Text of Test Method 1 (40 CFR Part 60, Appendix A) 

1994 QA Handbook Volume III  Method 1 Field Procedure 

Guideline Document (GD) 008  PM Sampling in Cyclonic Flow 

Draft Revision to GD008  PM Sampling in Cyclonic Flow 

Guideline Document (GD) 021  Traverse Point and Location for
Method 1 

FREQUENTLY ASKED QUESTIONS (FAQS) for Method 1
Regarding your answer to another question about the CEMS crossstack
slotted tube partially blocking the stack cross section, you recommended
that a person calculate the effective cross sectional area of the slotted
tube, that is, the area of the stack blocked by the tube, and from that
calculate an equivalent diameter. You noted that the pitot sampling location
can be two or more of those equivalent diameter. You noted that the pitot
sampling location can be two or more of those equivalent diameters downstream
of the tube and still meet the Method 1 location criteria. After I calculate
the effective area of the blockage, do I add or subtract that area from the
stack area?
The equivalent diameter calculated from the effective area of the CEMS
slotted tube becomes the distance of consequence. For example, if the
tube is 1 foot in diameter and 20 feet long, the area blocked by the
tube is 20 ft^{2}. The equivalent diameter for this area is 5 feet.
Using the two or more equivalent diameter distance guideline, the pitot
sampling location could be located as close as 10 feet downstream of the
slotted tube.
We have an awkward situation sampling for gas emission rate in a duct
to certify an insitu CEMS with a crossstack pipe (I.e., slotted tube). We
have to measure the stack flow rate at a location downstream of the CEMS,
but we don't want to go higher up the stack than necessary. That begs
the question "is the CEMS pipe a flow disturbance and how far downstream
of the disturbance must be the pitot measurement location?
I expect many of us will run into situations like this one now that
EPA is writing more mass emission rate and emission trading rules. In
this case, I think the answer lies in another method dealing with
troublesome locations for flow measurements and that is Method 5D.
Section 4.1.2 of this method describes the use of flow straighteners
for short stacks which are, in a way, flow disturbances much like the
slotted tube for the CEMS. In this section, the pitot sampling location
is defined in terms of the equivalent diameter of the area of vane
opening in meeting the twodiamter criteria as in Method 1.
For your situation, I recommend that you calculate the effective cross
sectional area of the slotted tube, that is, the area of the stack blocked
by the tube. Then, calculate from that an equivalent diameter. Your
pitot sampling locatin can be two or more of those equivalent diameters of
the tube and still meet the Method 1 location criteria. Note that this advice applies
only if the CEMS location meets the two equivalent stack diameter
upstream disturbance criterion
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