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CTL34 - Five-Litre Sphere Flammability Apparatus

For measurement of explosion pressure and rate of pressure rise resulting from liquid vapour / air ignitions. Data is also used in designing explosion protection measures.


  • Resulting data finds application in designing explosion protection measures
  • Versatility - equipment lends itself to Limited Oxygen Concentration (LOC) and maximum explosion pressure and rate of pressure rise testing
  • Simple ignition activation and pressure / temperature monitoring from PC
  • USB Connectivity
  • Magnetic stirrer built into oven giving capability of mixing the internal vessel environment thoroughly prior to ignition
  • Easy quick release pipe fittings

five-liter sphere flammability

5 Litre Sphere Apparatus

Explosion pressure and Rate of Pressure Rise (Kg) values are used for designing explosion protection measures, such as explosion shock resistant apparatus. Both of these values depend on the combustible properties of the material, the ambient or start temperature and pressure, volume and shape of the vessel and ignition source (type and energy).

Therefore it is necessary to standardise the conditions at which the explosion pressure and the explosion pressure and Kg values are measured. The standard test method is designed to determine the maximum explosion pressure and Kg value of a combustible liquid vapour / air mixture at ambient temperature and pressure. The tests are performed using a 5 litre, custom fabricated, metal spherical explosion chamber situated within a suitably sized oven enclosure. The pressure / time record of each explosion is recorded using computerised data logging via fast response pressure transducer and associated charge amplifiers.

The optimum ratio of fuel (sample) to oxidant (normally air) is determined by conducting a standard 5 litre test to determine the maximum explosion pressure and Kg values for the sample in question. Limiting Oxygen Concentration (LOC) tests may also be performed.

Functional Specification & Deliverables

  • 0-150 °C operation
  • Custom fabricated stainless steel 5 litre spherical vessel (ported to accept pressure transducers). Hydro-tested to 42 bar. Complete with certificate of conformity, hydro-test certificates, test gauge calibration certificates, hydro-test procedure
  • Explosion chamber head custom fabricated and ported for liquid injection, vacuum, exhaust, nitrogen inlet, thermocouple and pressure link
  • Arc ignition source / high voltage output ignition source. Operated via remote push-button on control box once vaporisation of the liquid sample has occurred
  • Pressure measurement system electronic timer circuit built in to charge amp enclosure control box to initiate charge amps following ignition
  • Oven enclosure. Capacity: approx 60 litres
  • Mains supply: 100 - 120 / 220 - 240 V single phase. Fan assisted with built in bottom stirrer
  • PID temperature controller and digital pressure display
  • Safety feature: Oven vent (N.B that testing should be conducted in a room facility with extraction)
  • Pressure transducers – fast response 10 kHz
  • Data acquisition - fast response data acquisition time resolution linked in to PC for accurate data logging

Optional Extras

  • Hastelloy sphere for testing particularly corrosive samples
  • Training and calibration services