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
Follow your site SOP
This is a typical operating sequence for learning. Your instrument model and approved SOP take precedence.
STAGE 1

Before you start

  1. 1Place the tester in a draught-free spot, inside a hood with the extraction off during the test or behind a draught shield, so that air currents do not blow the vapour away.
  2. 2Check the calibration status, the barometer reading and that the cup, lid and stirrer are clean and dry.
  3. 3Check the gas supply for leaks (soapy water, never a flame) or the electric igniter for function.
  4. 4Keep the sample sealed and cool. Do not open the container until it is well below the expected flash point (use the margin given in the current D93).
  5. 5Have a suitable fire extinguisher (CO₂ or dry powder) and a fire blanket within reach.
  • Never fill or open a sample container near a hot surface or an ignition source.
  • Samples containing water must be dried or treated as the method describes; water can make the sample foam over.
STAGE 2

Setting up

  1. 1Select the procedure: A for distillate fuels and clean lubricating oils, B for residual fuels, used oils and samples that form a skin, C for biodiesel.
  2. 2Enter the expected flash point. If it is unknown, run a screening test first and then a definitive test on a fresh portion.
  3. 3Mix the sample gently and fill the cup to the mark, avoiding splashes on the cup wall above the mark.
  4. 4Fit the lid, insert the temperature sensor and connect the stirrer; place the cup in the heater.
  • Overfilling or wetting the lid gives early, low flashes; empty, clean and refill if this happens.
STAGE 3

Testing

  1. 1Start the run. The tester heats at the procedure rate and stirs continuously except when the ignition source is applied.
  2. 2From about 23 ± 5 °C below the expected flash point, the ignition source is applied at every 1 °C (expected flash point up to 110 °C) or every 2 °C (above 110 °C).
  3. 3Record the temperature at which a distinct flash first appears; a blue halo around the flame is not a flash.
  4. 4If the flash occurs at the first application, abort and repeat with a fresh portion at a lower expected flash point.
  5. 5Read and record the barometric pressure at the time of the test.
  • Keep hands and face away from the lid openings when the ignition source is applied.
  • If the sample keeps burning, close the lid or let the suppression system act; cut the heater and gas. Do not use water.
STAGE 4

After testing

  1. 1Let the cup cool before removing it; it may be well above 100 °C.
  2. 2Dispose of the hot sample into a closed, labelled waste container once it has cooled.
  3. 3Clean the cup, lid, shutter and stirrer with a suitable solvent, then dry completely so no solvent remains.
  4. 4Correct the result to 101.3 kPa (if the instrument has not already done so), round to 0.5 °C and record it with the procedure used.
  • Solvent left in the cup will flash early in the next test; always dry the cup fully.
In LimsPulse · Calibration Management

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