTSA will examine
these
instructions to ensure that they provide sufficient information
about
this procedure. Products submitted without this information
will not be
tested.
(b) The Effect of Variable Atmospheric Pressure on Dry Gas
Calibrators
USAT commented that dry gas calibrating units may exhibit
a
pressure-dependent concentration effect that wet bath calibrating
units
do not. The packaging of a dry gas calibrator compresses
a large volume
of an alcohol-in-inert gas mixture into a metal cylinder
of only about
one (1) liter. The concentration of the alcohol in the gas
is given by
the Ideal Gas Law <SUP>4</SUP>: PV = nRT, where
P is the pressure of
the gas, V is the volume, n is the number of moles of gas,
R is the gas
constant, and T is the temperature of the gas. The concentration
of the
gas is obtained as a function of pressure and temperature:
Concentration = n/V = P/RT.
---------------------------------------------------------------------------
\4\ Farrington Daniels & Robert Alberty, ``Physical
Chemistry''
3rd Ed., John Wiley & Sons, New York, 1966.
---------------------------------------------------------------------------
When a calibration check is performed, some of the gas
in the
cylinder is released by operating the release valve. The
volume of the
released gas will expand and its pressure will drop until
prevailing
atmospheric pressure is reached. The gas is prepared so
that the
desired concentration is obtained at normal atmospheric
pressure, 760
millimeters of mercury. However, atmospheric pressure varies
slightly
from day to day and can change suddenly at times. The most
significant
effect comes from high elevations, where prevailing atmospheric
pressure is significantly lower than 760. Atmospheric pressure
corrections are made using an equation derived from the
Ideal Gas Law:
C = C<INF>760</INF> X P/760, where C is concentration
and P is the
prevailing atmospheric pressure.
In order for any calibrating unit to operate properly under
such
atmospheric pressures, accurate pressure correction must
be made. The
agency has tested the dry gas calibrating units placed on
the CPL in
this publication using this pressure correction procedure
and has
determined that these devices meet the Model Specifications.
The agency
concludes that the pressure dependent concentration effect
is
consistent and well established and that pressure correction
procedures
suggested by manufacturers are effective and produce accurate
results.
As described in the section on procedures for product submission
included at the end of this notice, when manufacturers submit
their
instruments for testing, they are required to submit copies
of the
instructions they provide to end users. While manufacturers
already
provide information on pressure corrections in their instructions
to
end users, these Model Specifications have been amended
to require that
the instructions include information about how atmospheric
pressure
corrections should be made. NHTSA will examine manufacturers'
instructions to ensure that they provide sufficient information
about
these pressure correction procedures. Products submitted
without this
information will not be tested. NHTSA believes that these
procedures
will be effective when used by properly qualified breath
alcohol
technicians.
(c) The Performance of Dry Gas Calibrators Over Range of
Temperatures
and Concentrations
Throughout its written comments, USAT argues that dry gas
standards
should not be accepted because they have not been shown
to be
comparable to wet bath standards. USAT argues:
Further substantial equivalence of the dry-EtOH and wet
simulators must be shown over the range of environmental
temperatures and pressures likely to be encountered during
normal
field usage of any of the devices appearing on the CPL *
* * [and]
over the range of NHTSA tested concentrations * * * throughout
the
operating lifetime of the dry gas [calibrating units] *
* *
Results of comparative performance of dry-ETOH [calibrating
units] versus wet simulator [calibrating units] need to
be publicly
presented in scientific forums and published in the technical
literature to establish a level of confidence that dry gas
[calibrating units] yield substantially equivalent results
to those
obtained for decades from conventional wet simulator [calibrating
units].
USAT commented that ``Dry gas EtOH [calibrating units]
must be required
to show equivalent performance over the entire range of
environmental
conditions used to test wet bath simulator [calibrating
units].'' The
agency tests both wet bath and dry gas calibrating units
according to
the Model Specifications. The agency believes that the Model
Specifications require testing over an appropriate range
of
temperatures and concentrations. Dry gas calibrating units
are required
to show equivalent performance over the entire range of
environmental
conditions used to test wet bath calibrating units.
[[Page 43419]]
4. Are Dry Gas Calibrating Units Sufficiently Accurate?
USAT states that it would favor use of dry gas calibrating
units
when ``it has been adequately demonstrated that dry EtOH
[calibrating
units] give results comparable to those obtained with conventional
`wet
bath simulator calibration units'.''
The same Model Specifications used to test the accuracy
and
precision of wet bath calibrating units are used to ensure
the quality
and performance of dry gas calibrating units. All units
are tested over
the same range of temperatures and concentrations. All dry
gas
calibrating units placed on the CPL in this publication
conform to the
Model Specifications. Any unit that fails to meet the requirements
of
the Model Specifications would not be included on the agency's
list of
conforming products.
5. Miscellaneous Issues
(a) Quality Assurance Plan
Scott Gas recommended that the agency require Quality Assurance
Plans (QAPs) for calibrating units. QAPs are used to provide
information on the correct use, proper maintenance procedures
and other
specific requirements of a calibration device. Scott Gas
recommended
that the QAP address issues such as NIST traceability, mechanisms
for
product coding and traceability, list of proper delivery
equipment,
specifications on the containers being submitted for approval,
shipping
and storage information, written laboratory certification
and
manufacturing procedures, DOT specification documentation
on
containers, a specified uncertainty at the 95% confidence
level and
shelf life results.
NHTSA strongly endorses the need for quality control in
manufacturing, but believes that this is addressed appropriately
by the
manufacturers of these instruments. When calibrating units
are used by
law enforcement officials, quality control measures are
also taken
under the programs of each state. In transportation workplace
testing,
quality control is ultimately handled by the existing requirement
for
QAPs for evidential breath testers and alcohol screening
devices
(Screeners) which address calibration accuracy. The evidential
breath
tester QAPs call for calibration checks using an approved
calibrating
unit. If an evidential breath tester or a Screener gives
an incorrect
reading when a calibration check or a calibration is conducted,
it
suggests that there is an error in the system consisting
of the
evidential breath tester (or Screener), the breath alcohol
technician,
or the calibrating unit. NHTSA believes that the safeguards
already in
place in the QAPs for evidential breath testers and Screeners
make it
unnecessary to require an additional QAP specific to the
calibrating
unit.
(b) Stability of Dry Gas Calibrators Over Their Operating
Life
USAT commented that ``Further substantial equivalence of
the dry-
EtOH and wet simulators must be shown over the range of
NHTSA tested
concentrations * * * throughout the operating lifetime of
the dry gas
[calibrating units] * * *'' Scott Gas also commented that
``presentation of gas manufacturer stability documentation
to NHTSA,
before inclusion on the CPL, plus NHTSA evaluation of aged
product
should be done in order to assess the ``real life'' performance
of the
product.''
The agency's experience indicates that dry gas calibrating
units
are normally stable even after years of storage. In addition,
NHTSA has
verified that National Institute of Standards and Technology
Reference
Gas Mixtures used to evaluate dry gas cylinders remained
stable to
within <SUP>plus-minus</SUP>0.001 BrAC for a
one year period. The
agency has concluded that manufacturers will not be required
to provide
stability documentation.
NHTSA shall certify that the CPL does, in fact, reflect
calibrating
units which meet the performance criteria set forth in the
Model
Specifications. NHTSA reserves the right to test any unit
on the CPL
throughout its useful life to ensure that the unit is performing
in
accordance with the Model Specifications. In addition, in
the section
on procedures for a product submission, included at the
end of this
notice, NHTSA requests that users of calibrating units provide
both
acceptance and field performance data to NHTSA's Office
of Traffic
Injury Control Programs. NHTSA will conduct a special investigation
if
information gathered from the field indicates that a device
on the CPL
is not performing in accordance with the Model Specifications.
After the recent expansion of the use of dry gas calibrators,
one
manufacturer found that the concentration of some dry gas
calibrators
had changed from the stated concentrations after weeks or
months of
storage. A recall of all cylinders in use was ordered. The
problem was
investigated and, after extensive testing it was traced
to defects in
certain cylinders and was corrected.
(c) National Institute of Standards and Technology Reference
Gas
Mixtures
In the Notice published on December 24, 1994, NHTSA proposed
to
revise the Model Specifications to permit use of National
Institute of
Standards and Technology Reference Gas Mixtures (NISTRGMs)
as reference
samples to evaluate the accuracy of dry gas calibrating
units by gas
chromatography.
Use of these dry gas standards allows reliable evaluation
of dry
gas calibrators by the gas chromatograph technique. USAT
commented
that:
It is rumored that NISTRGMs are manufactured by Scott
Specialty
Gases/Scott Medical Products Inc. If true, the NHTSA-proposed
substitution of NISTRGMs to replace wet bath simulator standards
for
the testing of any Scott Gas gaseous standards amounts to
one
manufacturer certifying itself and claiming the blessing
of both
NIST and NHTSA.
The NISTRGMs obtained by the Volpe center were manufactured
by Scott
Specialty Gases, but were obtained from and analyzed independently
by
the Department of Commerce National Institute for Standards
and
Technology (NIST). NIST attested in writing to the accuracy
of each
individual cylinder of gas which was obtained by the Volpe
Center.
(d) The Comparability of Dry Gas Calibrating Units When
Used With a
Variety of Evidential Breath Testing Devices
USAT commented that ``dry gas standards are likely to give
different results when used on [evidential breath testers]
based on
different technologies.'' According to USAT, there have
been reports
that dry gas calibrating units do not yield the same results
for
certain breath testers as wet bath calibrating units. USAT
asserts that
a small ``offset'' in test result reportedly occurs when
dry gas
calibrators are used for these breath testers compared with
wet
calibrators at the same concentration. The offset for fuel
cell breath
testers is reported to be -0.002 BrAC when dry calibrators
are used to
check calibration of fuel cell evidential breath testers.
Performance requirements contained in NHTSA's Model Specifications
for evidential breath testers require that these instruments
be
accurate to <plus-minus>0.005 or 5% of test BrAC,
whichever is greater,
with a standard deviation not greater than 0.004. The performance
requirements for calibrating units require the devices to
be accurate
to within 0.002 BrAC of the test BrAC with relative standard
deviation
of 2%. Any offset associated with a particular calibrator
is not
considered.
[[Page 43420]]
Agency testing indicates that dry gas calibrating units
can be used
with infra-red and fuel cell breath testers.<SUP>5</SUP>
The agency
tested four fuel cell testers, one fuel cell/infra-red combination
tester with readout from the fuel cell sensor, and one infra-red
tester
to obtain wet dry comparison data. The instruments tested
were:
\5\ Flores, Arthur, ``Dry Gas Calibrating Units Report'',
U.S.
Department of Transportation, Volpe National Transportation
Systems
Center, Cambridge, MA, September, 1996.
---------------------------------------------------------------------------
Life Loc, Inc. PBA 3000 and PBA 3000X (FC)
CMI, Inc. Intoxilyzer 400 (FC)
Intoximeters, Inc. AlcoSensor IV (FC)
National Draeger, Inc. Breathalyzer 7410-II (FC)
Intoximeters, Inc. EC-IR (FC/IR)
CMI, Inc. Intoxilyzer 5000 (IR)
Measurements were made alternately using first a sample
from a wet bath
calibrator, then a sample from a dry gas calibrator. Five
measurements
of each type of sample were made on each of the testers.
The wet
calibrator solutions were prepared to produce the same concentrations
as the corresponding dry gas. Wet samples were produced
using RepCo
Marketing simulators (wet bath calibrating units). Dry samples
were
obtained from dry gas calibrating units from Scott Specialty
Gases,
Inc. (0.04 BrAC) and Gateway Airgas, Inc. (0.04 and 0.088
BrAC). The
concentration of the Scott gas was verified by Intoximeters,
Inc. and
the concentration of the gas from Gateway Airgas was verified
by infra-
red spectroscopy at the Volpe center. The factory calibrations
of the
breath testers were not adjusted. The reliability of the
``true value''
of the wet or dry standards can be taken as known values
to within
about <plus-minus>0.001 BrAC. Thus, the true value
of a wet sample or a
dry sample at 0.040 BrAC can be expected to be correct to
within about
<plus-minus>0.001 BrAC.
The differences between wet bath and dry gas calibrating
units were
negligible when the comparisons were made using infra-red
breath
testers. These differences were around 0.002 BrAC and are
not
noticeable unless comparisons are made carefully, because
this value is
near the accuracy limit of the calibrating units.
The differences observed when comparisons were made using
fuel cell
type breath testers, the next most widely used type of breath
tester,
were more noticeable, especially at high alcohol levels.
The offset for
fuel cell breath testers averaged somewhat less than 4%
of the nominal
BrAC when dry gas calibrators were used to check calibration
of fuel
cell evidential breath testers. The offsets found for the
breath
testers ranged from -0.0014 BrAC to 0.0026 BrAC when compared
at the
0.04 BrAC level, and from -0.0020 to 0.0052 when compared
at the 0.088
level. The standard deviations for the wet and dry data
were in the
fourth decimal place except in one instance when a value
of 0.002 was
obtained, which was still acceptable. These results indicate
that the
offsets are small and reproducible enough that reliable
corrections can
be applied to ensure accurate test results. The offsets
observed cannot
be assumed to arise only from the inherent differences in
measurement
of moist samples compared to the measurement of dry samples
since there
are also uncertainties of <plus-minus>0.001 in the
true concentration
of wet bath or dry gas calibration unit vapors.
Offsets must be indicated by manufacturers in their instructions
to
end users. Manufacturers are required to include their instructions
in
a submission of a calibrating unit for testing. The agency
will examine
the instructions to ensure that they provide sufficient
information on
offsets necessary for certain breath testers. Products submitted
without this information will not be tested.
Gas Chromatograph breath testers depend on extensive surface
interaction with the sample being analyzed, and the greatest
differences between dry and wet standards are seen with
this type of
breath tester. In its laboratory, NHTSA has found that the
effects are
not stable. They vary with type and condition of resolving
column used.
Accordingly, NHTSA believes that dry gas calibrating units
should not
be used with gas chromatograph breath testers because the
results are
too variable. The agency will include a footnote on the
CPL concerning
the use of dry gas standards with gas chromatograph evidential
breath
testers, indicating that the agency does not recommend the
use of dry
gas calibrating units with gas chromatograph evidential
breath testers.
B. Procedures for a Product Submission
Testing of calibrating units submitted by manufacturers
to these
Model Specifications will continue to be conducted by the
DOT Volpe
National Transportation Systems Center (VNTSC). Tests will
continue to
be conducted semi-annually or as necessary. Manufacturers
wishing to
submit calibrating units for testing must apply to NHTSA
for a test
date (Office of Traffic Injury Control Programs, NTS-11,
NHTSA, 400
Seventh Street, S.W., Washington, D.C. 20590). Normally,
at least 30
days will be required from the date of notification until
the test can
be scheduled. One week prior to the scheduled initiation
of the test
program, the manufacturer will deliver at least one unit
of the device
to be tested to: VNTSC, DTS-75, 55 Broadway, Kendall Square,
Cambridge
MA 02142. The manufacturer shall be responsible for ensuring
that the
unit is operating properly. If the manufacturer wishes to
submit a
duplicate, backup unit, it may do so.
When a manufacturer delivers a device to be tested, it shall
also
deliver to VNTSC specifications and drawings that fully
describe the
unit and the Operator's Manual and Maintenance Manual normally
supplied
with purchase of the equipment. Proprietary information
will be
respected. (See 49 CFR Part 512, regarding the procedures
by which
NHTSA will consider claims of confidentiality.)
The manufacturer shall also deliver the instructions that
will
accompany the device when it is sold. The instructions shall
include
information about the procedures to be followed to protect
against
possible condensation that might occur as a result of freezing
during
shipment and to correct for atmospheric pressure. The instructions
shall also include information about any offsets that may
apply to the
use of a particular type of breath tester. NHTSA will examine
these
instructions to ensure that they provide sufficient information
about
these matters. Products submitted without this information
will not be
tested.
The manufacturer will have the right to check the calibrating
unit
between arrival in Cambridge and the start of the test,
and to ensure
that the calibrating unit is in proper working condition
but will have
no access to it during the tests. Any malfunction of the
calibrating
unit which results in failure to complete any of the tests
satisfactorily will result in a finding that it does not
conform to the
Model Specifications. If a unit fails to conform, it may
be resubmitted
for testing after appropriate corrective action has been
taken.
On the basis of these results, NHTSA will publish a Conforming
Products List (CPL) identifying the calibrating units that
conform to
the Model Specifications.
Retesting of units will be conducted when necessary. NHTSA
intends
to modify and improve these Model Specifications as new
data and
improved test procedures become available. (The test procedures
may be
altered in specific instances, if necessary, to meet the
unique design
features of a calibrating unit). If these Model Specifications
are
modified, notification will be provided in the Federal Register.
If
NHTSA determines that retesting to the modified
[[Page 43421]]
specifications is necessary, a manufacturer whose equipment
is listed
on the CPL will be notified to resubmit the equipment for
testing to
the modified specification only.
NHTSA will certify that the CPL does, in fact, reflect calibrating
units which meet the performance criteria set forth in the
Model
Specifications. NHTSA reserves the right to test any unit
on the CPL
throughout its useful life to ensure that the unit is performing
in
accordance with the Model Specifications.
If at any time a manufacturer plans to change the design
of a
calibrating unit currently on the CPL, the manufacturer
shall submit
the proposed changes to the Office of Traffic Injury Control
Programs
for review. Based on this review, NHTSA will decide whether
the change
will require retesting of the unit. Normally, such retesting
will be
accomplished the next time testing is performed. Guidance
to
manufacturers on considerations governing this decision
are available
from NHTSA's OTICP, upon request.
OTICP will be the point of contact for information about
acceptance
testing and field performance of equipment already on the
list. When it
is available, NHTSA requests that users of calibrating units
provide
both acceptance and field performance data to OTICP. Information
from
users will be used to: (1) help NHTSA determine whether
units continue
to perform according to the NHTSA Model Specifications and
(2) ensure
that field use does not indicate excessive breakdown or
maintenance
problems.
If information gathered indicates that a device on the CPL
is not
performing in accordance with the Model Specifications or
demonstrates
problems involving the device, NHTSA will direct VNTSC to
conduct a
special investigation. This investigation may include visits
to users
and additional tests of the unit obtained from the open
market. If the
investigation indicates that the units actually sold on
the market are
not meeting the Model Specifications, then the manufacturer
will be
notified that the unit may be removed from the list. In
this event the
manufacturer shall have 30 days from the date of notification
to reply.
Based on the VNTSC investigation and any data provided by
the
manufacturer, NHTSA will decide whether the unit should
remain on the
list. Upon resubmission, the manufacturer must submit a
statement
describing what has been done to overcome the problems that
led to the
dropping of the unit in question from the list.
C. Infra-red Spectroscopy
In this notice, NHTSA is proposing an alternate procedure
which
uses infra-red spectroscopy for the evaluation of dry gas
units (see
Appendix A). It is proposed as an amendment to the Model
Specifications
for Calibrating Units published in this notice. In infra-red
spectroscopy, the wet bath or dry gas sample to be analyzed
is passed
into a chamber through which infra-red radiation is transmitted.
The
wavelength of the transmitted radiation is chosen so that
some of it is
absorbed by alcohol. According to the Beer-Lambert Law of
absorption of
radiation,<SUP>6</SUP> the amount of energy
absorbed by the sample in
the chamber is proportional to the concentration of the
alcohol in the
sample. By measuring the amount of radiation transmitted
when the
sample chamber is empty and the amount transmitted when
the sample is
present, the concentration of the alcohol in the sample
can be
determined.
---------------------------------------------------------------------------
\6\ Farrington Daniels & Robert Alberty, ``Physical
Chemistry''
3d Ed. John Wiley & Sons, New York, 1966.
---------------------------------------------------------------------------
The agency believes that use of infra-red spectroscopy
will offer
several important advantages. First, the technique can be
used to
evaluate both wet bath calibrating units and dry gas calibrating
units
because surface interactions do not effect the analysis.
Second,
standards used in the evaluations can be prepared at the
Volpe Center,
eliminating the necessity of obtaining standards from an
outside
source.
D. Comments
Interested persons are invited to comment on the proposed
alternate
procedure described in this notice. It is requested, but
not required
that 10 copies be submitted. Comments must not exceed 15
pages in
length (49 CFR 553.221). Necessary attachments may be appended
to those
submissions without regard to the 15 page limit. This limitation
is
intended to encourage commentors to detail their primary
arguments in a
concise fashion.
All comments received before the close of business on the
comment
closing date indicated above will be considered, and will
be available
for examination in the docket at the above address, both
before and
after that date. To the extent possible, comments filed
after the
closing date will also be considered. However, the amendments
to the
Model Specifications may be published at any time after
that date, and
any comments received after the closing date and too late
for
consideration with regard to the action will be treated
as suggestions
for future revisions to the Specifications. NHTSA will continue
to file
relevant material in the docket after the closing date as
it becomes
available. It is recommended that interested persons continue
to
examine the docket for new material.
Those persons who desire to be notified upon receipt of
their
comments in the docket should enclose a self-addressed stamped
postcard
in the envelope with their comments. Upon receiving the
comments, the
docket supervisor will return the postcard by mail.
E. Conforming Products List
The Conforming Products List (CPL), which appears as Appendix
B to
this notice, lists the calibrating units that have been
retested to
date at the lower BACs (i.e., at 0.020, 0.040, 0.080, and
0.160) and
found to conform to the Model Specifications reprinted herein.
The CPL
also lists devices that have not been tested at these lower
BAC levels,
but which were listed on a previous CPL for calibrating
units (58 FR
26030) on the basis that they were tested and found to conform
to the
earlier model specifications when tested at BAC levels 0.050,
0.100 and
0.150. These devices have been identified with an asterisk.
This CPL also includes five new listings: four dry-gas calibrating
units and one wet-bath calibrating unit. The dry gas units
include:
Model EBS<SUP>TM</SUP>'' Gaseous Ethanol Breath
Standard submitted by
Scott Specialty Gases, Inc. of Plumsteadville, PA; the Ethanol
Breath
Alcohol Standard submitted by Gateway Airgas (previously
known as A.G.
Specialty Gas Company, or Acetylene Gas Company) of St.
Louis, MO; the
AlcoCal Breath Alcohol Standard submitted by Lion Laboratories,
plc of
Cardiff, Wales, UK; and Compressed ethanol-in-nitrogen submitted
by
Liquid Technology Corporation of Orlando, FL. All of the
dry-gas
calibrating units were tested using the alternate procedure
that uses
the NISTRGM. The new wet-bath unit is Model 3402C submitted
by RepCo
Marketing, Inc., of Raleigh, NC.
In consideration of the foregoing, NHTSA amends the Model
Specifications for Calibrating Units, as last published
in the Federal
Register on December 29, 1994 (59 FR 67377), as set forth
below. NHTSA
proposes to further amend these Model Specifications, as
set forth in
Appendix A.
[[Page 43422]]
Model Specifications for Calibrating Units for Breath Alcohol
Testers
1.0 Purpose and Scope
These specifications establish performance criteria and
methods for
testing of calibrating units which provide known concentrations
of
ethanol vapor for the calibration or calibration checks
of breath
alcohol testers.
The results of this testing are intended
for use in
the conformance testing for the maintenance of a Conforming
Products
List for calibrating units.
2.0 Definitions
2.1 Conformance testing. Testing to check the conformance
of a
product with these model specifications in advance of and
independent
of any specific procurement action.
2.2 Concentration units. Blood alcohol concentration: grams
alcohol per 100 milliliters blood or grams alcohol per 210
liters of
breath in accordance with the Uniform Vehicle Code, Section
11-
903(a)(5).<SUP>7</SUP> BrAC is often used to
indicate that the
measurement is a breath measurement, i.e. gram alcohol per
210 liters
of breath.
---------------------------------------------------------------------------
\7\ Available from National Committee on Uniform Traffic
Laws
and Ordinances, 405 Church Street, Evanston, IL 60201.
---------------------------------------------------------------------------
2.3 Relative Standard Deviation (RSD). The ratio of the
standard
deviation (SD) of a series of measurements to the mean of
the series
expressed as a percentage:
RSD=(SD/Mean) x 100 percent
2.4 Standard Deviation (SD). A common indication of precision
in
the measurement of the concentration of a succession of
N vapor
samples.
SD={Sum (X<INF>i</INF>-X<INF>m</INF>)\2\/(N-1)}\1/2\
where X<INF>i</INF>=a single measurement result;
X<INF>m</INF>=the average of the measurements;
N=the number of measurements made in the test.
2.5 Systematic Error (SE). An indication of the accuracy
of the
measurement of the concentration of a succession of vapor
samples.
SE=X<INF>m</INF>-test BrAC
2.6 Least Squares Fit Calibration Curve. A line fitted to
a number
of measurement pairs, one the independent value (X) and
the other the
dependent value (Y), over a measurement range.
The fitted line is of the form: Y=a+bX, where intercept,
a=Y<INF>m</INF>-bX<INF>m</INF>,
and slope,
b=(SumX<INF>i</INF>Y<INF>i</INF>-NX<INF>m</INF>Y<INF>m</INF>)/
(SumX<INF>i</INF>2-nX<INF>m</INF>2).
3.0 Tests and Requirements
If the BrAC of the CU is fixed, perform the tests at the
fixed
BrAC; otherwise, prepare the CU for testing at 0.08 BrAC
except as
otherwise required in Test 1 below. Each of the tests require
10
measurements to three decimal places using the test procedure
specified
in 3.1. The CU will be operated according to the manufacturer's
instructions. Unless otherwise specified, the tests will
be performed
in the absence of drafts and at prevailing normal laboratory
temperature, humidity, and barometric pressure. Performance
requirements are:
-0.002 BrAC <ls-thn-eq> SE <ls-thn-eq> + 0.002
BrAC; RSD <ls-thn-eq> 2%
Test 1. Precision and Accuracy. Test at each specified
BrAC.
Test 1.1: 0.020 BrAC
Test 1.2: 0.040 BrAC
Test 1.3: 0.080 BrAC
Test 1.4: 0.160 BrAC
Test 2. Ambient Temperature. Use a temperature chamber controllable
to <plus-minus>2 deg.C. Soak the CU at the specified
temperature for 1
hour, being careful to prevent drafts on the device, then
test at that
temperature.
Test 2.1: 10 deg.C
Test 2.2: 30 deg.C.
Test 3. Input Power. If the CU is powered by nominal voltages
of
120 volts AC or 12 volts DC, condition the device for one
half hour at
the appropriate input voltage specified below, then test
at that
voltage. Monitor the input power with a voltmeter accurate
to
<plus-minus>2% full scale in the range used and re-adjust
the voltage,
if necessary. If the voltage is AC, conduct tests 3.1 and
3.2. If the
voltage is DC, conduct tests 3.3 and 3.4.
Test 3.1: 108 Volts/AC
Test 3.2: 123 Volts/AC
Test 3.3: 11 Volts/DC
Test 3.4: 15 Volts/DC
Test 4. Electrical Safety Inspection. Examine the CU for
protection
of the operator from electrical shock. Examine for proper
use of input
power fuses, and verify that there are no exposed male connectors
at
high potential. Determine that overheating does not occur
during
operation and that undue fire hazards do not exist.
3.1 Test Procedure (Original, Wet-bath)
Equipment and Supplies: Gas Chromatograph capable of complete
resolution of ethanol in test samples, with heated gas sampling
valve.
Water bath thermostated at 34 deg.C <plus-minus>0.1
deg.C. Glass
Reference Sample Bottles (300 ml capacity or greater) with
Stopper and
Inlet and Outlet Air Hoses (see Figure 1). Hoses should
be about 1/8''
OD Teflon tubing. Reference Ethanol Solutions prepared using
class A
glassware and American Chemical Society reagent grade ethanol
or USP
grade ethanol. The purity of the ethanol used shall be compared
with
the National Institute of Standards and Technology (NIST)
Standard
Reference Material for ethanol. Use the value of Harger,
et al., for
the partition ratio for concentration of ethanol in head
space to
concentration in solution at 34 deg.C, Ka/w = 0.000393 <SUP>8</SUP>
to
prepare two solutions which, when thermostated at 34 deg.C,
produce
head space ethanol vapor concentrations that bracket the
test BrAC by
no more than <plus-minus>20%. Small Air Pump for bubbling
air through
reference solutions (see Figure 1).
---------------------------------------------------------------------------
\8\ RN Harger, BB Raney, EG Bridwell, MF Kitchel, J. Biol.
Chem.
183, 197-213 (1950). Additional data from Harger in a private
communication (see 49 FR 48869).
---------------------------------------------------------------------------
Step 1. Prepare the Gas Chromatograph for measurement
of vapor
samples. Adjust instrument temperatures, gas flows, detector,
and
recording device for optimum response for ethanol. Prepare
the CU for
use according to manufacturer's instructions.
Step 2. Fill two reference solution bottles to \3/4\ full
with
above reference solutions. Insert stopper assemblies with
bubble line
and alcohol vapor line in place and put bottles in the water
bath with
water level up to the stopper. Connect air pump to bubble
line. Connect
alcohol vapor line to gas chromatograph sampling valve inlet
fitting.
Allow 1 hour for temperature equilibrium to be achieved.
Step 3. Turn on air pump which has been pre-set to pump
air through
the reference solution bottle-gas chromatograph sampling
assembly at a
rate just sufficient to thoroughly flush the system in 10
seconds.
After flushing is complete, allow the sample to relax to
atmospheric
pressure, then inject the reference sample onto the gas
chromatograph
column. In this way, obtain 5 chromatograms of one of the
reference
solution head space ethanol vapors.
Step 4. Thoroughly flush the sample loop with vapors from
the CU
device, while avoiding over-pressurizing of the sampling
system. To
prevent condensation of alcohol, warm the transfer line
if necessary.
Allow the sample to relax to atmospheric pressure, then
inject the
sample onto the column. In this way, obtain 10 ethanol chromatograms
using the CU device.
Step 5. Repeat step 3 using the second reference solution.
Step 6. Calculations. Peak height to BrAC conversion factor.
For
each ethanol peak obtained in step 2 and step
[[Page 43423]]
5, calculate a conversion factor for ethanol concentration
by dividing
the equivalent BrAC of the vapor sample by the peak height
obtained for
that sample. From the ten samples, obtain the mean and the
RSD of the
conversion factors. If the RSD obtained fails to meet the
criteria for
RSD in 3.0, perform necessary troubleshooting and repeat
the procedure
from Step 1. Use the mean of the conversion factors to calculate
the
BrAC for each of the 10 ethanol peaks obtained in step 4.
Calculate the
mean, the RSD, and the systematic error of the experimental
BrACs.
BILLING CODE 4910-59-P
Figure 1. Wet Bath Reference Sample Set-up. Sample lines
\1/8\''
Teflon. The bubble line should extend at least 4 inches
below
surface of the solution. The length of the alcohol vapor
line from
the headspace to the gas chromatograph should be minimized.
[GRAPHIC] [TIFF OMITTED] TN13AU97.000
BILLING CODE 4910-59-C
3.2 Test Procedures (for dry gas Calibrating Units): Alternate
Test
Method Using National Institute of Standards and Technology
Reference
Gas Mixtures (NISTRGMs) in Place of Wet Bath Reference Samples
The following alternate method for the evaluation of dry
gaseous
ethanol calibration devices is presented.
Additional required material: For the alternate method for
evaluation of dry gaseous ethanol calibration devices, the
following
will be required: Four cylinders of National Institute of
Standards and
Technology ethanol-in-inert gas Technical Reference Gas
Mixtures
(NISTRGMs) which span the BrAC range 0.01 to 0.16.
Alternate Procedure for evaluation of dry gaseous ethanol
calibration devices. This procedure substitutes the use
of NISTRGMs in
place of the wet bath reference samples when evaluating
dry gas CUs.
Step A1. Connect one of the NISTRGM cylinders to the inlet
of the
gas chromatograph sampling valve and pass reference gas
through the
sampling system at a rate just sufficient to thoroughly
flush the
system in about 10 seconds. Allow the sample to relax to
atmospheric
pressure, then inject the sample onto the column. In this
way, obtain 5
chromatograms of the reference gas.
Step A2. Repeat Step A1 for each of the four NISTRGM reference
gas
mixtures.
Step A3. Calculate the RSD of the concentration divided
by peak
height data obtained in Step A1 and Step A2. If the calculated
RSD
meets the criteria of 3.0, calculate the slope and intercept
of the
least squares fit calibration line for conversion of peak
height to
BrAC. Using the average peak height of each NISTRGM and
the slope and
intercept data, calculate the concentration of each NISTRGM.
If the
resulting concentrations are within the stated accuracy
of the NISTRGM,
proceed to Step A4.
Step A4. Connect the calibrating device to the inlet of
the gas
chromatograph sampling system and allow the calibrating
device gas to
flow at a rate just sufficient to thoroughly flush the sampling
system
in about 10 seconds. Allow the sample to relax to atmospheric
pressure,
then inject the sample onto the column. In this way, obtain
10
chromatograms of the calibrating device gas.
Step A5. Calculations. Using the peak height data obtained
in Step
A4 and intercept and slope data obtained in Step A3, calculate
the BrAC
for each of the 10 peak heights. Calculate the mean, RSD,
and
systematic error of the calculated BrACs.
Authority: 23 U.S.C. 402; delations of authority at 49
CFR 1.50
and 501.
Issued: August 7, 1997.
James Hedlund,
Associate Administrator for Traffic Safety Programs.
Appendix A--Proposed Alternate Procedure Using Infra-Red
Spectroscopy
This appendix presents an alternate procedure using infra-red
spectroscopy that is suitable for evaluating vapor samples
from either
wet-bath CUs, or from dry-gas CUs.
[[Page 43424]]
3.3 Proposed Test Procedures (for dry gas or wet bath
calibrating
units).
3.3.1 General. General. The method uses the Beer-Lambert
Law of
absorption of radiant energy by fluids
I = I<INF>o</INF> X e<SUP>-abc</SUP>
Where:
I<INF>o</INF> is the energy entering the sample
chamber of a
spectrophotometer containing the sample to be analyzed.
I is the energy transmitted from the sample chamber.
a is the absorptivity of the sample.
b is the radiation path length of the sample chamber.
c is the concentration of the sample in the sample chamber.
A convenient form of the Beer-Lambert law is
Ln(I<INF>o</INF>/I) = abc
where the term (Ln(I<INF>o</INF>/I), the logarithm
of the ratio of
incident to transmitted energy, is called the absorbance
of the sample.
In the procedure described below, the terms a and b are
treated as a
single quantity, ab, and the term c is BrAC.
3.3.2 Test Procedure.
Equipment and Supplies. Infra-red Spectrophotometer with
sample
chamber that can be heated to above 40 deg. C. A non-dispersive
instrument with appropriate band pass filters and configured
to measure
breath alcohol samples, such as an infra-red evidential
breath tester
listed on the NHTSA Comforting Products List for evidential
breath
testers may be used. The detector voltage of the instrument
must be
accessible for measurement. The sampling hoses of the device
may be
altered for more convenient processing of test samples.
Water bath
thernostated at 34 deg.C <plus-minus>0.1 deg.C. Glass
Reference Sample
Bottles (300 ml capacity or greater) and Stoppers with Bubble
and
Alcohol Vapor lines (see Figure 2). Reference Ethanol Solutions
prepared using Class A glassware and American Chemical Society
reagent
grade ethanol or USP grade ethanol. The purity of the ethanol
used
shall be compared with the National Institute of Standards
and
Technology (NIST) Standard Reference Material for ethanol.
Use the
value of Harger, et al., for the partition ratio for concentration
of
ethanol in head space to concentration in solution at 34
deg. C,
K<INF>a/w</INF> = 0.000393<SUP>2</SUP>
to prepare two aqueous alcohol
solutions which bracket the test BrAC by no more than <plus-minus>20%.
A cylinder of inert Flushing Gas, which is optically clear
in the
absorption region used for measurement. This gas will be
used to flush
the sample chamber of the spectrophotometer and to deliver
reference
headspace vapors and wet bath sample vapors into the sample
chamber.
Pressure regulating valve with teflon delivery hose for
controlling
flow and delivery of flushing gas.
Step B1. Prepare the spectrometer for measurement of vapor
samples.
Prepare the CU for use according to manufacturer's instructions.
Step B2. Fill a reference sample bottle to \3/4\ full with
water
and two reference sample bottles to \3/4\ full with the
above reference
solutions. Insert stopper assemblies ensuring that the end
of the
bubble line reaches to at least 4 inches below the surface
of the
solution, then place the bottles in the water bath with
water level up
to the stopper. Allow 1 hour for temperature equilibrium
to be
achieved.
Step B3. Connect the bubble line of the sample bottle containing
water only to the flushing gas valve and the vapor line
to the
spectrophotometer inlet and flush the sample chamber with
water vapor
and obtain the detector voltage reading. Then flush the
detector
chamber with flushing gas only and obtain the detector reading.
Repeat
2 times to obtain 3 sets of readings. If the CU being evaluated
is a
wet bath device, skip this step and proceed to Step 4.
Step B4. In the manner of Step 3, obtain 5 sets of detector
readings using one of the reference alcohol solution bottles.
Step B5. In the manner of Step 3, obtain 10 sets of detector
readings from the CU being evaluated. If the CU is a wet
bath device,
use the flushing gas fill the sample chamber, operating
the device
according to manufacturer's instructions. If the CU device
is a dry gas
device, fill the sample chamber according to manufacturer's
instructions.
Step B6. Repeat Step 5 using the other reference alcohol
solution
bottle.
Step B7. Repeat Step 3.
Step B8. Calculations. For each measurement pair, I<INF>0</INF>
is
the detector voltage obtained for the flushing gas alone
in the sample
chamber and I is the voltage obtained for the flushing gas
with
reference sample or test sample in the sample chamber corrected
for
water vapor absorption, i.e.; the detector voltage obtained
for
headspace reference samples at 0.000 BrAC. Use the average
of 6 voltage
readings obtained for the water samples for the correction
for water
vapor absorption (I=I<INF>sample</INF>-I<INF>water</INF>).
In the case
of wet bath device samples, there is no correction for water
vapor
absorption. If the detector is biased, I will be the difference
between
the bias voltage and the above voltage.
Calulate the absorbance of each of the 10 reference samples.
Divide
each absorbance by the corresponding BrAC of the sample.
Obtain the
mean (which is the factor ab), SD, and RSD for the 10 ratios.
If the
RSD is more than 2%, trouble shoot the procedure and repeat.
Calculate the absorbance for each of the 10 CU test samples.
Divide
each by the ab factor to obtain the BrAC for each of the
10 CU samples.
Obtain the mean, SD, RSD, and SE.
BILLING CODE: 4910-59-P
[[Page 43425]]
Figure 2. Equipment set-up. Bubble and sample lines \1/8\''
teflon,
minimized length. Depth of bubble line into reference solution
at
least 4''. The alcohol vapor line from the headspace to
the IR
specrophotometer should be minimized.
[GRAPHIC] [TIFF OMITTED] TN13AU97.001
BILLING CODE: 4910-59-C
Appendix B--Conforming Products List of Calibrating Units
for Breath
Alcohol Testers [Manufacturer and Calibrating Unit].\1\
---------------------------------------------------------------------------
\1\ Infra-red (IR) and fuel cell breath testers may be
calibrated with either wet-bath or dry-gas CUs. However,
it is
inadvisable to use dry gas CUs when calibrating gas chromatograph
EBTs.
---------------------------------------------------------------------------
1. CMI, Inc., Owensboro, KY:
Toxitest II
2. Federal Signal Corporation, CMI, Inc., Minturn, CO:
Toxitest Model ABS120*
3. Gateway Airgas, Inc. (Formerly known as AG Specialty
Gas, and
Acetylene Gas Company), St. Louis, MO.
Ethanol Breath Alcohol Standard (a dry gas standard).
4. Guth Laboratories, Inc., Harrisburg, PA:
Model 34C Simulator \2\
---------------------------------------------------------------------------
\2\ Several variations of the Model 34C Simulator have
also been
submitted to NHTSA for evaluation and meet these Model
Specifications. They are: Model 34C Cal DOJ; Model 34-C-FM;
and 34C-
NPAS.
---------------------------------------------------------------------------
Model 3412
Model 10-4
Model 1214
5. Intoximeters, Inc., St. Louis, MO:
Alco Breath Alcohol Standard* (a dry gas standard)
6. Lion Laboratories, plc, Cardiff, Wales, UK (a subsidiary
of CMI,
Inc.)
AlcoCal Gas Standard (a dry gas standard).
7. Liquid Technology Corporation, Orlando, FL
Alcohol-in-Nitrogen Calibrating Unit (a dry-gas
standard).
8. Luckey Laboratories, Inc., San Bernadino, CA:
Simulator*
9. National Draeger, Inc., Durango, CO.
Mark II-A
10. PLD of Florida, Inc., Rockledge, FL:
BA 500
11. Protection Devices, Inc., U.S. Alcohol Testing, Inc.,
Rancho
Cucamonga, CA:
LS34 Model 6100*
12. Repco Marketing, Inc., Raliegh, NC:
AS-1
Model 3402C
13. Scott Specialty Gases, Inc., Plumsteadville, PA
Model EBS <SUP>TM</SUP> Gaseous Ethanol Breath
Standard (a
dry-gas standard).
14. Smith & Wesson Electronic Co., Springfield, MA:
Mark II-A Simulator*
15. Systems Innovation, Inc., Hallsteaed, PA
True-Test MD 901*
16. U.S. Alcohol Testing, Rancho Cucamonga, CA:
Alco-Simulator 2000*
Alco--Simulator 61000
* Instruments marked with an asterisk (*) meet the Model
Specifications in 49 FR 48864 (December 14, 1984), i.e.
instruments
tested at 0.050, 0.100, and 0.150). Instruments not marked
with an
asterisk meet the model specifications detailed in this
notice, and
were tested at 0.020, 0
040, 0.080, and 0.160 BrAC.
[FR Doc. 97-21331 Filed 8-12-97; 8:45 am]
BILLING CODE 4910-59-P
|
