**STANDARD OPERATING PROCEDURES**

**THERMO ELECTRON CORPORATION MODEL 48C-TLE**

**TRACE LEVEL CO INSTRUMENT**

**Version 1.10**

# **Final** 

![](media/image1.png){width="1.6583333333333334in"
height="1.6111111111111112in"}

**Section 1.1 Acknowledgments**

This Standard Operating Procedure (SOP) for Carbon Monoxide -- Trace
Level is the product of EPA's Office of Air Quality, Planning and
Standards. The following individuals are acknowledged for their
contributions.

**Principal Author**

Dennis K. Mikel, OAQPS-EMAD, Research Triangle Park, NC 27711

**Reviewers**

Joann Rice, Trace Gas Team Lead, OAQPS-EMAD, Research Triangle Park, NC
27711

Anna Kelly, OAQPS-EMAD, Research Triangle Park, NC 27711

Keith Kronmiller, Mantech, Inc. Research Triangle Park, NC 27711

**Comments and questions can be directed to:**

Joann Rice

EPA-OAQPS

Emission, Analysis and Monitoring Division

Mail Drop D243-02

Research Triangle Park, NC 27711

Email: [rice.joann](mailto:mikel.dennisk@epa.gov)\@epa.gov

Phone: (919)-541-3372

**Section 2.0 Table of Contents**

+------------------------------------------------------------+---------+
| Section                                                    | Page    |
+------------------------------------------------------------+---------+
| 1.0 Title Page                                             | 1       |
+------------------------------------------------------------+---------+
| 1.  Acknowledgements                                       | 2       |
+------------------------------------------------------------+---------+
| 2.0 Table of Contents                                      | 3       |
+------------------------------------------------------------+---------+
| 2.1 List of Tables and Figures                             | 4       |
+------------------------------------------------------------+---------+
| 3.0 Procedures                                             | 5       |
+------------------------------------------------------------+---------+
| 3.1 Scope and Applicability                                | 5       |
+------------------------------------------------------------+---------+
| 3.2 Summary of Method                                      | 5       |
+------------------------------------------------------------+---------+
| 3.3 Definitions                                            | 7       |
+------------------------------------------------------------+---------+
| 3.4 Health and Safety Warnings                             | 7       |
+------------------------------------------------------------+---------+
| 3.5 Cautions                                               | 7       |
+------------------------------------------------------------+---------+
| 3.6 Interferences                                          | 8       |
+------------------------------------------------------------+---------+
| 3.7 Personal Qualifications                                | 8       |
+------------------------------------------------------------+---------+
| 3.8 Equipment and Supplies                                 | 8       |
+------------------------------------------------------------+---------+
| 3.9 Procedure                                              | 10      |
+------------------------------------------------------------+---------+
| 3.9.1 Sample Collection                                    | 10      |
+------------------------------------------------------------+---------+
| 3.9.2 Sample Handling and Preservation                     | 10      |
+------------------------------------------------------------+---------+
| 3.9.3 Instrument Operation, Start up and Maintenance       | 10      |
+------------------------------------------------------------+---------+
| 3.9.3.1 Start up                                           | 10      |
+------------------------------------------------------------+---------+
| 3.9.3.2 Operation and Range Setting                        | 11      |
+------------------------------------------------------------+---------+
| 3.9.9.3 Diagnostic Checks/Manual Checks                    | 11      |
+------------------------------------------------------------+---------+
| 3.9.3.4 Preventive Maintenance                             | 13      |
+------------------------------------------------------------+---------+
| 3.9.3.5 Instrument Troubleshooting                         | 14      |
+------------------------------------------------------------+---------+
| 3.9.4 Calibration and Standardization                      | 14      |
+------------------------------------------------------------+---------+
| 3.9.4.1 Adjustment to Zero Air                             | 14      |
+------------------------------------------------------------+---------+
| 3.9.4.2 Adjustment to Calibration Gas                      | 14      |
+------------------------------------------------------------+---------+
| 3.10 Data Analysis and Calculations                        | 15      |
+------------------------------------------------------------+---------+
| 4.0 Quality Control and Quality Assurance                  | 15      |
+------------------------------------------------------------+---------+
| 4.1 Precision                                              | 15      |
+------------------------------------------------------------+---------+
| 4.2 Bias                                                   | 15      |
+------------------------------------------------------------+---------+
| 4.3 Representativeness                                     | 16      |
+------------------------------------------------------------+---------+
| 4.4 Completeness                                           | 16      |
+------------------------------------------------------------+---------+
| 4.5 Comparability                                          | 16      |
+------------------------------------------------------------+---------+
| 4.6 Method Detection Limit                                 | 16      |
+------------------------------------------------------------+---------+
| 5.0 References                                             | 17      |
+------------------------------------------------------------+---------+

**List of Tables**

  ------------------------------------------------------------ ----------
  Table Name and Number                                        Page

  3-1 Definition of Key Terms                                  7

  3-2 Diagnostic Checks                                        13

  3-3 Preventive Maintenance Schedule for the TECO 48C-TLE     13

  4-1 Measurement Quality Assurance Objectives                 16

  4-2 Operating Parameters for the TECO 48C-TLE Trace Gas      17
  Instrument                                                   
  ------------------------------------------------------------ ----------

**List of Figures**

  ------------------------------------------------------------ ----------
  Figure Name and Number                                       Page

  3-1 Schema of the TECO 48C-TLE                               9

  3-2 Menu Tree Schema                                         12

  A-1 Monthly Quality Control and Maintenance Record           18
  ------------------------------------------------------------ ----------

#### STANDARD OPERATING PROCEDURES

**THERMO 48C-TLE TRACE-LEVEL CO INSTRUMENT**

**3.0 PROCEDURES**

**3.1 Scope and Applicability**

Carbon Monoxide (CO), a colorless, odorless, tasteless, highly poisonous
gas has detrimental effects on human health. CO originates from the
partial oxidation of hydrocarbon fuels, coal and coke^1^. CO affects the
oxygen carrying capacity of the blood. CO can diffuse through the
alveolar walls of the lungs and compete with oxygen for one of the four
iron sites in the hemoglobin molecule. The affinity of the iron site for
CO is approximately 210 times greater than oxygen^2^. Low levels of CO
can cause a number of symptoms including headache, mental dullness,
dizziness, weakness, nausea, vomiting and loss of muscular control. In
extreme cases, collapse, unconsciousness and death can occur.

The Thermo Electron Corporation (TECO) model 48C-TLE is a state of the
science instrument for the determination of trace levels of CO by
Non-Dispersive Infrared Spectrophotometry (NDIR) using Gas Filter
Correlation (GFC). This SOP will detail the operation, preventive
maintenance, cautions and health warnings.

The Detection Limit (DL) for non-trace levels of CO is 1.0 parts per
million (ppm) *(Code of Federal Regulations,* Volume 40, Part 53.23c,
or, in the shortened format used hereafter, 40 CFR 53.23c)^3^. However,
the 48C-TLE has a DL to 20 parts per billion (ppb), which is
accomplished by modifications to the Federal Reference Method (FRM)
instruments. This document will discuss the Trace Level (TL) operating
procedures in detail.

**3.2 Summary of Method**

The analytical principle is based on absorption of IR light by the CO
molecule. NDIR-GFC analyzers operate on the principle that CO has a
sufficiently characteristic IR absorption spectrum such that the
absorption of IR by the CO molecule can be used as a measure of CO
concentration in the presence of other gases. CO absorbs IR maximally at
2.3 and 4.6 um. Since NDIR is a spectrophotometric method, it is based
upon the Beer-Lambert Law. The degree of reduction depends on the length
of the sample cell, the absorption coefficient, and CO concentration
introduced into the sample cell, as expressed by the Beer-Lambert law
shown below:

T = I/Io = e^(-axC)^ (equation 1)

where:

T = Transmittance of light through the gas to the detector

I = light intensity after absorption by CO

Io = light intensity at zero CO concentration

a = specific CO molar absorption coefficient

x = path length, and

C = CO concentration

For Gas Filter Correlation, there is only one sample cell. This cell
acts as the sample and reference cell. The broad band of IR radiation is
emitted from an IR source. The IR light passes through a very narrow
band pass filter which screens out most wavelengths and allows only the
light that CO absorbs to enter the sample cell. The GFC analyzer has a
chopper wheel with two pure gases: Nitrogen and CO. As the chopper wheel
rotates and allows the IR energy to enter "CO side" of the wheel, all IR
energy that could be absorbed by CO in the sample stream is absorbed by
the CO in the wheel. This technique effectively "scrubs out" any light
that could possibly be attenuated. The single detector records the light
level (Io). As the wheel spins, the "N2 side" of the wheel reaches the
IR energy beam. This side of the wheel allows all IR light to pass
through the wheel and be absorbed by any CO that might be in the sample
gas. This light level is CO sensitive (I). The detector records the
attenuation of this light, compares the two light levels (I/Io) and
sends a signal to the electrometer board that calculates the
concentration. The voltage is related to the CO concentration according
to the Beer-Lambert law in equation 1 shown above. Thus, TECO 48C-TLE
can be measured continuously. The 48C-TLE version has four distinct
features that allow it to measure CO at ppb levels:

-   Required sample stream dried using permeation dryer;

-   Analyzer baseline determined and corrected using heated Carolite
    catalytic converter;

-   Frequent auto-zero, at a minimum once per hour, through the
    catyalytic converter;

-   The instrument has an ultra-sensitive or "hot" detector.

### 

### The 48C-TLE instrument operates in the following fashion:

###  

### In sample mode, ambient air is allowed to enter through the rear bulkhead sample port. Solenoid #1 is in its Normally Open (NO) mode. The ambient air flows through the solenoid to the permeation dryer, which removes the moisture and water from the air stream. 

### The sample stream then passes through a sample filter, which removes particles that can build up on the mirror and sample chamber and attenuate the IR beam. 

### The sample then enters the sample cell. A major difference between a non-TL and TL instrument is the detector. The TL instrument has a detector that is more sensitive to the light emitted and absorbed in the sample cell. This detector must be more sensitive because the amount of attenuation by the CO gas in the sample stream is much lower. Therefore, the detector must be sensitive at lower ambient levels. Temperature of the sample cell is also critical. The sample cell and detector must be maintained at a constant temperature in order for the detector to keep a stable background. Fluctuations of more than 1^o^ Centigrade can cause the baseline to drift, giving false readings at low levels. 

### The detector sends the signal to the demodulator which interprets the signal. The demodulator sends a digital value to the Central Processor Unit (CPU).

### At the end of the hour, the CPU sends a voltage signal to the Solenoid #1 and switches it to the "Normally Closed" (NC) position. This allows room air to be drawn into the instrument and to pass through the catalytic converter. The catalytic converter uses a Carolite bed heated to 50^o^ Centrigrade to convert all CO to Carbon Dioxide (2CO + O~2~ ---\> 2CO~2~). This effectively "scrubs" all CO from the sample stream. The CO "free" air flows through the sample cell and the CPU interprets the signal from the demodulator as the "background" or "baseline" value. The baseline is then adjusted at that time. The baseline adjustment takes 10 minutes.

### The CPU then switches Solenoid #1 to its NO position and ambient air then drawn into the analyzer. 

**3.3 Definitions**

Here are some key terms for this method.

**Table 3-1, Definitions of Key Terms**

  ----------------------- -----------------------------------------------
  [Term]{.underline}      Definition

  DAS                     Data acquisition system. Used for automatic
                          collection and recording of CO concentrations.

  Interferences           Physical or chemical entities that cause CO
                          measurements to be higher (positive) or lower
                          (negative) than they would be without the
                          entity. (See Section 3.6).
  ----------------------- -----------------------------------------------

**3.4 Health and Safety Warnings**

[To prevent personal injury, please heed these warnings concerning the
48C-TLE.]{.underline}

1.  CO is a poisonous gas. Vent any CO or calibration span gas to the
    atmosphere rather than into the shelter or other sampling area. If
    this is impossible, limit exposure to CO by getting fresh air every
    5 to 10 minutes. If the operator experiences light headedness,
    headache or dizziness, leave the area immediately.

2.  The IR source is a filament resistor that has an electrical current
    running through it. The IR source can become very hot. When
    troubleshooting, allow the instrument to cool off especially if you
    suspect the IR source as the cause of trouble.

3.  Always use a third ground wire on all instruments.

4.  Always unplug the analyzer when servicing or replacing parts.

5.  If it is mandatory to work inside an analyzer while it is in
    operation, use extreme caution to avoid contact with high voltages.
    The analyzer has a 110 volt Volts Alternating Current (VAC) power
    supply. Refer to the manufacturer\'s instruction manual and know the
    precise locations of the VAC components before working on the
    instrument.

6.  Avoid electrical contact with jewelry. Remove rings, watches,
    bracelets, and necklaces to prevent electrical bums.

**3.5 Cautions**

[To prevent damage to the 48C-TLE, all cautions should immediately
precede the applicable step in this SOP. The following precautions
should be taken:]{.underline}

1.  Normally, if Teflon™ filters are used in the sample train, cleaning
    the optical bench will not be required. However, in the event that
    the bench is cleaned, be careful to avoid damaging the interior of
    the sample chamber. In addition, some GFC instruments have a series
    of mirrors that deflect the light in order to increase the path
    length. The mirrors are aligned at the factory. If the mirrors
    become misaligned, the IR light beam will not be directed to the
    detector. Use extreme caution when cleaning or servicing the sample
    chamber(s). In addition the mirrors are very fragile Avoid dropping
    the instrument. This may damage, misalign or crack the mirrors and
    cause expensive repairs.

2.  Keep the interior of the analyzer clean.

3.  Inspect the system regularly for structural integrity.

4.  To prevent major problems with leaks, make sure that all sampling
    lines are reconnected after required checks and before leaving the
    site.

5.  Inspect tubing for cracks and leaks. The permeation dryer may rest
    upon parts that vibrate, such as the air pump. Check the areas of
    the permeation dryer where they come into contact with other parts.

6.  It is recommended that the analyzer be leak checked after
    replacement of any pneumatic parts.

7.  If cylinders are used in tandem with Mass Flow Control (MFC)
    calibrators, use and transport of cylinders are a major concern. Gas
    cylinders can sometimes contain pressures as high as 2000 pounds per
    square inch. Handling of cylinders must be done in a safe manner. If
    a cylinder is accidentally dropped and valve breaks off, the
    cylinder can become explosive or a projectile.

8.  Transportation of cylinders is regulated by the Department of
    Transportation (DOT). It is strongly recommended that all agencies
    contact the DOT or Highway Patrol to learn the most recent
    regulations concerning transport of cylinders.

9.  CO is a highly poisonous gas. Long term exposure can cause problems
    with motor coordination and mental acuity. It is strongly
    recommended that all agencies have Material Safety Data Sheets
    (MSDS) at all locations where CO cylinders are stored or used. MSDS
    can be obtained from the DOT or from your vendor.

10. It is possible (and practical) to blend other compounds with CO. If
    this is the case, it is recommended that MSDS for all compounds be
    made available to all staff that use and handle the cylinders or
    permeation tubes.

11. Shipping of cylinders is governed by the DOT. Contact the DOT or
    your local courier about the proper procedures and materials needed
    to ship high-pressure cylinders.

**3.6 Interferences**

**Water Vapor:** Studies have shown conclusively that NDIR analyzers
have interference from water vapor. Water absorbs very strongly across
several bands of IR spectra. Water vapor interference occurs because
water vapor absorption of light in the region of 3.1, 5.0 -5.5 and 7.1
-10.0 *u*m in the IR region. Since water vapor absorbs light in this
region, this has a quenching effect on the reaction of CO. The TECO
48C-TLE is equipped with a permeation drier, which effectively scrubs
all water and water vapor. No maintenance is required on the dryer.

**Carbon Dioxide:** CO2 absorbs in the IR spectrum at 2.7, 5.2, and 8.0
to 12.0 *u*m. This is very close to the regions that CO absorbs within
as well. However, since atmospheric carbon dioxide is much higher in
concentration than CO, this UV spectral range must be avoided. To
prevent light in this spectral region, the TECO 48C-TLE analyzer has a
band pass filter that blocks these wavelengths.

**3.7 Personal Qualifications**

The person(s) chosen to operate the TECO 48C-TLE should have a minimum
of qualifications. The understanding of basic chemistry and electronics
are a must. The understanding of digital circuitry is helpful, but not
required. Also, courses in data processing and validation are also
welcome.

**3.8 Equipment and Supplies**

**Monitoring Apparatus:** The design of the 48C-TLE is identical to the
48C, with several major variations. A diagram of the TECO 48C-TLE
instrument is described in Figure 3-1. The three main components are:

-   *[Pneumatic System:]{.underline}* Consists of sample inlet line,
    particulate filter, filter holder, permeation dryer, reaction
    chamber, flowmeter, and pump, all used to bring ambient air samples
    to the analyzer inlet.

-   *[Analytical System]{.underline}*: This portion of the instrument
    consists of the IR source, the correlation wheel, motor, mirrors,
    detector and band pass filter.

-   *[Electronic Hardware:]{.underline}* The part of the analyzer that
    generally requires little or no maintenance. The brain of the 48C
    series is the CPU. It monitors and regulates motor speed,
    temperatures, flows and pressure. It also monitors and stores
    diagnostic information. If the 48C-TLE is operated above the
    manufacturer\'s recommended temperature limit, however, individual
    integrated chips can fail and cause problems with data storage or
    retrieval.

Other apparatus and equipment includes the following.

**Instrument Shelter:** A shelter is required to protect the analyzer
from precipitation and adverse weather conditions, maintain operating
temperature within the analyzer\'s temperature range requirements, and
provide security and electrical power. The recommended shelter
temperature range is 20-30^o^C.

**Spare Parts and Incidental Supplies:** See the TECO 48C-TLE operating
manual, Section 5-1for specific maintenance and replacement
requirements.

**Calibration System**: A system that creates concentrations of CO of
known quality is necessary for establishing traceability. This is
described in detail in the "Calibration of Trace Gas Instruments SOP."
Please reference this document.

**DAS**: A data acquisition system is necessary for storage of ambient
and ancillary data collected by the 48C-TLE. This is detailed in the
"Acquisition and Management SOP."

![](media/image2.png){width="6.524305555555555in"
height="3.88125in"}**Figure 3-1 Schema of the TECO 48C-TLE**

**Wiring, Tubing and Fittings***:* Teflon™ and borosilicate glass are
inert materials that should be used exclusively throughout the intake
system. It is recommended that Polytetrafluoroethylene (PTFE) or
Fluoroethylpropylene (FEP) Teflon™ tubing be used. PTFE and FEP are the
best choice for the connection between the intake manifold and the
48C-TLE bulkhead fitting. Examine and discard if particulate matter
collects in the inlet tubing. All fittings and ferrules should be made
of Teflon™ or stainless steel. Connection wiring to the DAS should
shielded two strand wire or RS-232 cables for digital connections.

**Reagents and Standard:** The TECO 48C-TLE does not require any
reagents since the instrument uses photometry to analyze for CO. All
standards for the CO method can be obtained in compressed cylinders and
must be NIST traceable. Please see the "Calibration of Trace Gas
Analyzers" SOP.

**3.9 Procedure**

**3.9.1 Sample Collection:** Sampling for Trace Level CO is performed by
drawing ambient air through a sample manifold directly into the analyzer
continuously via a vacuum pump. All inlet materials must be constructed
from Teflon™ or borosilicate glass as detailed in 40 CFR 58. The siting
criteria for CO Trace Level instruments in detailed in 40 CFR 58,
appendix A^4^ .

**3.9.2 Sample Handling and Preservation:** CO samples receive no
special preparation prior to analysis. Therefore this SOP does not need
a section on Sample Handling and Preservation.

**3.9.3 Instrument Operation, Startup and Maintenance**

This section discusses startup, operation and maintenance of the
48C-TLE. The TECO 48C-TLE series instrument has a digital front panel
screen with selection switches below. This allows the user to check
functions, switch operating parameters, adjust zero and span and read
warnings messages. **It is extremely important that the users
familiarize themselves with the menus available. Inadvertently changing
parameters within the analyzer can damage the instrument and possibly
invalidate data as well. Please reference the TECO 48C-TLE owner's
manual and read it carefully before adjusting any parameters that are
set by the factory.**

**3.9.3.1 Start up**

The following text is taken from the TECO 48C-TL manual. It is the
identical for the 48C-TLE model.

The Model 48C Trace Level is shipped complete in one container. If, upon
receipt of the analyzer, there is obvious damage to the shipping
container, notify the carrier immediately and hold for inspection. The
carrier, and not Thermo Environmental Instruments Inc., is responsible
for any damage incurred during shipment. Follow the procedure below to
unpack and inspect the instrument.

1.  Remove the instrument from the shipping container and set on a table
    or bench that allows easy access to both the front and rear of the
    instrument.

2.  Remove the instrument cover to expose the internal components and
    remove any packing material.

3.  Check for possible damage during shipment and check that all
    connectors and printed circuit boards are firmly attached.

4.  Re-install the instrument cover.

5.  Connect the sample line to the sample bulkhead on the rear panel.
    Ensure that the sample line is not contaminated by dirty, wet or
    incompatible materials. All tubing should be constructed of Teflon™
    or borosilicate glass with an OD of ¼" and a minimum ID of 1/8".

6.  The length of the tubing should be less than 10 feet.

7.  All gas must be delivered to the instrument at atmospheric pressure.
    It may be necessary to employ an atmospheric bypass plumbing
    arrangement or attach the instrument inlet line to a manifold that
    is vented to the atmosphere.

8.  Connect the exhaust bulkhead to a suitable vent. The exhaust line
    should be ¼" OD (outside diameter) with a minimum ID of 1/8" ΟD. The
    length of the exhaust line should be less than 10 feet. Verify that
    there is no restriction in this line.

9.  Connect a suitable recording device to the rear panel terminals. The
    EPA recommends, but does not require, recording of the data
    digitally. The TECO 48C-TLE has this option. Please refer to the
    "Data Acquisition and Management" SOP. If the DAS system that you
    have does not have the RS-232 capabilities, then proceed to the next
    section, Diagnostic Checks/Manual Checks. If you have connected the
    48C-TLE to a computer or DAS, review the Diagnostic Check from your
    computer screen. TECO offers TECO communication software, a computer
    program that allows the operator to log the diagnostic data that is
    collected by the 48C-TLE CPU. Several DAS manufacturers offer this
    type of software as well.

10. Plug the instrument into an outlet of the appropriate voltage and
    frequency. The Model 48C Trace Level is supplied with a three-wire
    grounding cord. Under no circumstances should this grounding system
    be defeated.

11. Turn the power on.

**3.9.3.2 Operation and Range Setting**

1.  The exhaust fan will start and the display will come on. The Central
    Processing Unit (CPU) will boot the system and load the firmware.

2.  The display has a 4 line by 20 character alphanumeric display that
    shows the sample concentration, instrument parameters, instrument
    controls and help/warning messages. The menus for access (as
    described in sections 3.9.3.4 and 3.9.3.5 of this SOP) are performed
    using the display and the 6 push-buttons just below the display.

3.  Once the instrument loads the firmware, the display will display "CO
    PPM XX.XX, below this value is the time and "REMOTE." This is the
    "RUN" menu and should always be left in the "RUN" menu when it is
    collecting ambient data.

4.  To access the Main Menu, press the "Menu." This will put you into
    the Main Menu.

5.  From the Main Menu, Use the ↑ and ↓ pushbuttons move the cursor down
    so that the arrow is next to "Range" selection. Press "Enter."

6.  The Range menu contains the gas units, CO ranges, and the custom
    ranges. In the upper right corner of the display, the words "SINGLE,
    DUAL, or AUTO" is displayed to indicate the active mode. The "Range"
    menu in the dual and auto-range modes appear the same except for the
    word DUAL or AUTO, displayed in the upper right corner. For more
    information about the SINGLE, DUAL, or AUTO-range modes, see page
    3-6 of the owner's manual. The default is set to single range.

7.  To set the upper scale range, use the ↑ and ↓ pushbuttons to move
    the cursor down so that the arrow is next to "CO Range" selection.
    Press "Enter."

8.  Use the "" buttons on the front panel to enter in the desired
    concentration, this should be "5." Press "Enter."

9.  Press "Menu" and then press "Run." The full scale range has now been
    set to 5.00 ppm. The default for the units is "ppm." It is
    recommended that this not be changed.

10. In single range mode, there is one range, one averaging time, and
    one span coefficient. The two CO analog outputs are arranged on the
    rear panel terminal strip as shown in Figure 3-3 of the owner's
    manual. To use the single range mode, set option switches 4 and 5
    off. For more information about setting the internal option
    switches, see .Internal Option Switches, on page 3-7.

**3.9.3.3 Diagnostic Checks/Manual Checks**

To determine whether the 48C-TLE is working properly, the field
operators should perform the Diagnostic Checks every time they visit the
monitoring station. It is good practice for the operator to check these
Diagnostic Checks either by the computer or manually. Figure 3-2 of this
SOP has the menu "tree" that was taken from the TECO 48 C-TL manual. By
pressing the "menu" button and following the tree, an operator can
easily get to the location needed.

![](media/image3.png){width="6.375in" height="4.155555555555556in"}

**Figure 3-2 Menu Tree Schema**

Below are instructions on how to perform the diagnostic checks manually.
Please note that the TECO 48C-TLE has set upper and lower ranges for
some of these Diagnostic checks. Please reference the owner's manual for
these ranges. Please use the following instructions to access the
Diagnostic data.

1.  While in the "Run" menu, press the "Menu" button. This will put you
    into the Main Menu.

2.  From the Main Menu, Use the ↑ and ↓ pushbuttons move the cursor down
    so that the arrow is next to "Diagnostics" selection. Press "Enter."

3.  In the Diagnostics Menu, the operator can toggle the arrow using the
    ↑ and ↓ pushbuttons to align the arrow to the selection. Once the
    operator has toggled the arrow to the diagnostic check desired,
    press "Enter." This will allow you to see the desired information.
    Record this information on your field work sheet. Please see Table
    3-2 for a list of Diagnostic Checks and a brief explanation. Please
    check the Owners Manual for the manufacturer's recommended ranges.

4.  Once the operator has reviewed all of the diagnostic information,
    return to the Main Menu by pressing "Menu" followed by "Run."

## Table 3-2 Diagnostic Checks

  --------------- -------------------------------------------------------
  Check           Explanation

  Program Number  The current software version used by the instrument

  Voltages        There are four voltages that should be recorded.

  Temperatures    There are two temperatures that should be recorded:
                  internal and chamber. Reference Page 3-47 for details.

  Pressure        This is the pressure inside of the optics bench.

  Flow            This is the actual flow rate through the optics bench.
                  Reference page 3-53 for specifications.

  S/R Ratio       Sample/Reference Ratio. This is the ratio of the
                  intensities of the light source through the sample side
                  and the reference side of the correlation wheel. Please
                  See page 3-38 for the optimal values.

  AGC Intensity   Automatic Gain Control. The AGC displays the intensity
                  (in Hertz) of the reference channel. The AGC circuit
                  optimizes the noise and resolution level of the
                  analyzer. Please see page 3-39 for details.

  Motor Speed     This displays, in percentage, the status of the chopper
                  motor. This value should be 100%.
  --------------- -------------------------------------------------------

Once the Diagnostic checks have been established and recorded for the
48C-TLE, it is time to calibrate the instrument. Please refer to section
3.9.4 of this SOP.

**3.9.3.4 Preventive Maintenance**

Preventive maintenance should **prevent** down-time and data loss. Table
3.3 lists the preventive maintenance items that are should be performed.
Please see section 5-1 of the owner's manual. Section 5-1 also has a
list of the spare parts that the operator should keep in stock.

**Table 3-3 Preventive Maintenance Schedule the TECO 48C-TLE**

**Item** **Schedule**

Replace particle filter Weekly

Diagnostics Checks Weekly

Perform Level I calibration Daily

Replace IR source As needed

Leak Check and Pump Check Out Annually

Inspect Pneumatic Lines Semi-annually

Clean inside of Chassis As needed

Rebuild or replace pump As needed

Clean optic bench As needed

Replace wheel motor As needed

Replace gases in correlation wheel As needed

**3.9.3.5 Instrument Troubleshooting**

The TECO 48C-TLE manual has an excellent troubleshooting guide in
Section 6-1 of the manual. For details on using the Test Functions for
predicting failures, please reference this section.

**3.9.4 Calibration and Standardization**

The calibration of the TECO 48C-TLE is performed by comparing the
digital or analog output of the instrument against standardized gases of
known quality. Generation of these gases is detailed in the "Calibration
of Trace Gas Analyzers" SOP. The recommended ranges for the calibration
are detailed in Table 4-2. This section will detail how to adjust the
48C-TLE to the standardized gases. Once the calibration has been
performed, compare the response of your DAS to the calculated "source"
value. If this is outside of +/-10%, then adjust the instrument response
as detailed in the next sections of this SOP.

**3.9.4.1 Adjustment to Zero Air**

In order to adjust the output of the 48C-TLE to zero air, perform the
following:

1.  Allow the instrument to sample zero air from a manifold that is at
    near atmospheric pressure for a minimum of 15 minutes.

2.  On the front panel press the "Menu" button. This will bring up the
    main menu. Using the  arrow until the cursor is on the
    "Calibration" selection. Press "Enter."

3.  This next screen is the "Calibration" screen. In this screen press
    the  buttons until you align the cursor at the "Calibrate Zero"
    selection. Press "Enter."

4.  The next screen will show a "CO PPM X.X above the words "SET TO
    ZERO?" If the analyzer has stabilized to zero air, press "Enter."
    Then Press "Menu" and then press "Run." This will adjust the
    baseline to the zero air. If you decide to adjust the higher range
    response, continue on to Section 3.9.4.2.

**3.9.4.2 Adjustment to Calibration Gas**

In order to adjust the output of the 48C-TLE to NIST traceable
calibration gas, perform the following:

1.  Switch the calibration unit to generate a known concentration of CO.
    Allow the instrument to sample calibration gas from a manifold that
    is at near atmospheric pressure for a minimum of 15 minutes.

2.  On the front panel press the "Menu" button. This will bring up the
    main menu. Using the  arrow until the cursor is on the
    "Calibration" selection. Press "Enter."

3.  This next screen is the "Calibration" screen. In this screen press
    the  buttons until you align the cursor at the "Calibrate CO"
    selection. Press "Enter."

4.  The first line of the display shows the current CO concentration
    reading. The second line shows the instrument range and the third
    line states, "SET TO...... XX.XX." The next line shows " INC/DEC."
    The cursor should be under one of the digits in the third line. Use
    the "" buttons on the front panel to enter in the desired
    concentration, that is being generated by the calibration system.
    Press "Enter."

5.  Then Press "Menu" and then press "Run." This will adjust the
    response of the instrument to the calibration gas concentration. The
    instrument is now calibrated.

    **3.10 Data Analysis and Calculations**

    Data analysis for this analyzer is detailed in "Data Acquisition and
    Management" SOP. For the TECO 48C-TLE, there is one design detail of
    which the operator must be aware; the auto-zero function. As
    detailed in Section 3.1 of this SOP, the TECO 48C-TLE has an
    auto-zero sequence that occurs at the end of the hour (default).
    During this period, the 48C-TLE analog output will be at or close to
    zero, since the detector is sampling air with the CO "scrubbed out."
    While this occurs the display will illustrate "ZERO." If the
    operator records the data during this sequence via the analog
    output, then the operator must be aware and flag this data in the
    DAS. The digital output via the RS-232 is flagged; therefore, no
    other flagging is required. The auto-zero function can be modified
    from once per hour to any increment up to once per day. It is
    recommended that the factory default not be changed from once per
    hour at this time.

**4.0 QUALITY CONTROL AND QUALITY ASSURANCE**

The following section has brief definitions of the QA/QC indicators.
Table 4-1 has the Measurement Quality Objectives (MQOs) of the TECO
48C-TLE. Please note that this section details primarily with the QA
indicators. Quality Control for continuous electronic instruments, such
as the TECO 48C-TLE consists of performing the diagnostic checks,
maintenance and calibrations. These procedures are detailed in sections
3.9.3 and 3.9.4: Instrument Operation, Startup and Maintenance and
Calibration and Standardization. Appendix A has an example of a Quality
Control and Maintenance Record developed by the EPA for this instrument.
In addition, please review Table 4-2, which has the recommended
operation parameters for the TECO 48C-TLE. The operation parameters
include recommended operating full scale range, calibration ranges and
recommended cylinder concentrations.

**4.1 Precision**

Precision is defined as the measure of agreement among individual
measurements of the same property taken under the same conditions. For
CO, this refers to testing the CO analyzer in the field at
concentrations between 0.250 and 0.500 ppm. The test must be performed,
at a minimum, once every two weeks. Calculations for Precision can be
found in Reference 4.

**4.2 Bias**

Bias is defined as the degree of agreement between a measured value and
the true, expected, or accepted value. Quantitative comparisons are made
between the measured value and the true, standard value during audits.
Generally, three upscale points and a zero point are compared. Two audit
types commonly used for CO, direct comparison and blind, are discussed
below. The SOP should discuss plans for each type of audit.

-   **Direct Comparison Audits:** An independent audit system is brought
    to the monitoring location and produces gas concentrations that are
    assayed by the monitoring station\'s CO analyzer. In most cases, a
    person outside of the agency or part of an independent QA group
    within the agency performs the audit. The responses of the on-site
    analyzer are then compared against the calculated concentration from
    the independent audit system and a linear regression is generated

-   **Blind Audits:** In blind audits (also called performance
    evaluation audits) State or Local agency staff are sent an audit
    device, such as the National Performance Evaluation Program (NPEP).
    The agency staff does not know the CO concentrations produced by the
    audit equipment. Responses of the on-site analyzer are then compared
    against those of the generator and a linear regression is
    calculated.

**4.3 Representativeness**

Representativeness refers to whether the data collected accurately
reflect the conditions being measured. It is the data quality indicator
most difficult to quantify. Unless the samples are truly representative,
the other indicators are meaningless. Since the NCORE Level I and II
siting criteria are urban and regional, the CO Trace Level criteria are
the same. Please reference the National Monitoring Strategy^5^ for a
discussion of NCORE Level II CO monitoring scale.

**4.4 Completeness**

Completeness is defined as the amount of data collected compared to a
pre-specified target amount. For CO, EPA requires a minimum completeness
of 75% (40 CFR 50, App.H.3). Typical completeness with the TECO 48C-TLE
values can approach 90-93%.

**4.5 Comparability**

Comparability is defined as the process of collecting data under
conditions that are consistent with those used for other data sets of
the same pollutant. The TECO 48C-TLE meets the MQOs for a Trace Level CO
instrument. Please see Table 4-1.

**4.6 Method Detection Limit**

The method detection limit (MDL) or detectability refers to the lowest
concentration of a substance that can be determined by a given
procedure. The TECO 48C-TLE must be able to detect a minimum value of
0.040 ppm of CO.

Table 4-1 Measurement Quality Assurance Objectives

  -------------------- --------------- ---------------------- --------------- -----------------
  **Requirement**      **Frequency**   **Acceptance           **Reference**   **Information or
                                       Criteria**                             Action**

  Bias                 NCORE, once per To be Determined from  40 CFR Pt.58    Use of NIST
                       year            Data Quality                           generated gas
                                       Objectives                             concentrations
                                                                              with Mass Flow
                                                                              Calibration unit
                                                                              that is NIST
                                                                              traceable

  Precision            1 every 2 weeks Concentration: 0.250   40 CFR Pt.58    To be determined
                                       -0.500 ppm,            Appendix A      
                                       Coefficient of                         
                                       Variance: To be                        
                                       determined                             

  Completeness         Quarterly,      NCORE, 75%             National        If under 75%,
                       Annually                               Monitoring      institute Quality
                                                              Strategy.       Control Measures

  Representativeness   N/A             Neighborhood, Urban or 40 CFR 58       N/A
                                       Regional Scale                         

  Comparability        N/A             Must be a Trace Level  National        N/A
                                       instrument. See        Monitoring      
                                       Sections 3.1 and 3.2   Strategy.       
                                       of this document.                      

  Method Detection     NA              0.040 ppm              National        Testing is
  Limit                                                       Monitoring      performed at the
                                                              Strategy        factory.
  -------------------- --------------- ---------------------- --------------- -----------------

**Table 4-2 Operating Parameters for the TECO 48C-TLE Trace Gas
Instrument**

  -------------- ----------------- --------------------------------------
  Item           Range             Comments

  Full Scale     0 to 5.000 ppm    Suggested Range. Reduce to 1.000 ppm
  Range                            if rural site

  Units          Part per million  Recommended
                 (ppm)             

  Compressed Gas 200 -- 250 ppm    NIST Traceable Protocol #1 cylinder
  Cylinder                         with CO concentration between 200 --
                                   250 ppm.

  Calibration    []{.mark}         []{.mark}
  Ranges                           

  a\. zero       0 -- 0.010 ppm    There are a number of commercially
                                   available vendors.

  b\. Level I    4.000 -- 5.000    NIST Traceable Protocol #1 cylinder
  Span           ppm               with CO concentration between 200 --
                                   250 ppm. Recommended gas flow range 75
                                   -- 90 cc/min. Zero air flow 4.80 --
                                   5.00 liters/min.

  c\. Mid Point  2.000 -- 2.500    NIST Traceable Protocol #1 cylinder
  Span           ppm               with CO concentration between 200 --
                                   250 ppm. Recommended gas flow range 75
                                   -- 90 cc/min. Zero air flow 8.00 10.00
                                   liters/min.

  d\. Precision  0.250 -- 0.500    NIST Traceable Protocol #1 cylinder
  Level          ppm               with CO concentration between 200 --
                                   250 ppm. Recommended gas flow range
                                   20 - 35 cc/min. Zero air flow 18.00 --
                                   20.00 liters/min.
  -------------- ----------------- --------------------------------------

**5.0 REFERENCES**

1.  Merck Index, twelfth edition 1996, page 296

2.  Seinfeld,, John H., Atmospheric Chemistry and Physics of Air
    Pollution, 1986, page 54

3.  Code of Federal Regulations, Title 40, Part 53.23c

> 4\. Code of Federal Regulation, Title 40, Part 58, Appendix A
>
> 5\. The National Air Monitoring Strategy, Final Draft, 4/29/04,
> [http://www.epa.gov/ttn/amtic/monstratdoc.html]{.underline}

**Appendix A**Number range CHAPTER

Environmental Protection Agency

Monthly Quality Control and Maintenance Records

TECO 48C-TLE CO Analyzer

Site Name/Location
[\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_]{.underline}

Technician\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Month/Year\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Serial Number Range\_\_\_\_\_\_\_\_\_\_\_\_\_\_

+--------------+-----------+-------------+------------+---------------+
| *            | **Date**  | **Date**    | **Date**   | **Acceptance  |
| *Parameter** |           |             |            | Criteria**    |
+--------------+-----------+-------------+------------+---------------+
| Program      |           |             |            | 48 TR007 00   |
| Number       |           |             |            |               |
|              |           |             |            | C             |
|              |           |             |            | ommunications |
|              |           |             |            |               |
|              |           |             |            | 48LTR007 00   |
+--------------+-----------+-------------+------------+---------------+
| Bias Voltage |           |             |            | -105-115V     |
+--------------+-----------+-------------+------------+---------------+
| +5 volt      |           |             |            | NA            |
| supply       |           |             |            |               |
+--------------+-----------+-------------+------------+---------------+
| +15 volt     |           |             |            | NA            |
| supply       |           |             |            |               |
+--------------+-----------+-------------+------------+---------------+
| -15 volt     |           |             |            | NA            |
| supply       |           |             |            |               |
+--------------+-----------+-------------+------------+---------------+
| Battery      |           |             |            | NA            |
+--------------+-----------+-------------+------------+---------------+
| Internal     |           |             |            | 8.0 -- 47     |
| Temp         |           |             |            | deg. C        |
+--------------+-----------+-------------+------------+---------------+
| Chamber Temp |           |             |            | 48.0 -- 52.0  |
|              |           |             |            | deg. C        |
+--------------+-----------+-------------+------------+---------------+
| Pressure     |           |             |            | 250 -- 1000   |
|              |           |             |            | mm Hg         |
+--------------+-----------+-------------+------------+---------------+
| Flow         |           |             |            | 0.35 - 2.5    |
|              |           |             |            | LPM           |
+--------------+-----------+-------------+------------+---------------+
| S/R Ratio    |           |             |            | 1.14 -- 1.18  |
+--------------+-----------+-------------+------------+---------------+
| AGC          |           |             |            | 200,000 --    |
| Intensity    |           |             |            | 300,000 Hz    |
+--------------+-----------+-------------+------------+---------------+
| Motor Speed  |           |             |            | 100%          |
+--------------+-----------+-------------+------------+---------------+
| Test Analog  |           |             |            | See note      |
| Outputs\*    |           |             |            | below         |
+--------------+-----------+-------------+------------+---------------+
| Option       |           |             |            | See note      |
| Switches\*\* |           |             |            | below         |
+--------------+-----------+-------------+------------+---------------+

\* When the operator needs to set the analog output against the DAS,
this function should be utilized. Please refer to page 3-41 to 3-44 of
the owner's manual to initiate this feature.

\* \*The option switches are set at the factory. Please reference
owner's manual, Page 3-62 "Service Mode Menu" on changing these options
switches.

  ------------ ----------------------------------------------------------
  **Date**     **Comments and Notes**

               

               

               

               
  ------------ ----------------------------------------------------------

**Figure A-1 TECO 48C-TLE Quality Control and Maintenance Record**