The Health & Safety Executive – HSE – has been drawing attention to the risks presented by Construction Dusts and has issued several relevant publications, for example Construction Dust Information Sheet No36

What is an “M Class” Vacuum Cleaner?

An M Class Industrial Vacuum Cleaner is a vacuum cleaner that has been designed to limit the risk of exposure to the operator of potentially hazardous dusts which over time may present a risk of occupational disease. Typically this will include dusts created by grinding, cutting and drilling activities and also machining e.g. wood, MDF and other materials used in construction processes. The user’s own risk assessments will indicate whether an M Class machine is suitable or whether the potential hazard is of high enough severity to warrant the use of a higher rated H Class or Type H unit.

M Class is not just about filtration, although M Class Industrial Vacuum Cleaners must have an essential filter system complying with a high standard; to be certified M Class the essential filter must be at least ISO30. As a minimum essential filters in BVC M Class vacuums are at least ISO35 H13 – HEPA filters.

In addition to good filtration, M Class machines must have a disposable bag system to allow dusts to be removed with minimal exposure to the users, and must provide an indicator to show when the airflow through the filters drops below a threshold beyond which the vacuum cleaner will not operate efficiently. The construction of the machine must comply with various tests all designed to help prevent exposure to recovered dusts, and the Vacuum Cleaner must be clearly labelled with its dust class.