Extraction system cleaning in workshops and production

Extraction system cleaning: which types do you find in workshops and production?

Not every extraction installation is the same. The type determines the contamination you find and how you deal with it.

Close to the source the concentration is highest. Volandis (Dutch construction industry knowledge centre) recommends a flexible extraction system close to the work in metalworking. Precisely those short, flexible parts and the first metres of duct behind them get dirty fastest. The broader sector approach, including legionella in cooling towers, is in the guide on extraction ducts in factories.

Why cleaning extraction installations is more than housekeeping

An extraction system is a protective measure. If the air velocity in the ducts drops because of deposits or a full filter, the capture hood takes away less and the dust stays in the operator's breathing zone.

• Exposure: according to Volandis, the limit values for inert dust are 10 mg/m3 inhalable and 5 mg/m3 respirable (8 hour time weighted average). An extraction system that no longer works properly makes it harder to stay below those values.
• Supplying clean air: article 4.5 of the Working Conditions Decree (Arbobesluit) states that when contaminated air is removed, enough clean air must be supplied at the same time. An extraction system that pulls away a lot of air therefore needs a working supply.
• In working order: Arboportaal (the Dutch government portal on working conditions) advises replacing dust filters regularly and cleaning the ducts. That is advice, not a statutory interval.

What the law does and does not literally require on ventilation is explained in the article on the legal duty for air ducts.

Combustible dust in dust extraction: what does it mean for your work?

Much of the dust released in production is combustible: think of wood dust, flour and sugar. Built up in a duct or filter, it becomes a risk as soon as it is stirred up.

• In a memo for the bakery sector, TNO states that a dust explosion is only possible above 60 g/m3 of fine dust, such as flour or sugar. Precisely when you loosen deposits, you can create such a cloud locally.
• For the wood processing industry, Brandveilig.com points to the explosion hazard from fine wood dust, with attention to extraction installations, spark detection and ATEX.
• According to TNO, an industrial, ATEX 114 certified vacuum cleaner is necessary in EX zones.
• TNO and the Belgian organisation Alimento advise against using compressed air for cleaning in bakeries, because it blows dust into the air.

Important: in an ATEX zone, only use equipment that is suitable and certified for it. Whether a machine or extraction unit from the Lamers range is suitable for your zone is something you check with Lamers beforehand. Never assume it. For bakeries there is a separate guide on flour dust in bakery ducts.

How often do you test or clean local exhaust ventilation?

Dutch law sets no fixed cleaning interval for workshop extraction. EN 15780, the European standard for the cleanliness of ventilation systems, does not apply to industrial process installations. You therefore base your schedule on measurements, contamination and the advice of the installation manufacturer.

For comparison you can look at the United Kingdom. There the HSE requires local exhaust ventilation to be thoroughly examined and tested at least every 14 months, with the record kept for 5 years. That is British regulation and does not apply in the Netherlands, but it is a useful benchmark for your own maintenance plan.

Keep a simple log of these signals per extraction point. Over a few rounds you will see which points need attention more often, and your planning becomes based on your own observations instead of guesswork.

Dust extraction cleaning: a five step approach

The approach below is practical advice. Adapt it to the dust type, the installation and the safety instructions of the site.

1. Assess the risk first: which dust, is it combustible, is there an EX zone? Your choice of equipment follows from that.
2. Switch off and seal: installation and machine off, section sealed so dust does not escape into the hall. With the products for duct sealing balloon you keep the section being cleaned under negative pressure.
3. Source first: clean or replace the capture hood, extraction arm and hose, as that is where most deposits are.
4. Ducts run by run: with a rotating brush through the hatches, dry and without blowing dust around.
5. Filter and fan: as the manufacturer specifies, followed by a function test and photos for the file.

If the installation has long horizontal runs without hatches, fit extra inspection hatches first. That stops you pushing dirt further into a duct.

Points to record in your job sheet after each round: the dust type found, the condition of hoses and arms, the filter pressure drop before and after, and any parts replaced. That record also helps the client show that the installation is kept in working order.

Which Lamers equipment suits extraction ducts?

For the round and rectangular ducts behind an extraction point, you need equipment that loosens dust without blowing it into the room. In the Lamers range of air duct cleaning tools, these options stand out:

With an DC4 duct cleaner you reach long runs from a single hatch. For sticky process deposits it helps to spend time air duct brush: a more aggressive Tynex brush loosens more than a soft one. Lamers also has categories such as industrial vacuum cleaners and oil mist and chip extractors, which often come up in workshops too.

Kitchen extraction and workshop extraction: not the same

Kitchen extraction in hospitality or a staff restaurant looks like process extraction, but the main problem is grease, and that comes with its own rules and measuring methods. For that, see the guide on removing grease from kitchen extraction. Comfort ventilation with an air handling unit and grilles is handled differently again: see the guide on cleaning a complete ventilation system.

Fictional example: an installer maintains the wood dust extraction at a furniture maker and the ventilation at an office. At the furniture maker he starts by asking about the EX zone and keeps the dust inside the sealed duct. At the office the focus is on filters and grilles. Same trade, different risk, different preparation.

If you offer this as a service, also look at the page for installers who clean ductwork. Questions about the right machine or zone suitability? Duct cleaner quotation.