SF6 Analysis and Testing Products

Switchgear, GIS and other compartments housing SF6 require a specific concentration/purity of SF6 to ensure optimal operation and to ensure full quenching of discharges. EMT manufacture a range of high quality, hi specification SF6 analysers which provide measurements of SF6 purity and levels of contaminants.

EMT analysis products are designed to aid operators in three main applications surrounding SF6:

    1. to ensure SF6 purity and concentration is inline with OEM guidelines for safe and efficient use of the asset
    2. to measure what breakdown products or contaminants are in the asset, why/where they have originated and how that may effect the operation of the asset
    3. To ensure the safety and well being of operators working with or in the vicinity of SF6 and its breakdown by-products

Simple, accurate testing using an analyser such as the EMT Rapide+ provides operators the gas purity levels to determine corrective actions to preventatively maintain the asset. Regular testing of an asset allows the operator to understand the current “health” of the asset. By understanding what contaminants are present, a basic understanding of the health of the asset can be determined. Analysing this “health” data over a period of time, provides operators with a better understanding of the long-term condition of their assets.

1min analysis

The inclusion of certain gases can give us a picture of the asset issue:

  • Measurement of CF4 can indicate Teflon cone wear
  • Measurement of CO/H2S can indicate solid insulation breakdown
  • Measurement of SO2 and HF can indicate heavy arcing with moisture present

EMT analysers can measure all these variables including ultra low levels of CF(0-4000ppm). This data provides operators guidance on fault finding, saving time & money – a classic example of operational data enabling business critical decision making.

EMT have used our expert knowledge in IR technology, and so produce our analysers focused on this technology

EMT testing parameters:

SF6 Volume % or Purity                               By IR Absorption

Dew Point or Moisture                                 By IR Absorption

SO2 in PPMv                                                   By Electrochemical Sensors

HF in PPMv                                                    By IR Absorption

CF4 in PPMv                                                   By IR Absorption

H2S in PPMv                                                  By Electrochemical Sensors

CO in PPMv                                                    By Electrochemical Sensors

EMT uses IR sensors in our analysers to measure the main constituents.

IR advantages:

  • Wavelength selective – allowing multiple gas measurements from one sample
  • Sensor lifetime – IR sensors typically have a lifetime >5yrs with little to no degradation as gas is not in contact with the sensor
  • No poisoning – other sensors can be overcome and “poisoned” by high concentrations of target gases or interference gases
  • Fast response – typically seconds to full concentration
  • Highly accurate – stable and accurate measurements depending on gas type


EMT IR advantages:

  • EMT H2O IR sensors are unaffected by arc by-products and are rugged for use in “unfriendly” environments and situations
  • EMT H2O IR sensors are fast response and require small volume gas samples giving readings <10ppm
  • EMT IR HF sensors give greater accuracy and specificity for HF, with no interference from SO2 or H2S
  • EMT IR HF sensors have a fast response with no issues of overwhelming
  • Life span is >5yrs, typically an Echem HF sensor lasts 18-24 months
  • EMT have developed market leading IR measurement of CFavailable in two versions
  • High range (0-65% Vol) for high CF4/SF6 mixtures in cold climates
  • Low range (0-4000ppmv) for checking arcing by-products in SF6
  • EMT utilise a long life and high specification SO2 sensor
  • Designed for measurement of SO2 in SF6 gas streams
  • Typical life span is 3yrs for the SO2 sensor
  • Good measurement accuracy and minimal drift over the lifetime of the sensor

Electrochemical sensor advantages

  • Low cost- most Echem sensors are low cost in comparison to IR, Photoacoustic or GC measurements
  • Speed of response- typically 30s to 5mins depending on gas
  • Gas types – there are many Echem sensor types available

Delivering accurate and reliable results from your EMT Zerowaste SF6 analyser is key to long term asset compliance and performance; ensuring maximum up-time and security of critical infrastructure.

Contact our team to discuss your requirements.