[Code of Federal Regulations]

[Title 40, Volume 31]

[Revised as of July 1, 2006]

From the U.S. Government Printing Office via GPO Access

[CITE: 40CFR1065.195]



[Page 698-699]

 

                   TITLE 40--PROTECTION OF ENVIRONMENT

 

         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)

 

PART 1065_ENGINE-TESTING PROCEDURES--Table of Contents

 

                   Subpart B_Equipment Specifications

 

Sec.  1065.195  PM-stabilization environment for in-situ analyzers.



    (a) This section describes the environment required to determine PM 

in-situ. For in-situ analyzers, such as an inertial balance, this is the 

environment within a PM sampling system that surrounds the PM sample 

media. This is typically a very small volume.

    (b) Maintain the environment free of ambient contaminants, such as 

dust, aerosols, or semi-volatile material that could contaminate PM 

samples. Filter all air used for stabilization with HEPA filters. Ensure 

that HEPA filters are installed properly so that background PM does not 

leak past the HEPA filters.

    (c) Maintain the following thermodynamic conditions within the 

environment before measuring PM:

    (1) Ambient temperature. Select a nominal ambient temperature, Tamb, 

between (42 and 52) [deg]C. Maintain the ambient temperature within 

1.0 [deg]C of the selected nominal value.

    (2) Dewpoint. Select a dewpoint, Tdew, that corresponds to Tamb such 

that Tdew = (0.95Tamb-11.40) [deg]C. The resulting dewpoint will control 

the amount of water associated with sulfuric acid 

(H2SO4) PM, such that 1.1368 grams of water will 

be associated with each gram of H2SO4. For 

example, if you select a nominal ambient temperature of 47 [deg]C, set a 

dewpoint of 33.3 [deg]C.

    (3) Dewpoint tolerance. If the expected fraction of sulfuric acid in 

PM is unknown, we recommend controlling dewpoint within 1.0 [deg]C. This would limit any dewpoint-related change 

in PM to less than 2%, even for PM that is 50% 

sulfuric acid. If you know your expected fraction of sulfuric acid in 

PM, we recommend that you select an appropriate dewpoint tolerance for 

showing compliance with emission standards using Table 1 of Sec.  

1065.190 as a guide:

    (4) Absolute pressure. Maintain an absolute pressure of (80.000 to 

103.325) kPa. Use good engineering judgment to maintain a more stringent 

tolerance of absolute pressure if your PM measurement instrument 

requires it.

    (d) Continuously measure dewpoint, temperature, and pressure using 

measurement instruments that meet the PM-stabilization environment 

specifications in subpart C of this part. Use these values to determine 

if the in-situ stabilization environment is within the tolerances 

specified in paragraph (c) of this section. Do not use any PM quantities 

that are recorded when any of these parameters exceed the applicable 

tolerances.

    (e) If you use an inertial PM balance, we recommend that you install 

it as follows:

    (1) Isolate the balance from any external noise and vibration that 

is within a frequency range that could affect the balance.

    (2) Follow the balance manufacturer's specifications.

    (f) If static electricity affects an inertial balance, you may use a 

static neutralizer, as follows:

    (1) You may use a radioactive neutralizer such as a Polonium 

(\210\Po)



[[Page 699]]



source or a Krypton (\85\Kr) source. Replace radioactive sources at the 

intervals recommended by the neutralizer manufacturer.

    (2) You may use other neutralizers, such as a corona-discharge 

ionizer. If you use a corona-discharge ionizer, we recommend that you 

monitor it for neutral net charge according to the ionizer 

manufacturer's recommendations.