[Code of Federal Regulations]
[Title 40, Volume 18]
[Revised as of July 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR92.118]

[Page 446]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 92--CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES--
Table of Contents
 
                       Subpart B--Test Procedures
 
Sec. 92.118  Analyzer checks and calibrations.

    (a)(1) Prior to initial use and after major repairs, bench check 
each analyzer for compliance with the specifications of Sec. 92.109.
    (2) The periodic calibrations are required:
    (i) Leak check of the pressure side of the system (see paragraph (b) 
of this section). If the option described in paragraph (b)(2) of this 
section is used, a pressure leak check is not required.
    (ii) Calibration of all analyzers (see Secs. 92.119 through 92.122).
    (iii) Check of the analysis system response time (see paragraph (c) 
of this section). If the option described in paragraph (c)(2) of this 
section is used, a response time check is not required.
    (b) Leak checks--(1) Vacuum side leak check. (i) Any location within 
the analysis system where a vacuum leak could affect the test results 
must be checked.
    (ii) The maximum allowable leakage rate on the vacuum side is 0.5 
percent of the in-use flow rate for the portion of the system being 
checked. the analyzer flows and bypass flows may be used to estimate the 
in-use flow rates.
    (iii) The sample probe and the connection between the sample probe 
and valve V2 may be excluded from the leak check.
    (2) Pressure side leak check. (i) The maximum allowable leakage rate 
on the pressure side in 5 percent of the in-use flow rate.
    (ii) Option: If the flow rate for each flow meter is equal to or 
greater than the flow rate recorded in paragraph (c)(2)(i) of this 
section, then a pressure side leak check is not required.
    (c) System response time; check procedure. (1) After any major 
change in the system, check the system response time by the following 
procedure:
    (i) Stabilize the operating temperature of the sample line, sample 
pump, and heated filters.
    (ii) Introduce an HC span gas into the sampling system at the sample 
probe or valve V2 at atmospheric pressure. Simultaneously, start the 
time measurement.
    (iii) When the HC instrument response is 95 percent of the span gas 
concentration used, stop the time measurement.
    (iv) If the elapsed time is more than 20.0 seconds, make necessary 
adjustments.
    (v) Repeat with the CO, CO2, and NOX 
instruments and span gases.
    (2) Option. If the following parameters are determined, the initial 
system response time may be generally applied to future checks:
    (i) Analyzer and bypass flow rates. (A) Determine by experimentation 
the minimum analyzer and bypass flow rates individually and in 
combination that will produce a response time as close as possible to 
20.0 seconds per paragraph (c)(1) of this section.
    (B) Record the highest minimum flow rate for each flow meter as 
determined in paragraph (c)(2)(i)(A) of this section.
    (ii) Capillary flow analyzers. This procedure is applicable only to 
analyzers that have sample capillaries such as the HFID and CL 
analyzers. It is also assumed that the system has sample/span valves 
that perform the function of valves V9 and V13 in.
    (A) Operate the analyzer(s) at the in-use capillary pressure.
    (B) Adjust the bypass flow rate to the flow rate recorded in 
paragraph (c)(2)(i)(B) of this section.
    (C) Measure and record the response time from the sample/span 
valve(s) per paragraph (c)(1) of this section.
    (D) The response time required by paragraph (c)(2)(ii)(C) of this 
section can be determined by switching from the ``sample'' position to 
the ``span'' position of the sample/span valve and observing the 
analyzer response on a chart recorder. Normally, the ``sample'' position 
would select a ``room air'' sample and the ``span'' position would 
select a span gas.
    (E) Adjust the bypass flow rate to the normal in-use value.
    (F) Measure and record the response time from the sample/span 
valve(s) per paragraph (c)(1) of this section.
    (G) Determine the slowest response time (step in paragraph 
(c)(2)(ii)(C) of this section or step in paragraph (c)(2)(ii)(D) of this 
section) and add 2 seconds to it.

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