Nitrous Oxide Monitor

N2O Monitor Front PanelNitrous oxide, often referred to simply as “laughing gas,” is colorless and non-flammable at room temperature and is widely used in medical and dental surgery, as well as high performance automotive racing. When N2O leaks occur in the workplace, personnel may become exposed to low levels of anaesthetic due to fugitive emissions. There is an ongoing concern that small quantities of nitrous oxide can accumulate over time and become large enough to affect health or performance. Because of these concerns, OSHA has issued guidelines for minimum exposure to nitrous in the parts per million concentration range, driving the need for better monitoring solutions.

Occupational Safety and Health Administration (OSHA) is considering requirements for residual nitrous oxide, but there has never been a way to accurately monitor them in a cost-effective manner. The National Institute for Occupational Safety and Health (NIOSH) has established a recommended exposure limit (REL) for nitrous oxide of 25 parts per million (ppm) as a time-weighted average for the duration of the exposure.

One solution in the past involved hiring an outside testing service to sample the room air several times a year, but this can be highly unproductive in terms of achieving consistent measurements. What’s needed is a means to measure not only NIOSH-recommended levels of nitrous oxide, but even smaller levels as well (5 ppm or less). The N2O monitor we helped patent and develop is accurate, inexpensive, and makes real-time continuous monitoring down to 5 ppm a reality.

Basic Operation

Gas Cylinder

The nitrous oxide monitor is a multiband instrument that uses inexpensive narrow-band pyroelectric detection to minimize background effects.

Each nitrous oxide monitor may be connected to a data logger or microprocessor, and each has some on-board data processing capability of its own. For instance, a given monitor may display the total dose integrated over the preceding hour in addition to the current reading. Units will have additional software to stabilize operation and to perform the gas-concentration calculations.

References/Further Reading

  1. The National Institute of Standards and Technology (NIST) – Nitrous oxide Infrared Spectrum
  2. Occupational Safety and health Administration (OSHA) – OCCUPATIONAL SAFETY AND HEALTH GUIDELINE FOR NITROUS OXIDE
  3. Carnegie Mellon Research Institutes Highlights for 1996 – 1996, pp. 6-7
  4. Non-dispersive infrared gas analyzer with interfering gas correction – US Patent No. 5,886,348 – March 23, 1999