Dust Extraction Classes on Vacuums – What class do I need?

Outsource Safety Ltd BlogSafety newsDust Extraction Classes on Vacuums – What class do I need?
June 18, 2019 Posted by Roger Hart

Firstly, good for you for even stopping to ask yourself about Dust Extraction Classes.  A lot of people are still using extraction equipment which is designed for domestic vacuuming – something not designed or capable of protecting you from hazardous dust.  Think about it, would you take something you know to be harmful and then suck it up only to spray the very finest (and most hazardous) parts of it into the air around you and your workmates?  Not a good idea but if you would like some good ideas on protecting yourself and others from hazardous dust please do contact us or request a call back from one of our safety consultants or an occupational hygienist.

What do I need?respirable crystalline silica, RCS welding fume

Something which can extract it and keep it inside a bag until you dispose of it.  Don’t use a vacuum without bags – unless you like inhaling dangerous dust and are hoping to get a lung disease! On the same subject be wary of small on tool extractors which collect dust efficiently only to leave you with having to ‘knock them out’ giving you dust exposure which a well-designed vacuum extractor would deal with.  For the smallest of these systems that can mean quite a few times a day, and when you’re dealing with RCS (respirable crystalline silica) that’s a bad idea for you and those around you.

Added benefits: time and money

If you, or your boss, still aren’t convinced how about considering time and money saved?  If you’re not cleaning up afterwards you’re saving money.  If you’re on domestic work creating dust and spreading it throughout a nice house good extraction can mean no cleanup and that equals happy lungs and happy clients.  Believe it or not, good extraction will also prolong the life of your tools and equipment, by up to 3 times!  When you’ve got expensive professional tools that’s a significant payback.

More reasons to choose good dust extraction

Don’t forget there are also some harsher reasons why not using good extraction could cost you money.

  1. Main contractors don’t want you exposing other trades to dangerous dust and value those with good dust practices;
  2. They also have to factor in for your clean up if you create a lot of dust or delaying other trades;
  3. The HSE would very happily fine you under FFI or issue a notice to you if you’re not taking good precautions to control dust generation;
  4. No win no fee cases are rising massively for health-related issues with payouts in the tens of thousands happening regularly (see our sentencing guidelines blog).

Types of vacuum: (MAC = maximum allowable concentration)

  1. L Class ≤ 1.0% Dust with maximum allowable concentrations (MAC) > 1 mg/m³ (soft wood dust, other lower hazard dust such as Corian)
  2. M Class < 0.1% Dusts with maximum allowable concentrations (MAC) ≥ 0.1 mg/m³ (hard wood dust, concrete and brick dust)
  3. H Class < 0.005% Dusts with maximum allowable concentrations (MAC) < 0.1 mg/m³ (asbestos, mould spores, carcinogenic dusts)

Notes on vacuum types

In practice, you may see very little to distinguish a type L from a type M vacuum but there are differences. Although their extraction rates and filtration levels are often similar features will vary, for example, a true type M vacuum will have an audible alarm to warn when the suction rates drop due to a full dust bag or a hose blockage. For the majority of construction sites, M class will be a minimum requirement and we would suggest this is also the case within any factory environment.  Interestingly, HSE set a minimum requirement of M class, a strong reason why you should make the step up to a better level of extraction.

Other factors to consider relate to use in practice which means in practice;

  1. A bag size adequate for the amount of use / level /volume of dust being extracted;
  2. A power take-off which helps to ensure that the extractor is running all the time the tool is active (and then switches off when not needed);
  3. A delayed shut off is preferable which ensures some over-run to extract remaining dust after the tool itself shuts down (typically 5 seconds and clears the tool and hose of dust);
  4. A filter cleaner which can be manual or automatic, this dislodges dust from the filter and maintains good flow.  Improving capture efficiency and reducing the likelihood of a motor overheat or burnout;
  5. Attachments which make your vacuum far more effective, see below (whale tail for extracting mixing containers, impact breaker attachment, grinder guard / extractor, drilling shroud).

HSE guidance