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Scott brand RATA and Compliance Class specialty gas mixtures from Air Liquide

Products and Services

Air Liquide offers pure and mixed gases as well as gas handling equipment and related services for nearly every application imaginable. Developing custom products is our specialty.

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RATA and Compliance Classes™ EPA Protocols
Specialty Gas Mixtures

Scott brand specialty gas mixtures from Air Liquide

Scott Brand RATA Class and Compliance Class EPA Protocol Gases are unique in the environmental industry. They provide the highest levels of performance, reliability and confidence for meeting environmental compliance regulations. Both classes of mixtures are prepared in strict accordance with the latest EPA guidelines. Compliance Class protocol gases meet EPA's minimum ±2% analytical accuracy requirement, while RATA class mixtures provide an extra measure of confidence with ±1% analytical accuracy.

All Scott protocol gases are traceable to metrology institute reference standards. These include NIST Standard Reference Materials (SRMs), NIST-Traceable Reference Materials (NTRMs) or VSL (formerly NMi) Primary Reference Standards (PRMs). RATA Class protocol gases are directly traceable to metrology institute reference standards. Air Liquide maintains the largest inventory of SRMs, NTRMs and other MISs (Metrology Institute Standards). This allows us to offer the widest availability of protocol gases in the industry as well as shortest lead times.

Guaranteed Certification and Stability

Air Liquide follows current revisions of EPA procedures G1 and G2 found in "EPA Traceability Protocol for Assay and Certification of Gaseous Calibration Standards" dated September, 1997. By incorporating rigorous quality assurance procedures and many decades of experience manufacturing environmental calibration mixtures, we are able to offer the most comprehensive portfolio of reactive and nonreactive protocol gases.

Recommended Applications for Scott Brand EPA Protocol Gases

  • Relative Accuracy Test Audits (RATA tests)
  • Linearity checks
  • Stack monitor calibration
  • Cylinder Gas Audits (CGAs)
  • Ambient monitor calibration
  • Scrubber efficiency verification
  • Certification of CEM systems
  • Environmental auditing

RATA Class™ Protocol Gases: Most Accurate Protocol Available

Scott Brand RATA Class protocol gases are recommended for all environmental applications requiring the highest degree of compliance certainty. RATA Class protocol mixtures are engineered to achieve ±1% accuracy, which makes RATA Class protocol gases especially valuable for Relative Accuracy Test Audits. Many utilities and other industrial facilities are pushing the performance of their continuous emissions monitoring systems (CEMS) far below the ±10% RATA requirement of the EPA's Acid Rain Program to save the $30,000 - $70,000/year cost for RATA testing by achieving the EPA ±7.5% accuracy limit. The RATA Class protocol is a critical element in achieving these savings. This class also provides accurate measurements of SO2 and NOx emissions thereby facilitating emissions trading credits where allowed.

RATA Class mixtures are dual-analyzed. For each reactive component, two separate analyses are performed and analyzed directly against metrology institute standards to determine the concentrations. Air Liquide's proprietary analytical technology created the capability for these two measurements to agree with each other within ±1%, even in two, three or four-component mixtures. An easy-to-read Certificate of Accuracy is provided with each (see sample certificate to the right).

Click here to see available Scott EPA protocol gases from Air Liquide.

Compliance Class™ Protocol Gases: ±2% Accurate

Scott Brand Compliance Class protocol gases meet EPA requirements for less demanding environmental measurements. Compliance Class mixtures also feature dual-analysis and NIST standard traceability. A Certificate of Accuracy is provided with each Compliance Class mixture.

Click here to see available Scott EPA protocol gases from Air Liquide.

Scott Interference-Free™ Multi-Component Protocol Gases

With the advent of acid rain legislation, Air Liquide pioneered the development of Interference-Free multi-component protocol gases. This innovation set a new industry standard by allowing utilities to switch to multi-component protocol gases in order to save time and money in calibration auditing and cylinder handling. Interference-free technology also alleviated the concern regarding mixtures of sulfur dioxide, nitric oxide and carbon dioxide where high concentrations of CO2 can interfere with NO analysis on certain traditional analytical instrumentation. This interference-free technology is built into every RATA and Compliance Class multi-component product.

Air Liquide also manufactures CEM DAILY STANDARDS™ and PROTOCOL ELEVEN™ mixtures.

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Air Liquide participates in EPA Protocol Gas Verification Program

All five of our specialty gas facilities are
registered participants of EPA’s Protocol
Gas Verification Program.

EPA PGVP vendor ID numbers for these facilities are listed below.

  • Plumsteadville, PA: A12013
  • Troy, MI: A22013
  • LaPorte, TX: A32013
  • Longmont, CO: A42013
  • Santa Fe Springs, CA: A52013

Everything you always wanted to know about EPA’s new Protocol Gas Verification Program

Download our informative pamphlet

Benefits and Features

  • Reduce RATA testing costs by achieving Acid Rain Program relative accuracies below the EPA's 7.5% specification.
  • Earn emissions reductions for sale of allowances on the open market.
  • Certification expiration dates based on EPA G1 and EPA G2 requirements, with expiration email alerts available via SHOP@airliquide.
  • Certificates of Accuracy are available on demand at SHOP@airliquide™.
  • Guaranteed stability of multi-component mixtures provides an extra level of confidence.
  • Multi-component Interference-Free™ protocol gases reduce the number of cylinders needed for lower overall costs.
  • Just-in-time delivery minimizes need for on-site inventory; automatic reorders can be placed via SHOP@airliquide.
Sample Certificate of Accuracy for RATA Class Gas Mixture

Certificate of Accuracy

Click the certificate on
the left to see a sample
of a cert that is included
with your Scott Brand RATA
Class gas mixture.

Download a PDF