BRILON – Except for self-igniting materials such as biologically active solids, silos do not normally contain their own sources of ignition.
This means that they lack any significant components that might cause explosions (see Fig. 2: Five explosion requirements). Nevertheless, there is the hazard that a source of ignition might enter the silo from upstream sections of the plant. Outdoor silos therefore need to be protected with explosion vents, while indoor silos must have flameless venting or explosion suppression systems. Depending on the material that is conveyed by the system, it is also possible to take preventative measures. One prevention system, for instance, is to combine spark detectors with spark extinguishers or quench valves, as this may prevent sources of ignition from entering the silo. However, dispensing the use of explosion protection measures and should therefore always be discussed with and assessed by the relevant experts.
The probability of an explosion in a dust collector (DC) is higher than usual, and many DC manufacturers therefore include explosion protection measures within their products. This is because sparks and hot embers can enter the system together with aspirated dust from other parts of the plant. One situation which may get particularly critical is the purging of the filter hoses themselves. This leads to high dust concentrations. In indoor used DC are therefore protected through flameless venting, and in outdoor use through explosion vents. If vehicle routes or thoroughfares are situated within the explosion venting range, the solution is to use smart add-on modules for explosion vents to deflect flames and pressure waves into non-dangerous areas.
Based on the above, all parts of a plant can be protected separately. However, this method is not usually economically viable. Cost-effective solutions can only be achieved through a comprehensive treatment of the entire plant, covering all interaction between its parts and also any specific arrangements in the production operations. Professional explosion protection does, of course, have its price, but unprofessional over-engineering or insufficient protection are far more costly – not just in monetary terms. In the worst case, people may pay with their lives.
Independent experts therefore always recommend that plant operators work with experienced professionals who take a comprehensive approach and who implement an all-encompassing, fully customised explosion safety solutions. Turnkey solutions never exonerate a prospective plant operator from ensuring efficient explosion prevention. It therefore follows logically that experts should be involved in the process.