Administrative Code

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Virginia Administrative Code
Title 9. Environment
Agency 5. State Air Pollution Control Board
Chapter 91. Regulations for the Control of Motor Vehicle Emissions in the Northern Virginia Area

9VAC5-91-700. Calibration of exhaust gas analyzers.

The department shall use, and require for use, gases and containers meeting the following parameters, blends, and specifications in the calibration of exhaust gas analyzers:

1. The calibration gases for standardizing instruments shall conform to the provisions outlined in EPA420-B-04-011.

2. Gas analyzers shall pass a two-point gas calibration for HC, CO, CO2 and NO, within 72 hours before each test.

3. Gas analyzers shall pass a five-point gas audit for HC, CO, CO2, and NO at least two times within 12 months, and each time an analyzer system emissions measurement system, sensor, or other electronic components are repaired or replaced in response to an audit failure.

4. The director may reduce the frequency of calibrations in subdivision 2 of this section and audits in subdivision 3 of this section or both if evidence indicates accuracy would not be adversely affected.

Statutory Authority

§ 46.2-1180 of the Code of Virginia; § 182 of the Clean Air Act; 40 CFR Part 51, Subpart S.

Historical Notes

Derived from Virginia Register Volume 13, Issue 5, eff. January 24, 1997; amended, Virginia Register Volume 18, Issue 20, eff. October 1, 2002; Volume 29, Issue 24, eff. August 28, 2013.

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