LimsPulse
Petroleum testing

Flash Point Tester (Pensky-Martens Closed Cup)

Heats a fuel or oil in a closed brass cup while stirring and dips a small flame or electric igniter into the vapour space at set intervals. The lowest temperature at which the vapour flashes is the flash point, a key safety and quality property.

  • Petroleum refining
  • Fuel terminals and depots
  • Lubricant blending
  • Marine fuel testing
  • Biodiesel production
  • Power utilities (transformer oil)
  • Independent testing laboratories
Photo of a Flash Point Tester (Pensky-Martens Closed Cup)
Photo: Sirflashpoint, CC BY-SA 3.0 (cropped), via Wikimedia Commons
TROUBLESHOOTING

Common problems, causes and fixes

Flash point lower than expected
Likely causes
  • • Solvent residue left in cup
  • • Sample contaminated with a lighter product
  • • Sample overfilled or lid wetted
  • • Heating rate too high
What to do
  • • Clean and dry cup thoroughly
  • • Re-sample and check the chain of custody
  • • Refill exactly to the mark
  • • Check the heating programme and procedure selection
Flash point higher than expected
Likely causes
  • • Light ends lost from the sample (warm storage, open container, half-empty bottle)
  • • Draught in the test area
  • • Ignition source too small or not dipping fully
  • • Barometric correction applied with wrong units
What to do
  • • Use a fresh, cool, well-filled sample
  • • Switch off extraction during the test or use a draught shield
  • • Adjust flame size or replace igniter; check shutter mechanism
  • • Enter pressure in kPa and recheck the correction
No flash detected although flash seen
Likely causes
  • • Flash detector dirty or misaligned
  • • Detector sensitivity set wrongly
What to do
  • • Clean and reposition the detector
  • • Set sensitivity per the manual and verify with a CRM
Sample foams or spatters
Likely causes
  • • Water in the sample
  • • Heating too fast for a viscous sample
What to do
  • • Dry or treat the sample as the method allows
  • • Use Procedure B for residual or viscous samples
Flame goes out during the test
Likely causes
  • • Gas pressure low
  • • Pilot flame not lit
  • • Draught
What to do
  • • Check gas supply and regulator
  • • Relight and check pilot
  • • Remove draughts
CRM result outside tolerance
Likely causes
  • • Temperature sensor drift
  • • Barometer error
  • • Worn cup or lid
What to do
  • • Calibrate the sensor
  • • Check the barometer
  • • Replace worn parts and repeat the CRM
In LimsPulse · Calibration Management

Keep every PMCC tester in control: usage logs, calibration and maintenance schedules, and automatic blocking of overdue instruments.

See how