The next consideration must be the size of the ‘bin’ or bag attachment in which the dust is contained prior to disposal. The capacity must be suitable to deal with the quantity of dust and large enough to contain the debris for the duration of the operation. It is not practical to have to continually empty the ‘bin’ or to seal bags.
When there is a need to vacuum both wet and dry materials, there are dual purpose dry/wet industrial models on the market that effectively remove both, without the need to change the filter system.
For situations where dust is critical or where toxic and hazardous substances are present, there are vacuums that feature a Longopac® Safe Bagging System such as the 202DSLP or M450LP. Here, instead of a bin, dust and solid material is collected into a continuous anti-static feeding bag which is twisted and sealed by the operator into bags for disposal. This gives the operator confidence that airborne particles are safely contained.
With any operation, it is essential that the correct filter is fitted. In many projects clarifying the filter grade capacity and the level of filtration in comparison with the intended operation and the level or type of dust produced is essential. There are three main types of filters; L, M and H (low, medium and high). A vacuum must be fitted with an L or M type filter in order to correctly function, but can also be fitted with an additional H grade filter for collecting very fine particle dust and dust containing asbestos. A vacuum fitted with an H filter is by definition an H-type Vacuum. L grade filters are only suitable for containment of sand shed particles and the simplest applications.
Vacuums fitted with an H grade filter should have an ‘H’ sticker on them. To double check that one is fitted, take the head off the vacuum to confirm that there are two filters inside (one will be an H filter).