Purchases of ESRL/GMD reference gas preparation and calibration services can only be initiated through a project contract.
Here is an example Memorandum of Understanding [MOU] Contract.

For more information on calibration services, contact refgas@noaa.gov

  • Your project MOU can be obtained by contacting our standards coordinator at refgas@noaa.gov
  • No alteration of MOU text please
  • Two signed hard copy MOUs would be mailed to the attention of Duane Kitzis
  • MOU stipulates payment terms of "Net 30 days after invoice".
  • MOU includes a statement of requested materials, shipping and contact information.
  • Total cost for each standard includes a cost from each of the following sections, 'Filling of Compressed Gas Cylinders' 'Calibrations of Compressed Gas Cylinders' 'Shipping and Handling'

Purchase and Filling of Compressed Gas Cylinders

The cost of a standard varies with the cylinder type and level of complexity. For cylinders filled with natural air (Niwot Ridge, Colorado) fees are listed below.
  • CO2 can be adjusted and calibrated between 250 and 3000 μmol/mol. The target CO2 value is usually within 5 μmol/mol for near ambient concentrations. Increasing the amount of CO2 over ambient levels requires adding CO2 which is isotopically lighter than ambient. The closer to ambient CO2 levels we target, the closer the air will be in regards to the stable isotopes of CO2. Lower than ambient standards usually have very close to ambient stable isotopes of CO2.
  • CH4, CO and N2O can be adjusted but with greater targeting variability.
  • Halocarbon concentrations can sometimes be adjusted to user requirements on an individual basis (contact Brad Hall for information).
  • Cylinder valve connection is CGA-590.
  • A standard gas cylinder requires 4-6 weeks to fill and 3 weeks for each trace gas species to calibrate. The normal turn-around time varies due to seasonal logistics and calibration queue
  • Note that for filling tanks to be used for halocompound reference gases, a different Rix compressor is used than for the filling of cylinders for CO2/CH4/CO/N2O, SF6. This compressor has been modified to reduce contaminants that can interfere with gas chromatography with electron capture detection.

Cylinder Types

Different types of cylinders are used depending on the molecule of interest.
  • Cylinders for CO2/CH4/CO/N2O/SF6 are aluminum AL-150 type, with a volume of 29 liters, which is approximately 4014 liters when pressurized to 134 atmospheres. Cylinder valves are Ceodeux, brass packless. Other sizes of cylinders are available but with extra ordering time of about 6 weeks. Sizes include N30, N60, N80, N265.
  • The majority of halocompound standards are prepared in Aculife-treated aluminum cylinders (size AL-30 or AL-150) purchased from Scott Specialty Gases.
  • The third type of cylinder used is a stainless steel cylinder certified for transport at 900 psig (Essex Cryogenics). These electopolished cylinders are used primarily for compounds known to be unstable in Aculife-treated aluminum, such as CH3Br and CH3Cl.
You can also read a description about how standard reference gases are filled.
Cylinder Type Cylinder Size Price (US Dollars)
Aluminum untreated cylinder, filled
(For CO2/CH4/CO/N2O/SF6)
N265 $2498
N150 $1088
N80 $978
N60 $860
N30 $722
Multi-species targeting $85 per gas
Aculife-treated Aluminum
(For most halocarbon compounds.)
6-L $900
29-L $1601
Stainless Steel
(For certain compounds.)
34-L $5040

Calibrations of Compressed Gas Cylinders

NOAA ESRL GMD is the World Meteorological Organization (WMO), Global Atmosphere Watch (GAW) Central Calibration Laboratory (CCL) for CO2, CH4, N2O, SF6, and CO. Calibrations results for these species are on official WMO scales. Calibrations for other gases are on internal NOAA scales.

Calibrations can be performed on the stable isotopes of CO2 (C13 and O18). The CO2 stable isotope calibration is based on a provisional scale maintained by INSTAAR at the University of Colorado. Values given for the stable isotopes of CO2 are informational values only.

Costs for Standard Reference Gas Calibrations as of October 2018

Compound Price (US Dollars)

CO2 on WMO scale 250-600 µmol/mol, CH4 WMO scale 300-5000 nmol/mol


CO2 Range < 250 PPM or > 600 PPM


CO Range 40-500 PPB


Stable Isotopes of CO2 [C13 & O18]


N20 / SF6 analysis by ECD


CFC-11, CFC-12, CFC-113, CH3CCl3, CCl4, halon-1211


HCFCs, HFCs, methyl halides, COS, + others




One recalibration for CO2, CH4 or CO after use is included in the cost of the standard gas. This is HIGHLY RECOMMENDED every 3 years for precision work and should at least be performed at the end of the cylinder's use (20 atm pressure). The cost of recalibrations after the first recalibration is:

Additional recalibrations Price (US Dollars)

CO2, CH4 or CO


Shipping and Handling

Destination Price per Cylinder

US East/West Coast




Service Cost

Financial Management Service Collection Cost* $2.32
*Financial Management Service is required on all agreements by the Department of Treasury per Office of Management & Dubdget Circular A-25, Policy Memorandum 14-02 dated July 25, 2014.

Pre-purchase Quotes

For more information and pre-purchase quotes, e-mail refgas@noaa.gov. A quote is necessary before accepting a purchase order. Inquiries can also be made through the following address, fax, or phone:

National Oceanic and Atmospheric Administration
Global Monitoring Division
Carbon Cycle Greenhouse Gases group
325 Broadway
Boulder, CO. 80305
E-Mail refgas@noaa.gov
Fax 303-497-6290