Product Overview

Summary: This Breathing Gas Mixture Analysis Safe Operating Procedure sets out a clear, repeatable method for testing and verifying breathing gases before use in work or diving operations. It helps Australian businesses control critical risks such as hypoxia, oxygen toxicity and contamination, while demonstrating due diligence under WHS legislation and relevant Australian Standards.

Breathing gas mixtures used in occupational diving, hyperbaric operations and specialised industrial tasks must be precisely controlled to prevent life‑threatening incidents. Even small errors in oxygen percentage, inert gas balance, or contamination levels can lead to hypoxia, oxygen toxicity, narcosis or acute poisoning. This Safe Operating Procedure provides a structured, step‑by‑step approach for analysing, documenting and approving breathing gas mixtures before they are supplied to workers, patients or contractors. It covers the full workflow from cylinder identification and labelling checks, instrument calibration and bump tests, through to sampling methods, analysis criteria, acceptance limits and quarantine of non‑conforming cylinders.

Developed for the Australian regulatory environment, the SOP helps organisations align with WHS duties, relevant Australian Standards and industry best practice for compressed gas handling and occupational diving. It resolves common problems such as inconsistent testing methods between shifts, poor recordkeeping, uncertainty about acceptance ranges, and inadequate controls around contaminated or incorrectly mixed gas. By implementing this procedure, businesses can reduce the likelihood of catastrophic incidents, strengthen their safety culture, and provide clear evidence of risk management to regulators, clients and auditors.

Key Benefits

• Ensure every breathing gas mixture is analysed, verified and documented before use in line with defined safety limits.
• Reduce the risk of hypoxia, oxygen toxicity, narcosis and contamination incidents during diving and hyperbaric operations.
• Standardise gas analysis methods across all sites and shifts, improving consistency, training and auditability.
• Demonstrate compliance with Australian WHS legislation and relevant standards for compressed and breathing gases.
• Strengthen incident prevention and investigation by providing clear traceability of gas batches, test results and approvals.

Who is this for?

• Diving Supervisors
• Commercial Divers
• Hyperbaric Chamber Operators
• Gas Blenders and Compressor Technicians
• WHS Managers
• Laboratory Technicians (Gas Analysis)
• Emergency Response Team Leaders
• Marine Operations Managers
• Aquarium and Zoo Dive Coordinators
• Technical Services Managers in Hospitals and Hyperbaric Facilities

Hazards Addressed

• Incorrect oxygen concentration leading to hypoxia or oxygen toxicity
• Inappropriate inert gas balance causing narcosis or decompression sickness risk
• Contamination of breathing gas with carbon monoxide (CO)
• Contamination of breathing gas with carbon dioxide (CO2)
• Oil vapour, particulates and moisture contamination from compressors and filling systems
• Use of out‑of‑date, mislabelled or unidentified gas cylinders
• Cross‑contamination between different gas mixtures during filling or handling
• Use of uncalibrated or faulty gas analysis instruments
• Inadequate documentation leading to use of unverified gas supplies

Included Sections

• 1.0 Purpose and Scope
• 2.0 Definitions and Abbreviations (O2, He, N2, MOD, ppO2, etc.)
• 3.0 Roles and Responsibilities (Gas Blender, Diving Supervisor, WHS Manager)
• 4.0 Applicable Legislation, Standards and Reference Documents
• 5.0 Required Equipment, Instruments and Calibration Gases
• 6.0 Competency and Training Requirements for Personnel
• 7.0 Pre‑Use Checks and Instrument Calibration Procedure
• 8.0 Cylinder Identification, Labelling and Traceability Requirements
• 9.0 Sampling and Analysis Procedure for Breathing Gas Mixtures
• 10.0 Acceptance Criteria and Tolerances for Common Gas Mixes (Air, Nitrox, Trimix, Heliox, Medical Oxygen)
• 11.0 Management of Non‑Conforming or Suspect Gas (Quarantine, Tagging and Disposal)
• 12.0 Documentation, Records and Batch Traceability
• 13.0 Hazard Identification and Risk Controls for Gas Analysis Activities
• 14.0 Emergency Procedures for Suspected Contamination or Adverse Events
• 15.0 Equipment Maintenance, Calibration Schedule and Verification
• 16.0 Review, Audit and Continuous Improvement of the SOP

Legislation & References

• Model Work Health and Safety Act 2011 (Cth) and associated WHS Regulations as implemented in each state and territory
• Safe Work Australia – Managing Risks of Hazardous Chemicals in the Workplace Code of Practice
• AS/NZS 2299.1: Occupational diving operations – Standard operational practice
• AS 3848 series: Filling of portable gas cylinders
• AS/NZS 1715: Selection, use and maintenance of respiratory protective equipment
• AS/NZS 60079.29.2: Explosive atmospheres – Gas detectors – Selection, installation, use and maintenance of detectors for flammable gases and oxygen
• AS 4775: Emergency eyewash and shower equipment (for decontamination in case of exposure to contaminants during analysis)
• Relevant manufacturer instructions for gas analysers, compressors and filling systems