From: <Myers.Ron@epamail.epa.gov>

To: MDMARET@mactec.com CC: Sorrell.Candace@epamail.epa.gov; WCGRAY@mactec.com; Segall.Robin@epamail.epa.gov; Ray.Merrill@erg.com; Westlin.Peter@epamail.epa.gov;

. . . Date: 7/10/2009 5:00 PM Subject: RE: Duct diameter re OTM 27 Attachments: Pages from OTM27_PM2.5cyclone dimensions.pdf; PM2.5Cylcone Sketches.pdf

Mike: Thanks for all the work and thought into the measur ements and applicability to sampling real stacks. I guess we should not have assumed that the CTM40 (Which was based upon the PR E-4) methods were correct in all their aspects. I guess this means t hat the area of 20.5 square inches that is in the method for the combine d PM10 and PM2.5 cyclone, filter and Pitot are a little (greatly) off. As a result, for our response to comments, we would need to think ab out how we will address this in the final rule. Also, we will need to think real fast to provide guidance to those recipients of the ICR. I think that we might be able to segway into the issue of PM2.5 tes ting only with the comment from CT that comments on sampling in very h ot stacks and the commentors suggestion to place the PM2.5 cyclone in a heated box external to the stack and use a traditional heated probe to get the sample to the cyclone. I think we would need the e xpertise of a particle physisist (Joe McCain who designed this in the first place). Another option would be to revert to single point s ampling based upon the assumption (probably pretty good) that PM2.5 be have very similar to a gas and that isokenetic sampling may not be requi red. I'm open to other suggestions.

When I used the measurements in the Method, I did n ot think about the cyclone being backward and that the filter and prob e were as wide as they are. Also, I did not think that the machinistwould not trim down the external dimensions to parallel the inside dime nsions. I am also attaching a copy of the page in the Metho d with some annotated dimensions from Mikes measurements.

I'll see Ray on Monday and we can discuss the next step.

I wonder what other glitches lurk in all the equati ons and procedures of the particle sizing method. (See attached file: Pages from OTM27_PM2.5cyclone d imensions.pdf)

_________________________________ Ron Myers U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Sector Policy and Programs Division Monitoring Policy Group, D243-05 RTP NC 27711 Tel. 919.541.5407 Fax 919.541.1039 E-mail myers.ron@epa.gov

|------------> | From: | |------------>

>------------------------------------------------

--------------------------------------------------- -----------------------------------------| |"Maret, Michael" <MDMARET@mactec.com> |

>------------------------------------------------

--------------------------------------------------- -----------------------------------------| |------------> | To: | |------------>

>------------------------------------------------

--------------------------------------------------- -----------------------------------------| |Ron Myers/RTP/USEPA/US@EPA |

>------------------------------------------------

--------------------------------------------------- -----------------------------------------| |------------> | Cc: | |------------>

>------------------------------------------------

--------------------------------------------------- -----------------------------------------| |"Werner, Arthur" <ASWerner@mactec.com>, "Gray, W alter" <WCGRAY@mactec.com>, Barrett Parker/RTP/USEP A/US@EPA,Peter Westlin/RTP/USEPA/US@EPA,|

|Jason Dewees/RTP/USEPA/US@EPA, Robin Segall/RTP/ USEPA/US@EPA, <Ray.Merrill@erg.com>, "Joe Fanjoy" <joe.fanjoy@erg.com>, "Danny Greene" | |<Danny.Greene@erg.com> |

>------------------------------------------------

--------------------------------------------------- -----------------------------------------| |------------> | Date: | |------------>

>------------------------------------------------

--------------------------------------------------- -----------------------------------------| |07/10/2009 12:38 PM |

>------------------------------------------------

--------------------------------------------------- -----------------------------------------| |------------> | Subject: | |------------>

>------------------------------------------------

--------------------------------------------------- -----------------------------------------| |RE: Duct diameter re OTM 27 |

>------------------------------------------------

--------------------------------------------------- -----------------------------------------|

Hi Ron,

As we discussed yesterday on the telephone, I have made numerous measurements on a PM2.5 cyclone head, a 47-mm filte r holder, and a probe assembly in order to calculate the projected area ( i.e., blockage of the stack cross-section) when the OTM27 components are inserted into an 18-in diameter stack.

One interesting item of note is that since the inle t to a PM2.5 cyclone is located about 2.75 inches from the end of the cy clone, the tester would be unable to collect a stack gas sample from traverse points 5 or 6. The traverse points would be located 2.6 and 0. 8 inches from the far wall of the stack, respectively. So, aside from th e blockage issue, one might say that the minimum stack diameter for which a PM2.5 cyclone head could be used (and still sample at all traverse poi nts) would be about 62.5 inches.

Using a PM2.5 cyclone only, the minimum blockage wo uld be approximately 4.82 square inches (in2) at the first sample point. The maximum blockage would occur when the cyclone head is inserted into the stack to a depth of 18 inches, and would be approximately 19 .6 in2. These values would correspond to a minimum blockage of about 1.9 percent, a maximum blockage of 7.7 percent, and an average blockage ofabout 4.8 percent. These values include the contribution to blockage o f the cyclone as well as the probe sheath.

When you add the pitot tube assembly (a 3/8-in diam eter tube) the minimum blockage for the example above is about 5.3 2 in2 at the first sample point, and about 30.8 in2 when the assembly in inserted all the way into the stack. Minimum blockage would be abou t 2.1 percent, maximum would be about 12.1 percent and average wou ld be about 7.1 percent.

I also made several measurements of a PM2.5 head wi th a 47-mm filter holder attached. The design of these filter holders varies from manufacturer to manufacturer, so these blockage cal culations should be considered as estimates of a typical PM2.5 cyclone with a filter holder attached to the probe. Our measurement for this co nfiguration indicates that the minimum blockage (at the first sample poin t) would be about 4.82 inches (identical to the case where only the P M2.5 cyclone is used). The maximum blockage (when the cyclone head is inserted into the stack to a depth of 18 inches) would be approximate ly 20.7 in2. These values would correspond to a minimum blockage of ab out 1.9 percent, a maximum blockage of 8.1 percent, and an average blo ckage of about 5.0 percent.

When the pitot assembly is added, the minimum block age for the case when the PM2.5 cyclone and the 47-mm filter holder is us ed would be about5.32 in2 at the first sample point (once again, ide ntical to the first

case) and about 32.0 in2 when the assembly in inserted all the way into the stack. Minimum blockage would be about 2.1 percent, maximum would be about 12.6 percent and average would be about 7. 3 percent.

When only the blockage area calculations are taken into account, it would seem that when the PM2.5 cyclone head (withou t the filter holder or pitot tube) is inserted into the stack, a 16-inc h diameter stack would be the minimum diameter which would yield an average blockage of less that 6 percent. However, the tester would sti ll not be able to locate the nozzle at all of the required sample poi nts due to the geometry of the cyclone head. When the blockage du e to the pitot tube is added, the minimum diameter is approximately 19. 5 inches.

Lastly, in the case where the PM2.5 cyclone head an d the filter holder are inserted into the stack, a minimum diameter of about 16.5 inches would result in an average blockage of less than 6 percent. When the pitot tube is included, a minimum diameter of about20 inches would result in a average blockage of less than 6 percent

. I have attached two rough sketches of the two confi gurations for you. Please feel free to call or e-mail if you would lik e to discuss this issue further.

-M

Michael D. Maret, PE | Project Manager MACTEC Engineering and Consulting, Inc. 5001 S. Miami Boulevard | Suite 300 | Durham, NC 27 703 P.O. Box 12077 | Research Triangle Park, NC 27709-2 077 Office 919-941-0333 ext. 234 | Fax 919-941-0234 E-mail mdmaret@mactec.com | Web www.mactec.com

From: Myers.Ron@epamail.epa.gov [mailto:Myers.Ron@e pamail.epa.gov] Sent: Wednesday, July 08, 2009 2:02 PM To: Maret, Michael Cc: Werner, Arthur; Gray, Walter; Parker.Barrett@ep a.gov; Westlin.Peter@epamail.epa.gov; Dewees.Jason@epamail .epa.gov; Segall.Robin@epamail.epa.gov; Ray.Merrill@erg.com; Joe Fanjoy; Danny Greene Subject: Duct diameter re OTM 27

Mike: We received a question on the use of OTM 27 in a sm all duct. Paragraph 8.3.2.2 provides procedures for adjusting the veloc ity pressures for ducts between 18 and 24 inches due to blockage effe cts when the sampling device blocks between 3 and 6% of the duct area. I n addition, Paragraph 8.7.2.2 describes the basis for needing t he adjustment and the basis for evaluating the blockage amount. In this paragraph, the average combined PM10 and PM2.5 cyclone projected a rea of 20.5 square inches is provided as the basis of calculating the 3 to 6% blockage. While not stated, these adjustments imply that OTM2 7 can not be used in ducts less than 18 inches in diameter. In other pa rts of OTM27, the use of this method with only the PM10 cyclone or only w ith the PM2.5 cyclone is supported. Under these conditions, the use of t he blockage area of 20.5 square inches is incorrect and the need for ve locity pressure adjustments would occur at different diameters than stated in paragraph 8.3.2.2. Here is a link to the proposed methods ( http://www.epa.gov/ttn/emc/proposed/m-201Ar1.pdf ) and OTM27 ( http://www.epa.gov/ttn/emc/prelim/otm27.pdf ). The existing promulgated Method 201A has no stated blockage area but has thesame duct diameters where velocity pressure adjustments are required.

For OTM27 where only the PM2.5 cyclone is used, wha t is the projected area (maximum, minimum and average) for the cyclone , filter holder, probe assembly and the assembly including the pitottube? What is the smallest duct diameter where the average blockage i s less than 6%? Lastly, would it be appropriate to use only the PM2 .5 cyclone in ducts smaller than 18 inches if the blockage is less than 6%?(Ray - for the promulgation package we need to cons ider the revision of

the paragraphs on blockage to include the various p rojected areas, blockages etc. for the promulgated rule)

Mike - By my estimation, the total projected area of the PM2.5 cyclone and filter holder is about 12 square inches and ave rage 6 square inches. This would mean that the minimum duct diameter wher e the cyclone is useable would be about 12 inches (duct area = 113 s quare inches). If the pitot tube was also included in the projected a rea this would add about 1 square inch to the projected area and requi re a duct diameter of about 16 square inches.

_________________________________ Ron Myers U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Sector Policy and Programs Division Monitoring Policy Group, D243-05 RTP NC 27711 Tel. 919.541.5407 Fax 919.541.1039 E-mail myers.ron@epa.gov(See attached file: PM2.5 Cylcone Sketches.pdf)