|
What tests do I need to have carried out?
If the flammability of the dust / powder is unknown, start with a classification test. If the powder is classified as combustible, then consider the following tests based upon potential ignition sources etc:
| Potential ignition sources |
| Ignition |
Test |
Action |
| Hot surfaces |
Layer ignition temperature
Minimum ignition temperature |
Specifies equipment surface temperature limits |
| Electrostatic spark |
Minimum ignition energy test |
Influences the choice of plant materials (conductors / non conductors), earth bonding and personnel antistatic precautions |
| Self heating |
Isothermal basket test |
Specifies maximum storage size and configuration, storage temperature and storage time |
| Explosion prevention |
| Method |
Test |
Action |
| Dust control |
Lower explosible limit |
Plant should be operated with low levels of dust present e.g. use dust suppressed materials |
| Oxygen control |
Limiting oxygen concentration |
Plant should be operated under an inert gas such as nitrogen. Minimum permissible oxygen concentration (MPOC) should be determined based on the test result, inert gas control system, plant layout and safety margin required. |
| Explosion protection - see www.shapa.co.uk for equipment suppliers |
| Method |
Test |
Action |
| Explosion venting |
Pmax and Kst explosion indices test |
Verify plant design is adequate for the materials being handled |
| Explosion suppression |
Pmax and Kst explosion indices test |
Verify suppression design is based upon suitable explosion data |
| Explosion containment |
Pmax and Kst explosion indices test |
Verify containment and explosion isolation design is based upon suitable explosion data |
How much will it cost?
The classification test is £240 per sample. Prices for other tests will depend upon the total order value and how many samples are involved. Please contact us for a quotation.
How much sample is needed?
| Test |
Sample |
Test |
Sample |
| Classification test |
500g |
Flashpoint |
100ml |
| Explosion indices Kst & Pmax |
1000g |
Flammability limits in air |
TBA |
| Minimum ignition energy |
750g |
Flammability diagrams in air |
TBA |
| Minimum ignition temperature |
500g |
Autoignition temperature in air |
300ml |
| Layer ignition temperature |
500g |
Adiabatic pressure dewar |
TBA |
| Limiting oxygen concentration |
1000g |
|
|
| Lower explosible limit |
750g |
|
|
| Isothermal basket test |
TBA |
|
|
| Volume resistivity |
300g |
|
|
| Train firing |
300g |
|
|
| TBA - quantity will depend on exact test undertaken and nature of the sample |
How long will it take?
Lead times will depend on the number of tests involved and demand in the laboratory. Please contact us at time of order placement for an accurate estimate.
|
