Dust Sampling &
      Preparation for Test

Dust Sampling

Combustion hazard properties of dusts become more dangerous as the mean particle size and moisture content become lower. In the interest of obtaining conservative combustion hazard safety data, it is important that dust sampling take into consideration the location in a process system where the finest and driest dust may occur. As an example, the dust accumulating on dust collector filter media (bags or filter elements) will usually be much finer than material that accumulates in the hopper where the largest particles settle more quickly. Always select the finest dust available from the hazard area for evaluation.

Preparation

Combustion hazard tests are conducted on fine dry dusts, as recommended by test standards. Test standards recommend that tests be performed on dusts that pass through a No. 200 sieve screen. If the moisture content is more than 5% then the sample is dried.  If a dust sample is not “fine” it is recommended that the available material be pre-screened to remove coarser particles before submitting for test.

Dust Evaluation on Receipt

Each dust sample is evaluated on receipt to determine its moisture content and sieve analysis.

Dust Sample Preparation Services

If a dust is deemed too coarse to yield conservative combustion hazard data, the CRC can prepare the dust for testing by classifying and drying. The as-received and as-tested forms of a dust are stated in the test report. Sample size recommendations given on other pages of this website assume that the sample is supplied in the form for testing as described above.  If sample preparation is required, larger quantities of dust may need to be supplied.