( Adopted : 07/17/12)

AVAQMD RULE 218.1 218.1-1 Continuous Emission Monitoring Performance Specific ations



# RULE 218.1 Continuous Emission Monitoring Performance

Specifications

(A) General

(1) Purpose

(a) The purpose of this rule is to specify standard s, specifications and requirements for new, modified and existing Continu ous Emission Monitoring Systems (CEMS).

(2) Applicability

(a) The provisions of this rule shall apply to all sources that require CEMS pursuant to Rule 218 – Continuous Emission Monitoring

. 

### (B) Definitions

(1) “Analyzer” - The part of the CEMS that analyzes the appropriate gaseous constituents of the conditioned gaseous sample or m easures stack gas volumetric flow and fuel flow rates, as applicable.

(a) Contaminant Analyzer - The part of the CEMS tha t detects the air contaminant concentrations and represents those con centrations in a signal output.

(b) Diluent Analyzer - The part of the CEMS that de tects oxygen (O 2 ), carbon dioxide (CO 2 ) or other Diluent Gas concentrations and represents those concentrations in a signal output.

(c) Fuel Flowmeter - The part of the CEMS that dete cts the parameters of all essential measurement sub-systems (e.g., tem perature, pressure, differential pressure, frequency, gas den sity, gas composition, heating value) and generates signal ou tputs which are a function of the fuel flow rate and all essential measurement subsystem parameters.

(d) Stack Flowmeter - The part of the CEMS that det ects the parameters from all essential measurement sub-syste ms (e.g., temperature, static and atmospheric pressure, gas d ensity, gas composition, molecular weight, gas moisture content ) and generates signal outputs which are a function of th e stack gas218.1-2 AVAQMD RULE 218.1 Continuous Emission Monitoring Performance Specific ations volumetric flow rate and all essential measurement sub-system parameters.
(2) “Calibration” - A procedure performed to ensure that the CEMS accurately measures and records the concentration o f the specific air contaminant or Diluent Gas, flow rate and other par ameters necessary to generate the required data, as evidenced by Calibra tion Checks and achieved by periodic manual or automatic adjustment

. (3) “Calibration Check” - A procedure performed to determine CEMS response to a given gaseous compound concentration by means of injecting a certified calibration gas mixture into the CEMS as close to the probe tip as practical.

(4) “Calibration Drift” (CD) - Change in the CEMS o utput or response over a specific period of normal continuous operation when the air contaminant or Diluent Gas concentration at the time of the mea surements is the same known upscale value. CD is expressed as the sum of the absolute value of the mean difference and the absolute value of the C onfidence Coefficient of a series of tests, to the Full Span Range, expre ssed as a percentage as follows:

100

× +

= FSR CC d CD

Where:

FSR = Full Span Range

CC = Absolute value of the 95% Confidence Coefficient

d = Absolute value of the mean difference. The mean

difference, d , is calculated as:



# ∑

= = n

i i d
n d

1 1AVAQMD RULE 218.1 218.1-3

Continuous Emission Monitoring Performance Specific ations

Where


# ∑

= n

i i d

1 = Algebraic sum of the individual differences d i

n = Number of data points

i d = The difference between the paired response

values of the monitoring system

(5) “Calibration Error” (CE)

(a) Calibration Error (as applicable to Section (D) - Standards for Existing CEMS) - The ratio of the difference betwee n the air contaminant or Diluent Gas concentration indicated by the CEMS and the known concentration of the calibration gas, to the known concentration of the calibration gas. CE is calcul ated as the ratio of the sum of the absolute values of the mean diffe rence and the 95 percent Confidence Coefficient of a series of tests , to the gas concentration, expressed as a percentage, as follow s:

100 × +

= C CC d CE

Where:

C = Calibration gas concentration CC = Absolute value of the 95% Confidence Coefficient

d = Absolute value of the mean difference. The mean

difference is calculated as:


# ∑

= = n

i i d
n d

1 1218.1-4 AVAQMD RULE 218.1 Continuous Emission Monitoring Performance Specific ations Where:



# ∑

= n

i i d

1 = Algebraic sum of the individual differences d i

n = Number of data points

i d = The difference between the paired monitoring system

response value and the known gas concentration or the equivalent rating of the Reference Method value

, both in units of the applicable standard

(b) Calibration Error (as applicable to Section (C) - Standards for New or Modified CEMS) - The ratio of the absolute value of the difference between the air contaminant or Diluent G as concentration indicated by the CEMS and the known c oncentration of the calibration gas, to the Full Span Range, exp ressed as a percentage, as follows:

100 × −

= FSR A C CE

Where:

C = Calibration gas concentration

A = Actual response or the concentration indicated by t he

monitoring system

FSR = Full Span Range of the instrument

(6) “CEMS Availability Percentage” - A percentage c alculated as the ratio of the total unit operating hours for which the CEMS p rovided qualityassured data, to the source total unit operating ho urs during a specified period, excluding periods of Calibration, maintenan ce, repair, or audit, up to a maximum of 40 hours per month.

(7) “Certified CEMS” - A CEMS installed, tested, op erated, maintained, and calibrated according to the applicable requirements of Rules 218 and 218.1; that has met the applicable performance spec ifications of Rule 218.1 and, has received written approval and condit ions thereto applying, from the APCO.AVAQMD RULE 218.1 218.1-5

Continuous Emission Monitoring Performance Specific ations (8) “Certified Gas Mixture” - A gas mixture manufac tured, analyzed and certified in accordance with the “EPA Traceability Protocol for Assay and Certification of Gaseous Calibration Standards” - E PA-600/R97/121, September 1997 Revision (EPA Traceability Protocol) or any subsequent version published by EPA. This definition incorpor ates by reference EPA Protocol.

(9) “Confidence Coefficient” (CC) - The 2.5 percent error Confidence Coefficient for the 95 Percent Confidence Interval of a series of tests. The CC is calculated as follows:

n S t CC d

975.0 =

Where:

S d = Standard deviation

n = Number of data in a series of tests

t 0.975 = t-value (see Table of t-Values below)

Table of t-Values*

n t 0.975 n t 0.975 n t 0.975

2 12.706 7 2.447 12 2.201

3 4.303 8 2.365 13 2.179

4 3.182 9 2.306 14 2.160

5 2.776 10 2.262 15 2.145

6 2.571 11 2.228 16 2.131

*The t-values in this table are already corrected f or n-1 degrees of freedom. Use n equal to the number of data points.

(10) “Continuous Emission Monitoring System” (CEMS) – The total combined equipment and systems required to continuously dete rmine air contaminants and Diluent Gas concentrations and/or mass emission rate of a source effluent (as applicable). The CEMS consis ts of three (3) major subsystems: Sampling Interface, Analyzer and Data A cquisition System.218.1-6 AVAQMD RULE 218.1 Continuous Emission Monitoring Performance Specific ations (11) “Continuous Monitoring” - A monitoring in whic h a minimum of one (1) measurement (e.g., concentration, mass emission, fl ow rate) is taken and recorded each minute.

(12) “Data Acquisition System” (DAS) - The part of the CEMS that processes data generated by the Analyzer and records the resu lts, thus creating a permanent record of the output signal in terms of c oncentration, flow rate, and any other applicable parameter necessary to gen erate the required data in units of applicable standard. The DAS consists of all equipment such as a computer required to convert the original recorde d values to any values required for reporting.

(13) “Diluent Gas” - A gas present in a calibration gas mixture or in source emissions that is present in quantities significant ly larger than the air contaminant.

(14) “Full Span Range” (FSR) - The full range of va lues or data display output that a monitor component is calibrated to measure.

(15) “Linearity Error” (LE) - The percentage error in linearity expressed in terms of the ratio of the absolute value of the dif ference between the reference value and the mean CEMS response value, t o the reference value. LE is calculated as follows:

100 × −

= R C R LE

Where:

C = Mean of the CEMS response values

R = Certified gas concentration as reference value

(16) “Modification Requiring Recertification” - Any change to the basic equipment, control equipment, contaminant concentra tion, interfering substances, or CEMS that is deemed by the APCO to h ave a potential for adversely affecting the ability of the CEMS to prov ide accurate, precise and timely data representative of the stack emissio ns for which the CEMS (or SCEMS) is required.

(17) “Ninety-Five Percent Confidence Interval” - Th e statistical estimation denoting a range of values which is expected to inc lude a true value with a 95 percent probability.

(18) “Operating Day” - Each calendar day that emiss ions pass through the stack or duct.AVAQMD RULE 218.1 218.1-7

Continuous Emission Monitoring Performance Specific ations (19) “Operational Period” - A minimum period of 168 continuous hours during which the CEMS shall operate, according to the manu facturer’s written performance and equipment specifications, without u nscheduled maintenance, repair, or adjustment.

(20) “Quality Assurance/Quality Control (QA/QC) Pla n” – A written document in which the specific procedures for the operation, Calibration and maintenance of a Certified CEMS are described in de tail, including additional quality assurance assessments and the co rrective action system. The purpose of this plan is to ensure that the CEMS generates, collects and reports valid data that is precise, accurate, compl ete, and of a quality that meets the requirements, performance specifications, and standards of Rules 218 and 218.1.

(21) “Reference Method” (RM) - The official test me thod employed by the District to determine compliance with the rules or permit conditions. A list of Reference Methods is identified in Table 1.

(22) “Relative Accuracy” (RA) - The absolute mean d ifference between the gas concentration or emission rate determined by the CE MS and the value determined by the RM plus 2.5 percent error of Conf idence Coefficient of a series of tests, divided by the mean of the RM te sts.
(23) “Relative Accuracy Audit” (RAA) - The RA test expressed in terms of the ratio of the relative difference between the mean R eference Method value and the mean CEMS response value, to the mean value determined by the Reference Method or applicable standard for concent ration, flow or mass emission rate. Unless otherwise specified, RAA sha ll have the same specifications and requirements as the Relative Acc uracy Test Audit (RATA), except that the RAA shall require a minimum of three (3) data sets. When a rule requires a correction of the air contaminant concentration to a specific O 2 or CO 2 concentration, the RA requirement shall apply to the corrected concentration value. The RA of a RAA data set is calculated and expressed as a percentage as follows:

100 × −
= RM RM r RA

Where:

RM = Mean of the values determined by the referenced m ethod or

applicable standard

r = Mean of the CEMS response values218.1-8 AVAQMD RULE 218.1 Continuous Emission Monitoring Performance Specific ations (24) “Relative Accuracy Test Audit” (RATA) - The RA test expressed in terms of the ratio of the sum of the absolute mean differ ence between the CEMS-generated data and the value determined by the applicable Reference Method or applicable standard and the abs olute Confidence Coefficient, to the mean of the Reference Method or applicable standard value for concentration, flow or mass emission rate . When a rule requires a correction of the air contaminant concentration t o a specific O 2 or CO 2 concentration, the RA requirement shall apply to th e corrected concentration value. The RA of a RATA data set is calculated and expressed as a percentage as follows:

100 × +

= RM CC d RA

Where:

d = Absolute value of the mean difference

CC = Absolute value of the 95% Confidence Coefficient

RM = Average RM value or applicable standard

The arithmetic mean of the difference, d, of a set of data is calculated as follows:


# ∑

= = n

i i d
n d

1 1

Where:



# ∑

= n

i i d

1 = Algebraic sum of the individual differences d i

i d = The difference between the Reference Method value and

the CEMS value, both in units of the applicable sta ndard

n = Number of data points

(25) “Response Time” - The time interval from a ste p change in the air contaminant or gas diluent concentration to the tim e when 95 percent ofAVAQMD RULE 218.1 218.1-9

Continuous Emission Monitoring Performance Specific ations

the corresponding final value is reached as display ed on the CEMS data recorder or acquisition system. The Response Time is determined by introducing a Certified Gas Mixture into the CEMS u pstream of the Sampling Interface and as close to the probe inlet as practicable.

(26) “Routine Maintenance” - Preventive evaluation and repair (if necessary) of CEMS performed at specified intervals to preclud e System Failure. Routine Maintenance may be performed as recommended by the manufacturer or a documented standard operating pro cedure determined through operating experience and approved by the AP CO. Repairs to a malfunctioning system are excluded from this defini tion.

(27) “Sampling Interface” - That part of the CEMS t hat performs sample acquisition using one (1) or more of the following operations: extraction, physical/chemical separation, transportation or con ditioning of a representative sample from a designated source.

(28) “Semi-Continuous Emission Monitoring System” ( SCEMS) - The total combined equipment and systems required to semi-con tinuously determine air contaminants and Diluent Gas concentr ations and/or mass emission rate of a source effluent (as applicable). The SCEMS consists of three (3) major subsystems: Sampling Interface, Ana lyzer and Data Acquisition System. This class of monitoring inclu des but is not limited to gas chromatography, integrated sensitized tape a nalyzer, other sample integration based technologies, and time-shared CEM S.

(29) “South Coast Air Quality Management District” (SCAQMD) - The air quality district created pursuant to Division 26, P art 3, Chapter 5.5 of the California Health & Safety Code (commencing with §4 0400).

(30) “System Bias” - The difference between the gas concentrations exhibited by the CEMS when a calibration gas is introduced at a location upstream of the Sampling Interface, and as close to the samp ling probe inlet as practicable, and when the same calibration gas is i ntroduced directly to the Analyzer.

(31) “System Failure” - Inability of the CEMS to me et the requirements of Rule 218.1.

(32) “Time-Sharing” - A monitoring technique where an Analyzer and possibly the associated sample conditioning system is used o n more than one (1)

source.
(33) “Zero Check” - A procedure performed to determ ine the response of the CEMS to a given Zero Gas standard by means of injec ting the Zero Gas into the CEMS as close to the probe tip as practica l.218.1-10 AVAQMD RULE 218.1 Continuous Emission Monitoring Performance Specific ations (34) “Zero Drift” (ZD) - The change in the monitori ng system output/response over a stated period of time of normal continuous o peration when the air contaminant or Diluent Gas concentration at the tim e of the measurements is zero. The values for ZD shall be expressed as t he ratio of the sum of the absolute value of the mean of the difference betwee n paired instrument response values and the absolute value of the CC, t o the Full Span Range, calculated as a percentage as follows:

100 × +

= S CC d ZD

Where:

S = Full Span Range

CC = Absolute value of the Confidence Coefficient

d = Absolute value of the mean difference. The mean

difference is calculated as:



# ∑

= = n

i i d
n d

1 1

Where:


# ∑

= n

i i d

1 = Algebraic sum of the individual differences d i

n = Number of data pairs

i d = The difference between a pair of instrument respo nse

values

(35) “Zero Gas” - A gas containing less than a spec ified amount of the contaminant or Diluent Gas which, when periodically injected into the CEMS, is used to check CEMS’ response to the absenc e of the air contaminant or Diluent Gas.


### (C) Standards for New or Modified CEMS

In order to be a Certified CEMS, a CEMS subject to the provisions of Rule 218, Sections (D)(1), (E)(1)(c), (E)(2)(c) and (E)(2)(d) , as applicable, shall meet the operational requirements, performance specification s, and standards as follows:AVAQMD RULE 218.1 218.1-11

Continuous Emission Monitoring Performance Specific ations (1) Pre-Certification Testing Requirements for New or Modified CEMS

Before any certification or Relative Accuracy test is performed, the CEMS shall meet the following standards:

(a) CEMS Location

The CEMS shall be installed at a location that enab les measurements of air contaminant and Diluent Gas con centration, and flow rates can be made which are representative of the stack emissions of the source.

(b) Sampling Location

The monitoring system sampling probe tip and the Re ference Method sampling port locations shall be determined according to SCAQMD Method 1.1. The monitoring sampling probe s hall be located where a sample may be obtained which is rep resentative of the source emissions. Each probe shall not interfe re with the other when in use. Other locations may be chosen subject to a written approval of the APCO. If an alternate location is chosen which does not conform with SCAQMD Method 1.1, the absenc e of flow disturbance shall be demonstrated using the SCAQMD method in the source Test Manual, Chapter X, Section 1.4 – “A lternative Site Selection Method,” or 40 CFR, Part 60, Appendix A, Method 1, Section 2.5 – “Alternative Measurement Site Selecti on Procedure,” and, the absence of stratification shall be demonst rated using the SCAQMD method in the source Test Manual, Chapter X, Section 13 – “Determination of Gaseous Constituent Stratifi cation”. Alternatives to sampling site selection in the pres ence of stratification are presented in Rule 218.1 Section (C)(3)(c)(ii).

(c) Full Span Range

(i) The FSR for mass emission rate, air contaminant , diluent and flow analyzers shall be set such that all data points are within 10 to 95 percent of the range. (ii) For air contaminant monitors, the FSR shall be set between 150 and 200 percent of the concentration limit as s pecified in the applicable rule or permit condition. The FS R may be set at a value other than that specified, but no lo wer than 120 percent, provided that the CEMS owner or operat or demonstrates to the satisfaction of the APCO that t he FSR will not be exceeded. Such demonstrations may incl ude, but are not limited to, historical emissions data, historical process information, and historical operational inf ormation. A written approval from the APCO shall be obtained before218.1-12 AVAQMD RULE 218.1 Continuous Emission Monitoring Performance Specific ations the FSR may be modified outside of the 150 to 200 p ercent of the concentration limit. (iii) For air contaminant monitors, a multiple-span -range may be required to satisfy the provisions of Sections ( c)(i) and (c)(ii) above in situations where the normal concen tration of the air contaminant emitted is significantly les s than the allowable concentration limit. The CEMS shall have the capability to automatically change from one range t o the other as appropriate to the monitor’s measured concentration. (iv) For diluent monitors, the FSR shall be set suc h that the full range of O 2 and CO 2 concentrations can be measured. The FSR shall be set at 25.0 percent O 2 (maximum) and 1.0 percent CO 2 (minimum) concentrations, or at a value approved by the APCO. (v) Should any data points fall below ten (10) perc ent of the FSR, those data points shall be reported according the following, as applicable: a. For CEMS with certified multiple span ranges, th e owner shall report data that falls below 10.0 perce nt of the higher FSR and above 95 percent of the lower FSR, at the 10.0 percent value of the higher FSR; b. In the event that any of the data points gathere d by the CEMS fall below 10.0 percent of the FSR, the owner or operator may elect to report the contaminant concentrations at the 10.0 percent FSR value; or c. In the event that any data points gathered fall below 10.0 percent of the lowest vendor guaranteed FSR for that CEMS (defined as the lowest FSR that the vendor guarantees to be capable of meeting all current certification requirements of Rule 218 and Rule 218.1, as applicable) the owner or operator may elect to use the following to measure and report contaminant concentrations: 1. Report data at 10.0 percent FSR value; or 2. Report data at actual measured value, provided that the CEMS meets the Supplemental and Alternative Performance Requirements in Attachment A. (vi) Should any data points fall above 95 percent o f FSR, the value shall be invalid for quantification and the C EMS shall be considered unavailable for the purposes of determining CEMS Availability Percentage. All excursions above 95 percent of FSR and the duration ofAVAQMD RULE 218.1 218.1-13

Continuous Emission Monitoring Performance Specific ations these excursions shall be reported in the CEMS summ ary report as prescribed under Rule 218 Section (G).

(d) Strip Chart Recorder

(i) For CEMS where the strip chart recorder is used as the only means of data recording, the strip chart shall have a minimum width of at least 10 inches, a readability of 0.5 percent of the span, and a minimum of 100 chart div isions. (ii) For CEMS where the strip chart recorder is use d as a backup system or for recording data from only a sin gle parameter, a strip chart of lesser size than specif ied in Section (d)(i) above, may be proposed in the applic ation. (iii) For CEMS equipped with multiple-span ranges, the chart recorder shall have the capability to automatically change span, as appropriate.

(e) Data Acquisition System (DAS)

(i) The DAS shall maintain all recorded data in acc ordance with Rule 218, Section (F). (ii) For CEMS, DAS shall acquire data from monitore d parameters at least once every minute. (iii) For SCEMS, DAS shall acquire data from monito red parameters at least once every 15 minutes. (iv) DAS acquisition rate shall be set at a constan t rate such that the data points are equally spaced. (v) All valid data points shall be used to determin e compliance with applicable limit(s), and, for certification te sting and RATA(s). (vi) DAS sample acquisition rate during certificati on and RATA(s) shall be the same as the DAS sample acquisi tion rate during normal CEMS, or SCEMS, operation.

(f) Operational Period

(i) The Operational Period before any certification tests shall be a minimum of 168 continuous hours.

(2) Certification Requirements and Performance Spec ifications for New or Modified CEMS

Rule 218 Section (D)(1) provides that a series of c ertification tests shall be performed to demonstrate the acceptability of CEMS performance. The requirements and specifications in conducting initi al certification tests follow:218.1-14 AVAQMD RULE 218.1 Continuous Emission Monitoring Performance Specific ations (a) Calibration Error (CE) Testing

The 24-Hour CE Test shall be performed at the low a nd high ranges, namely 0 to 20 and 80 to 100 percent of FSR, respec tively. CE specifications shall be less than or equal to:

(i) 2.5 percent of the FSR for all Analyzers; and (ii) 3.0 percent of the FRS of the Analyzer, for fl ow monitors, when an electronic Calibration Check is applicable.

The 24-hour CE Test shall be performed once each da y as close to 24-hour intervals as practicable, with a total of e ight (8) consecutive tests performed. The CE specifications shall not be exceeded on any of the tests during the entire test ing period.

(b) Analyzer Enclosure

(i) The Analyzer shall be contained in an environme ntally controlled enclosure. An alarm and recording devic e shall be incorporated into the system to alert the operat or to make corrective action should the Analyzer exceed t he manufacturer’s recommended specifications for temperature drift. (ii) Alternatively, the owner or operator of the CE MS may choose to perform the 2-hour CE Tests in lieu of me eting the Analyzer enclosure requirement in Section (C)(2 )(b)(i). The 2-hour CE Test shall be performed once every tw o (2) hours as close to 2-hour intervals as practicable, with total of thirteen consecutive tests performed. The 2-hou r CE Test shall be performed when ambient temperature is expected to vary diurnally at least 30°F. The test shall be performed at the low and high ranges of FSR, namely 0 to 20 and 80 to 100 percent, respectively. The specif ications in Sections (C)(2)(a)(i) and (ii) shall apply to 2- hour CE. (iii) The owner or operator of the CEMS may qualify for an exemption from Section (C)(2)(b)(i) to provide environmental controls for the Analyzer enclosure b y demonstrating, to the satisfaction of the APCO, tha t the CEMS is located: a. In a geographic area where seasonal high and low temperatures do not exceed the operational temperature specifications for the Analyzer; b. In a geographic area where monthly maximum temperature variation is less than 30°F for all months of the year; and c. The CEMS is located in a site that is protected from radiation and convection heating sources.AVAQMD RULE 218.1 218.1-15

Continuous Emission Monitoring Performance Specific ations

(c) Relative Accuracy

RATA shall be performed for raw contaminant concent ration, and if applicable, for corrected concentration, emissio n rate, O 2 concentration, CO 2 concentration analyzers, and stack and fuel flow monitors. There shall be a minimum of nine (9 ) sets of test data generated. If the number of tests exceeds nin e (9) sets, data may be discarded if it is identified as an outlier by the technical guidance set forth by the APCO, or for valid reason s (e.g., process upsets, CEMS malfunction, etc.) which must be subst antiated with appropriate documentation and subject to approval b y the APCO. All data collected shall be submitted to the APCO. The CEMS shall meet the following RA performance specificati ons:
(i) Less than or equal to 20.0 percent of the mean valu e of the Reference Method for pollutant concentrations, or t he de minimus concentration as follows, whichever is grea ter:
Pollutant De minimus Concentration SO 2 2.0 ppm Reduced sulfur compounds 4.0 ppm (ii) Less than or equal to 10.0 percent of the mean valu e of the Reference Method for diluent concentrations, or the de minimus value of 1.0 percent O 2 , whichever is greater. (iii) Less than or equal to 15.0 percent of the mean valu e of the Reference Method for flow monitors, or the de minim us value equivalent to a calculated volumetric flow ra te based on two (2) feet per second stack gas velocity for c ases where the mean stack gas velocity obtained by the Reference Method test is less than 15 feet per seco nd. (iv) Less than or equal to 20.0 percent of the mean value of the Reference Method for mass emission rates, or the de minimus value equivalent to a calculated mass emiss ion rate based on two (2) feet per second stack gas vel ocity for cases where the mean stack gas velocity obtained by the Reference Method test is less than 15 feet per seco nd.

The Relative Accuracy requirement may be met if the average of the differences between the CEMS measure d data and the Reference Method test data plus the Confidence Coefficient is less than or equal to the Relative Accuracy de minimus value.

(3) Relative Accuracy Test Requirements for New or Modified CEMS

Within fourteen days of, or during all Relative Acc uracy tests, the CEMS shall meet the following requirements, except those that may be waived as allowed in Rule 218.1, Section (C)(4)(c):218.1-16 AVAQMD RULE 218.1 Continuous Emission Monitoring Performance Specific ations (a) Response Time

The Response Time for carbon monoxide (CO) CEMS sha ll not exceed 1.5 minutes except where there is a technica l limitation, in which case the Response Time shall be five (5) minu tes. The Response Time for all other CEMS and flow monitors, as applicable, shall not exceed five (5) minutes.

(b) Calibration Error

The CE Testing requirements are specified in Sectio n (C)(2)(a).

(c) Concentration Stratification

(i) The owner or operator shall demonstrate the abs ence of stratification through testing performed according to the method in Chapter X, Section 13 - “Non-Standard Met hods and Techniques”, of the SCAQMD Source Testing Manua l. The number of tests shall be determined as follows: a. Test(s) shall be conducted at one (1) load level if the owner or operator demonstrates to the satisfaction of the APCO that the equipment operates within a 20 percent load range for at leas t 80 percent of the time; b. Test(s) shall be conducted at two (2) different load levels if the owner or operator demonstrates to the satisfaction of the APCO that the equipment operates within a 50 percent load range for at leas t 80 percent of the time; or, c. Test(s) shall be conducted at three (3) differen t load levels if the equipment operates outside of the criteria in Sections (C)(3)(c)(i)[a] and [b].

The absence of stratification is considered verifie d if the difference between the highest measured concentration (time normalized) and the lowest measured concentration (time normalized) divided by the average measured concentration (time normalized), when expressed as a percentage, is les s than or equal to 10 percent. Upon verification of the absence of stratification, the owner or operato r may position the CEMS sampling probe at any point within the stack with the exception of those points that are adjacent to the stack wall. The CEMS sampling probe should be located in the stack at least one-third of the stack diameter. Th e RM for RATA may be conducted at a single pointAVAQMD RULE 218.1 218.1-17

Continuous Emission Monitoring Performance Specific ations within the stack that is not adjacent to the stack wall and does not interfere with the sampling and the operation of the facility CEMS. (ii) Should testing demonstrate the presence of str atification, the owner or operator may elect one (1) of the foll owing alternatives: a. If the stratification is greater than 10 percent but the difference between the highest measured concentration (time normalized) and the lowest measured concentration (time normalized) is less than or equal to 1.0 ppmv: 1. Then the CEMS sampling probe may be located at any point within the stack except any points that is adjacent to the stack or adjacent to the highest measured concentration (time normalized) and the lowest measured concentration (time normalized); or 2. If it is not possible to avoid using a point adjacent to either the highest measured concentration (time normalized) or the lowest measured concentration (time normalized), then locate the CEMS sampling probe such that the placement minimizes the difference between the concentration at the proposed probe location and the concentration at the point of highest measured concentration (time normalized) or the lowest measured concentration (time normalized). b. Determine a representative CEMS probe location such that the following criteria are met: 1. All traverse point concentrations are within 10.0 percent of the average of all traverse point concentrations (time normalized), or, the difference is less than or equal to 1.0 ppm, whichever is greater; 2. There exists at least one (1) traverse point concentration (Xr), not located next to the stack or duct wall, that is less than or equal to 10.0 percent each adjacent traverse point concentration of Xr, or the difference is less than or equal to 1.0 ppm, whichever is greater; and 3. The CEMS probe is located at (or as near as practical) Xr with minimum adjacent218.1-18 AVAQMD RULE 218.1 Continuous Emission Monitoring Performance Specific ations traverse point concentration fluctuations as determined in Section (C)(3)(c)(ii)[b][2], above. c. Determine a representative multiple point sampli ng configuration as approved by the APCO, following the guidance document by Emission Measurement Technical Information Center, “Evaluation Procedure for Multi-Hole Sample Probes” (EMTIC GD-031). d. Modify the stack and/or CEMS sampling probe location and retest for the absence of stratificati on.
(d) Cyclonic Flow

The owner or operator shall perform tests to verify the absence of cyclonic flow for the CEMS and Reference Method sam pling probes. The cyclonic flow test shall be required w hen measuring mass emission rates and shall be performed accordin g to the SCAQMD method in the Source Test Manual, Chapter X: NonStandard Methods and Techniques following the testi ng conditions of Section (C)(3)(c)(i)[a], [b] or [c], as applicab le.

(e) Interference

The owner or operator shall perform tests to verify the absence of sampling, analytical and flow interference, as appl icable.

(f) Linearity Error

LE tests shall be performed at the low, middle and high ranges of concentration, namely 20 to 30, 50 to 60, and 80 to 100 percent. Each calibration gas shall be introduced into the C EMS three (3) times. The same gas shall not be used twice in suc cession. LE shall be less than or equal to 5.0 percent of the c alibration gas concentration.

(g) Multiple-Span-Range

For CEMS that have multiple-span-range, all certifi cation tests shall be performed at the lowest range. Except for RA and interference tests, all other certification tests s hall be performed on other ranges.

(4) Operational Requirements and Performance Specif ications for New or Modified CEMS

After final approval, the CEMS shall be subsequentl y operated and maintained according to the following requirements and specifications:AVAQMD RULE 218.1 218.1-19

Continuous Emission Monitoring Performance Specific ations

(a) 24-Hour CE

CE Tests shall be performed once each Operating Day as close to 24 hour intervals as practicable at the low (0 to 2 0 percent) and high (80 to 100 percent) ranges of concentration. CE Test results which are greater than the limits specified in Sect ions (C)(2)(a)(i) and (ii), but less than or equal to 5.0 percent of the FSR shall be addressed by QA/QC Plan remediation. The CEMS shal l be deemed out-of-control during such period when any C E Test result is greater than the specified limits and greater th an 5.0 percent of the Full Span Range, until the CE Test meets the sp ecifications. All data generated by the CEMS during an out-of-con trol period shall be deemed invalid but shall not be deleted or excluded from the records or database.

(b) System Bias Test

A System Bias shall be conducted every 12 months in conjunction with RAA required under Rule 218.1 Section (C)(4)(c ). The CEMS System Bias shall not exceed ±5.0 percent of t he FSR for contaminant Analyzers. In addition, the owner or o perator shall include in the facility QA/QC Plan, criteria for ex cessive drift (e.g. control limits on cumulative drift) and appropriate diagnostic techniques to identify sources of Analyzer drift an d System Bias when control limits are exceeded.

(c) Relative Accuracy Testing

RATA and RAA, as applicable, shall be performed at least once every 12 months. The test shall be completed annua lly no later than the end of the calendar quarter in which the d ate of the original certification test was performed. During any RA tests after CEMS certification, the owner or operator may request a waiver from stratification, cyclonic flow, and/or i nterference requirements in Sections (C)(3)(c), (d) and (e), re spectively, by submitting to the APCO, for approval, any applicabl e documentation or previous test or historical data t hat meets the stratification, cyclonic flow, and/or interference requirements.

(d) Cylinder Gas Audit (CGA)

A CGA shall be performed every calendar quarter but in no more than three (3) quarters in succession. The CGA sha ll be conducted according to the provisions of 40 CFR 60, Appendix F. The audit gases shall be according to the certification requi rements of Rule 218.1.218.1-20 AVAQMD RULE 218.1 Continuous Emission Monitoring Performance Specific ations (e) The APCO may require recertification of the CEM S if the annual availability percentage is below 95 percent. Annua l CEMS Availability Percentage calculations will be based on the year ending on the last day of the calendar quarter in w hich the CEMS was originally certified.

(f) The owner or operator of a CEMS that requires m oisture correction in reporting flow and concentration shall measure a nd monitor moisture in the stack gas used for emission data ca lculations in accordance with the written technical guidance docu ment set forth by the APCO. Alternatively, with APCO approval, fo r equipment whose moisture source is only from fuel combustion, the operator may calculate the moisture content using fuel prope rties and ambient air humidity data or, for processes that sa turate the exhaust gas with moisture, such as a wet scrubber s ystem, the operator may use the saturation temperature for moi sture content data.


### (D) Standards for Existing CEMS

In order to be a Certified CEMS, a CEMS subject to the provisions of Rule 218 Sections (E)(1) and (E)(2), shall meet the followin g operational requirements and performance specifications, and the standards of Ru le 218.1 Section (E):

(1) Performance Specifications for Existing Gaseous Air Contaminant CEMS

Parameter Specifications

(a) Operational Period Greater than or equal to 168 hours

(b) Calibration Error Less than or equal to 5 perce nt of the calibration gas value

(c) Response Time Less than or equal to 10 minutes

(d) Zero Drift (2-hour) Less than or equal to 2 per cent of FSR

(e) Zero Drift (24-hour) Less than or equal to 2 pe rcent of FSR

(f) Calibration Drift (2-hour) Less than or equal t o 2 percent of FSR

(g) Calibration Drift (24-hour) Less than or equal to 2.5 percent of FSR

(h) Relative Accuracy Less than or equal to 20 perc ent of the mean value of the RM test data, or, less than or equal to 10 percent of the allowed concentration, whichever is greaterAVAQMD RULE 218.1 218.1-21

Continuous Emission Monitoring Performance Specific ations (2) Performance Specifications for Existing Diluent Gas CEMS

Parameter Specifications

(a) Operational Period Greater than or equal to 168 hours

(b) Calibration Error Less than or equal to 5 perce nt of the calibration gas value

(c) Response Time Less than or equal to 10 minutes

(d) Zero Drift (2-hour) Less than or equal to 0.4 p ercent CO 2 or O 2 (e) Zero Drift (24-hour) Less than or equal to 0.5 percent CO 2 or O 2 (f) Calibration Drift (2-hour) Less than or equal t o 0.4 percent CO 2 or O 2 (g) Calibration Drift (24-hour) Less than or equal to 0.5 percent CO 2 or O 2

(3) Full Span Range for Existing CEMS

The instrument FSR shall be equivalent to approxima tely 200 percent of the concentration limit as specified in the applica ble rule, or at a value approved by the APCO. O 2 and CO 2 instrument full span readings shall be such that the full range of concentrations encou ntered can be measured.

(4) Cycle of Operation for Existing CEMS

The CEMS shall complete a minimum of one (1) cycle of operation (sampling, analyzing and data recording), for each successive 15 minute period.


### (E) Standards, Specifications and Requirements for New, Modified and Existing CEMS:

(1) Calibration Gas

(a) Calibration gas mixtures, as defined in Rule Se ction 218.1 (B)(8), shall be manufactured, analyzed and certified in ac cordance with the “EPA Traceability Protocol for Assay and Certif ication of Gaseous Calibration Standards” - EPA-600/R97/121, S eptember 1997 Revision (EPA Protocol). The certification pe riod and218.1-22 AVAQMD RULE 218.1 Continuous Emission Monitoring Performance Specific ations recertification requirements, as applicable, shall be according to the EPA Protocol.

(b) For gas calibration standards not explicitly co vered by the EPA Protocol, the CEMS owner or operator shall submit t he gas manufacturer’s alternative certification protocol f or the specific compound or compounds.

(i) The procedures of the EPA Protocol shall be use d for gas calibration standards not explicitly covered therei n, except that the gas manufacturer must identify a recertifi cation period and submit data documenting the applicabilit y of this period. The gas manufacturer may submit alter native performance standards for certification and recerti fication, based on supporting technical data also provided by the manufacturer. This alternative shall be subject to the approval of APCO. (ii) If there is no existing National Institute of Standards and Technology (NIST) standard for the measured paramet er, the gas manufacturer may submit an alternative refe rence standard and the supporting technical data that def ine the stability, accuracy, and precision of the alternati ve reference standard. This alternative shall be subj ect to the approval of APCO. (iii) The CEMS owner or operator may submit an alte rnative protocol to the EPA Protocol, provided that the CEM S owner or operator demonstrates through supporting technical data that the procedures therein are not applicable to the constituent in the calibration gas standard being certified. This alternative shall be subject to th e approval of APCO.

(c) Compressed and/or filtered air, such as instrum ent air, may also be used in lieu of oxygen span gas provided that the C EMS owner or operator demonstrates, to the satisfaction of the A PCO, that it is of equivalent quality to the calibration gas standards above. As part of such documentation, the owner or operator shall include in their QA/QC Plan the process or operation in producing su ch compressed and/or filtered air and periodically che cking that compressed air and/or filtered air continues to mee t the calibration gas standards.

(2) Zero Gas

Zero Gases used shall meet the following criteria:AVAQMD RULE 218.1 218.1-23

Continuous Emission Monitoring Performance Specific ations

(a) For gaseous air contaminant monitors, the Zero Gas shall be certified by the manufacturer to contain no more th an 0.1 ppm of the air contaminant analyzed by the subject monitor or 1.0 percent of the applicable standard, whichever is less.

(b) For CO monitors, the Zero Gas shall be certifie d by the manufacturer to contain less than 0.5 ppm carbon CO or 1.0 percent of the applicable standard, whichever is le ss.
(c) For CO 2 and O 2 monitors, the Zero Gas shall be certified by the manufacturer to contain less than 1.0 ppm CO 2 or O 2
. (d) Compressed and/or filtered air, such as instrum ent air, may also be used in lieu of Zero Gas provided that the CEMS own er or operator demonstrates, to the satisfaction of the A PCO, that it is of equivalent quality to the above Zero Gas standards. As part of such documentation, the owner or operator shall inc lude in their QA/QC plan the process or operation in producing su ch compressed and/or filtered air and periodically che cking that compressed air and/or filtered air continues to mee t the Zero Gas standards.

(3) Automatic Calibration Data

If automatic adjustments to the monitor settings ar e made, conduct the calibration tests in a way that the magnitude of th e adjustments can be determined and recorded.

(4) F-Factors

The owner or operator shall use in the CEMS calcula tions the Fd factors listed in 40 CFR Part 60, Appendix A, Method 19, Ta ble 19-1, as applicable. When alternative fuels are fired, the owner or operator shall submit data to develop Fd factors and obtain APCO a pproval.

(5) NO 2 to NO Conversion Efficiency

The conversion efficiency tests shall be conducted according to the requirements of SCAQMD Method 100.1. The value for the NO 2 gas shall be greater than or equal to the maximum expec ted or recorded NO 2 and greater than or equal to 20 percent of the FSR.


### (F) Time-Sharing Requirements

A time-shared CEMS for which an application is subm itted after July 17, 2012 shall meet all of the performance specifications as well as the following requirements:218.1-24 AVAQMD RULE 218.1 Continuous Emission Monitoring Performance Specific ations (1) All sources shall have mutually compatible rang e(s) of air contaminant gases at all times.

(2) Each source shall have a data-reading period, a t a minimum, equal to three (3) times the longest Response Time of the system. For shared systems the Response Time is measured at the input or probe at each source. A demonstration of Response Time for each source shal l be made during certification testing. Data are not to be collecte d following a switch of sample sources until a period of time equal to one (1) Response Time has passed.

(3) The CEMS shall be capable of performing and rec ording zero and span calibrations at each source, including the calibrat ion factors and correction values before and after every automatic Calibration

.AVAQMD RULE 218.1 218.1-25

Continuous Emission Monitoring Performance Specific ations 

### Table 1 REFERENCE METHODS RULE 218.1

SCAQMD Method 1.1 Sample and Velocity Traverses for Stationary Sources

SCAQMD Method 1.2 Sample and Velocity Traverses for Stationary Sources with Small Stack or Ducts

SCAQMD Method 2.1 Determination of Stack Gas Veloci ty and Volumetric Flow Rate (S-type Pitot tube)

SCAQMD Method 2.2 Direct Measurement of Gas Volume through Pipes and Small Ducts

SCAQMD Method 2.3 Determination of Gas Velocity and Volumetric Flow Rate from Small Stacks or Ducts

SCAQMD Method 3.1 Gas Analysis for Dry Molecular We ight and Excess Air

SCAQMD Method 4.1 Determination of Moisture Content in Stack Gases

SCAQMD Method 6.1 Determination of Sulfuric Acid an d Sulfur Oxides from Stationary Sources

SCAQMD Method 7.1 Determination of Nitrogen Oxide E missions for Stationary Sources

SCAQMD Method 100.1 Instrumental Analyzer Procedure s for Continuous Gaseous Emission Sampling

SCAQMD Method 307.91 Determination of Sulfur in a G aseous Matrix

EPA Method 6 Determination of Sulfur Dioxide Emissi ons from Stationary Sources

EPA Method 19 Determination of Sulfur Dioxide Remov al Efficiency and Particulate, Sulfur Dioxide and Nitrogen Oxides Emi ssion Rates from Electric Utility Steam Generator (40 CFR Part 60, Appendix A)

ASTM Method D 4294-03 Standard Test Method for Sul fur in Petroleum and Petroleum Products by Energy Dispersive X-Ray Fluorescence Spectrometry ASTM Method D2622 -05 Standard Test Method for Sulf ur in Petroleum Products by Wavelength Dispersive X-ray Fluorescence Spectromet ry218.1-26 AVAQMD RULE 218.1 Continuous Emission Monitoring Performance Specific ations This page intentionally left blank.AVAQMD RULE 218.1 218.1-27

Continuous Emission Monitoring Performance Specific ations 

### ATTACHMENT A

SUPPLEMENTAL AND ALTERNATIVE CEMS PERFORMANCE REQUIREMENTS

(A) Applicability of Supplemental and Alternative P erformance Requirements

The CEMS operator who elects (or who may be require d) to measure concentrations that fall below 10 percent of the lo west vendor guaranteed full scale span range, shall satisfy the performance req uirements as specified in Table A-1 listed below.

TABLE A-1

Alternative Performance Requirement(s)

CEMS Certified per Rule 218.1 Yes or No Performance Requirement(s)

LLSR/BFD HLSR/BFD LLR/BFD LLCE Yes X + X No X X + X

(1) + (plus) denotes an additional performance requ irement that shall be conducted if the mandatory performance requirement( s) cannot be met.

(2) If the concentration of the CEMS is such that t he specifications for the low level spike recovery/bias factor determination cann ot be met, the facility permit holder shall conduct a low level RATA/bias f actor determination.

(3) Abbreviations used in this attachment are:

Low Level Spike Recovery/Bias Factor Determination (LLSR/BFD) High Level Spike Recovery/Bias Factor Determination (HLSR/BFD) Low Level RATA/Bias Factor Determination (LLR/BFD) Low Level Calibration Error (LLCE) Relative Accuracy Test Audit (RATA) Relative Accuracy (RA) National Institute of Standards Traceability (NIST)


### (B) Test Definitions, Performance Specifications an d Test Procedures

This section explains in detail how each performanc e requirement is to be conducted.

(1) Low Level Calibration Error218.1-28 AVAQMD RULE 218.1 Continuous Emission Monitoring Performance Specific ations The low level CE test is defined as challenging the CEMS (from probe to monitor) with certified calibration gases (e.g., NO in N 2 ) at three (3) levels in the 0-20 percent Full Span Range. Since Certifi ed Gas Mixtures or standards may not be available at the concentration s required for this test, gas dilution systems may be used, with District app roval, if they are used according to either District or EPA protocols as sp ecified in Rule 218.1, for the verification of gas dilution systems in the field. The CEMS highlevel calibration gas may be diluted for the purpos e of conducting the low level CE test.

(a) Performance Specifications

Introduce pollutant concentrations at approximately the 20 percent, 10 percent, and 5 percent of full span levels throu gh the normal CEMS Calibration system. No low level CE shall exc eed 2.5 percent of full scale span.

(b) Testing Procedures

(i) Perform a standard zero/span check; if zero or span check exceeds 2.5 percent full span, adjust monitor and r edo zero/span check. (ii) After zero/span check allow the CEMS to sample stack gas for at least 15 minutes. (iii) Introduce any of the low level CE or standard s through the CEMS Calibration system. (iv) Read the CEMS response to the calibration gas starting no later than three (3) system Response Times after introducing the calibration gas; the CEMS response shall be averaged for at least three (3) Response Times and for no longer than six (6) Response Times. (v) After the low level CE check allow the CEMS to sample stack gas for at least 15 minutes. (vi) Repeat steps (iii) through (v) until all three (3) low level CE checks are complete. (vii) Conduct post test calibration and Zero Checks

. (2) Spike Recovery and Bias Factor Determinations

Spiking is defined as introducing known concentrati ons of the pollutant of interest (e.g., gas standard to contain a mixture o f NO and NO 2 is representative of the ratio of NO and NO 2 in stack gas) and an appropriate non-reactive, noncondensable and non-soluble tracer gas from a single cylinder (EPA Protocol as specified in Rule 218.1 o r NIST traceable to two (2) percent analytical accuracy if no EPA Proto col is available) near the probe and upstream of any sample conditioning s ystems, at a flow rate not to exceed 10 percent of the total sample gas fl ow rate. The purpose ofAVAQMD RULE 218.1 218.1-29

Continuous Emission Monitoring Performance Specific ations

the 10 percent limitation is to ensure that the gas matrix (water, CO 2 , particulates, interferences) is essentially the sam e as the stack gas alone. The tracer gas is monitored in real time and the ra tio of the monitored concentration to the certified concentration in the cylinder is the dilution factor. The expected pollutant concentration (dilu tion factor times the certified pollutant concentration in the cylinder) is compared to the monitored pollutant concentration.

(3) High Level Spike Recovery/Bias Factor Determina tion

The high level spike recovery/bias factor determina tion is used when it is technologically not possible to certify the CEMS pe r the standard Rule 218.1 requirements. The spiking facility/interface shall be a permanently installed part of the CEMS sample acquisition syste m and accessible to the APCO as well as the CEMS operator.

(a) Performance Specifications

The CEMS shall demonstrate a RA ≤ 20 percent, where the spike value is used in place of the Reference Method in the normal RA calculation, as described below.

(b) Testing Procedures

(i) Spike the sample to the CEMS with a calibration standard containing the pollutant of interest and CO or othe r nonsoluble, non-reacting alternative tracer gas (alter native tracer gas) at a flow rate not to exceed 10 percent of the CEMS sampling flow rate and of such concentrations as to produce an expected 40-80 percent of full scale spa n for the pollutant of interest and a quantifiable concentrat ion of CO (or alternative tracer gas) that is at least a fact or of 10 higher than expected in the unspiked stack gas. Th e calibration standards for both pollutants of intere st and CO (or alternative tracer gas) must meet Rule 218.1 requirements. (ii) Monitor the CO (or alternative tracer gas) usi ng an appropriate continuous (or semi-continuous if neces sary) monitor meeting the requirements of SCAQMD Method 100.1 and all data falling within the 10-95 percent full scale span, and preferably within 30-70 percent full scal e span. (iii) Alternate spiked sample gas and unspiked samp le gas for a total of nine (9) runs of spiked sample gas and ten runs of unspiked sample gas. Sampling times should be sufficiently long to mitigate Response Time and ave raging effects.218.1-30 AVAQMD RULE 218.1 Continuous Emission Monitoring Performance Specific ations (iv) For each run, the average CEMS reading must be between 40 percent full scale span and 80 percent full scal e span. If not, adjust spiking as necessary and continue runs, but expected spike must represent at least 50 percent o f the total pollutant value read by the CEMS. (v) Calculate the spike recovery for both the pollu tant and the CO (or alternative tracer gas) for each run by firs t averaging the pre- and post-spike values for each r un and subtracting that value from the spiked value to yie ld nine (9) values for recovered spikes. (vi) Using the CO (or alternative tracer gas) spike recovery values for each run and the certified CO (or altern ative tracer gas) concentration, calculate the dilution r atio for each run. Multiply the certified pollutant concent ration by the dilution factor for each run to determine the e xpected diluted pollutant concentrations. Using the expect ed diluted concentrations as the “Reference Method” va lue, calculate the Relative Accuracy. The RA shall be ≤ 20 percent.
(4) Low Level Spike Recovery/Bias Factor Determinat ion

The low-level spike recovery/bias factor determinat ion is used to determine if a significant bias exists at concentra tions near the 10 percent full scale span level. The spiking facility/interf ace shall be a permanently installed part of the CEMS sample acquisition syste m and accessible to the APCO staff as well as the CEMS operator.

(a) Performance Specifications

There are no pass/fail criteria with respect to the magnitude of the percent RA. There are performance criteria for the range of concentration on the CEMS the extent to which the s pike must be greater than the background pollutant level.

(b) Testing Procedures

(i) Spike the sample to the CEMS with a calibration standard containing the pollutant of interest and CO or othe r nonsoluble, non-reacting alternative tracer gas (alter native tracer gas) at a flow rate not to exceed 10 percent of the CEMS sampling flow rate and of such concentrations as to produce an expected 10-25 percent of full scale spa n for the pollutant of interest and a quantifiable concentrat ion of CO (or alternative tracer gas) that is at least a fact or of 10 higher than expected in the unspiked stack gas. Th e calibration standards for both pollutants of intere st and COAVAQMD RULE 218.1 218.1-31

Continuous Emission Monitoring Performance Specific ations (or alternative tracer gas) must meet Rule 218.1 requirements. (ii) Monitor the CO (or alternative tracer gas) usi ng an appropriate continuous (or semi-continuous if neces sary) monitor meeting the requirements of SCAQMD Method 100.1 and all data falling within the 10-95 percent full scale span, and preferably within 30-70 percent full scal e span. (iii) Alternate spiked sample gas and unspiked samp le gas for a total of nine (9) runs of spiked sample gas and ten runs of unspiked sample gas. Sampling times should be sufficiently long to mitigate Response Time and ave raging effects. (iv) For each run, the average CEMS reading must be below 25 percent full scale span and >10 percent full scale span. If not, adjust spiking as necessary and continue runs; but expected spike must represent at least 50 percent o f the total pollutant value read by the CEMS. (v) Calculate the spike recovery for both the pollu tant and the CO (or alternative tracer gas) for each run by firs t averaging the pre- and post-spike values for each r un and subtracting that value from the spiked value to yie ld nine (9) values for recovered spikes. (vi) Using the CO (or alternative tracer gas) spike recovery values for each run and the certified CO (or altern ative tracer gas) concentration, calculate the dilution r atio for each run. Multiply the certified pollutant concent ration by the dilution factor for each run to determine the e xpected diluted pollutant concentrations. Using the expect ed diluted concentrations as the “Reference Method” va lue, calculate the RA as specified in Rule 218.1. If th e average difference is less than the CC then no low level bi as factor is applied. If the average difference is greater t han the CC and the average expected spike is less than the ave rage CEMS measured spike, then no low level bias factor is applied. If the average difference is greater than the CC and the average expected spike is greater than the average CEMS measured spike, then a low level bias factor e qual to the absolute value of the average difference is add ed to data reported at or below the 10 percent of full scale s pan.
(5) Low Level RATA/Bias Factor Determination using Enhanced Reference Method 6.1

A low level RATA/bias factor determination is desig ned to determine if there exists a statistically significant bias at lo w level concentrations. It consists of nine (9) test runs that measure the sta ck concentration and the CEMS concentration concurrently.218.1-32 AVAQMD RULE 218.1 Continuous Emission Monitoring Performance Specific ations (a) Performance Specifications

There are no pass/fail criteria with respect to the magnitude of the percent Relative Accuracy. There are performance c riteria for the special RATA with respect to the Reference Method a nd range of concentration on the CEMS.

(b) Testing Procedures

The Reference Method for the low level RATA/bias fa ctor determination is SCAQMD Method 100.1

(i) Perform a minimum of nine (9) runs of low level RATA for CEMS versus the Reference Method at actual levels (unspiked). (ii) The full scale span range for the Reference Me thod shall be such that all data falls with 20 - 95 percent of fu ll scale
span range. (iii) The Reference Method shall meet all SCAQMD Me thod 100.1 performance criteria. (iv) Calculate the average difference (d = CEMS - R eference Method, ppm) and CC (cc = statistical calculated, p pm). (v) If d > 0 then the bias = 0 ppm; if d < 0 and |d | > cc then bias = d; if d <0 and |d| < cc then bias = 0 ppm.


### (C) Testing Frequency

For each CEMS, perform the aforementioned performan ce requirements once a year thereafter. These annual assessments shall be completed within six (6) months of the end of the calendar quarter in which the CEMS was originally certified.

See SIP Table at http://www.avaqmd.ca.gov/Modules/ShowDocument.aspx? documentid=921