['Air Programs']
['Air Quality']
06/06/2024
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(a) Overview. This test is intended to verify adequate aerosol transport through any modified or air flow splitting components that may be used in a Class I candidate equivalent method sampler such as may be necessary to achieve sequential sampling capability. This test is applicable to all Class I candidate samplers in which the aerosol flow path (the flow path through which sample air passes upstream of sample collection filter) differs significantly from that specified for reference method samplers as specified in 40 CFR part 50, appendix L or appendix O, as applicable. The test requirements and performance specifications for this test are summarized in table E-1 of this subpart.
(b) Technical definitions. (1) Aerosol transport is the percentage of a laboratory challenge aerosol which penetrates to the active sample filter of the candidate equivalent method sampler.
(2) The active sample filter is the exclusive filter through which sample air is flowing during performance of this test.
(3) A no-flow filter is a sample filter through which no sample air is intended to flow during performance of this test.
(4) A channel is any of two or more flow paths that the aerosol may take, only one of which may be active at a time.
(5) An added component is any physical part of the sampler which is different in some way from that specified for a reference method sampler in 40 CFR part 50, appendix L or appendix O, as applicable, such as a device or means to allow or cause the aerosol to be routed to one of several channels.
(c) Required facilities and test equipment. (1) Aerosol generation system, as specified in §53.62(c)(2).
(2) Aerosol delivery system, as specified in §53.64(c)(2).
(3) Particle size verification equipment, as specified in §53.62(c)(3).
(4) Fluorometer, as specified in §53.62(c)(7).
(5) Candidate test sampler, with the inlet and impactor or impactors removed, and with all internal surfaces of added components electroless nickel coated as specified in §53.64(d)(2).
(6) Filters that are appropriate for use with fluorometric methods (e.g., glass fiber).
(d) Calibration of test measurement instruments. Submit documentation showing evidence of appropriately recent calibration, certification of calibration accuracy, and NIST-traceability (if required) of all measurement instruments used in the tests. The accuracy of flow rate meters shall be verified at the highest and lowest pressures and temperatures used in the tests and shall be checked at zero and at least one flow rate within ±3 percent of 16.7 L/min within 7 days prior to use for this test. Where an instrument's measurements are to be recorded with an analog recording device, the accuracy of the entire instrument-recorder system shall be calibrated or verified.
(e) Test setup. (1) The candidate test sampler shall have its inlet and impactor or impactors removed. The lower end of the down tube shall be reconnected to the filter holder, using an extension of the downtube, if necessary. If the candidate sampler has a separate impactor for each channel, then for this test, the filter holder assemblies must be connected to the physical location on the sampler where the impactors would normally connect.
(2) The test particle delivery system shall be connected to the sampler downtube so that the test aerosol is introduced at the top of the downtube.
(f) Test procedure. (1) All surfaces of the added or modified component or components which come in contact with the aerosol flow shall be thoroughly washed with 0.01 N NaOH and then dried.
(2) Generate aerosol. (i) Generate aerosol composed of oleic acid with a uranine fluorometric tag of 3 ±0.25 µm aerodynamic diameter using a vibrating orifice aerosol generator according to conventions specified in §53.61(g).
(ii) Check for the presence of satellites and adjust the generator to minimize their production.
(iii) Calculate the aerodynamic particle size using the operating parameters of the vibrating orifice aerosol generator. The calculated aerodynamic diameter must be 3 ±0.25 µm aerodynamic diameter.
(3) Verify the particle size according to procedures specified in §53.62(d)(4)(i).
(4) Collect particles on filters for a time period such that the relative error of the resulting measured fluorometric concentration for the active filter is less than 5 percent.
(5) Determine the quantity of material collected on the active filter using a calibrated fluorometer. Record the mass of fluorometric material for the active filter as Mactive (i) where i = the active channel number.
(6) Determine the quantity of material collected on each no-flow filter using a calibrated fluorometer. Record the mass of fluorometric material on each no-flow filter as Mno-flow.
(7) Using 0.01 N NaOH, wash the surfaces of the added component or components which contact the aerosol flow. Determine the quantity of material collected using a calibrated fluorometer. Record the mass of fluorometric material collected in the wash as Mwash.
(8) Calculate the aerosol transport as:
Equation 29
where:
i = the active channel number.
(9) Repeat paragraphs (f)(1) through (8) of this section for each channel, making each channel in turn the exclusive active channel.
(g) Test results. The candidate Class I sampler passes the aerosol transport test if T(i) is at least 97 percent for each channel.
[62 FR 38799, July 18, 1997, as amended at 71 FR 61293, Oct. 17, 2006]
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