Secure relevant powder test values
Many issues that arise in the performance of bulk handling plants relate to the condition of the material and disputes centre on the party responsible. By Lyn Bates, Ajax, Bolton, UK
A key factor is whether the unacceptable material condition is the result of the supply being outside the range defined in the contract specification , or is a result of changes taking place during the handling processes.
Various properties of the material must be known or assumed with a high degree of confidence for design purposes and a responsible supplier would be assured of these values before proceeding to manufacture, either by experience, or testing ‘representative’ samples in the case of any uncertainty. The following steps are recommended to secure and record the essential details.
1. Have clear reasons for conduction of the tests, to make sure that the tests conducted are necessary and relevant to the purpose of interest.
2. Identify and record the true source and history of powder sample(s) for testing. Secure an authorised and dated signature by a responsible person to verify that it is, Or they are), fully ’Representative’ sample’ of the worst handling condition that may be required to handle in the working life of the equipment. Subjecting values, such as appearance), should be indicated by samples of what is, and what is not, acceptable.
3. Have a complete data sheet for handling hazards of the material to be tested.
Read and respect the details.
4. Have full control, and record, the test conditions. Relative humidity, temperature, date and time of testing and the presence of witnesses. Use a standard data sheet that has a prepared form to record the above details with an identifying reference, as well as the test measurements.
5. Have adequate safety protection close to hand, and support facilities available or well identified, as appropriate. Use the protective gear specified.
6. Have a robust and traceable procedure for the receipt, identification, recording, storage and disposal of samples. Maintain detailed recording of the associated documentation.
7. Ensure that the preparation of the sample for the test is not affected by the stress history of the material. Use devices that measure relevant bulk properties and have an approve published methodology and design value, such as bulk density, wall friction and shear strength, rather than phenomena based empirical methods that are sensitive preparation and handling of the sample.
8. Ensure that the equipment, location and re-useable safety equipment are decontaminated immediately following the test, and record that this is done. Have a safe disposal arrangement for disposable items.
9. Check that ancillary equipment, such as vacuum cleaners, are subjected to the same discipline of decontamination as relevant to the materials tested.
10. Check that the test results are understood, adequate and sensible. Check or confirm the results for consistency by repeat testing, comparison with prior tests on like or similar product, or with known values, as practical and appropriate, Particularly, with samples that will not be re-available.
