(Adopted May 14,1999) 

- RULE 218.1. CONTINUOUS EMISSION MONITORING 

PERFORMANCE SPECIFICATIONS 

(a) Definitions 

(1) ANALYZER - the part of the continuous emission monitoring system 

(CEMS) that analyzes the appropriate gaseous constituents of the conditioned 

gaseous sample or measures stack gas volumetric flow and fuel flow rates, as 

applicable. 

(A) Contaminant Analyzer - the part of the CEMS that detects the air 

contaminant concentrations and represents those concentrations in a 

signal output. 

(B) Diluent Analyzer - the part of the CEMS that detects oxygen, carbon 

dioxide or other diluent gas concentrations as represents those 

concentrations in a signal output. 

(C) Fuel Flowmeter - the part of the CEMS that detects the parameters of 

all essential measurement sub-systems (e.g., temperature, pressure, 

differential pressure, frequency, gas density, gas composition, heating 

value) and generates signal outputs which are a function of the fuel 

flow rate and all essential measurement sub-system parameters. 

(D) Stack Flowmeter -. the part of the CEMS that detects the parameters 

fiom all essential measurement sub-systems (e.g., temperature, static and 

atmospheric pressure, gas density, gas composition, molecular weight, 

gas moisture content) and generates signal outputs which are a function 

of the stack gas volumetric flow rate and all essential measurement subsystem parameters. 

(2) CALIBRATION - a procedure performed to ensure that the CEMS accurately 

measures and records the concentration of the specific air contaminant or 

diluent gas, flow rate and other parameters necessary to generate the required 

data, as evidenced by calibration 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 output or response over 

a specific period of normal continuous operation when the air contaminant or 

diluent gas concentration at the time of the measurements is the same known 

Rule 218.1 - 1 
RULE 218.1 (Cont.) (Adopted May 14,199) 

upscale value. .CD is expressed as the sum of the absolute value of the mean 

difference and the absolute value of the confidence coefficient of a series of 

tests, to the hll span range, expressed as a percentage as follows: 

CD = 121 + ICCI 

x 100 

FSR 

Where: 

FSR = Full span range 

ICC( = Absolute value of the 95% confidence coefticient 

121 = Absolute value of the mean difference. The mean 

difference, d, is calculated as: 

Where: 

n 

1 di = Algebraic sum of the individual differences di 

i= 1 

n = Number of data points 

di = The difference between the paired response values 

of the monitoring system 

(5) CALIBRATION ERROR (CE) 

(A) CALIBRATION ERROR , as applicable to Section (c), "Standards for 

Existing CEMS" - the ratio of the difference between 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 calculated as the ratio of the sum of the absolute 

values of the mean difference and the 95 percent confidence coefficient 

of a series of tests, to the gas concentration, expressed as a percentage, as 

follows: 

CE = ldl+ lCCI x 100 

C 

Where: 

C = Calibration gas concentration 
RULE 218.1 (Cont.) (Adopted May 14,199) 

ICC~ = Absolute value of the 95% confidence coefficient 

Id1 = Absolute value of the mean difference. The mean 

difference is calculated as: 

Where: 

n 

di = Algebraic sum of the individual differences di 

i=l 

n = Number of data pairs 

di = 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 (b), "Standards for 

New or Modified CEMS" - the ratio of the absolute value of the 

difference between the air contaminant or diluent gas concentration 

indicated by the CEMS and the known concentration of the calibration 

gas, to the full span range, expressed as a percentage, as follows. 

CE = --- IC-AI x 100 

FSR 

Where: 

C = Calibration gas concentration 

A = Actual response or the concentration indicated by the 

monitoring system 

FSR = Full span range of the instrument 

(6) CEMS AVAILABILITY PERCENTAGE - a percentage calculated as the 

ratio of the total unit operating hours for which the CEMS provided qualityassured data, to the source total unit operating hours during a specified period, 

excluding periods of calibration, maintenance, repair, or audit, up to a 

maximum of 40 hours per month. 

(7) CERTIFIED CEMS - a CEMS installed, tested, operated, maintained, and 

calibrated according to the applicable requirements of Rules 21 8 and 21 8.1; 

that has met the applicable performance specifications of Rule 2 18.1 and, has 
RULE 218.1 (Cont.) (Adopted May 14,199) 

received written approval and conditions thereto applying, from the Executive 

Officer. 

(8) CERTIFIED GAS MIXTURE - a gas mixture manufactured, analyzed and 

certified in accordance with the "EPA Traceability Protocol for Assay and 

Certification of Gaseous Calibration Standards" - EPA-600/R97/12 1, 

September 1997 Revision (EPA Traceability Protocol) or any subsequent 

version published by EPA. This definition incorporates 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: 

Where: 

S d = Standard deviation 

n = Number of data in a series of tests 

b.975 = t-value (see Table of t-Values below) 

Table of t-Values* 

* The t-values in this table are already corrected for 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 determine air 

contaminants and diluent gas concentrations andfor mass emission rate of a 

source effluent (as applicable). The CEMS consists of three major 

subsystems: sampling interface, analyzer and data acquisition system. 
RULE 218.1 (Cont.) (Adopted May 14,199) 

(1 1) CONTINUOUS MONITORING - a monitoring in which a minimum of one 

measurement (e.g., concentration, mass emission, flow 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 results, thus creating 

a permanent record of the output signal in terms of concentration, flow rate, 

and any other applicable parameter necessary to generate the required data in 

units of applicable standard. The DAS consists of al1,equipment such as a 

computer required to convert the original recorded 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 significantly larger than the air 

contaminant. 

(14 ) FULL SPAN RANGE - the full range of values 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 difference between the reference 

value and the mean CEMS response value, to the reference value. LE is 

calculated as follows: 

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 concentration, interfering 

substances, or CEMS that is deemed by the Executive Officer to have a 

potential for adversely affecting the ability of the CEMS to provide accurate, 

precise and timely data representative of the stack emissions for which the 

CEMS (or SCEMS) is required. 
RULE 218.1 (Cont.) (Adopted May 14,199) 

(17) NINETY-FIVE PERCENT CONFIDENCE INTERVAL - the statistical 

estimation denoting a range of values which is expected to include a true value 

with a 95 percent probability. 

(18)' OPERATIONAL PERIOD - a minimum period of 168 continuous hours 

during which the CEMS shall operate, according to the manufacturer's written 

performance and equipment specifications, without unscheduled maintenance, 

repair, or adjustment. 

(19) QUALITY ASSURANCEIQUALITY CONTROL (QA/QC) PLAN - a 

written document in which the specific procedures for the operation, 

calibration and maintenance of a certified CEMS are described in detail, 

including additional quality assurance assessments and the corrective action 

system. The purpose of this plan is to ensure that the CEMS generates, 

collects and reports valid data that is precise, accurate, complete, and of a 

quality that meets the requirements, performance specifications, and standards 

of Rules 218 and 218.1. 

(20) REFERENCE METHOD (RM) - the official test method employed by the 

District to determine compliance with the rules or permit conditions. A list of 

reference methods is identified in Table 1. 

(21) RELATIVE ACCURACY (RA) - the absolute mean difference between the 

gas concentration or emission rate determined by the CEMS and the value 

determined by the RM plus 2.5 percent error of confidence coefficient of a 

series of tests, divided by the mean of the RM tests. 

(22) RELATIVE ACCURACY AUDIT (RAA) - the RA test expressed in terms of 

the ratio of the relative difference between the mean reference method value 

and the mean CEMS response value, to the mean value determined by the 

reference method or applicable standard for concentration, flow or mass 

emission rate. Unless otherwise specified, RAA shall have the same 

specifications and requirements as the Relative Accuracy Test Audit (RATA), 

except that the RAA shall require a minimum of three data sets. When a rule 

requires a correction of the air contaminant concentration to a specific 02 or 

C02 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: 
RULE 218.1 (Cont.) (Adopted May 14,199) 

Where: 

- 

RM. = Mean of the values determined by the reference 

method or applicable standard 

- 

r = Mean of the CEMS response values 

(23) RELATIVE ACCURACY TEST AUDIT (R4TA) - the R4 test expressed in 

terms of the ratio of the sum of the absolute mean difference between the 

CEMS-generated data and the value determined by the applicable reference 

method or applicable standard and the absolute 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 to a specific 02 or C02 concentration, the relative 

accuracy requirement shall apply to the corrected concentration value. The 

R4 of a RATA data set is calculated and expressed as a percentage as follows: 

Where: 

Id1 = Absolute value of the mean difference 

lCCl = Absolute value of the 95% confidence coefficient 

RM = Average RM value or applicable standard 

The arithetic mean of the difference, d, of a set of data is calculated as 

follows: 

Where: 

n 

di = Algebraic sum of the individual differences di 

i=l 

di = The difference between the reference method value 

and CEMS value, both in units of the applicable 

standard 

n = Number of data points 

(24) RESPONSE TIME - the time interval from a step change in the air 

contaminant or gas diluent concentration to the time when 95 percent of the 

corresponding final value is reached as displayed on the CEMS data recorder 

or acquisition system. The response time is determined by introducing a 
RULE 218.1 (Cont.) (Adopted May 14,199) 

certified gas mixture into the CEMS upstream of the sampling interface and 

as close to the probe inlet as practicable. 

(25) ROUTINE MAINTENANCE - preventive evaluation and repair (if 

necessary) of CEMS performed at specified intervals to preclude system 

failure. Routine maintenance may be performed as recommended by the 

manufacturer or a documented standard operating procedure determined 

through operating experience and approved by the Executive Officer. 

Repairs to a malhctioning system are excluded from this definition. 

(26) SAMPLING INTERFACE - that part of the CEMS that performs sample 

acquisition using one or more of the following operations: extraction, 

physicaVchemical separation, transportation or conditioning of a 

representative sample from a designated source. 

(27) SEMI-CONTINUOUS EMISSION MONITORING SYSTEM (SCEMS) - 

the total combined equipment and systems required to semi-continuously 

determine air contaminants and diluent gas concentrations andlor mass 

emission rate of a source effluent (as applicable). The SCEMS consists of 

three major subsystems: sampling interface, analyzer and data acquisition 

system. This class of monitoring includes but is not limited to gas 

chromatography, integrated sensitized tape analyzer, other sample integration 

based technologies, and time-shared CEMS. 

(28) 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 sampling probe inlet as practicable, 

and when the same calibration gas is introduced directly to the analyzer. 

(29) SYSTEM FAILURE - inability of the CEMS to meet the requirements of 

Rule 218.1. 

(30) TIME-SHARING - a monitoring technique where an analyzer and possibly 

the associated sample conditioning system is used on more than one source. 

(31) ZERO CHECK- a procedure performed to determine the response of the 

CEMS to a given zero gas standard by means of injecting the zero gas into the 

CEMS as close to the probe tip as practical. 

(32) ZERO DRIFT (ZD) is the change in the monitoring system outputfresponse 

over a stated period of time of normal continuous operation when the air 

contaminant or diluent gas concentration at the time of the measurements is 

zero. The values for ZD shall be expressed as the ratio of the sum of the 

absolute value of the mean of the difference between paired instrument 
RULE 218.1 (Cont.) (Adopted May 14,199) 

response values and the absolute value of the CC, to the full span range, 

calculated as a percentage as follows: 

Where: 

S = Full span range 

JCCI = Absolute value of the confidence coefficient . . 

Id1 = Absolute value of the mean difference. The mean 

difference is calculated as: 

Where: 

n 

di = Algebraic sum of the individual differences di 

i=l 

n = Number of data pairs 

di = The difference between a pair of instrument response 

values 

(33) ZERO GAS - a gas containing less than a specified amount of the contaminant 

or diluent gas which, when periodically injected into the CEMS, is used to 

check CEMS' response to the absence of the air contaminant or diluent gas. 

(b) Standards for New or Modified CEMS 

In order to be a Certified CEMS, a CEMS subject to the provisions of Rule 218 

Sections (c)(l), (d)(l)(C), (d)(l)(D)(i), (d)(2)(C) and (d)(2)(D), as applicable, shall 

meet the operational requirements, performance specifications, and standards as 

follows: 

(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 enables measurements of 

air contaminant and diluent gas concentration, and flow rates can be 

made which are representative of the stack emissions of the source. 

(B) Sampling Location 
RULE 218.1 (Cont.) (Adopted May 14,199) 

The monitoring system sampling probe tip and the reference method 

sampling 'port locations shall be determined according to District 

Method 1 .I. The monitoring sampling probe shall be located where a 

sample may be obtained which is representative of the source emissions. 

Each probe shall not interfere with the other when in use. Other 

locations may be chosen subject to a written approval of the Executive 

Officer. If an alternate location is chosen which does not conform with 

District Method 1.1, the absence of flow disturbance shall be 

demonstrated using the District method in the source Test Manual, 

Chapter X, Section 1.4 - "Alternative Site Selection Method", or 40 

CFR, Part 60, Appendix A, Method 1, Section 2.5 - "Alternative 

Measurement Site Selection Procedure", and, the absence of 

stratification shall be demonstrated using the District method in the 

source Test Manual, Chapter X, Section 13 - "Determination of Gaseous 

Constituent Stratification". Alternatives to sampling site selection in the 

presence of stratification are presented in Rule 2 18.1 (b)(3)(C)(ii). 

(C) Full Span Range (FSR) 

(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 specified in the 

applicable rule or permit condition. The FSR may be set at a value 

other than that specified, but no lower than 120 percent, provided 

that the CEMS owner or operator demonstrates to the satisfaction 

of the Executive Officer that the FSR will not be exceeded. Such 

demonstrations may include, but not limited to, historical 

emissions data, historical process information, and historical 

operational information. A written approval from the Executive 

Officer shall be obtained before the FSR may be modified outside 

of the 150 to 200 percent 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 (ii) above in 

situations where the normal concentration of the air contaminant 

emitted is significantly less than the allowable concentration limit. 

The CEMS shall have the capability to automatically change from 
RULE 218.1 (Cont.) (Adopted May 14,199) 

one range to the other as appropriate to the monitor's measured 

concentration. 

(iv) For diluent monitors, the FSR shall be set such that the full range 

of oxygen and carbon dioxide concentrations can be measured. 

The FSR shall be set at 25.0 percent 0, (maximum) and 1.0 

percent CO, (minimum) concentrations, or at a value approved by 

the Executive Oficer. 

(v) Should any data points fall below 10 percent of the FSR, those data 

points shall be reported according the following, as applicable: 

(I) For CEMS with certified multiple span ranges, the owner 

shall report data that falls below 10.0 percent of the higher 

FSR and above 95 percent of the lower FSR, at the 10.0 

percent value of the higher FSR, 

(11) In the event that any of the data points gathered 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, 

(111) 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 21 8 and Rule 21 8.1, as applicable) the owner or 

operator may elect to use the following to measure and report 

contaminant concentrations: 

(a) Report data at 10.0 percent FSR value, or, 

(b) 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. of FSR, the value 

shall be invalid for quantification and the CEMS shall be 

considered unavailable for the purposes of determining CEMS 

availability percentage. All excursions above 95 percent of FSR 

and the duration of these excursions shall be reported in the CEMS 

summary report as prescribed under Rule 2 18(f). 

Strip Chart Recorder 
RULE 218.1 (Cont.) (Adopted May 14,199) 

(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% of the span, and 

a minimum of 100 chart divisions. 

(ii) For CEMS where the strip chart recorder is used as a back-up 

system or for recording data from only a single parameter, a strip 

chart of lesser size than specified in Section (D)(i) above, may be 

proposed in the application. 

(iii) For CEMS equipped with multiple-span ranges, the chart 

recorder shall have the capability to automatically change span, 

as appropriate. 

Data Acquisition System (DAS) 

(i) The DAS shall maintain all recorded data in accordance with 

Rule 21 8, Section (e). 

(ii) For CEMS, DAS shall acquire data from monitored parameters at 

least once every minute. 

(iii) For SCEMS, DAS shall acquire data from monitored parameters 

at least once every 15 minutes. 

(iv) DAS acquisition rate shall be set at a constant rate such that the 

data points are equally spaced. 

(v) All valid data points shall be used to determine compliance with 

applicable limit(s), and, for certification testing and RATA(s). 

(vi) DAS sample acquisition rate during certification and RATA(s) 

shall be the same as the DAS sample acquisition rate during 

normal CEMS, or SCEMS, operation. 

(F) Operational Period 

The operational period before any certification tests shall be a minimum 

of 168 continuous hours. 

(2) Certification Requirements and Performance Specifications for New or 

Modified CEMS 

Rule 2 18(c)(l) provides that a series of certification tests shall be performed to 

demonstrate the acceptability of CEMS performance. The requirements and 

specifications in conducting initial certification tests follow: 

(A) Calibration Error (CE) Testing 
RULE 218.1 (Cont.) (Adopted May 14,199) 

The 24-Hour CE test shall be performed at the low and high ranges, 

namely 0 to 20 and 80 to 100 percent of FSR, respectively. 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 flow monitors, when an 

electronic calibration check is applicable. 

The 24-hour CE test shall be performed once each day as close to 24- 

hour intervals as practicable, with a total of eight (8) consecutive tests 

performed. The CE specifications shall not be exceeded on any of the 

tests during the entire testing period. 

(B) Analyzer Enclosure 

(i) The analyzer shall be contained in an environmentally controlled 

enclosure. An alarm and recording device shall be incorporated 

into the system to alert the operator to make corrective action 

should the analyzer exceed the manufacturer's recommended 

specifications for temperature drift. 

(ii) Alternatively, the owner or operator of the CEMS may choose to 

perform the 2-hour CE tests in-lieu of meeting the analyzer 

enclosure requirement in Section(b)(2)(B)(i). The 2-hour CE test 

shall be performed once every two hours as close to 2-hour 

intervals as practicable, with total of thirteen consecutive tests 

performed. The 2-hr 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 specifications in 

Sections (b)(2)(A)(i) and (ii) shall apply to 2-hour CE. 

(iii) The owner or operator of the CEMS may qualify for an 

exemption fiom Section(b)(2)(B)(i) to provide environmental 

controls for. the analyzer enclosure by demonstrating, to the 

satisfaction of the Executive Officer, that the CEMS is located: 

(I) In a geographic area where seasonal high and low 

temperatures do not exceed the operational temperature 

specifications for the analyzer, 

(11) In a geographic area where monthly maximum temperature 

variation is less than 30°F for all months of the year, and 
RULE 218.1 (Cont.) (Adopted May 14,199) 

(111) The CEMS is located in a site that is protected from 

radiation and convection heating sources. 

Relative Accuracy 

RATA shall be performed for raw contaminant concentration, and if 

applicable, for corrected concentration, emission rate, 02 concentration, 

C02 concentration analyzers, and stack and fuel flow monitors. There 

shall be a minimum of nine sets of test data generated. If the number of 

tests exceeds nine sets, data may be discarded if it is identified as an 

outliers by the technical guidance set forth by the Executive Officer, or 

for valid reasons (e.g., process upsets, CEMS malfunction, etc.) which 

must be substantiated with appropriate documentation and subject to 

approval by the Executive Officer. All data collected shall be submitted 

to the Executive Officer. 

The CEMS shall meet the following RA performance specifications: 

(i) Less than or equal to 20.0 percent of the mean value of the 

reference method for pollutant concentrations, or the de-minimus 

concentration as follows, whichever is greater: 

Pollutant De minimus Concentration 

NOx 1.0 ppm 

so2 2.0 ppm 

CO 2.0 ppm 

Reduced Sulfur Compounds 4.0 ppm 

(ii) Less than or equal to 10.0 percent of the mean value of the 

reference method for diluent concentrations, or the de minimus 

value of 1.0 percent 02, whichever is greater. 

(iii) Less than or equal to 15.0 percent of the mean value of the 

reference method for flow monitors, or the de minimus value 

equivalent to a calculated volumetric flow rate based on 2 feet per 

second stack gas velocity for cases where the mean stack gas 

velocity obtained by the reference method test is less than 15 feet 

per second. 

(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 emission rate based on 2 feet per 

second stack gas velocity for cases where the mean stack gas 
RULE 218.1 (Cont.) (Adopted May 14,199) 

velocity obtained by the reference method test is less than 15 feet 

per second. 

The relative accuracy requirement may be met if the average of the 

differences between the CEMS measured 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 accuracy tests, the CEMS shall 

meet the following requirements, except those that may be waived as allowed 

in Rule 2 18.1, Section (b)(4)(C): 

(A) Response Time 

The response time for CO CEMS shall not exceed 1.5 minutes except 

where there is a technical limitation, in which case the response time 

shall be 5 minutes. The response time for all other CEMS and flow 

monitors, as applicable, shall not exceed 5 minutes. 

(B) Calibration Error 

The CE testing requirements are specified in Section (b)(2)(A). 

(C) Concentration Stratification 

(i) The owner or operator shall demonstrate the absence of 

stratification through testing performed according to the method in 

Chapter X, Section 13 - "Non-Standard Methods and Techniques", 

of the District Source Testing Manual. The number of tests shall 

be determined as follows: 

(I) Test(s) shall be conducted at one load level if the owner or 

operator demonstrates to the satisfaction of the Executive 

Officer that the equipment operates within a 20 percent load 

range for at least 80 percent of the time; 

(11) Test(s) shall be conducted at two different load levels if the 

owner or operator demonstrates to the satisfaction of the 

Executive Officer that the equipment operates within a 50 

percent load range for at least 80 percent of the time; or, 

(111) Test(s) shall be conducted at three different load levels if the 

equipment operates outside of the criteria in Sections 

(b)( 1 )(C)(i)(I) and (11). 

The absence of stratification is considered verified if the difference 

between the highest measured concentration (time normalized) and 
RULE 218.1 (Cont.) (Adopted May 14,199) 

(ii) 

the lowest measured concentration (time normalized) divided by 

the 'average measured concentration (time normalized), when 

expressed as a percentage, is less than or equal to 10 percent. Upon 

verification of the absence of stratification, the owner or operator 

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. The RM for RATA 

may be conducted at a single point 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. 

Should testing demonstrate the presence of stratification, the 

owner or operator may elect one of the following alternatives: 

(I) 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: 

(a) 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 

(b) 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). 

(11) Determine a representative CEMS probe location such that 

the following criteria are met: 

(a) all traverse point concentrations are within 10.0% of 

the average of all traverse point concentrations (time 
RULE 218.1 (Cont.) (Adopted May 14,199) 

normalized), or, the difference is less than or equal to 

1.0 ppm, whichever is greater, and 

(b) there exists at least one traverse point concentration 

(Xr), not located next to the stack or duct wall, that is 

less than or equal to 10.0% each adjacent traverse 

point concentration of Xr, or the difference is less than 

or equal to 1.0 ppm, whichever is greater, and, 

(c) the CEMS probe is located at (or as near as practical) 

Xr with minimum adjacent traverse point 

concentration fluctuations as determined in section 

(ii)(II)(b), above. 

(111) Determine a representative multiple point sampling 

configuration as approved by the Executive Officer, 

following the guidance document by Emission Measurement 

Technical Information Center, "Evaluation Procedure for 

Multi-Hole Sample Probes" (EMTIC GD-03 1) 

(IV) Modify the stack andlor CEMS sampling probe location and 

retest for the absence of stratification. 

(D) Cyclonic Flow 

The owner or operator shall perform tests to verify the absence of 

cyclonic flow for the CEMS and reference method sampling probes. 

The cyclonic flow test shall be required when measuring mass emission 

rates and shall be performed according to the District method in the 

Source Test Manual, Chapter X: Non-Standard Methods and Techniques 

following the testing conditions of Section (3)(C)(i)(I), (11) or (111), as 

applicable. 

(E) Interference 

The owner or operator shall perform tests to verify the absence of 

sampling, analytical and flow interference, as applicable. 

(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 CEMS three times. The same 

gas shall not be used twice in succession. LE shall be less than or equal 

to 5.0 percent of the calibration gas concentration. 

(G) Multiple -Span-Range 
RULE 218.1 (Cont.) (Adopted May 14,199) 

For CEMS that have multiple- span range, all certification tests shall be 

performed at the lowest range. Except for R4 and interference tests, all 

other certification tests shall be performed on other ranges. 

Operational Requirements and Performance Specifications for New or 

Modified CEMS 

After final approval, the CEMS shall be subsequently operated and maintained 

according to the following requirements and specifications: 

(A) 24-HowCE 

CE tests shall be performed once each day as close to 24 hour intervals 

as practicable at the low (0 to 20 percent) and high (80 to 100 percent) 

ranges of concentration. CE test results which are greater than the limits 

specified in Sections (b)(2)(A)(i) and (ii), but less than or equal to 5.0 

percent of the full span range shall be addressed by QNQC Plan 

remediation. The CEMS shall be deemed out-of-control during such 

period when any CE test result is greater than the specified limits and 

greater than 5.0 percent of the full span range, until the CE test meets the 

specifications. All data generated by the CEMS during an out-of-control 

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 

relative accuracy audit required under Rule 2 18 Section (b)(4)(C). The 

CEMS system bias shall not exceed + 5.0 percent of the full span range 

for contaminant analyzers. In addition, the owner or operator shall 

include in the facility QNQC Plan, criteria for excessive drift (e.g. 

control limits on cumulative drift) and appropriate diagnostic techniques 

to identify sources of analyzer drift and system bias when control limits 

are exceeded. 

(C) Relative Accuracy Testing 

UTA and RAA, as applicable, shall be performed at least once every 

12 months. The test shall be completed annually no later than the end of 

the calendar quarter in which the date of the original certification test 

was performed. During any relative accuracy tests after CEMS 

certification, the owner or operator may request a waiver from 

stratification, cyclonic flow, andlor interference requirements in Sections 

(b)(3)(C), (D) and (E), respectively, by submitting to the Executive 
RULE 218.1 (Cont.) (Adopted May 14,199) 

Officer, for approval, any applicable documentation or previous test or 

historical data that meets the stratification, cyclonic flow, andlor 

interference requirements. 

(D) Cylinder Gas Audit (CGA) 

A CGA shall be performed every calendar quarter but in no more than 

three quarters in succession. The CGA shall be conducted according to 

the provisions of 40 CFR 60, Appendix F. The audit gases shall be 

according to the certification requirements'of Rule 2 18.1. 

(E) The Executive Officer may require recertification of the CEMS if the 

annual availability percentage is below 95 percent. Annual CEMS 

availability percentage calculations will be based on the year ending on 

the last day of the calendar quarter in which the CEMS was originally 

certified. 

(F) The owner or operator of a CEMS that requires moisture correction in 

reporting flow and concentration shall measure and monitor moisture in 

the stack gas used for emission data calculations in accordance with the 

written technical guidance document set forth by the Executive Officer. 

Alternatively, with Executive Officer approval, for equipment whose 

moisture source is only from fuel combustion, the operator may 

calculate the moisture content using fuel properties and ambient air 

humidity data or, for processes that saturate the exhaust gas with 

moisture, such as a wet scrubber system, the operator may use the 

saturation temperature for moisture content data. 

(c) Standards for Existing CEMS 

In order to be a Certified CEMS, a CEMS subject to the provisions of Rule 21 8 

Sections (d)(l) and (d)(2), shall meet the following operational requirements and 

performance specifications, and the standards of Rule 2 18.1 Section (d): 

(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 percent 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 percent of FSR 

(E) Zero Drift (24-hour) Less than or equal to 2 percent of FSR 
-- 

RULE 218.1 (Cont.) (Adopted May 14,199) 

(F) Calibration Drift (2-hour) Less than or equal to 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 percent of the mean 

value of the RM test data, or, less than or 

equal to 10 percent of the allowed 

concentration, whichever is greater 

(2) Performance Specifications khi&m+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 percent 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 percent C02 or 02 

(E) Zero Drift (24-hour) Less than or equal to 0.5 percent C02 or 02 

(F) Calibration Drift (2-hour) Less than or equal to 0.4 percent C02 or 02 

(G) Calibration Drift (24 hour) Less than or equal to 0.5 percent C02 or 02 

(3) Full Span Range for Existing CEMS 

The instrument FSR shall be equivalent to approximately 200 percent of the 

concentration limit as specified in the applicable rule, or at a value approved by 

the Executive Officer. Oxygen and carbon dioxide instrument full span 

readings shall be such that the fill range of concentrations encountered can be 

measured. 

(4) Cycle of Operation for Existing CEMS 

The CEMS shall complete a minimum of one cycle of operation (sampling, 

analyzing and data recording), for each successive 15 minute period. 

(d) Standards, Specifications and Requirements for New, Modified and Existing 

CEMS: 

(1) Calibration Gas 

(A) Calibration gas mixtures, as defined in Rule218.1 (a)(8), shall be 

manufactured, analyzed and certified in accordance with the "EPA 

Traceability Protocol for Assay and Certification of Gaseous 

Calibration Standards" - EPA-600/R97/12 1, September 1997 Revision 

(EPA Protocol). The certification period and recertification 

requirements, as applicable, shall be according to the EPA Protocol. 
RULE 218.1 (Cont.) (Adopted May 14,199) 

(B) For gas calibration standards not explicitly covered by the EPA 

Protocol, the CEMS owner or operator shall submit the gas 

manufacturer's alternative certification protocol for the specific 

compound or compounds. 

(i) The procedures of the EPA Protocol shall be used for gas 

calibration standards not explicitly covered therein, except that 

the gas manufacturer must identify a recertificaton period and 

submit data documenting the applicability of this period. The 

gas manufacturer may submit alternative performance standards 

for certification and recertification, based on supporting technical 

data also provided by the manufacturer. This alternative shall be 

subject to the approval of Executive Officer. 

(ii) If there is no existing National Institute of Standards and 

Technology (NIST) standard for the measured parameter, the gas 

manufacturer may submit an alternative reference standard and 

the supporting technical data that define the stability, accuracy, 

and precision of the alternative reference standard. This 

alternative shall be subject to the approval of Executive Officer. 

(iii) The CEMS owner or operator may submit an alternative protocol 

to the EPA Protocol, provided that the CEMS 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 the approval of Executive Officer. 

(C) Compressed andor filtered air, such as instrument air, may also be 

used in lieu of oxygen span gas provided that the CEMS owner or 

operator demonstrates, to the satisfaction of the Executive Officer, 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 

QAIQC plan the process or operation in producing such compressed 

andor filtered air and periodically checking that compressed air andor 

filtered air continues to meet the calibration gas standards. 

Zero Gas 

Zero gases used shall meet the following criteria: 

(A) For gaseous air contaminant monitors, the zero gas shall be certified 

by the manufacturer to contain no more than 0.1 ppm of the air 
RULE 218.1 (Cont.) (Adopted May 14,199) 

contaminant analyzed by the subject monitor or 1.0 percent of the 

applicable standard, whichever is less. 

(B) For carbon monoxide monitors, the zero gas shall be certified by the 

manufacturer to contain less than 0.5 ppm carbon monoxide or 1.0 

percent of the applicable standard, whichever is less. 

(C) For carbon dioxide and oxygen monitors, the zero gas shall be certified 

by the manufacturer to contain less than 1.0 ppm carbon dioxide or 

oxygen. 

(D) Compressed and/or filtered air, such as instrument air, may also be 

used in lieu of zero gas provided that the CEMS owner or operator 

demonstrates, to the satisfaction of the Executive Officer, that it is of 

equivalent quality to the above zero gas standards. As part of such 

documentation, the owner or operator shall include in their QAIQC 

plan the process or operation in producing such compressed and/or 

filtered air and periodically checking that compressed air and/or 

filtered air continues to meet the zero gas standards. 

(3) Automatic Calibration Data 

If automatic adjustments to the monitor settings are made, conduct the 

calibration tests in a way that the magnitude of the adjustments can be 

determined and recorded. 

(4) F-Factors 

The owner or operator shall use in the CEMS calculations the Fd factors listed 

in 40 CFR Part 60, Appendix A, Method 19, Table 19-1, as applicable. When 

alternative fuels are fired, the owner or operator shall submit data to develop 

Fd factors and obtain Executive Officer approval. 

(5) NO, to NO Conversion Efficiency 

The conversion efficiency tests shall be conducted according to the 

requirements of District Method 100.1. The value for the NO, gas shall be 

greater than or equal to the maximum expected or recorded NO, and greater 

than or equal to 20 percent of the FSR. 

Time-Sharing Requirements 

A time-shared CEMS for which an application is submitted after [date of adoption] 

shall meet all of the performance specifications as well as the following 

requirements: 

(1) All sources shall have mutually compatible range(s) of air contaminant gases 

at all times. 
RULE 218.1 (Cont.) (Adopted May 14,199) 

(2) Each source shall have a data-reading period, at a minimum, equal to three 

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 shall be made during 

certification testing. Data are not to be collected following a switch of sample 

sources until a period of time equal to one response time has passed. 

(3) The CEMS shall be capable of performing and recording zero and span 

calibrations at each source, including the calibration factors and correction 

values before and after every automatic calibration. 
RULE 218.1 (Cont.) (Adopted May 14,199) 

Table 1 

REFERENCE METHODS 

RULE 218.1 

District Method 1.1 - Sample and Velocity Traverses for Stationary Sources 

District Method 1.2 - Sample and Velocity Traverses for Stationary Sources with Small 

Stack or Ducts 

District Method 2.1 - Determination of Stack Gas Velocity and Volumetric Flow Rate 

(S-type Pitot tube) 

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

District Method 2.3 - Determination of Gas Velocity and Volumetric Flow Rate from 

Small Stacks or Ducts 

District Method 3.1 - Gas Analysis for Dry Molecular Weight and Excess Air 

District Method 4.1 - Determination of Moisture Content in Stack Gases 

r - District Method 6.1 - Determination of Sulfuric Acid and Sulfur Oxides from Stationary 

Sources 

District Method 7.1 - Determination of Nitrogen Oxide Emissions for Stationary Sources 

District Method 100.1 - Instrumental Analyzer Procedures for Continuous Gaseous 

Emission Sampling 

District Method 307.91 - Determination of Sulfur in a Gaseous Matrix 

EPA Method 6 - Determination of Sulfur Dioxide Emissions from Stationary Sources 

EPA Method 19 - Determination of Sulfur Dioxide Removal Efficiency and Particulate, 

Sulfur Dioxide and Nitrogen Oxides Emission Rates from Electric Utility Steam 

Generator (40 CFR Part 60 Appendix A) 

ASTM Method D 4294 or D 2622-82 - Determination of Sulfur in Liquid Fuels