Texas Commission on Environmental Quality Chapter 2.0 Sampling Procedures Manual

CHAPTER 2

STACK SAMPLING FACILITIES

General

Most sampling for representative results requir es minimum sampling facilities for which the TCEQ has established the guidelines presented in this chapter. Stack sampling oper ations utilize a system of equipment to traver se a cross-section of the stack or duct thr ough ports located such that a representative sa mple can be obtained. No rmally, a monorail structure is erected so the
cross-section of the stack may be traversed on two axes for circular stacks and on a matrix layout for rectangular or other shaped stacks.

These guidelines cannot anticipate all situations, and special cases will occur. Non-standard or
alternate installations are theref ore evaluated on an individual basis, and in such instances detailed plans should be sent to the local TCEQ Regional Office sufficiently in advance for review and approval before the construction of stack sampling facilities is initiated.

Various rules and regulations require that “safe and easy acces s” be provided for sampling. Facilities deemed insufficient by a TCEQ obser ver whether due to unsafe, crowded, or other conditions may preclude the observation of the sample and, in turn, the acceptance of the results.

The following guidelines constitute minimum requirements for safe and accessible stack sampling facilities

. No attempt has been made to incorporat e official safety rules, but all such applicable regulations must be followed.

Physical Features

Before consideration is given to the installa tion of sampling ports and platforms, certain
dimensions and other features of the stack and stack gas must be veri fied in order that a representative sample is possible.

● Stack diameter must be at least four inches.

● Stack gas velocity head must be at least 0.05 inches of water.

● The stack must have at least 2-1/2 diameters of uniform undisturbed cross-section.

Sampling Ports

Port Location

The optimum location of sampling ports is at least eight stack diameters downstream of any bends, inlets, constrictions, abatement equipment, straightening vanes, or other flow disturbance; and at least two stack diameters upstream of the st ack exit or other flow disturbance. Hydraulic
diameter is used for non-circular stacks and is defined later in this chapter. This location permits a sample traverse to be taken using a minimum of twelve sampling points. A greater number of sampling points is necessary on stacks which fail to meet this location criteria. For a valid

Revision No.: One 2-1 1/2003Texas Commission on Environmental Quality Chapter 2.0 Sampling Procedures Manual

sample traverse to be obtained, however, sampling ports must be located at least two stack
diameters downstream and at leas t one-half stack diameter upstream from any disturbance. If a 2-1/2 diameter length of unifo rm undisturbed stack cross-sect ion is not available, stack modification must be made or an alternate samp ling location must be chosen which will satisfy
this criteria.

To minimize the increase in the number of sampling points re quired on stacks with undisturbed cross-section less than 10 but gr eater than 2-1/2 stack diameters in length, the sampling ports
should be located such th at the distance from the ports to the nearest upstream disturbance is four times the distance from the ports to the near est downstream disturbance (see Figure 2-1 for minimum number of sampling points required). The 2-1/2 diameter criteria must be met; while
the 4:1 distance ratio is a recommendation.

Port Size

Ports are minimum three-inch ID standard indus trial flanged pipe with six-inch bolt circle diameter and closed by a removable blind fla nge. Larger port sizes are necessary on large diameter, double-walled stacks which necessitate longer ports, and six-inch ports are necessary for proportional PM-10 sampling. These ports should also be standard industrial flanged pipe.
Ports no smaller than four inches inside diameter must be provided on stacks greater than ten feet
in diameter.

Port Installation

Ports shall be installed flush w ith the interior stack wall a nd shall extend outward from the
exterior stack wall no less than three inches nor mo re than eight inches unless additional length is required for gate valves. Gate valves should be installed only when extreme stack conditions and/or the presence of hazardous materials require such devices for the safety of personnel.
Ports should be installed no less than five feet nor more than six feet above the floor of the platform and the clearance zone described la ter in this chapter must be maintained.

Revision No.: One 2-2 1/2003Texas Commission on Environmental Quality Chapter 2.0 Sampling Procedures Manual

Figure 2-1
Minimum Number or Traverse Points

Number and Location of Ports on Circular Stacks

A minimum of two ports shall be installed on diameters 90 o apart if the stack diameter plus one port length (stack inside wall to en d of port extension) is less than ten feet. Four ports shall be installed on diameters 90 o apart if the stack diameter plus on e port length is equal to or greater
than ten feet. One traverse should be located in the plane of any bend or other disturbance that may have inertial effects on pa rticles in the flow stream.

Number and Location of Ports on Non-Circular Stacks

The same upstream and downstream distance re quirements discussed previously apply to noncircular stacks. The hydraulic diameter (four tim es the area divided by th e perimeter) is used in place of the circular diameter. This becomes (2AB)/(A+B) for a rectangular stack, where A and

Revision No.: One 2-3 1/2003Texas Commission on Environmental Quality Chapter 2.0 Sampling Procedures Manual

B are the cross-sectional dimensions of the stack. The streamwise location of the sampling ports
is determined in the same manner as for circ ular stacks using the hydr aulic diameter. The hydraulic diameter is used only for determining the location of sampling ports and the required number of sampling points. Hydraulic di ameter is not used in data reduction.

The cross-stream location of the sampling ports is dependent upon the total number of sampling points required. Figure 2-1 is used to determ ine the required minimum number of sampling points by reading the curve co rresponding to the numbe r of upstream hydraulic diameters (B) and downstream hydraulic diameters (A) and selecting the higher number.

The stack cross-section of square or rectangular stacks is divided into a matrix (i, j) of equal area rectangles such that i = j or i = j + 1 and i + j is equal to or gr eater than the total number of sampling points required. The number of sampling por ts required is either i or j located along
one side of the stack such that the centerline of each port is colinear with the centroid of each row of sampling points.

Stacks with cross-sections which are not circular or rectangular must be equipped with an adequate arrangement of sampling ports so that the stack cross-section may be divided into a sufficient number of area increments for a repres entative sample. If equal area increments are not possible, time weighting of the sample at the various sampling points may be necessary. Detailed plans of such installations s hould receive advance approval by the TCEQ.

Monorail Support Structure

The installation of a permanent monorail support structure is recommended to reduce set-up time and to eliminate the load-bearing requirement s for the sampling ports. Figure 2-2 shows a drawing of the monorail support st ructure including the relative pos ition of the bracket to the sampling port. This bracket is intended to be compatible with several types of sampling equipment. The loading requirements for ports or the monorail support structure are shown
below.

Port or Monorail Support Loading

The port or monorail support inst allation shall be capable of supporting the following loads:

● Vertical load of 200 pounds

● Horizontal load of 200 pounds

● Radial load of 1000 pounds (along stack diameter)

Work Platform

A work platform shall be provided around the st ack circumference between the sampling ports and extending at least three feet beyond each port. If four ports are required, the work platform
shall extend around the entire circum ference of the stack. The mini mum platform width shall be at least three feet measured radially with stack diameter. The work platform must be capable of supporting at least 2000 pounds.

Revision No.: One 2-4 1/2003Texas Commission on Environmental Quality Chapter 2.0 Sampling Procedures Manual

Safe and easy access to the work platform shall be provided via ladder, stairway, or other suitable means. Safe guardrails shall be pr ovided around the platform . No open ladder well, stairwell, or other such opening shall be located within three feet of any sampling port. Ladder wells shall be covered at the platform and any opening to the platform shall be equipped with a safety bar or chain at the opening.

A temporary work platform for sampling ope rations is acceptable if proper safety and accessibility is provided. All other requirements de tailed in this chapter such as for monorails, ports, loading, clearance, and power must be met by the temporary facilities.

Figure 2-2 Monorail Support

Revision No.: One 2-5 1/2003Texas Commission on Environmental Quality Chapter 2.0 Sampling Procedures Manual

Clearance Zone

A three-dimensional obstruction-free cleara nce zone shall be provided around each sampling port. The zone shall extend one foot above the port, two feet below the port, and two feet to either side of the port. The zone shall extend out ward from the exterior wall of the stack at least one stack diameter (or stack radius if four ports are provided), plus one por t length (inside wall to end of port extension) plus thr ee feet. Although this clearance zone is ge nerally adequate for most sampling efforts, sampling contractors may have other clearance needs. A general
clearance zone is illu strated in Figure 2-3.

Power Supply

Power requirements may vary from site to site and the complexity and frequency of testing requirements. For complex test efforts the te st firm and source owner/operator should verify adequate power is available. For normal test e fforts electrical power outlets shall be provided as
follows:

Platform Power

At least one 115-volt, 15-amp, single phase, 60 he rtz alternating current circuit with a grounded two-receptacle weather-proof outlet. Recept acles shall accept standard three-prong grounded household-type plugs or suitable adapters shall be provided.

Stack Base Power

Two 115-volt, 15-amp, single phase 60 hertz alte rnating current circuits with grounded tworeceptacle weather-proof outlets. Receptacles shall accept standard three-prong grounded household-type plugs or suitable adapters shall be provided.

Vehicle Access and Parking Vehicle access and parking space should be provided near the base of the stack for various communications and equipment transport line s to be strung to the stack platform.

Gaseous Sampling - Concentration Only

Standard sampling ports and platforms are norma lly necessary for gaseous sampling because a velocity traverse is needed for flow rate determination in most cases. In sampling situations for which only pollutant concentration is needed or fo r which an accurate flow rate is available by other approved means, less elaborate sampling faci lities may be acceptable. All facilities must, however, meet strength and safety requirements.

Revision No.: One 2-6 1/2003Texas Commission on Environmental Quality Chapter 2.0 Sampling Procedures Manual

Figure 2-3 Stack Facilities

Gaseous sampling facilities for concentration only shall be sufficient for collection of a sample of stack gas according to standard gaseous sampling procedures. Adequate minimum facilities such as a one inch nipple shall be installed in the stack at a location where sufficient turbulence exists (no stratification) to insure a representa tive sample. Proper clearance must be provided for sampling operations or a permanent probe and samp le line can be installed at the port location and extended to a more accessible sampling location. The probe and sample line must be
installed so that leak checks can be made.

Revision No.: One 2-7 1/2003Texas Commission on Environmental Quality Chapter 2.0 Sampling Procedures Manual

Revision No.: One 2-8 1/2003 Permanent Monorail Systems

Source operators are encouraged to install permanent monora il systems on large stacks.
Monorails must extend the full ra dial length of the clearance zone described previously, and must be capable of supporting a 200 pound load anywhere along the monorail track. Rollers must be properly lubricated and maintained in working condition. The sample box attachment hooks should be six inches above the port centerline. If the monorail is installed with the hooks more than six inches above the port center line, suitable adapters must be provided.

Miscellaneous Requirements

In addition to the specific requirem ents detailed in this chapter, other miscellaneous requirements
are as follows:

● Power hoists shall be provided for sampling platforms 200 feet or more above ground
level.

● Non-circular horizontal ducts should have provisions for vertical sampling. Circular
horizontal ducts should have one vertical and one horiz ontal port. Suitable work platforms are necessary in both cases.

● Heat insulation shall be installed as nece ssary on high temperature stacks for safety in the vicinity of the work platform.

● The source operator is res ponsible for maintaining all sa mpling facilities in safe,
useable condition at all times.

● As mentioned earlier, one traverse should be located in the plane of any bend or other disturbance that may have inertial eff ects on particles in the flow stream.

● Stacks may taper by as much as 15 degrees without the taper being considered a
disturbance.

Excess Air

Additional facilities may be necessary for determining the composition and flow rates of feed stock and fuel on certain processes such as incine rators. This information, obtained at the time of sampling, is necessary to calculate the amount of air in the stack effluent in excess of
stoichiometric.

Cyclonic Flow

Cyclonic or swirling flow may be encountered in a stack or duc t due to certai n circumstances such as cyclone collectors or tangential duct entr y. Corrective measures such as straightening vanes may be necessary to alleviate the cyclonic condition.

The existence of cyclonic flow may be determined as described in Chapter 5. A method for sampling cyclonic flow is described in Appendi x H, but advance approv al should be obtained concerning its applicability for determining compliance status.Texas Commission On Environmental Quality

Sampling Procedures Manual Chapter 14.0

Revised: 02/22/2013 Page 14 - 1 

## CHAPTER 14

CONTENTS OF AIR EMISSION TEST REPORTS



## General

This chapter provides guidance for submitting air emission test reports. Special sampling situations may arise that do not fit these categories; however, this chapter has been broadly designed to serve as a guide to the standardization and quality assurance practices that are generally necessary for a report to be considered complete. The four most common deficiencies of test reports are: insufficient documentation of process conditions, insufficient documentation of test activities, inadequate calibration of test equipment, and the lack of approval for alternate methods or method deviations. All testing activities should incorporate good laboratory practices. The procedures used for testing and reporting of results should be those which are commonly accepted in the field of air pollution control per 30 Texas Administrative Code (TAC) Section (§ ) 101.14. Incomplete reports may be considered as noncompliance, and could result in enforcement action against the owner or operator of the
facilities

. Texas Water Code, § 7.179, addresses intentionally or knowingly omitting material

in formation, making false statements, concealing, and or altering any notice, report or other document required by chapter, rule or permit.

Report reviews are conducted by the Texas Commission of Environmental Quality (TCEQ) to determine acceptability of the report based on the following general criteria:

a. Is the air emissions test report in an acceptable and logical format?
b. Is the air emissions test report complete?

c. Have the Source ’ s applicable test requirements been fulfilled?
d. How valid is the testing event ’ s raw test data?

e. Were correct equations and terms used in the report ’ s calculations?

A TCEQ conducted report review is the basis upon which an air emissions test Report is officially accepted or rejected by the Agency (TCEQ). The acceptability of a report is easier to determine if contents are complete and presented in a logical, organized manner, as illustrated in this chapter. Use of the TCEQ or Environmental Protection Agency (EPA) format for presentation of field data and calibration is encouraged to expedite report evaluation. Where possible, reports should conform to Texas Accessibility Standards. Guidance may be located at http://governor.state.tx.us/disabilities/accessibledocs or by contacting any TCEQ office for
additional information.Texas Commission On Environmental Quality

Sampling Procedures Manual Chapter 14.0

Revised: 02/22/2013 Page 14 - 2 The regulated entity should submit at least three copies of the report to the appropriate TCEQ regional office. Air permit Special Conditions may specify additional distribution of the report. One copy should be a bound hard copy

. The other two may also be a bound hard copy, or contained in an electronic format. For electronic formats, the TCEQ can only accept a read-only compact di sc (CD) and should be submitted in a slim jewel case

. The currently acceptable file types for the CDs are :

 .pdf (document format/image - Adobe)

 .tiff (photographic/image)

 .xml (extensible markup language

– can be used to describe documents)

 .doc (Microsoft Word)

 .xls (Microsoft Excel)

 .ppt (Microsoft PowerPoint)

The regional office will forward a bound hard copy or CD copy to Central Records in Austin. The copy being sent to the Central File Room will be considered the official agency record. It is recommended that the following list be used as a checklist for the report to insure it is complete.



## Stack Sampling

Organization and submission of stack test reports in the following manner will facilitate TCEQ

review.

1) Table of Contents: Or an equivalent means of locating sections of the report, including additional volumes or appendices which may be required. Each page of the report should
be numbered.

2) Introduction: Background information pertinent to the test and testing requirements (title page may be sufficient if it contains the information below). a) Name and physical location of source sampled and date(s) of sampling. b) Identification of the process and name and number of the unit sampled using TCEQ Regulated Entity Numbers (RN), TCEQ Account Numbers, TCEQ Permit Numbers, and
Emission Point Numbers. c) List of applicable testing requirements with brief explanation: i) Specific citations of TCEQ Rule numbers; TCEQ Permit numbers or permit by rule requirements; ii) The specific subparts and emission limit, testing, and reporting requirement rules of EPA New Source Performance Standards (NSPS)

, National Emissions Standards forTexas Commission On Environmental Quality

Sampling Procedures Manual Chapter 14.0

Revised: 02/22/2013 Page 14 - 3

Hazardous Air Pollutants (NESHAP) National Emissions Standards for Hazardous Air Pollutants for Source Categories, commonly called Maximum Achievable Control Technology (MACT) Standards; iii) Other ( e.g., Notice of Violation resolution, increased production rates, etc.). d) List of pollutants sampled. e) State whether this is the initial test, quarterly, or otherwise. f) A detailed explanation of any tests which were not completed for any reason.

3) Summary: The portion of the air emissions test report that states the final results of the testing event and compares the results to the requirements, provisions and allowances of the applicable governing rules and standards.

a) In the Test Report summary, include all pollutant mass emission rates, concentrations,

re moval or destruction efficiencies, emission to operation standard (e.g. lb./MMBTU, lbs./hp hr, lbs./MMgal loaded) or other applicable standard being determined during the air emissions testing event. Compare each result with the applicable standard(s), including: NSPS, NESHAP, MACT, TCEQ general and/or special provisions/conditions of the source ’ s Permit, Permit Application Representations, Exemption Demonstration Requirements, et cetera (etc.). Submit the reading, sum or averages of pertinent support data measured during the testing event, in time units which are appropriate for use in the determination of the mass emission rate(s) of the air pollutants required to be tested for (by the source ’ s operating permit or the applicable Federal Subpart). i) Particulate emission rates including and excluding the impinger catch portion of the sample. The impinger portion of the sample may be excluded only in certain cases. ii) Percent isokinetic for each isokinetic sample. iii) Schedule of intermittent periods during sampling and the normal schedule of such events ( e.g., Soot blowing, CEMS blowback, process downtime, batch process, etc.). iv) Operating level of the process during each sample or sample run, the normal

o perating level (usual), design maximum and maximum achievable operating levels. v) Statement of operating condition of all abatement equipment during sampling including any cleaning cycles associated with the abatement equipment (e.g., absorber regeneration, baghouse bag cleaning cycles, ESP rapping, etc.). b) Where previous testing was conducted summarize differences in the results, testing and operating conditions.

4) Procedures: Description of equipment and procedures used during sampling and analysis a) If equipment, procedures, and analysis methods were exactly those described in the applicable sections of the TCEQ Sampling Procedures Manual, the Federal Register, and the Test Plan, include a statement to that effect along with a list of specific methods, procedures, and test equipment; schematic of instrumental analyzer sampling system, including all pumps, valves, mass flow controls, sample conditioning systems, heated lines, manifolds and atmospheric vents as configured during the test; any ReferenceTexas Commission On Environmental Quality

Sampling Procedures Manual Chapter 14.0

Revised: 02/22/2013 Page 14 - 4 Method deviation(s) approved by the TCEQ, including the date approved, and name & title of the TCEQ representative who approved the deviation(s). b) If any equipment, procedures, and analysis methods were consistent with, but not identical to TCEQ Sampling Procedures Manual, the Federal Register, and the Test Plan, provide additional information for those efforts including a detailed description of such methods, procedures, and equipment used; written approval for any deviations from standard procedures including: the name and description of all special apparatus and alternative testing methods used during test; copy of the method and publication references; written documentation of alternate test method approval. c) Written approval for any major modification to a Reference Method. Written approval for any method(s) which was used that is not published in an EPA document, along with a copy of the method(s) detailing minimum and maximum detection limits, interferences, etc.

5) Process Data: The averages of all process or production parameters recorded, calculated or determined during the air emissions testing event, in time units which are appropriate for use in the determination of the mass emission rate(s) of the air pollutants required by the

source ’ s permit, state rule or the applicable Federal Subpart. Include the source of all parameter information. a) All other information necessary to calculate emissions or determine process activity to determine compliance with the standards or limitations being evaluated and show the proper operation of the facility for the tests being conducted, regardless of whether it is specifically or directly identified in the permit, state rule or the applicable Federal

Su bpart. Note: this information should generally be discussed and agreed on during a pretest meeting or other documented communication. b) All measured pollutant emissions: both including and excluding the impinger catch portion of extracted samples. c) Detail(s) of the following process or production rates for the facility, or the production or process unit in which the emission source is in service: i) Logs of process parameters as may be necessary to document levels of operation. All printouts obtained from process, such as load etc., must be accompanied by a description which identifies the parameters and units used; ii) Designed Rate; iii) Permitted Rate (if applicable); iv) Maximum Rate (if different from the designed rate); v) Production Rate(s) Demonstrated during the testing event(s); vi) Production Rates(s) Demonstrated during the Immediately Previous air emissions testing event, if applicable (recommended).

6) Calibrations: Dated calibration records with dates and worksheets for all equipment used during sampling. The name and description of all primary air emissions testing equipmen t used during the air emissions testing event, including manufacturer, model number andTexas Commission On Environmental Quality

Sampling Procedures Manual Chapter 14.0

Revised: 02/22/2013 Page 14 - 5 serial numbers. If in question, the adequacy of the calibrations will be compared to the procedures in the current edition of the Quality Assurance Handbook for Air Pollution Measurement Systems

.

7) Lab data: Include laboratory analysis worksheets and results including tare weights, blank results, spiked samples, audit samples and recovery studies required by the test method. Additional information sufficient for an independent evaluation of the procedure may be required for complex methods such as daily calibrations, date and time analysis were conducted, audit materials, and laboratory certifications and accreditations or exemption
from accreditation

. Note: all analytical data generated by a mobile or stationary laboratory in support of compliance with air permits must be obtained from a National Environmental Laboratory Accreditation Conference (NELAC) accredited laboratory under the Texas Laboratory Accreditation Program or meet one of several exemptions. Specific information concerning which laboratories must be accredited and which are exempt may be found in 30 TAC § 25.4 and § 25.6. For additional information regarding the laboratory accreditation program and a list of accredited laboratories and their fields of accreditation, please see the following Web site: www.tceq.texas.gov/compliance/compliance_support/qa/env_lab_accreditation.html

For questions regarding the accreditation program, you may contact the Texas Laboratory Accreditation Program at (512) 239-3754 or by e-mail at labprgms@tceq.texas.gov . Also
include: a) A record of the chain of custody of the samples from sampling collecting through the final sample analysis. b) Visible emission determination, opacity data sheets, observer certification, etc., if

c onducted.

8) Calculations: Example calculations of all applicable stack gas parameters, emission rates, and analytical results for the test which minimally include: a) Emission rates; b) Allowable emission rates (TCEQ, EPA); c) Excess air in stack; d) Cyclonic flow; e) Percent isokinetic; f) F factor; g) Soot blowing; h) Stack gas parameters (velocity, moisture content, ACFM, SCFM); i) Intermediate steps during analysis (titrations, aliquots, blanks); j) Assumptions and constants used; k) An example calculation using actual data from one of the valid test runs.

9) Testing Personnel information:Texas Commission On Environmental Quality

Sampling Procedures Manual Chapter 14.0

Revised: 02/22/2013 Page 14 - 6 a) Name and affiliations of all (including plant personnel) present during testing and their responsibilities during the test; b) Name, address, and telephone number of testing organization, laboratories used and consultants overseeing or responsible for the testing report or results with an appropriate contact name for acquiring additional information.

10) Appendices: The portions of the air emissions test report that include various categories of supplementary and support information which is included to enhance the validity of the practices and procedures conducted prior, during and subsequent to the air emissions testing event. a) Schematic drawing of stack (elevation and plan views) showing all dimensions, sampling port locations, inlets, outlets, and nearest upstream and downstream flow disturbances with sampling point locations shown on plan view. Pictures of emission points may be substituted for drawings; however, measurements of the interior dimensions of the emission point are required. b) Cop ies of all raw data taken during sampling. Record all handwritten data exclusively in indelible ink by all test and plant personnel, during the air emissions testing event. Include all data generated during the test by any instrumentation such as strip charts, integrator printouts, data acquisition system printouts; ensure that it is completely reproduced legibly. Clearly indicate the duration of all test runs, calibrations, and other significant events. c) Also required as part of the report submittal is pretest meeting documentation, if a pretest meeting was held. d) A copy of the TCEQ permit, if any, which applied to the unit(s) at the time of the testing to document the language and emission limits at the time of the testing. For testing required under the provisions of TCEQ flexible permits, include a calculation of emissions to compare to the cap on the day of testing for all emissions sources under the cap. Use the Hourly Cap Compliance Demonstration Summary Table (HCCDST) to report the data.Texas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-1 APPENDIX P

COOLING TOWER MONITORING

General

Cooling tower monitoring describes the characteriza tion of volatile organic air pollutants that are capable of being air-stripped from a water matrix. While generic or indicator monitoring may be required to identify the existence of volatile organic compound (VOC) emissions, speciated compound characterizations may also be required in some instances to characterize the specific compounds present.

Historically, a method for cooling tower water ch aracterization was devel oped for use by El Paso Products Company in the early 70's. This met hod utilized a dynamic or flow-through system for air stripping a sample of the water and analyzing the resultant off-gases for VOCs using a common flame ionization detector (FID) analyzer, and ha s been the popular choice in Texas for many years. The El Paso Products method, however, has been overshadowed nationally by the use of purge and trap analysis of water samples utilizing gas ch romatography and/or mass spectrometry techniques. While direct water analysis has been shown to be effective for cooling tower measurements of heavier molecular weight organic compounds with relatively high boiling points, Texas Commission on Environmental Quality (TCEQ) has determined th at this approach may be ineffective for capture and measurement of volatile organic compounds with lower boiling points, such as ethylene, propylene, 1,3-butadiene, and butenes. VOCs with a low molecular weight and boiling point are generally lost in the sample collection step of purge/trap type analyses. Consequently, TCEQ requires that the air stripping method presented in this manual be used for cooling tower and other applicable water matrix emission measurem ents of VOCs with boiling points below 140 o F. Specific procedures for cooling tower sampling and analysis for VOCs with boiling points of 140 o F and greater must be submitted to TCEQ for approval on a case-by-case basis.Texas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-2 Air Stripping Method (Modified El Paso Method) for Determination of Volatile Organic Compound Emissions from Water Sources

1.0 Principle and Applicability

1.1 Principle. A continuous stream of coo ling water, process water, or wastewater is supplied via a hard pipe or direct interface to an air stripping column apparatus for analysis. Air flowing countercurrent to the water strips volatile organic compounds from the water for analysis. Some gases may flash from the wa ter immediately upon entering the apparatus and these gases are trapped and mixed with the air stripped compounds. The concentration of the air stripped compounds combined with the fl ashed gases is determined at the apparatus air outlet by a suitable detector and/or by sampling. Concentrations of air stripped compounds in the air exhaust, along with the air and water flow rates, are used to determine concentrations of strippable vol atile compounds in the water. A FID analyzer is used to
determine a value of “combined” or “total” strippable volatile organic compounds. Samples may also be collected in sample canisters for shipment to analytical laboratories for speciation of air contaminants. A gas chromat ograph (GC) with an appropriate detector may be used to determine specific stripped species.

1.2 Applicability. This method is applicable to cooling tower water systems and may be applicable to qualitative and/or quantitative m easurements on other sources such as API separators and wastewater systems.

2.0 Sensitivity

2.1 The sensitivity of this method for the onsite analysis by FID analyzer is typically 0.1 to 0.5 part-per-million, by volume (ppmv) meth ane in the stripped air, depending on the specific analyzer. The sensitivity of the GC speciation analysis will vary depending on the
detector used. Detection limits as low as 2 - 50 part-per-billion, by volume (ppbv) in the stripped air may be possible with the use of a gas chromatograph equipped with a mass spectrometer (GC/MS).

2.2 FID Response. Response factors are not us ed to correct the total VOC measurement by FID analyzer. Speciation analysis of the VOCs present in the stripped gas would be required to correctly apply any proportioned response factor to the total VOC measurement, in which case, the results should be calculated from the speciated analysis rather than the total VOC results. Some chemicals, such as form aldehyde, will not respond well on a FID, having particularly high response factors and, therefore, high detection limits. The total VOCTexas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-3 procedure by FID should not be used on sources for which any potential targeted VOC has a response factor multiplier greater than 2 relativ e to methane. Such sources must either be sampled following the speciation procedure in Section 6.2, or an alternative detector, approved by the TCEQ, must be used in the to tal VOC procedure in Section 6.1. Alternative sampling and analysis procedures such as sorbent tube sample collection and analysis by high performance liquid chromatography (HPLC) are subject to TCEQ approval.

3.0 Equipment and Materials

3.1 Air stripping apparatus. An air stripping apparatus as pres ented in Figure 1 and meeting the following requirements: 3.1.1 The stripping chamber shall be a cylinde r 36 inches in length with an internal diameter of 3 inches, and constructed of clear, heavy-walled glass. 3.1.2 The stripping chamber packing material shall be beryl saddles between 6 to 8 millimeter size. The depth of the packing material will be 26 inches. 3.1.3 The end caps of the stripping chamber mu st meet the dimensions specified in Figure 2. Neoprene stoppers are recommended; however, securing clamps will be required to prevent leakage. Black rubber stoppers are not allowed due to the potential absorption and release of organi c compounds. Alternative designs for the end caps, such as customized threaded plastic caps with Neoprene gaskets, are acceptable provided the materials used are non-reactive with the sample matrix or target compounds, and the end caps meet th e specifications in Figure 2. The tip of the water sample inlet line is intentionally left 5 to 6 inches above the water level in the stripping chamber to help accelerate th e response of the system as some VOCs will be released immediately as the water falls into the chamber. 3.1.4 Tubing used in the air stripping appara tus for transporting gas and water shall
be 1/4 inch stainless steel or Teflon mate rial. Stainless steel or Teflon 1/4 inch tubing of minimal length shall be used to route water sample from the sample tap to the air stripping apparatus. The water sample tubing from the sample tap shall not be more than 50 feet in length. 3.1.5 Drying agents, such as DrieriteTM, for removing moisture from the stripped air stream before analysis by FID or collection in sample canisters are strictly prohibited to prevent loss of VOCs to the drying agents. An empty, clear-glass flask is used as
a knock-out to remove some of the moistu re in the stripped air stream, but gas exiting the stripping chamber will essentially be at saturated moisture for the ambient conditions. Different styles of knockout flasks are acceptable; however, the flask must be clear-glass and 500 ml or less in si ze. Some FID analyzers may not be able to monitor for prolonged periods under such conditions and intermittent monitoring may be required. 3.1.6 A T-union with one leg leading to a bubbler must be included as shown in Figure 1. Excess air not drawn into the anal yzer probe or sample canister is ventedTexas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-4 through the bubbler and serves to indicate th at sufficient flow has been established. This is to assure that the sample is only from the stripped air and is not drawing in any external air. With the bubbler in place, care must be taken not to pull water into the FID analyzer or sample canister.
3.1.7 Gas bubble formation in the water rotameter can sometimes result from the pressure drop across the water rotameter c ontrol valve. Significant gas bubbles can interfere with accurate measurement of the sample water flow to the stripping chamber. A suggested possible solution to this problem is to place a control valve downstream of the water rotameter. By opening the rotameter to the fully open position or using a non-metering rotameter, and controlling the flow with the valve after the rotameter, the pressure drop occu rs after the rotameter and bubble formation may be minimized. This approach may require a fine-adjusting control valve to achieve the flow rate control desired, and th e tester must be certain that the water rotameter can withstand the pressure in the water source being sampled

. Note: The TCEQ air stripping apparatus de sign is based on the apparatus designed by El Paso Products Company of Odessa, Texas (see Reference 9.1)

3.2 Flame Ionization Detector (FID) Analyzer . Analyzers with analog type readouts and those normally used for leak detection are ge nerally not appropriate for this method because such instruments are designed for much higher concentration measurement than would be expected in the air stripping apparatus effluent . FID analyzers used in conjunction with the
method must: 3.2.1 be a digital readout type, readable to 0.1 ppmv. 3.2.2 be able to meet the calibration requirements specified in Section 4.1. 3.2.3 have a sampling rate less than 2000 ml/m in since the stripping air flow rate is 2500 ml/min and an excess air flow is required.

3.3 Gases for Air Stripping Apparatus Op eration and FID Analyzer Calibration. 3.3.1 Zero Calibration Gas and Stripping Air. Air, certified to contain less than or equal to 0.1 ppmv of total hydrocarbon (THC). 3.3.2 High-Level Calibration Gas. Cylinder gas standard of methane in air, certified by the manufacturer to be with in ±2% of the specified c oncentration. If the sample concentration of VOCs in the stripped gas is less than 10 ppmv as methane, the span gas calibration standard shall be 10 ppmv methane. Higher concentration span calibration standards may be necessary for some sources. If a higher calibration standard is required, select a high-level concentration such that the measured sample concentrations are between 10% and 100% of the high-level calibration gas
concentration.

3.3.3 Mid-Level Calibration Gas. Cylinder gas standard of methane in air, certified by the manufacturer to be with in ±2% of the specified concentration. The mid-level calibration gas concentration shall be between 20% and 50% of the high-levelTexas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-5 calibration gas concentration. (See note under 4.1.2.4.) 3.3.4 Certified gases must be used within the manufacturer’s specified shelf life, or recertified upon expiration. 3.3.5 Subject to TCEQ approval, calibration gas standards other than methane may be used for sources that have only one or a predominate potential VOC present in the
water matrix.

3.4 A gas chromatograph equipped with appropr iate detector(s) for laboratory or field speciation of the specific organic components.

3.5 Sample canisters. Internally passivated stainless steel canisters for collection of air stripped samples for speciation analysis by GC. Sample canisters shall meet all requirements of Compendium Method TO-14A (US EPA Co mpendium for Determination of Toxic Organic Compounds in Ambient Air, EPA Docu ment Number 625/R96/010B). Each sample canister shall be equipped with a) a vacuum ga uge and b) either a needle valve for manually regulating flow rate or an automated flow re gulator (i.e., a critical orifice or mass flow controller). 3.5.1 TedlarTM bags may be used in place of stainless steel sample canisters, if the following provisions are met: 3.5.1.1 Bag samples must be analyzed according to Title 40 Code of Federal Regulations, Part 60, Appendix A, Method 18. 3.5.1.2 The recovery study for bag sa mpling in Section 8.4.2 of Method 18 must be performed for all the target compounds. The recovery study is performed by metering a known volume of zero air through a water blank stripping apparatus into the TedlarTM ba g and then spiking the bag with the target compounds. This step checks not only the potential loss of compounds due to the permeability of the TedlarTM, but also loss due to condensed moisture in the bag. Percent recovery for each target compound must be between 70 - 130%, or TedlarTM bags are not acceptable for sample collection. When TedlarTM bags are acceptable, as specified in Method 18, analysis results for target compounds must be corrected for the percent
recoveries. 3.5.1.3 TedlarTM bags must be new and unused. 3.5.1.4 TedlarTM bags shall be checked for leaks and contamination as described in Method 18, Section 16.1.3.2. 3.5.1.5 Samples in TedlarTM bags must be analyzed within 72 hours of collection. Recovery study bags must be stored for the same period of time as the sample bags.

4.0 Calibration.

4.1 FID Analyzer Calibration.Texas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-6 4.1.1 Initial/Periodic Instrument Performance Evaluation. Perform the calibration precision and response time tests as desc ribed in Sections 8.1.2 and 8.1.3 of Method 21 in 40 CFR 60, Appendix A.
4.1.2 Calibration Procedure. 4.1.2.1 Warmup period. Follow manufacturer’s recommendations. 4.1.2.2 Zero calibration. Introduce the zero gas (or stripping air) to the FID analyzer. Calibrate the analyzer to read 0.0 ± 0.2 ppmv. 4.1.2.3 High-level calibration. Introduce the high-level calibration gas (10 ppmv methane) to the FID analyzer. Calib rate the analyzer to read within ± 5.0% of the calibration gas certified value.
4.1.2.4 Mid-level calibration check. Introduce the mid-level calibration to the FID analyzer. The FID analyzer response on the mid-level calibration gas must agree within ± 5.0% of the calibration gas certified value. Note: The mid-level calibration step is optional if the VOC emissions determination is based solely on the re sults of the GC speciation analysis of the sample canister or TedlarTM bag samples.

4.2 GC Calibration. 4.2.1 GC analysis by Method 18. 4.2.1.1 Follow the calibrations procedures described in Sections 8.2.1.5.2.1
and 10.0 in Method 18. 4.2.1.2 Alternative procedure. If a facility or laboratory is performing the same analysis on samples collected by th is method on a daily basis, then the calibration and standardization pro cedures in Section 10.0 of 40 CFR 60, Appendix B, Performance Specification ( PS) 9, may be used. The initial and periodic calibrations must satisfy all the requirements of Method 18 Sections 8.2.1.5.2.1 and 10.0, as well as those in Section 10.0 of PS9. 4.2.2 GC analysis by Compendium Method TO-14A (US EPA Compendium for Determination of Toxic Organic Compounds in Ambient Air, EPA Document Number 625/R96/010B) 4.2.2.1 Follow the appropriate calibration procedures described in Section 10 of TO-14A for the selected detector(s) in the GC system.

4.3 Air rotameter calibration. 4.3.1 Calibrate the air supply rotameter system with a dry gas meter, soap film flowmeter, or similar direct volume measuring device with an accuracy of ± 2 percent. 4.3.2 Operate the rotameter at 2500 cc/min fo r at least three calibration runs for 10 minutes each. When three consecutive calibration flow rates agree within ± 5 percent, average the three flow rates. 4.3.3 If the average measured calibration flow rate agrees within ± 5% of the rotameter reading, the rotameter is accepta ble. If the difference between theTexas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-7 rotameter reading and the measured calibra tion flow rate exceeds ± 5%, then remark
the rotameter to the calibrated flow rate.
4.3.4 Perform the rotameter calibration before the first field test and semiannually,
thereafter.

4.4 Water rotameter calibration. 4.4.1 Calibrate the water rotameter with a Class A volumetric flask, graduated cylinder, or similar container with a volume known to ± 2% accuracy and capable of holding a volume at least 4 times the calibration flow rate (i.e., a 500 ml volumetric flask to calibrate the rotameter at 125 ml/min.) 4.4.2 Operate the water rotameter at 125 ml/min while filling the container. Record the time required to fill the container and cal culate the actual flow rate based on the
container volume and time re quired to fill the container. Repeat until three consecutive flow rates agree within ± 5% of the mean. 4.4.3 If the average measured calibration fl ow rate agrees within ± 5% of the rotameter reading, the rotameter is acceptable. If the difference between the rotameter reading and the calibration flow rate exceeds ± 5%, then remark the
rotameter to the calibrated flow rate.
4.4.4 Perform the rotameter calibration before the first field test and semiannually,
thereafter. 4.4.5 Alternatively, a Class A volumetric flas k or graduated cylinder may be used in the field test to collect water at the stripping chamber water exit and recording the time required to fill the container. If this approach is used, the water rotameter need
not be calibrated.

4.5 Temperature probe calibration. 4.5.1 Calibrate the stripping chamber temperature probe against an ASTM mercury thermometer or equivalent. The calibra tion shall be performed at or near 0 o C, 20 o C,
and 40 o C. 4.5.2 If the absolute temperature (in degrees Kelvin) measured by the temperature probe agree within ± 1.5% at each reference point, the temperature probe is acceptable. 4.5.3 Perform the temperature probe calibration before the first field test and semiannually, thereafter.

5.0 Pretest Preparations

5.1 Selection of the sampling site. 5.1.1 Sample sites for cooling towers must meet the following criteria: 5.1.1.1 The sample port in the cooling tower return line header must be in a
location where the feed rates to th e cooling tower wa ter are still underTexas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-8 pressure and prior to the release of th e pressure to atmospheric or any vents
in the return line header . For example, if the cooling tower has an open trough along the top of the tower which dist ributes water to each of the cells, the water supply for the test should be taken prior to the cooling water entering the distributing trough. 5.1.1.2 The sample port/probe should not extend beyond the plane of the pipe wall into water matrix. 5.1.1.3 Samples should be drawn from either the vertical section near the base of the riser pipe (from the inside of the elbow to the riser) or the top of a horizontal section prior to the riser pi pe at a location where the pipe will be completely full. 5.1.1.4 For cooling towers with multiple risers, samples must be drawn from a location prior to the risers unless sample ports are installed on each riser
and the distribution of water flow to each riser can be determined. 5.1.2 Sample sites for sources other than cooling towers were not considered during the development of this method and selecti on criteria for such sources may be subject to TCEQ approval.

5.2 Sample canister preparation. These procedures are typically performed by the laboratory conducting the speciation analysis. 5.2.1 Before each use, sample canisters shall be cleaned, certified, and prepared according the procedures described in Section 11.1 of TO-14A. 5.2.2 Evacuate canisters to less than 0.05 mm Hg pressure at least 24 hours prior to sample collection. Record the canister ID, vacuum, date, and time on a label attached to the sample canister.

5.3 Setup of Apparatus. 5.3.1 Assure the unit is vertically level us ing a bubble indicator or some other level indicator. If the stripping chamber is not level, channeling of the water or air flow may occur in the chamber and result in inefficient stripping. 5.3.2 Connect the zero air supply to the air inlet of the air stripping apparatus.

5.4 Perform the calibration procedures for the FID analyzer as described in Section 4.1. 5.4.1 If VOC emissions are to be determined only by sampling with sample canisters and GC speciation, the mid-level calibration is optional since the FID analyzer is only used for monitoring for system stabilization. 5.4.2 Record calibration results on a data sheet similar to that in Figure 3. 5.4.3 Some analyzers draw fuel air for the FID separately from the sample stream.
If the fuel air is drawn from ambient ai r without purification, variations in the ambient level of THC may cause the instrume nt to drift. This can be especially problematic if the analyzer is calibrated indoors and then taken out to process areas
for the test. Dramatic ch anges in ambient temperature may also cause instrumentTexas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-9 drift. Every effort should be made to calibrate the instrument under the same conditions it is to be used. When moving from source to source, a calibration check shall be performed on the analyzer to dete rmine if changes in the ambient conditions (i.e., temperature or ambient THC) have caused instrument drift. Calibration drift
checks shall be documented on the field data sh eets. If the analyzer is not within the calibration specifications given in 4.1.2, the FID analyzer must be recalibrated.

5.5 Blank/Background Determination: The bl ank checks are especially important for stripping systems that are used on multiple sources and the possibility of cross contamination
exists.
5.5.1 Zero Air Check 5.5.1.1 A zero air check is mandatory before each test, regardless if the system was previously used on a different source or not. 5.5.1.2 Open the zero air supply to the apparatus and adjust rotameter to read
2500 ml/min.
5.5.1.3 Monitor the air effluent from th e apparatus with the FID analyzer to determine the baseline reading of the empty stripping chamber and apparatus. Record the analyzer reading on the data sheet. 5.5.1.4 If the zero air check indicates a background $ 1.0 ppmv as methane in the stripped gas, then the apparatus should be purged thoroughly to remove the contamination until an acceptable background is measured (< 1.0 ppmv as methane).
5.5.2 Water Blank Check. 5.5.2.1 Water blank checks shall be performed by the following schedule: 5.5.2.1.1 A water blank check shall be performed on all stripping apparatus systems, mobile and dedicated systems, before initial use in the field and at least once per month thereafter. 5.5.2.1.2 For mobile systems used on multiple sources, a water blank check between sources is optional (except as noted in 5.5.2.1.3), but is strongly recommended. 5.5.2.1.3 A water blank check is mandatory before beginning a test if the previous test or source for which the stripping apparatus was used indicated a total VOC reading (ppmv as methane in the stripped air) 10 times greater than the applicable allowable emission rate or action level on the current source. See Equation 7-3 in Section 7.4. 5.5.2.2 In order to ensure the entire sampling system is free of contamination, the water blank check is performed through the sampling line and water rotameter. Using either a pump or gravity, fill the stripping chamber with clean distilled water through the sample line and water rotameter until the packing is just submerged. Adjust the water flow rate to 125 ml/min. 5.5.2.3 Restart the air supply and adjust to 2500 ml/min. Monitor the air effluent from the apparatus with the FID analyzer to determine the baselineTexas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-10 reading of the apparatus while the sy stem is flowing with clean water. Record the analyzer reading on the data sheet. 5.5.2.4 If the water blank check indicates a background $ 1.0 ppmv as methane in the stripped gas, then the apparatus should be cleaned and purged thoroughly to remove the contamination until an acceptable background is measured (< 1.0 ppmv as methane). 5.5.2.5 Drain the blank water from the stripping chamber before sampling. 5.5.3 Recommended cleaning procedure. If air and water blanks are not sufficient to remove contamination from the system, the system should be disassembled and the components cleaned thoroughly. 5.5.3.1 The stripping chamber should be cleaned with hot soapy water, followed by 5 rinses of ta p water and 5 rinses of distilled water. The chamber may be baked off at 150 o C for at least 1 hour, if an oven is available large enough to hold the chamber. Otherwise, the chamber will
have to be air dried. 5.5.3.2 The beryl saddles, moisture knoc k-out flask, and Neoprene stoppers should be cleaned with hot soapy water, followed by 5 rinses of tap water, 5 rinses of distilled water, then baked off in an oven at 150 o C for at least 1
hour.
5.5.3.3 TeflonTM and stainless steel tubi ng, unions, and valves that contact water or stripped air sample should be cleaned with hot soapy water, rinsed by flushing with 5 volumes of tap water and 5 volumes of distilled water, then purged with zero air or nitrogen while baked at 150 o C in an oven for at
least 1 hour. Stainless t ubing too long to fit inside an available oven without bending should just be purged with zero air or nitrogen after cleaning. 5.5.3.4 The water rotameter should be cleaned according to the manufacturer’s recommendations, followed by flushing with distilled water and purging with zero air or nitrogen. 5.5.3.5 Some components, such as plastic caps for the knock-out flasks and some valves, may be heat sensitive and may be damaged if baked at 150 o C. Such components should be baked at a lower temperature for longer periods, purged with zero air or nitrogen wit hout heating, or simply air dried, as appropriate.

6.0 Sampling. This method presents two sampling a pproaches; an on-site determination of total VOC using a FID analyzer, and an off-site determination of speciated VOCs by sample collection in sample canisters followed by laboratory gas chromatography. Permit or applicable rule requirements may prohibit using the on-site FID analyzer approach without prior approval by the TCEQ. If the tester wishes to use both the on-s ite total VOC results and the laboratory speciated results for mass emission determinations, then all requirements of both approaches must be followed, including the mid-level calibration for the FID analyzer.Texas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-11 6.1 On-site determination of VOC emissions by FID analyzer. 6.1.1 Connect the water sample supply line to the sample port on the source (i.e., cooling tower return line header). Before connecting the water sample line to the air stripping apparatus water inlet, allow the sample water to flush through the sample line for at least 5 sample line volumes. 6.1.2 With the stripping air flowing at 2500 ml/min to the column, connect the sample line to the water inlet of the air st ripping apparatus and start the sample water flow into the chamber. Sample water fl ow rates higher than 125 ml/min during the filling stages are permissible; however, re duce the flow to 125 ml/min once the beryl saddles are submerged. Adjust the water ove rflow as necessary to maintain the water level just above the beryl saddle packing. The column drain valve should not be used to control the water level, particular ly if the overflow is used to obtain the sample water flow rate as described in Section 4.4.5. Periodically check the water rotameter during sampling for gas bubble formation and the bubbler to assure that
sufficient air flow is maintained. Reco rd a notation in the data sheet comments section if any gas bubbles are observed in the water rotameter. 6.1.3 After the water level in the stripping ch amber has reached the appropriate level and the air and sample water flow rates are set to 2500 ml/min and 125 ml/min, respectively, allow the stripping apparatus system to stabilize for a minimum of 10 minutes before making sample measurements. Longer stabilization time may be required depending on the organic compounds present and the particular water matrix. Before starting the test run record the time required for stabilization, barometric pressure, ambient temperature, and the process water flow rate (i.e., cooling tower water flow rate in gallons per minute). 6.1.4 At two minute intervals, record the FID analyzer measurement, water rotameter flow rate, air rotameter flow rate, and stri pping chamber temperature. Adjust the air and water rotameter flows as necessary to maintain the target flows of 2500 ml/min and 125 ml/min, respectively; however, actua l measured flows must be recorded.
Monitor and record the data for a minimum of ten minutes. 6.1.5 Average the data from Section 6.1.4 and follow the calculations described in Section 7.0 to determine the air strippable concentration and, if applicable, the mass
emission rate of VOCs from the water matrix.

6.2 Off-site determination of VOC by GC an alysis. Samples of the stripped compound(s) may be taken from the exhaust of the air stripping apparatus and analyzed off-site by gas chromatography for speciated VOC results. It is strongly recommended that multiple samples be collected since a sample container may leak or be lost during shipment to the laboratory. 6.2.1 Connect the water sample supply line to the sample port on the source (i.e., cooling tower return line header). Before connecting the water sample line to the air stripping apparatus water inlet, allow the sample water to flush through the sampleTexas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-12 line for at least 5 sample line volumes. 6.2.2 With the stripping air flowing at 2500 ml/min to the column, connect the sample port of the water to be analyzed to the wate r inlet of the air stripping apparatus and start the sample water flow into the chamber. Sample water flow rates higher than 125 ml/min during the filling stag es are permissible; however, reduce the flow to 125 ml/min once the beryl saddles are submerged. Adjust the water overflow as necessary to maintain the water level just above the beryl saddle packing. The
column drain valve should not be used to c ontrol the water level, particularly if the overflow is used to obtain the sample wate r flow rate as described in Section 4.4.5. Periodically check the water rotameter during sampling for gas bubble formation
and the bubbler to assure that sufficient air flow is maintained. Record a notation in the data sheet comments section if any gas bubbles are observed in the water

rotameter. 6.2.3 After the water level in the stripping chamber has reached the appropriate level and the air and sample water flow rates are set to 2500 ml/min and 125 ml/min, respectively, allow the stripping apparatus system to stabilize for a minimum of 10 minutes before making sample measurements. Longer stabilization time may be required depending on the organic compounds present and the particular water matrix. Record the time required for stabilization, barometric pressure, ambient temperature, process water flow rate (i.e., cooling tower water flow rate in gallons per minute), and the total VOC concentration measured by the FID analyzer. 6.2.4 Before collection of a canister sample, check and record the initial canister
vacuum. If the canister vacuum has cha nged by more than 50 mm Hg (2 in Hg) from the initial evacuation, then the canister sha ll be considered as leaking and cannot be
used. 6.2.5 Connect the sample canister to the ai r outlet of the air stripping apparatus with the stripping air flowing and the sample canister valve shut. Excess air flow will be vented through the bubbler. 6.2.6 Open the sample canister valve to begin sampling. During collection, monitor and record the water rotameter flow rate, air rotameter flow rate, and stripping chamber temperature at 2 minute intervals. Adjust the air and water rotameter flows as necessary to maintain the target flows of 2500 ml/min and 125 ml/min, respectively; however, actual measured flows must be recorded. When using an automated flow controller to regulate the flow rate into the sample canister, such as a critical orifice or mass flow controller, se lect a flow rate equivalent to 1/10th the canister volume per minute or less. If th e canister flow rate is controlled manually (i.e., without a critical orifice or other fl ow controller), great care must be taken to not sample at a rate over the stripping air flow rate. For manually controlled sampling, adjust the needle valve such that the change in canister vacuum is between 75 to 125 mm Hg (3 to 5 in Hg) per minute. The canister must be only partially filled to help prevent condensation in the canister. Fill the sample canister until the vacuum gauge reads between 125 and 250 mm Hg subambient pressure (-5 and -10Texas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-13 in Hg). 6.2.7 Once sample collection is complete, r ecord the final sample canister vacuum, sample collection time, and sample ID on the data sheet. Connect the FID analyzer to the stripping chamber air exhaust and record the final total VOC concentration. 6.2.8 Where the possibility of condensibles ex ists in a sample, the sample container may be heated above the stripping cham ber temperature to help assure a representative sample analysis. Copies of field data sheets should be included with the samples so the laboratory is aware of the conditions at which the samples were
collected. 6.2.9 Upon receipt of the sample(s) and prio r to analysis, the laboratory must check and record the vacuum of the canister(s) to determine if any leakage has occurred. Dilution air (meeting the specifications of Section 3.1.1) should only be added to the canister at the laboratory performing the an alysis and after the canister vacuum has
been recorded. 6.2.10 If TedlarTM bags are acceptable (s ee Section 3.5.1) for the target compounds then follow the procedures in Steps 6.2.1 through 6.2.9 with the following exceptions: 6.2.10.1 References to canister vacuum/pressure are not applicable to TedlarTM bags. 6.2.10.2 Flow rate into the sample bag may be controlled by placing a
rotameter downstream of the bubbler a nd controlling the flow rate of the bypass. Maintain a bypass flow of approximately 1.5 to 2.0 liter/min to fill the bag at approximately 0.5 to 1.0 liter/min. 6.2.10.3 TedlarTM bags must be at least 10 liter size. 6.2.10.4 TedlarTM bags shall be filled to approximately 80% capacity during sampling. 6.2.10.5 If sample dilution is required, dilu tion gas should not be added to the bag. Instead, a known volume of gas may be extracted from the bag and
diluted with a known volume of zero air. 6.2.11 The sample(s) obtained for speciation analysis shall be analyzed according to the procedures in either EPA Method 18 (Title 40 Code of Federal Regulations Part 60 Appendix A) or Compendium Method TO-14A (US EPA Compendium of Methods for Determination of Toxic Organic Compounds in Ambient Air, EPA Document Number 625/R96/010B). 6.2.11.1 The target list of compounds for the analyses shall be determined by permit or regulatory requirements. In the absence of such requirements, a target list shall be generated based on a presurvey sample and analysis by GC/MS. Subject to TCEQ approval, process knowledge may also be used to generate a target list for the analysis. 6.2.11.2 All unidentified compounds detected beyond the target compounds shall be quantified based an appropriate surrogate, such as propane. 6.2.11.3 Calibration of the GC system for speciation analyses shall beTexas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-14 

### C M P bc

RT a atm inHg



### = × × ××

×+ × (. )
( ) 0 03342

273 performed according to Section 4.2. 6.2.12 Appropriate chain of custody documents should be completed and accompany all canister and TedlarTM bag samples, even in cases where a single company performs sampling and analysis. 6.2.13 Average the stripping chamber air and water flow rates and the stripping chamber temperature. Follow the calculations described in Section 7.0 to determine the air strippable concentration and, if applicable, the mass emission rate for each compound in the water matrix.

7.0 Calculations.

7.1 Calculation of the concentration of air st rippable compound(s) in the water matrix is by the following equation:

Equation 7-1

Where: a = Sample water flow rate, ml/min. b = Stripping air flow rate, ml/min. c = Concentration of compound in the stripped air, ppmv, from the FID analyzer or GC
results. The total VOC result from the FI D analyzer may be corrected based on the background check from either the zero air or water blank check, but only from the pretest background check. Post-test background checks may include residual
contamination from the current test run. In no case shall the total VOC concentration by the FID analyzer be corrected by more than 1.0 ppmv as methane. C = Concentration of air strippable compound in the water matrix, part-per-million by weight (ppmw). M = Molecular weight of the compound, g/mol. P = Pressure in the stripping chamber, in Hg (typically assumed to be same as atmospheric pressure).
R = 82.054 ml-atm/mol-K. T = Stripping chamber temperature, o C.

The equation is a material balance and the va lue “C” represents the concentration in ppmw of the compound in the water matrix that was stripped and does not represent the total concentration of the compound in the water matr ix prior to air stripping. The concentration of stripped VOC in the air is on a volume basi s, but the concentration of strippable VOC in the water is on a weight basis in a liquid phase; so the concentration value will appear muchTexas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-15 

### ECF hr lb gallon ppm =×× × × 60 8 337 1

1 000 000 min .

, ,

c RT a

P b E ppm

F lb mol atm inHg lb gallon hr 

### ' ( ) . (. ) ', ,

. min 

### = ×+ ×

×× × × ×

× × 273

16 04 0 03342 1 000 000

8 337 60 higher for the air phase.

7.2 Molecular weight. For total VOC based on the portable FID analyzer procedure in Section 6.1, calculate total VOC concentration in the water and emission rate based on the molecular weight of methane, unless an a lternative reference calibration standard is approved by the TCEQ. For speciated VOC re sults based on procedures in Section 6.2, calculate individual compound concentrations and emission rates based on the respective compound molecular weights.

7.3 Calculation of VOC mass emission rate(s) from the concentration of strippable VOCs
in the water and the water circulation rate:

Equation 7-2

Where: C = Concentration of air strippable compound in the water matrix, part-per-million by weight (ppmw). E = Mass emission rate of VOCs, lb/hr. F = Water circulation rate of source, gallons/min.

7.4 Calculation of methane concentration in st ripped air equivalent to a mass emission rate or action level (see Section 5.5.2.1.3). Equati ons 7-1 and 7-2 above are combined as
follows:

Equation 7-3

Where: E’ = Allowable mass emission rate of VOCs or action level, lb/hr. c’ = Methane concentration in the stripped air equivalent to emission limit or action level,

ppmv.Texas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-16 16.04 = Molecular weight of methane, lb/m ol. If a different calibration gas is used for the portable FID analyzer, such as ethylene, use the appropriate molecular weight.

8.0 Use of Portable GC for Field Specia tion Analysis. A portable GC, calibrated for a specific suite of compounds, may be used in place of a FID analyzer, in which case the calculations remain the
same and the final result is the concentrations of speciated air strippable compounds in the water
matrix.

8.1 Setup. Same as Section 5.1, except calibra tion procedures for field GC analysis will
follow Section 4.2.

8.2 Blank/Background Check. Same as Section 5.5. 8.2.1 Note: In some situations where very low detection for specific compounds is required, it may be preferable to check for background using the field GC.

8.3 Sample Measurement. Same as Section 6.1 with the following exceptions: 8.3.1 The FID analyzer can be used during the stabilization period to monitor the air stripping apparatus effluent. Alternatively, the GC can be used to monitor during the stabilization period; however, such an appr oach may drastically increase the time
needed. 8.3.2 A test shall consist of three separate injection/analyses of the stripped gases.

9.0 References. 9.1 Vernon, W. D. et. al., “A Device for Measuring Volatile Organic Carbon Emissions from Cooling Towers Water,” Journal of Air Pollution Control Association, December, 1981, pages 1280-1282.

9.2 United States Environmental Protecti on Agency Method 18 “Measurement of Gaseous Organic Compound Emissions by Gas Chromatogr aphy,” Code of Fede ral Regulations, Title 40, Part 60, Appendix A, as amended through October 17, 2000 (65 FR 61744).

9.3 United States Environmental Protection Agency Method 21 “Determination of Volatile Organic Compound Leaks,” Code of Federal Re gulations, Title 40, Part 60, Appendix A, as amended through October 17, 2000 (65 FR 61744).

9.4 United States Environmental Protection Agency Compendium Method TO-14A “Determination of Volatile Organic Compounds (VOCs) in Ambient Air Using Specially Prepared Canisters with Subsequent Analysis by Gas Chromatography,” Compendium ofTexas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-17 Methods for Determination of Toxic Organi c Compounds in Ambient Air, EPA Document Number 625/R96/010B, January 1999.Texas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-18 

### Air Stripping Apparatus for Strippable VOCs from Water

To FID Analyzer/ Sample Canister

Bubbler (250 ml flask) Vent

Water Overflow Water Level

Stripping Chamber 36" x 3" Packed 26" Deep w/ Beryl Saddles (6 - 8 mm size) Air Rotameter Water Rotameter
Temperature Probe

Moisture Knock-out (250 ml flask) Sample Water In

Stripping Air In

Column Drain Valve Securing Clamp

Neoprene Stopper 1/4" Stainless Steel or Teflon Tubing

Excess Stripped Air Neoprene Stopper

Water Flow Path

Air Flow Path Figure 1Texas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-19 

### Air Stripping Apparatus Stripping Chamber End Cap Design

Temperature Probe

Water Inlet Line (must be centered) Stripped Gas Exit Line Stripping Chamber Top

Top View Side View

Stripped Gas Exit Line

Water Inlet Line (must be centered)

Stripping Chamber Bottom

Top View Side View3 - 4 inches 0.5 inch

0.5 inch 0.25 inch

Stripping Air Inlet Line

(must be centered) Water Drain Line Water Drain Line Stripping Air Inlet Line

(must be centered) Figure 2Texas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-20 Figure 3 

### Air Strippable VOCs in Water FID Analyzer Measurement Data Sheet

Regulated Entity : __________________________ Regul ated Entity No: __________________________

Air Account No: __________________________ Instrument Model: __________________________

Unit Name: __________________________ Instrument Serial No: __________________________

EPN/FIN ID No: __________________________ Operator(s): __________________________

Process Description: _______________________ Certified Gas Value: Zero: ___________________

Date/Time: __________________________ Mid-level: ___________________

Barometric Pressure: ___________________ High-level: ___________________

Process Water Flow: ___________________ FID Response Zero: ___________________

Zero Air Background VOC: ______________ Mid-level: ___________________

Zero Water Background VOC: ______________ High-level: ___________________

Stabilization Time: ___________________ Expected VOC(s): __________________________

Time* Air Stripping Apparatus Data FID Reading (ppmv, wet) Comments Water Flow

(ml/min) Air Flow (ml/min) Temp. ( o C)

Average

* Data recording time (after stabilization period), recorded as actual time of day.Texas Commission on Environmental Quality Appendix P Sampling Procedures Manual

Revision No.: One 1/2003 P-21 Figure 4



### Air Strippable VOCs in Water Canister Sampling Data Sheet

Regulated Entity : __________________________ Regul ated Entity No: __________________________

Air Account No: __________________________ Instrument Model: __________________________

Unit Name: __________________________ Instrument Serial No: __________________________

EPN/FIN ID No: __________________________ Operator(s): __________________________

Process Description: _______________________ Certified Gas Value: Zero: ___________________

Date/Time: __________________________ High-level: ___________________

Canister ID: __________________________ FID Response Zero: ___________________

Sample ID: __________________________ High-level: ___________________

Barometric Pressure: ___________________ Zero Air Background VOC: ___________________

Ambient Temperature: ___________________ Zero Water Background VOC: ___________________

Stabilization Time: ___________________ Expected VOC(s): __________________________

Process Water Flow: ___________________

Time* Air Stripping Apparatus Data Canister Flow Rate, if applicable

(cc/min) Canister
Vacuum (mm Hg) FID Reading, (ppmv, wet) Comments
Water (ml/min) Air (ml/min) Temp. ( o C)

Average

* Data recording time (after stabilization period), recorded as actual time of day.