LimsPulse
Petroleum testing

Copper Strip Corrosion Bath

A thermostatic bath that holds a polished copper strip immersed in a fuel or oil at a set temperature (for example 50 °C or 100 °C) for a set time. The tarnished strip is then compared with the ASTM colour standards to grade corrosiveness.

  • Petroleum refining
  • Fuel terminals
  • Lubricant blending
  • Aviation fuel quality
  • Independent testing laboratories
Illustration of Copper Strip Corrosion Bath
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. 1Check the bath is at the specified temperature on the calibrated thermometer.
  2. 2Check the pressure vessels and seals are in good condition and within their pressure-test date.
  3. 3Check the colour standards are within their use period and have been kept away from light.
  • Use only vessels that have passed their pressure test; a failing vessel can release hot flammable vapour.
STAGE 2

Preparing the strip

  1. 1Remove surface blemishes with silicon carbide paper, then final-polish with silicon carbide grains on cotton, always along the strip's length.
  2. 2Handle only with forceps or ashless filter paper; do not touch it with fingers.
  3. 3Inspect for scratches or pits; use the strip immediately after polishing.
  • Fingerprints and polishing residue cause stains that look like tarnish.
STAGE 3

Testing

  1. 1Place 30 mL of sample in a clean, dry test tube and slide the polished strip in within one minute.
  2. 2For volatile samples, put the tube in the pressure vessel and close the cap tightly.
  3. 3Place in the bath for the specified time and temperature.
  4. 4Remove, empty the sample into a beaker, take out the strip with forceps and wash it in wash solvent.
  5. 5Blot dry with filter paper and compare at once with the standards, under good lighting at about a 45° angle.
  • Let pressure vessels cool before opening; open them in a hood, pointing away from you.
STAGE 4

Reporting

  1. 1Report the class (e.g. 1a) with test time and temperature, e.g. 'Copper corrosion (3 h at 50 °C): 1a'.
  2. 2If the strip is between two classes, report the more tarnished class.
  3. 3Repeat the test if the strip shows unusual spots that may be due to handling or polishing.
In LimsPulse · Calibration Management

Keep every Copper corrosion bath in control: usage logs, calibration and maintenance schedules, and automatic blocking of overdue instruments.

See how