BREATHING AIR SPECIFICATIONS
This is only a partial list of the specifications that we routinely work with.

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General Information About Breathing Air Specifications

At Analytical Chemists Inc., we ensure that breathing air specifications are clear, practical, and aligned with industry standards. Below is a breakdown of key considerations related to air purity specifications, helping clients make informed decisions about air quality testing and compliance.

Volatile Hydrocarbons

We use Total Volatile Hydrocarbons as a more accurate term than “Total Hydrocarbons” because standard tests can only detect volatile (vaporized) hydrocarbons, not oil mist. This distinction applies universally across laboratories.

• CGA Grade D Limitation: The absence of a Total Volatile Hydrocarbon test in CGA Grade D specifications removes a key indicator for contamination detection. To address this, we include this test in every analysis.

Oxygen Content in Compressor Air

• Typical Levels: Oxygen in standard compressor air remains at 20.95% unless synthetic air is improperly prepared or the intake is in an oxygen-deficient environment (e.g., ship cargo holds or air liquefaction areas).
• Important Note: Compressors cannot alter oxygen content independently.

Potential Contaminants

1. Nitric Oxide & Nitrogen Dioxide:
   These gases may occur near welding sites, carbon arc searchlights, or high-temperature combustion. However, their presence in compressor air is highly unlikely unless intake air is sourced from such locations.
2. Sulfur Dioxide:
   This contaminant originates from the combustion of sulfur compounds (e.g., engines or catalytic converters). It is generally irrelevant unless operating near steel foundries, oil refineries, or large combustion sources without molecular sieve filters.
3. Nitrous Oxide (Laughing Gas):
   Though not typically part of medical air specifications, nitrous oxide may accumulate near compressors in hospitals. Including it in medical air programs can prevent risks in such environments.

Odor Testing

Odor detection is a vital test and the first line of defense, particularly for divers. Strong odors signal immediate danger and are unacceptable.

• General Air Quality: Well-maintained compressor air typically has no odor or a faint smell, except for Navy air.

Dew Point and Moisture Content

Dew point specifications vary by use case and climate:

• U.S. Navy Diver’s Air: Dew point limits apply when air is passed through a drying system.
• CGA Recommendations: The CGA suggests a dew point 10°F below the lowest ambient temperature, often considered as low as -64°F.
• Testing Methods: For critical applications below -40°F, on-site testing with a NIST-traceable dew point meter is recommended.

Halogenated Hydrocarbons

These include organic compounds with fluorine, chlorine, bromine, or iodine atoms, such as chlorofluorocarbons (CFCs). The Canadian specification limits these to 2 ppmv each for common CFCs like trichlorotrifluoroethane and dichlorodifluoromethane.

Common Misconceptions and Clarifications

1. CGA Grade J Misuse:
   Some labs mistakenly use CGA Grade J as a standard for Nitrox preparation, which is incorrect. This specification applies only to instrument air, not compressor air.
2. Modified CGA Grade J Air:
   The term is misleading. Modifications often render it unrecognizable from the original CGA Grade J specification.

Specification Sources for Breathing Air

• NAVSEA: Recompression chambers (NAVSEA PI 00C3-PI-001).
• Military Air: Aviator’s breathing oxygen (Mil-O-27210 Type 1).
• Nitrox: U.S. Navy Air Specification for Nitrox (U.S. Navy Diving Manual, Vol. 2, Chapter 10, Table 10-2).
• NASA Safety Manual: Chapter 5 oxygen system guidelines.
• Industry Standards: ANDI (American Nitrox Divers International), IANTD (International Association of Nitrox and Technical Divers), and AAUS (American Academy of Underwater Sciences).

Moisture Specifications and Regional Adjustments

• Moisture requirements are relative to regional climates or client-specific needs.
• U.S. Navy: Dew point specifications apply only in select conditions.
• Medical Air: Typically requires a dew point of +32°F.

For a deeper understanding of breathing air specifications or to schedule an air quality test, contact Analytical Chemists Inc. today!
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