# Procedure Z: Quality Assurance Requirements for X-Ray-Fluorescence Based Multi-Metals Continuous Emission Monitoring Systems at Stationary Sources



# DRAFT

June 9, 2005

Submitted to: The Environmental Protection Agency Research Triangle Park, NC

Prepared by: Cooper Environmental Services, LLC 10180 SW Nimbus Blvd Suite J6 Portland, Oregon 97223

# Procedure Z: Quality Assurance Requirements for X-Ray-Fluorescence Based Multi-Metals Continuous Emission Monitoring Systems at Stationary Sources



# DRAFT

June 9, 2005

Prepared by: J.A. Cooper, K. Petterson, B.E. Johnsen, C. A. Yanca, M. Nakanishi, D. Barth

Prepared by: Cooper Environmental Services, LLC 10180 SW Nimbus Blvd Suite J6 Portland, Oregon 97223

# Procedure Z: Quality Assurance Requirements for X-Ray-Fluorescence Based Multi-Metals Continuous Emission Monitoring Systems at Stationary Sources

Prepared by:___________________________________ Date:_________ Krag A. Petterson, Environmental Scientist Reviewed by: ___________________________________ Date:_________ Cay A. Yanca, Environmental Scientist Reviewed by: ___________________________________ Date:_________ Bruce E. Johnson, QA Manager Approved by: ___________________________________ Date:________ John A. Cooper, DirectorQuality Assurance for XRF Based Multi-Metals CEMS (Procedure Z ) Page i of iv 

### Executive Summary Procedure Z outlines the continuing quality control and quality assurance requirements for an x-ray fluorescence based multi -metal CEMS. Procedure Z requires daily checks of the upscale, zero and vol ume measurement drift. It al so specifies quarterly checks of the x-ray fluorescence calibration and of the volume measurement calibration. Finally procedure Z requires that the entire XRF multi metal CEMS accuracy be verified on an annual basis.Quality Assurance for XRF Based Multi-Metals CEMS (Procedure Z ) Page ii of iv 

### List of Symbols
b o = The y intercept of the best fit line b 1 = The slope of the best fit line

i CA = X-ray fluorescence calibration accuracy

C i C = Corrected CEMS concentration for the i th element

CEMS i C = The concentration of the i th element as reported by the CEMS

CEM i C = The average reported concentration of the CEMS for the i th element

PT i CF = Correction factor for pe rcent transport for the i th element

RB i CF = The relative bias corr ection factor for the i th element

L i C = The emission limit of the i th element

S i C = Concentration of the i th element at the stack

sm i C = Concentration of the i th element at the sampling module or as reported by the XRF multi-metals CEMS.

i d = Difference between two paired measurements
d = Arithmetic mean of differences FS = Full scale value of your CEMS volume (or flow) measurement device

0 i L = The calibrated value of the i th element on the zero standard

cem i L = The value of the standard reported by your CEMS

cemo i L = The measured CEMS response to the zero standard for the i th element

cemu i L = The measured CEMS response to the i th element in the upscale standard

std i L = The known value of the XRF calibration check standard

u i L = The value of the i th element of the upscale standard

n = Number of data points

i PT = The percent transport of the i th elementQuality Assurance for XRF Based Multi-Metals CEMS (Procedure Z ) Page iii of iv i PT = Average percent transport for the i th element PRB i = Percent relative Bias of the i th element

RM i R = The average of the reference method measurements for the i th metal

i PRSD = The relative percent standard deviation for the i th metal

r = The correlation coefficient SD i = The standard deviation of differences for the i th element V

cemr = Sample gas volume (or flow) as measured by the CEMS volume check device VD = Volume drift V

m = Volume (or flow) reported by your multi-metals CEMS

i UD = The upscale drift of the i th element on your CEMS in percent.

x = Arithmetic mean

x i = Value of each data point y i = CEMS reported concentration for the i th element ZD i = The zero drift of the i th element on your CEMS in percentQuality Assurance for XRF Based Multi-Metals CEMS (Procedure Z ) Page iv of iv 

### Table of Contents Executive Summary.............................................................................................................. ..... i List of Symbols................................................................................................................ ......... ii Table of Contents.............................................................................................................. ....... iv 1.0 Using Procedure Z .......................................................................................................... . 1 1.1 What is the purpose and app licability of Procedure Z?............................................. 1 1.2 What are the basic requirements of Procedure Z ? ..................................................... 1 1.3 What special definitions apply to procedure Z? ........................................................ 1 2.0 Interferences, Safety, a nd Equipment Requirements....................................................... 2 2.1 What interferences are asso ciated with procedure Z? ............................................... 2 2.2 What do I need to know to ensure the safety of persons using Procedure Z? ........... 2 2.3 What equipment and supplies do I need? .................................................................. 3 2.4 What reagents and standards do I need?.................................................................... 3 2.5 What sample collection, preservation, stor age, and transport proc edures are relevant to Procedure Z? ............................................................................................................... 4 3.0 Quality Control, Calibration, and Standardization .......................................................... 4 3.1 What quality control measures are requi red by this procedure for my multi-metal CEMS? .......................................................................................................................... .. 4 3.2 What calibration checks and audit proce dures must I perform for my multi-metal CEMS? .......................................................................................................................... .. 4 4.0 Calculations ............................................................................................................... ...... 7 4.1 What calculations and data analysis must I perform?................................................ 7 4.2 What waste management procedures are required for procedure Z?....................... 13 5.0 Other Requirements and Information ............................................................................ 13 5.1 What pollution prevention measures mu st I take when using procedure Z?........... 13 5.2 What criteria are necessary for my XR F multi-metal CEMS to be in control and what do I do if it is out of control?................................................................................ 13 5.3 What tables, diagrams and flow char ts are relevant to Procedure Z?...................... 16 5.4 What references are relevant to Procedure Z? ......................................................... 18Quality Assurance for XRF –Based Multi-Metal CEMS (Procedure Z ) Page 1 of 1 

### 1.0 Using Procedure Z
1.1 What is the purpose and applic ability of Procedure Z? The purpose of Procedure Z is to establish the minimum requirements for quality control (QC) and quality assurance (QA) procedures for x-ray fluorescence (XRF) based multimetals CEMS. These quality control and quality assurance procedures are in place to ensure the accuracy and validity of the data reported by your multi-metal CEMS for emission compliance purposes. You must meet these mini mum requirements if you plan to use your multi-metal CEMS for reporting purposes, howev er, we encourage you to develop a more extensive QA program or to continue with su ch programs where they already exist. Any XRF multi-metals CEMS used to report to us, th e state, or a local enforcement agency must comply with procedure Z immediately after the completion of the initial performance specification test outlined in Performance Specification YY 1

. 1.2 What are the basic requir ements of Procedure Z ? Procedure Z requires you to perform several drift checks and audits which ensure the accuracy of the data reported by your XRF mu lti-metals CEMS. You are required to, on a daily basis, record and calculate zero drift, upscale drift, a nd, a sample volume drift. On a quarterly basis you are required to perform an XRF calibration audit (XFCA) and a sample volume audit (SVA). On an annual basis you are required to execute eith er a linearity audit (LA) or a relative bias audit ( RBA) and, if applicable, a trans port efficiency audit (TEA). The criteria for passing these audits and drift ch ecks are outlined in pr ocedure Z. Procedure Z also summarizes the requirements for when and if your CEMS fails an audit or drift test. Finally, Procedure Z also covers the requirements for and timelin es associated with periods when your XRF multi-metals CEMS is out of control.
1.3 What special definitions apply to procedure Z? Linearity Audit: (LA) An assessment of the validity of the original line ar correlation of your CEMS. Reference material: A material of known value used to check the calibration drift of your XRF multi-metal CEMS. Relative Bias: The difference between a reference method or aerosol concentration and the concentration recorded by your CEMS divide d by the concentration of the reference measurement. Relative Bias Audit: (RBA) An assessment of the bias in your CEMS. Sample Interface: The portion of the CEMS used for one or more of the following: sample acquisition from the stack or duct effluent, sample transport, sample conditioning, or protection of the monitor from the effects of stack gas.Quality Assurance for XRF Based Multi-Metals CEMS (Procedure Z ) Page 2 of 2 Sample Module: The portion of the XRF multi-metal CEMS that traps the metals and delivers them to the x-ray fluorescence module. Standard Volume Audit: (SVA) This is an evaluation of your XRF multi-metals CEMS sample volume measurement system. This is required if your CEMS uses a volume measurement to report metal concentrations and is accomplished by comparing the volume measured by your CEMS with the volume meas ured by an independently calibrated device. Transport Efficiency Audit: (TEA) An assessment of the transport efficiency of the sample interface of your multi-metals CEMS. This audi t applies to your XRF multi-metals CEMS if either the RBA or LA challenged only the sampling and XRF modules. Transport System: The portion of the CEMS that tran sports a representative sample of source effluent from the sample probe to the sample module. X-Ray Fluorescence Calibration Audit: (XFCA) This is an evaluation of how well the xray fluorescence portion of your multi-metals CEMS has maintained its original calibration. This is accomplished by challenging th e XRF module with a standard of known concentration for each metal measured by your CEMS for compliance. The analyzer response is compared with the know n concentration of the standard. X-Ray Fluorescence Module: The portion of an XRF based multi-metal CEMS which identifies and measures metal masses or concentrations using x-ray fluorescence. XRF Multi-Metals Continuous Emission Monitor (CEMS): All of the equipment required for determining metal concentrations using x-ra y fluorescence as an analytical technique.The system may consist of several major subsystems including the sample interface, the xray fluorescence module, the volume measuremen t module, diluent analyzer, data recorder, and sampling module. 

### 2.0 Interferences, Safety, and Equipment Requirements
2.1 What interferences are associated with procedure Z? There may be interferences arising from the x -ray fluorescence, the trapping media, or from condensation in the effluent gas. Check with your multi-metal CEMS manufacturer to find out more about poten tial interferences.
2.2 What do I need to know to ensure the safety of persons using Procedure Z? Persons using procedure Z may be exposed to hazardous materials, equipment, and operations. Procedure Z does not pu rport to address all of the sa fety issues associated with its use. It is your responsibil ity to establish appropriate safe ty and health practices before using this procedure. You may consult with your CEMS manual and/ or manufacturer for precautions specific to your multi-metal CEMS. If standard reference methods are used then you may also consult the appr opriate reference methods to address safety concerns.Quality Assurance for XRF Based Multi-Metals CEMS (Procedure Z ) Page 3 of 3 2.3 What equipment and supplies do I need? [reserved]
2.4 What reagents and standards do I need? Reference materials for the zero and upscale drifts along with a reference measurement device for the sample volume check.
2.4.1 Zero drift reference Every XRF multi-metals CEMS must be equipp ed with a zero reference that can be checked on a daily basis. This referen ce should produce a CEMS response indicating the absence of metals. If this is not f easible this standard should produce a value between zero and 20% of the emission limit fo r at least two elemen ts measured by your XRF multi-metals CEMS when the instrument is operating appropriately.
2.4.2 Upscale drift reference The reference for the upscale drift check s hould generate a response for at least one metal from each condition used in the XRF an alysis. This response must be at least 80 percent of the emission limit.
2.4.3 Sample volume or flow check If your XRF multi-metals CEMS makes volum e or flow measurements it must be equipped to perform a daily sample volume check.
2.4.4 Sample volume audit standard If your XRF multi-metals CEMS makes vol ume or flow measurements, periodic standard volume or flow audits must be performed. An independently calibrated volume or flow measurement device or standard such as a Dry Cal ® is required for these audits. The standard must be able to acquire a volume or flow measurement at sampling rates typical of your XRF multi-metals CEMS.
2.4.5 X-ray Fluorescence Calibration Check Standards
Your XRF multi-metals CEMS must in clude a means of checking the x-ray fluorescence calibration against an external standard. NIST traceable thin film standards are an example of a suitable x-ra y fluorescence calibra tion check standard.
2.4.6 Reagents and standards for the Linearity Au dits and Relative Bias Audits You will need other reagents and standards for th e linearity audit or relative bias audit. The regents and standards required will differ depending on how these audits are performed.Quality Assurance for XRF Based Multi-Metals CEMS (Procedure Z ) Page 4 of 4 2.4.7 Regents and standards for the Tr ansport Efficiency Audit The regents and standards fo r the transport efficiency audit also depend upon how the audit is performed.
2.5 What sample collection, pres ervation, storage, and transpor t procedures are relevant to Procedure Z? [reserved]



### 3.0 Quality Control, Calibration, and Standardization
3.1 What quality control measures are required by this procedure for my multi-metal CEMS? You must develop and implement a quality c ontrol program that, at a minimum includes detailed written procedures for all of the following activities. 1. Procedures for performing drift checks on a daily basis, includ ing but not limited to, zero drift, upscale drift, and sample volume measurement drift. 2. Procedures and methods of adjusting your multi-metal CEMS in response to the results of the drift checks. 3. Preventative maintenance of your XRF multi-metals CEMS. 4. Data recording, calculations, and reporting. 5. Procedures for required audits, including tr ansport efficiency audits (if necessary), linearity audits, and relative bias audits. 6. Procedures for adjusting your CEMS based on audit results.
7. A program of corrective action and stack ope ration procedures in case of a CEMS malfunction and an out of control period. You are required to keep written document ation of your QA/QC procedures on record and available for inspection for the life of th e CEMS or until you ar e no longer subject to the requirements of this procedure. If you fail two consecutive audits you must revise your QA/QC procedures.
3.2 What calibration checks and audit procedures must I perform for my multi-metal CEMS?
3.2.1 Daily drift check procedures
Your XRF multi-metals CEMS must have the capacity to perform each of the following checks on at least a daily basis.Quality Assurance for XRF Based Multi-Metals CEMS (Procedure Z ) Page 5 of 5 • Zero drift: You must check the zero drift to ensure the stabili ty of your CEMS response to the zero drift reference. Th e zero drift must be less than plus or minus 20% of the emission limit each da y. Follow your CEMS manufacturer’s instructions for proper zero drift check procedures.

• Upscale drift: You must check the upscale drift to ensure the stability of your XRF multi-metal CEMS response to the ups cale standard. The daily upscale drift must be less than 15% of th e upscale reference value determined immediately after the x-ray fluorescence module has been calibrated. Follow your CEMS manufacturer’s instructions for pr oper upscale drift check procedures.

• Daily volume or flow check: You must check the sample volume or flow measurement to verify the accuracy of the volume measurement on your CEMS. This volume check must be done at the normal sampling rate for the CEMS. Your CEMS is out of control if the one day value exceeds 20% of the full scale of the volume or flow meas urement device. Follow your CEMS manufacturer’s inst ructions for proper volume or flow check procedures.
3.2.2 Audit procedures Audit procedures and criteria are listed below. These requirements are also summarized in Table 1 in section 5.3.
1. X-Ray Fluorescence Calibration Audit (XFCA): You must perform an XFCA once each quarter. To perform an XFCA you must challenge the x-ray fluorescence module of your multi-metal CEMS with a standard of known concentration for each metal measured by your CEMS for compliance purposes and compare the value reported by the CEMS with the known value of the standard. If you wish you may make onl y one measurement of a standard for each element. If your multi-metal CE MS fails on the initial measurement you may make two more measurements of each standard and average all three measurements. If the average CEMS response over the three measurements deviates by less than 10% from the know n standard the CEMS has passed the XFCA. If the average exceeds 10% your CEMS has failed the XFCA and is out-of-control. You must follow the pr ocedures outlined in Section 5.2. An XFCA is required once per quarter. The minimum allowed time between each audit is two months and the maximu m allowed time is four months. 2. Sample volume (or flow) audit (SVA): You must perform a sample volume audit of your XRF multi-metals CEMS at least once per quarter and prior to any linearity or relative accuracy a udit. To perform an SVA you must independently measure the volume of sample gas extracted from the stack or duct over the sampling period. You may ma ke this measurement either at the inlet or outlet of your CEMS. You must make volume measurements during three different sampling cycles and the measurements must be able to make corrections for moisture content if necessary.Quality Assurance for XRF Based Multi-Metals CEMS (Procedure Z ) Page 6 of 6 If your CEMS measures flow and totali zes that flow to determine volume you may perform a flow audit instead. You must make flow measurements during three different sampling cycles and fo r each sampling cycle you must make at least 3 to 5 simultaneous measurements of flow on your CEMS and on the independent flow measurement device. You must calculate the error from each set of measurements according to equa tion 6 and then calculate the average error in the flow during each sampling period. Finally you must calculate the average error from all three sampling periods and this average must be less than 10% of the independent flow or volume measurement device. A sample volume audit is required on a quarterly basis. The minimum required time between each SVA is at least two months while the maximum allowed time between audits is four months. Accuracy Audits: As outlined in Performance Specification YY it is acceptable during the initial performan ce specification test to assess the accuracy and precision of the XRF a nd sampling modules of your XRF multimetal CEMS separately from the samp le interface. You may also do this during the Linearity or Relati ve Bias Audits that are required for Procedure Z. If you choose to challenge the sampli ng module and XRF systems separately from the sampling interface you must also perform a Transport Efficiency Audit (TEA). If you challenge the en tire XRF multi-metals CEMS during the Linearity and Relative Bias Audits you are not required to perform an independent check of the CEMS trans port efficiency. For the purposes of Procedure Z you are required to perform either a linearity audit or a relative bias audit, but not both. You are also not required to perform the same kind of tests for the audit as were perfor med during the initi al performance specification test. For example, if a linearity test was pe rformed during the initial accuracy tests, either a relativ e bias audit or a linearity audit is acceptable. There are four different options availa ble for the accuracy audits depending on whether or not a linearity or relative bias audit is performed and depending on whether or not the entire CEMS is challenged by the audit. The audit requirements are listed below. Linearity Audits Option A In this option a linearity audit is perf ormed on the entire CEMS. The types of metals generation and their associated requirements are identical to those for Option A in performance specification YY section 3.1.4. 1 If you do not meet the linearity criteria you must apply a correction according to the procedures outlined in performance specification YY. 1 Option B In this option a linearity audit is pe rformed on the sampling and XRF modules of the CEMS separately from the samp le interface. The types of metals generation and their associat ed requirements are identical to those for Option BQuality Assurance for XRF Based Multi-Metals CEMS (Procedure Z ) Page 7 of 7 in performance specification YY section 3.1.4. 1 A transport efficiency audit must also be completed. Relative Bias Audit Option C In this option a relative bias audit is pe rformed on the entire CEMS. The types of metals generation and their associated requirements are identical to those for Option C in performance specification YY section 3.1.4. 1 If your CEMS fails to meet the criteria you must apply a correction factor according to the procedures in performance specification YY. 1 Option D In this option a relative bias audit is performed on the sampling and XRF modules of the CEMS separately from the sample interface. The types of metals generation and their associated requirements are identical to those for Option D in performance specification YY section 3.1.4. 1 A transport efficiency audit must also be completed. An accuracy audit is required on an annual basis. The minimum time between successive accuracy audits is 9 months while the maximum allowed time is 15 months. 3. Transport Efficiency Audit (TEA): You are required to perform a TEA only if you choose to challenge the sampli ng and XRF modules of your XRF multimetals CEMS separately from the sampling interface. The procedures for performing a TEA are the same as those for determining the transport efficiency during the initial perf ormance specification test a nd are outlined in Performance Specification YY 1 . If the transport efficiency of your CEMS is between 90 and 110 percent no correction is n ecessary. If your transport efficiency is less than 90 percent or greater than 110 percent then you must establish a correction factor according to the procedures outlined in section 3.1.7 of Performance Specification YY 1 . The minimum time between successive transport efficiency tests is 9 months while the maximum allowed time is 15 months. 

### 4.0 Calculations
4.1 What calculations and data analysis must I perform?
4.1.1 Arithmetic Mean
Calculate the arithmetic mean of a data set as follows 

# ∑ = i x n x 1 Equation 1

Where :

x = Arithmetic mean

n = Number of data pointsQuality Assurance for XRF Based Multi-Metals CEMS (Procedure Z ) Page 8 of 8 x i = Value of each data point
4.1.2 Arithmetic Mean of Difference
To calculate the arithmetic mean of differe nce use the above equation substitute d for x
. Then

i i i y x d

− = Equation 2
Where x and y are paired data points fr om the CEMS and either the reference aerosol or the reference method.
4.1.3 Daily Zero Drift

100 0 × −
= L i i cemo i i C L L ZD Equation 3

Where: ZD i = The zero drift of the i th element on your CEMS in percent

cemo i L = The measured CEMS response to the zero standard for the i th element

0 i L = The calibrated value of the i th element on the zero standard

L i C = The emission limit of the i th element
4.1.4 Daily Upscale Drift

100 × −
= u i u i cemu i i L L L UD Equation 4

Where:

i UD = The upscale drift of the i th element on your CEMS in percent.

cemu i L = The measured CEMS response to the i th element in the upscale standard

u i L = The calibrated value of the i th element of the upscale standard
4.1.5 Daily Sample Volume Check

100 × − = FS V V VD m cemr Equation 5

Where:Quality Assurance for Batch Multi-Metals CEMS (Procedure Z ) Page 9 of 9 VD = Volume drift V

cemr = Sample gas volume or flow m easured by the CEMS volume or flow check measurement device V

m = Sample gas volume or flow reported by your multi-metal CEMS FS = Full scale value of the CEMS volume measurement device
4.1.6 Sample Volume Audit Accuracy

100 × − =

r m r V V V VA Equation 6

Where: VA = Volume or flow measurement accuracy V

r = Sample gas volume or flow measured by the independent calibrated reference device V

m = Sample gas volume or flow reported by your multi-metal CEMS
4.1.7 X-Ray Fluorescence Calibr ation Audit Calibration

100 × −
= std i std i cem i i L L L CA Equation 7

Where:

i CA = X-ray fluorescence calibration accuracy

cem i L = The value of the standard reported by your CEMS

std i L = The known value of the standard
4.1.8 Relative Bias

100 × = RM i i i R d PRB Equation 8

Where i d is the mean difference, RM i R is the average of the reference method set or reference aerosol concentration for the i th element, and PRB i is the relative bias for the i th element
4.1.9 Transport EfficiencyQuality Assurance for XRF –Based Multi-Metals CEMS (Procedure Z ) Page 10 of 18 100 × = S i sm i i C C PT Equation 9
Where:

S i C = Concentration of the i th element at the stack

sm i C = Concentration of the i th element at the sampling module or as reported by the XRF multi-metals CEMS.

i PT = The percent transport of the i th element Report the average percent transport ( P T ) of all measurements for each element that was tested (only one el ement is required though more can be tested).
4.1.10 Linearity Audit – Least S quares Linear Regression Calculate the linear correlat ion equation given below.

x b b y o 1 ˆ +

= Equation 10
Where: b o = The y intercept b 1 = The slope The intercept is calculated according to the following equation.

x b y b o 1 − = Equation 11
Where: 

# ∑

= = n

i i x n x 1 1 

# ∑

= = n

i i y n y 1 1

The slope of the line is calcul ated according to equation below.



## ∑ ∑

= =

− − −

= n

1 i 2 i n

1 i i i
1 ) x x ( ) y y )( x x ( b Equation 12

The linear correlation coefficient is calcul ated according to the following equation.Specifications for Batch Multi-Metals CEMS (PS-YY ) Page 11 of 18 

## ∑ ∑

∑

= = =

− − −

−

= n

i i n

i i n

i i i

y y x x y y x x
r

1 2
1 2

1 ) ( ) ( ) )( ( Equation 13

4.1.11 Standard Deviation (of differences)

1 1 2 2

− ∑ ∑

−

= ⎟ ⎠ ⎞ ⎜ ⎝ ⎛

n d

n d SD i i
i Equation 14

Where: SD i = The standard deviation of differences for the i th element

n = The number of data points d i = The difference between the concentration measured by the reference method or the concentration of the reference aerosol and the CEMS reported concentration.
4.1.12 Percent standard deviation

100 × = RM i i i R SD PRSD Equation 15

Where:

RM i R = The average of the reference method data set for the i th element

i PRSD = The relative percent standard deviation for the i th metal

4.1.13 Linearity Test Correction Factors (Applic able only when the linearity test challenges the entire CEMS)
1. Correction equation if CEMS does not meet either the slope or the intercept criteria.

1 0 b b y C i

C i − = Equation 16

Where:Quality Assurance for XRF Based Multi-Metals CEMS (Procedure Z ) Page 12 of 18 C i C = Corrected CEMS concentration for the i th element
y i = CEMS reported concentration for the i th element b 0 = The intercept of the least squares linear regression line b 1 = The slope of the least squares linear regression line

2. Correction factor if CEMS meets inte rcept criteria, but does not meet the slope criteria.

0 b y C i

C i − = Equation 17
3. Correction factor if CEMS meets slope criteria but does not meet intercept criteria.

1 b y C i

C i = Equation 18

4.1.14 Relative Bias Correction Factors

CEM i RM i

RM i i RB i C R

R

d CF = + = 1 1 Equation 19

Where:

RB i CF = The relative bias co rrection factor for the i th element

CEM i C = The average reported concentration of the CEMS for the i th element

RM i R = The average of the reference method measurements for the i th metal
4.1.15 Percent transport correction factor

i PT i PT CF 1

= Equation 20

Where

PT i CF = Correction factor for percent transport for the i th element

i PT = Average percent transport for the i th elementQuality Assurance for XRF Based Multi-Metals CEMS (Procedure Z ) Page 13 of 13 4.2 What waste management procedures are required for procedure Z? All chemicals used to produce a reference aeroso l or in performing standard methods need to be disposed of properly. Please cons ult the appropriate reference methods.



### 5.0 Other Requirements and Information
5.1 What pollution prevention measures must I take when using procedure Z? [reserved]
5.2 What criteria are necessary for my XRF mu lti-metal CEMS to be in control and what do I do if it is out of control?
5.2.1 Required Corrective Action for Drift Checks and Audits

• Daily Zero Drift: If the one day drift exceeds 20% you are required to rerun your zero drift reference. If the XR F multi-metal CEMS m eets the criteria during the second test you may continue to operate. If the CEMS fails to meet the zero drift criteria again then it is out of control. It is recommended that you examine the zero drift standard for def ects. After repairs to the CEMS are completed you are required to perform at least five successful zero drift checks within a 24 hour period. After the fi ve checks have been successfully completed then you CEMS is in control. If the repairs were made to the XRF module of the multi-metals CEMS you are also required to complete an x-ray fluorescence calibration audit (XFCA) to verify the accuracy of your x-ray fluorescence calibration.

• Daily Upscale Drift: If the one day drif t exceeds 15% you are required to retest the upscale drift reference. If the XRF multi-metals CEMS meets the criteria during the second test you may continue to operate, however, if the CEMS fails the second upscale drift check it is out of control. It is recommended that you examine the upscale drift standard for defects. After repairs to the CEMS are completed you are required to perform at least five successful upscale drift checks within a 24 hour period. After the five drift checks are successfully completed the CEMS is back in control. Again, if repairs were made to the XRF module of the multi-metal CEMS you are also required to successfully complete an x-ray fluorescence calibration audit (XFCA) to verify the accuracy of the calibration.

• Daily Sample Volume Check: If your sample volume or flow drift exceeds 20% it has failed the daily volume check and you must perform another daily volume check. If the CEMS passes the second check you may continue to operate. If your CEMS fails the second te st it is out of control and your CEMS must be repaired. After repairs have been made the CEMS must successfully complete five sample volume checks w ithin a 24 hour period. Upon successful completion of the five checks your CEMS is back in control. If the repairsQuality Assurance for XRF Based Multi-Metals CEMS (Procedure Z ) Page 14 of 14 were made to a volume or flow measur ement device you are also required to successfully complete a sample volume audit (SVA).

• Quarterly Sample Volume Audit (SVA): Your XRF multi metals CEMS is out of control if volume (or flow) meas ured by your CEMS differs from that measured by the independent standard by mo re than 10% percent. A failure of this audit may indicate that repairs need to be made to the volume measurement system. Upon completion of these repa irs you must perform and pass another SVA.

• Quarterly X-Ray Fluorescence Calibration Audit (XFCA): The response of your XRF multi-metals CEMS must be with in 10% of the standard’s value for each metal measured for compliance purposes by your CEMS. If your CEMS fails the XFCA initially, rerun each standard two more times and take the average of the three measurements. If the average CEMS response meets the XFCA criteria you may continue to operate, however, if the CEMS fails to meet the criteria then it is out of control. After the CEMS has been repaired you must complete another XFCA. Upon su ccessful completion of the XFCA the CEMS is back in control.

• Annual CEMS Accuracy Tests Linearity Audit Option A (Linearity audit of the entire CEMS). If you challenge the entire CEMS system (including sampling interface and the sampling and XRF modules) with a linea rity audit you do not need to apply a correction factor to your CEMS data if it meets the following criteria:
1. a slope between 0.85 and 1.15
2. the correlation coefficient equal to 0.90 or more 3. an intercept of less than 20 percent of the emission limit If your CEMS does not meet the slope or intercept criteria you must apply a correction factor according to the pr ocedures described in Performance Specification YY Section 4.2.12. 1 Your CEMS, however, must still meet the correlation criteria. If your CEMS fails the linearity test it is out of control. After the necessary repairs are made it must pass a linearity or relative bias test to be considered back in control. Option B (Linearity audit of the sampling module and XRF module only followed by a TEA) If you challenge the sampling and XRF modules separately from the sample interface, your XRF multi-metal CEMS is out of control if the linear least squares regression analysis of your aud it data does not meet the following criteria for each of the metals measured by your CEMS for compliance purposes:Quality Assurance for XRF Based Multi-Metals CEMS (Procedure Z ) Page 15 of 15 1. a slope between 0.85 and 1.15
2. the correlation coefficient equal to 0.90 or more 3. an intercept of less than 20 percent of the emission limit If your XRF multi-metals CEMS fails a linearity audit you must make the necessary repairs to your CEMS and successf ully complete either a relative bias audit or a linearity audit before it is c onsidered to be back in control. You must also complete a transport efficiency audit (TEA) along with your linearity audit. Relative Bias Audit Option C (Relative bias test of the entire CEMS) If your CEMS meets the following criteria it has passed the relative bias audit and you do not need to apply a correction factor to your CEMS.
1. the percent relative bias ( PRB ) exceeds 15%
2. the percent relative standard deviation( PRSD) exceeds 10% 3. the correlation coefficient (r) for linearit y portion of the relative bias audit is less than 0.90 If your XRF multi-metals CEMS fails to meet the relative bias criteria you may apply a correction factor according the procedures described in performance specification YY Section 4.2.13 1 . However, if your CEMS fails to meet either the percent relative standard deviation criteria or the correlation coefficient criteria it is out of control. If your XRF multi-metal CEMS fails a relative bias audit it must successfully compete another linearity or relative bias audit to be considered in control. Option D (Perform a relative bias test on the sampling and XRF modules) Your XRF multi-metals CEMS is out of control if:
1. the percent relative bias ( PRB ) exceeds 15% 2. the percent relative standard deviation( PRSD) exceeds 10% 3. the correlation coefficient (r) for linearit y portion of the relative bias audit is less than 0.90 You must successfully complete another RBA or a linearity audit before your CEMS is considered to be in control. You must also successfully complete a transport efficiency audit along wi th the relative bias audit. Transport Efficiency Audit (TEA): A TEA is only required if you challenge your sampling XRF modules separately fr om your sample interface (Options B and D). If the percent transport is between 90 and 110 percent no correction factor is necessary, however, if the percent transport is less than 90 percent or greater than 110 percent then you must apply a correcti on factor to the results reported by your multi metal CEMS. The procedures for applying a correction factor using the equation in Section 4.1.15.Quality Assurance for XRF Based Multi-Metals CEMS (Procedure Z ) Page 16 of 16 5.2.2 General out of control guidelines

• Out of control period: The out of control period begins immediately after the failed drift test or audit and is ove r immediately following the successful completion of required procedures associated with the failure of the audit test. During the out of control period you may not use the data generated by your XRF multi-metal CEMS for compliance purposes.

• Reporting guidelines: You must include in your repor t to us, the state, or local enforcement agency the results of the fa iled audit or drift check, the corrective action that was taken, and th e results of the successful audit or drift check.

• Rules governing auditing time periods: The X-Ray Fluorescence Calibration Audit (XFCA) and the Sample Volume Audit (SVA) are required once a quarter. Two months must pass between successive quarterly audits and no more than four months may pass.. Th e Linearity Audit (LA) and the Relative Bias Audit (RBA) are required on an a nnual basis. Successive LAs and RBAs must be separated by at least nine mont hs and no more than 15 months.
5.3 What tables, diagrams and flow charts are relevant to Procedure Z?Quality Assurance for XRF Based Multi-Metals CEMS (Procedure Z ) Page 17 of 17 Table 1: Continuing QA Procedures for XRF Multi-Metals CEMS Test Frequency Test Test Procedures Passing Criteria

Zero Drift Check zero standard and calculate drift < 20% drift each day Upscale Drift Check upscale standard and calculate drift < 15% drift each day Daily Volume or Flow Drift Check flow drift and calculate drift < 20% drift each day X-Ray Fluorescence

Calibration Audit Test a standard for each element measured for compliance by your CEMS (1 time per standard) • < 10% difference for every element measured for compliance by your CEMS
• If criteria not initially met you may take the average of 3 measurements Quarterly Sample Volume (or Flow) Audit Volume
• Compare CEMS volume against a standard during 3 sampling cycles
• Average all three Flow
• 3 to 5 flow measurements with standard and CEMS per sample cycle
• Measure in 3 CEMS sample cycles
• Calculate average difference between CEMS and standards over all measurements <10% difference from the standard

Option A Perform a linearity test on entire CEMS • At least one metal from each category
• Need at least 3 concentration levels which include a 2 fold conc. change and the emission limit
• If spiking, spike into source, or spike into transport line as close as possible to the probe • Slope = 0.85 to 1.15
• r > 0.90
• intercept < 20% of emission limit
• if above criteria is met then no correction
• if not met apply a correction Option B

• Perform a linearity test on sampling and XRF modules only
• Determine transport efficiency separately • At least one metal from each category
• Need at least 3 concentration levels which include a 2 fold conc. change and the emission limit
• Spike or measure concentrations with reference method as close as possible to the sampling module Linearity Criteria
• Slope = 0.85 to 1.15
• r > 0.90
• intercept < 20% of emission limit
• the linearity criteria must be met Percent Transport Criteria
• 90< PT< 110
• If percent transport criteria are not met apply a correction factor Option C
Perform a relative bias test on entire CEMS • At least one metal from each category at 80 to 120 percent of emission limit
• One other metal at 3 conc. levels which include a 2 fold conc. change and the emission limit
• If spiking, spike into source or spike into transport line as close as possible to the probe • Percent relative Bias
• RB< 15%
• %RSD < 10%
• r > 0.90 for metal with three fold conc. change
• If Criteria not met apply a correction factor (correlation coefficient criteria must be met Annually

Option D

• Perform a relative bias test on sampling and XRF modules only
• Determine transport efficiency separately • At least one metal from each category at 80 to 120 percent of emission limit
• One other metal at 3 conc. levels which include a 2 fold conc. change and the emission limit
• Spike or measure concentrations with reference method as close as possible to the sampling module Percent Relative Bias Criteria
• RB< 15%
• %RSD < 10%
• r > 0.90 for metal with three fold conc. change Percent Transport Criteria
• 90< PT< 110
• If percent transport criteria are not met apply a correctionQuality Assurance for XRF Based Multi-Metals CEMS (Procedure Z ) Page 18 of 18 5.4 What references are rel evant to Procedure Z? 1. Performance Specification YY: Specificati ons and Test Procedur es for Batch MultiMetals Continuous Emission Monitoring Sy stems at Stationary Sources. 2005.