Greenhouse Gas Initiatives-Measure, Report, Evaluate, Manage, Reduce

For US based businesses and organizations the EPA provides valuable information at http://www.epa.gov/climatechange/emissions/index.html .
At the time of writing, detailed performance standards were available for:

• Captured Methane End Use (new project type) (PDF) (23 pp, 244K) August 2008
• Commercial Boiler (PDF) (21 pp, 233K) August 2008
• Industrial Boiler (PDF) (28 pp, 505K) August 2008
• Landfill Methane (PDF) (21 pp, 291K) August 2008
• Manure Management: Anaerobic Digester (PDF) (27 pp, 350K) August 2008
• Reforestation/Afforestation
  Project accounting methodology (PDF) (22 pp, 201K) August 2008
  Reforestation/Afforestation Project Carbon Online Estimator Tool (RAPCOE) 
• Transit Bus Efficiency (PDF) (21 pp, 256K) August 2008

Periodic "calibration" requirements must be considered.  It is suggested that measuring devices be evaluated by their ability to be "calibrated" in place or cost effectively swapped with devices "calibrated" off line.  We can evaluate and discuss alternatives.  ("Calibration" is used generically to denote the act of verifying accuracy of a measuring device.  Terminology varies with type of device and regulatory agency requirement.)