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Environmental monitoring

Testing volatile particle removers for the aerospace and automotive industries

We offer volatile particle remover (VPR) testing services to assess adherence to automotive and aviation regulations

Current regulations for vehicle engines (e.g. EURO 6) and aircraft engines (e.g. ICAO 2017) require the measurement of solid particle numbers in exhaust emissions. A VPR is a critical and mandatory conditioning component for this measurement as it removes any volatile particles and conditions the exhaust for measurement with particle counters. 

Calibration of VPRs

NPL offers calibration and measurement services for VPRs for regulatory purposes: 

  • Calibration for particle concentration reduction factor (PCRF). The concentration of gold or silver nanoparticles (15 – 100 nm) upstream and downstream of the VPR is measured using reference particle counters.  
  • Calibration of gas dilution factor. The amount fraction of a trace gas is measured using certified gases and reference gas analysers. 
  • Calibration of particle penetration efficiency. The values of PCRF and gas dilution factor are used to determine VPR penetration for different particle sizes.  
  • Calibration of volatile removal efficiency. The concentration of tetracontane volatile particles (30 nm) upstream and downstream of the VPR is measured using reference particle counters. 
  • Calibration of VPR flow rate (for internal parameters) and pressure. The VPR flow rate is used to correct particle losses from the engine output to the VPR. 

VPR calibration procedure for aerospace testing

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