CFR > Title 40 - Protection of Environment > CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY > SUBCHAPTER C—AIR PROGRAMS (Parts 50–99) > PART 86—CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES > SUBPART P—Emission Regulations for Otto-Cycle Heavy-Duty Engines, New Methanol-Fueled Natural Gas-Fueled, and Liquefied Petroleum Gas-Fueled Diesel-Cycle Heavy-Duty Engines, New Otto-Cycle Ligh > 86.1511—Exhaust gas analysis system.

86.1511—Exhaust gas analysis system.

(a) Analyzers used for this subpart shall meet the following specifications:
(1) The analyzer used shall conform to the accuracy provisions of 40 CFR part 1065, subparts C, D, and F.
(2) The resolution of the readout device(s) for the range specified in paragraph (a)(1) of this section shall be equal to or less than 0.05 percent for the CO analyzer.
(3) For the range specified in paragraph (a)(1) of this section, the precision shall be less than ±3 percent of full-scale deflection. The precision is defined as two times the standard deviation of five repetitive responses to a given calibration gas.
(4) For the range specified in paragraph (a)(1) of this section, the mean response to a zero calibration gas shall not exceed ±3 percent of full-scale deflection during a 1-hour period.
(5) For the range specified in paragraph (a)(1) of this section the drift of the mean calibration response shall be less than ±3 percent of full scale during a 1-hour period. The calibration response is defined as the analyzer response to a calibration gas after the analyzer has been spanned by the electrical spanning network at the beginning of the 1-hour period.
(6) The analyzer must respond to an instantaneous step change at the entrance to the sampling system with a response equal to 90 percent of that step change within 15 seconds or less on the range specified in paragraph (a)(1) of this section. The step change shall be at least 60 percent of full-scale deflection.
(7) The interference gases listed shall individually or collectively produce an analyzer reading less than ±2 percent of full scale on the range specified in paragraph (a)(1) of this section.
Interference gas Concentration Applicable analyzer
CO2 14 percent CO
C3H8 1 percent CO
Code of Federal Regulations 261
H2O Saturated vapor at 100 °F CO
NOX 1,000 ppm CO
O2 5 percent CO
(8) The analyzer shall be able to meet the specifications in paragraph (a) of this section under the following conditions:
(i) After a 30 minute warm-up from the prevailing ambient conditions;
(ii) Between 0 to 85 percent relative humidity; and
(iii) During variations of ±50 percent of nominal sample flow.
(b) The inclusion of a raw CO2 analyzer as specified in 40 CFR part 1065 is required in order to accurately determine the CVS dilution factor.

Code of Federal Regulations

[48 FR 52252, Nov. 16, 1983, as amended at 60 FR 34377, June 30, 1995; 70 FR 40441, July 13, 2005. Redesignated at 73 FR 37194, June 30, 2008]