Many household chemicals contain formaldehyde and other solvents

Many household chemicals contain formaldehyde and other solvents

LCS Laboratory offers testing of wood stains, coatings, wood oils, varnishes, glazes, and similar products for spontaneous ignition when in contact with cleaning rags.

Little is known about chemistry of self-ignition but the key points are well understood.

  • Rags, absorbent pads, or paper towels are commonly used to apply and remove excess stain from wood surface. Once on rag, the stain rapidly losses volatile solvents producing thin layer of oil dispersed on cotton fibres.
  • At this point oil starts to react with oxygen of air producing some heat. If the heat can dissipate, or chemical reaction is too slow, than no ignition occurs.  If the heat loss is restricted, like inside the pile of rags, the temperature in the sample core start to rise, which only accelerates the process. Temperature rises exponentially, and the self ignition may occur.
  • Self heating can be aerobic (requires constant supply of oxygen) or anaerobic (can run without air).
    • Example of aerobic ignition is self heating of mineral (hydrocarbon) oil on rags. If the sample is placed in airtight container, self heating reaction is seised once the oxygen from air is consumed.
    • Anaerobic self heating can occur without supply of air, often in result rapid curing (polymerization) of stain. Example: curing of “drying” oils like linseed oil.
  • Size of the container with oil waste is crucial.
    • Single piece of rag dropped on a cement floor will not produce enough heat for ignition.
    • Garbage bin with spent rags may ignite one night.
    • Industrial size dumpster packed with oil/rags waste will most definitely cause a major fire.

Burning dustIn our tests, about 100 g of liquid stain is applied on equal amount of cotton rags and dried at room temperature overnight to evaporate solvent. Dry sample is placed in sample holder of special design, and is exposed to 140°C for 24 hours. The maximum difference between core temperature and oven temperature is used as a criteria for possibility of self heating (self ignition). In this accelerated self heating test, we follow UN procedure for classification of dangerous goods. Once temperature in sample core exceeds 200 °C of smoke is detected, the sample is classified as capable for spontaneous self heating and ignition.

The results of the test will be reported to you in form of maximum temperature developed in the sample core during 24 hour test.

The test will be performed in our London laboratory. Laboratory requires 200 ml of liquid sample for testing. Request form can be downloaded from our website. Please provide batch and sample ID for each sample.

This test can be used for classification purposes as well as for development of safer products. Please email us to discuss your project