[Code of Federal Regulations]
[Title 40, Volume 17]
[Revised as of July 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR86.114-79]

[Page 462]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 86_CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND 
ENGINES--Table of Contents
 
 Subpart B_Emission Regulations for 1977 and Later Model Year New Light-
 
Sec. 86.114-79  Analytical gases.

    (a) Analyzer gases. (1) Gases for the CO and CO2 
analyzers shall be single blends of CO and CO2 respectively 
using nitrogen as the diluent.
    (2) Gases for the hydrocarbon analyzer shall be single blends of 
propane using air as the diluent.
    (3) Gases for NOX analyzer shall be single blends of NO 
named as NOX, with a maximum NO2 concentration of 
5 percent of the nominal value, using nitrogen as the diluent.
    (4) Fuel for the evaporative emission enclosure FID shall be a blend 
of 40 2% hydrogen with the balance being helium. 
The mixture shall contain less than 1 ppm equivalent carbon response. 98 
to 100 percent hydrogen fuel may be used with advance approval by the 
Administrator.
    (5) The allowable zero gas (air or nitrogen) impurity concentrations 
shall not exceed 1 ppm equivalent carbon response, 1 ppm carbon 
monoxide, 0.04 percent (400 ppm) carbon dioxide and 0.1 ppm nitric 
oxide.
    (6) ``Zero grade air'' includes artificial ``air'' consisting of a 
blend of nitrogen and oxygen with oxygen concentrations between 18 and 
21 mole percent.
    (7) The use of precision blending devices (gas dividers) to obtain 
the required calibration, as defined below, is acceptable, provided that 
the calibration curver they produce name a calibration gas within 2 
percent of its certified concentration. This verification shall be 
performed at between 15 and 50 percent of the full scale concentration 
of the range and shall be included with each gas calibration 
incorporating a blending device. Alternative procedures to verify the 
validity of the analyzer calibration curves generated using a gas 
divider are acceptable provided the procedures are approved in advance 
by the Administrator.
    (b) Calibration gases shall be traceable to within 1 percent of NBS 
gas standards, or other gas standards which have been approved by the 
Administrator.
    (c) Span gases shall be accurate to within 2 percent of true 
concentration, where true concentration refers to NBS gas standards, or 
other gas standards which have been approved by the Administrator.

[42 FR 32954, June 28, 1977, as amended at 43 FR 52920, Nov. 14, 1978; 
54 FR 2121, Jan. 19, 1989]