Illinois Administrative Code › Title 35 - ENVIRONMENTAL PROTECTION › Part 276 - PROCEDURES TO BE FOLLOWED IN THE PERFORMANCE OF INSPECTIONS OF MOTOR VEHICLE EMISSIONS › Subpart F - EQUIPMENT MAINTENANCE AND CALIBRATION › Section 276.602 - Steady-State Idle Test Equipment Calibration

Current through Register Vol. 48, No. 28, July 12, 2024
All operators of steady-state idle exhaust test gas analyzers
				  shall comply with the following calibration and operating procedures unless
				  alternative procedures have been approved by the Agency:
a) Exhaust gas analyzers shall be warmed up
				prior to each vehicle inspection, zero check, span check, or calibration.
				Analyzers shall be considered to be in a warmed-up condition once stabilized
				zero readings (readings stabilize for one minute within ±2 percent of
				full scale, low range on all 3 channels) are obtained.
b) The analyzer shall conduct a zero and span
				check prior to each test. The span check shall include the HC, CO and
				CO2 channels, and the NO and O2
				channels, if present. If zero and/or span drift cause the signal levels to move
				beyond the adjustment range of the analyzer, it shall lock out from
				testing.
c) The system shall lock
				out from testing if sample flow falls below 3 percent of full scale, or causes
				system response time to exceed 13 seconds to 90 percent of a step change in
				input, whichever is less.
d) A
				system leak check shall be performed within 24 hours before the test, and may
				be performed in conjunction with the gas calibration described in subsection
				(e)(1) of this Section. If a leak check is not performed within 24 hours or if
				the analyzer fails the leak check, the analyzer shall lock out from testing.
				The leak check shall be a procedure demonstrated to effectively check the
				sample hose and probe for leaks and shall be performed in accordance with good
				engineering practices. An error of more than +2 percent of the reading using
				low range span gas shall cause the analyzer to lock out from testing and shall
				require repair of leaks.
e) Gas
				Calibration
1) Analyzers must undergo a
				two-point calibration within 72 hours before each test unless changes in
				barometric pressure are compensated for automatically and statistical process
				control demonstrates equal or better quality control using different
				frequencies. Gas calibration shall be accomplished by introducing span gas that
				meets the requirements of subsection (e)(3) of this Section into the analyzer
				through the calibration port. If the analyzer reads the span gas within the
				allowable tolerance range (i.e., the square root sum of the squares of the span
				gas tolerance described in subsection (e)(3) of this Section and the
				calibration tolerance, which shall be equal to 2 percent), no adjustment of the
				analyzer is necessary. The gas calibration procedure shall correct readings
				that exceed the allowable tolerance range to the center of the allowable
				tolerance range. The pressure in the sample cell shall be the same with the
				calibration gas flowing during calibration as with the sample gas flowing
				during sampling. If the system is not calibrated, or the system fails the
				calibration check, the analyzer shall lock out from testing.
2) A two point gas calibration procedure
				shall be followed. The span shall be accomplished at one of the following pairs
				of span points:
A) Low
300 - ppm propane (HC)
1.0 - percent CO
6.0 - percent CO2
1000 - ppm nitric oxide (if equipped with NO)
High
1200 - ppm propane (HC)
4.0 - percent CO
12.0 - percent CO2
3000 - ppm nitric oxide (if equipped with NO)
B) Low
0 - ppm propane (HC)
0.0 - percent CO
0.0 - percent CO2
0 - ppm nitric oxide (if equipped with NO)
High
600 - ppm propane (HC)
1.6 - percent CO
11.0 - percent CO2
1200 - ppm nitric oxide (if equipped with NO)
3) The span gases used
				for the gas calibration shall be traceable to NIST standards within two percent
				and shall be within two percent of the span points specified in subsection
				(e)(2) of this Section.