# Presentation: 438708

## Implementing Rectangular Duct Wall Effects (CTM-041)

- John Schakenbach, USEPA
- Steve Norfleet, RMB Consulting & Research, Inc.
- EPRI CEM User Group
- Milwaukee, WI
- May 4-6, 2004

## What is CTM-041?

- CTM-041 is an optional conditional test method to account for wall effects in rectangular ducts or stacks

## What’s a Conditional Test Method?

- A CTM has been evaluated by EPA, but is not published in the Code of Federal Regulations
- Must be approved by EPA before being used to meet Parts 60, 61, 63 or 75
- May be used by, e.g., Title V permits and SIPs with EPA oversight and public notice and comment
- EPA staff may not be the technical experts
- Additional info at: www.epa.gov/ttn/emc, then click on Methods

## What is a Rectangular Duct Wall Effect?

- Velocity decreases to zero at duct wall
- More wall effects than circular stack due to higher circumference to cross-sectional area ratio

## Why is This a Problem?

- Neither Method 2 nor 2H account for these wall effects; may cause  overreporting of emissions

## How Do I Use CTM-041?

- DR or AAR submits a one time written request to EPA (for address, go to: www.epa.gov/airmarkets, click on Recent Additions near top left corner, and scroll to December 18, 2003)
- Request may cover all units for which DR/AAR is responsible

## How Do I Use CTM-041?

- Request must contain:
- Plant name
- Unit ID
- Stack/pipe ID
- ORISPL #
- Wall effects start date and time

## How Do I Use CTM-041?

- Part 75 or NOx SIP Call units may provisionally apply CTM-041 retroactively to Jan 1 of the year CTM-041 is performed, but no earlier than Jan 1, 2004.  If necessary, EDRs may be resubmitted.
- All EPA approvals will be conditioned:
-     “The rectangular duct cross-sectional area may not be adjusted to account for any build-up of particulate matter or other material in the bottom of the duct when calculating stack gas volumetric flow.”

## Get Detailed Info

- www.epa.gov/airmarkets, then click on “Recent Additions” near top left corner and scroll to February 2, 2004 and December 18, 2003
- A copy of CTM-041
- General info on conditional test methods
- Where to send the request to use CTM-041
- Detailed EDR reporting instructions
- Spreadsheets
- Most recent version of MDC software (v 4.2.46) to QA data

## Summary of CTM-041

- May use site-specific default WAF, or
- May make wall effects measurements and calculate average WAF using 3 or more test runs
- The run (for default) or 3 run average (for measured) used to calculate a WAF must have same number of Method 1 traverse points as is used in the most recent flow monitor RATA
- Not load level dependent
- Not necessarily connected with a RATA
- WAF entered as correction to cross-sectional area
- During RATA, WAF would be applied to both installed flow monitor and RM data

## Summary of CTM-041

- A site-specific default WAF can be calculated using Section 8.4.2 of CTM-041, and either a run from the most recent flow RATA, or from a single Method 2, 2F or 2G non-RATA run.
- The run used to calculate a default WAF must have same number of Method 1 traverse points as is used in the most recent flow monitor RATA

## Report CTM-041 Using RT 910s

- Each quarter you use WAF, report 6 to 11 RT 910s
- The WAF RT 910s must be reported consecutively and the sequence must be uninterrupted
- If non-WAF RT 910s are required, separate them from WAF RT 910s with blank RT 910s

## Report CTM-041 Using RT 910s

- (1) Report “RECTANGULAR DUCT WAF”
- (2) Report width of rectangular duct at test location
- (3) Report depth of rectangular duct at test location
- (4) Report the WAF applied to flow rate data
- (5)Indicate WAF calculation approach, I.e., report “D” for default or “T” for tested (measured) value
- (6) Report the date on which WAF was first applied to flow data

## Report CTM-041 Using RT 910s

- (7) If WAF is a measured value, report date of WAF test
- (8) If WAF is a measured value, report the number of runs in the WAF test
- (9) If WAF is a measured value, report the number of Method 1 traverse points in WAF test runs
- (10) If WAF is a measured value, report the number of test ports at which measurements were made during WAF test runs
- (11) Report number of Method 1 traverse points in flow RATA test runs.  This record required only if a flow RATA was done during the quarter using Method 2, 2F, or 2G, corrected for wall effects with a measured WAF.

## Report CTM-041 Using RT 910s

- Report the RT 910s in each quarterly EDR for as long as the WAF is used.  If a new WAF is determined, update the RT 910s.

## Reporting Example #1

- Unit 2 discharges through a rectangular stack 14 ft  wide and 12.5 ft deep.  A certified flow monitor is installed on the stack.  A default WAF of 0.9650 is obtained using CTM-041, the WAF is first applied to the flow data on Oct 15, 2003.
- 	In this example, the following WAF information is required to be reported in RT 910 in the 4Q 2003 EDR:
- 		9102    RECTANGULAR DUCT WAF
- 		9102    14.0
- 		9102    12.5
- 		9102    0.9650
- 		9102    D
- 		9102    20031015

## Reporting Example #2

- Unit 3 has a flow monitor in a rectangular duct 10.3 ft wide and 8.9 ft deep.  On Oct 15, 2003, CTM-041 is used to obtain a measured WAF.  Three wall effects runs are performed with 12 Method 1 traverse points per run, measured at 4 different test ports, and an average WAF of 0.9550 is obtained.  The WAF is applied to the flow data starting Oct 16, 2003.  The annual flow RATA for Unit 3 is performed on Dec 10, 2003 using Method 2, with 12 Method 1 traverse points per run.  The measured WAF is applied to the reference method flow rate data.

## Reporting Example #2

- 	In Example #2, the following WAF information is required to be reported in RT 910 in the 4Q 2003 EDR:
- 		9103    RECTANGULAR DUCT WAF
- 		9103    10.3
- 		9103    8.9
- 		9103    0.9550
- 		9103    T
- 		9103    20031016
- 		9103    20031015
- 		9103    3
- 		9103    12
- 		9103    4
- 		9103    12	[Note: This RT 910 would not be submitted
- 				every quarter]

## Hints Regarding Flow-to-Load

- WAF may cause flow to decrease by about 5% which may cause flow-to-load test failure if the RATA on which reference Q/L is based was unadjusted for WAF.  Effect is temporary and will disappear when next normal load flow RATA is done and WAF is applied to it.

## Hints Regarding Flow-to-Load

- In interim, if the flow-to-load test is failed:
- Copy your quarterly flow rate data, export it outside of DAHS, perform the flow-to-load analysis using uncorrected hourly flow rates (uncorrected flow = reported flow / WAF).  If you exercise this option, report results in RT 606 and put a note in RT 910 (insert a blank RT 910 to separate this comment from the required sequence of RT 910s) indicating that WAF was removed from flow rate data before running flow-to-load ratio test.  Keep results of data analysis on-site in format suitable for inspection.

## Hints Regarding Flow-to-Load

- In RT 220, report the WAF corrected flow in columns 29 and 39 whether or not you remove WAF from flow rate data to perform flow-to-load ratio test

## Reporting CTM-041 Data

## Sources Approved to Use CTM-041

## For a Copy of Presentation

- www.epa.gov/airmarkets, click on “Recent Additions” near top left corner
- 					or
- 			John Schakenbach
- 			Phone:  202-343-9158
- 		  	schakenbach.john@epa.gov