How is construction dust controlled next to occupied classrooms?

Dust is the complaint that arrives fastest on an occupied site, and it is the one most likely to stop the work.

It travels further than people expect, it settles on everything, and in a building with ducted air conditioning it can reach rooms a long way from the work in minutes.

Separate the work area properly

**Sealed hoarding** rather than plastic taped to a wall. Full height, sealed at the floor, the ceiling and the edges, with a door that closes.

**Negative pressure inside the work area** where the dust load is significant, so air moves into the work area rather than out of it. This is the single most effective control and it is routinely left out.

**A clean transition** at the entry, so the route out of the work area does not carry dust with it.

The separation also serves the noise and the visual control, which is why it is designed with the arrangements in [site establishment, hoarding and fencing](/answers/site-establishment-hoarding-and-fencing).

Control it at the source

**On-tool extraction** for cutting, grinding, drilling and chasing. Mandatory for silica generating work rather than optional, and the only control that works at the point the dust is created.

**Water suppression** where extraction is not practical and water will not create another problem.

**Air scrubbers** with filtration inside the work area, running continuously rather than when somebody remembers.

**Enclosed cutting stations** for repetitive cutting, positioned away from occupied areas and from air intakes.

Silica is a health control, not a housekeeping one

Cutting, grinding or drilling concrete, masonry, tile or engineered stone generates respirable crystalline silica, which carries specific obligations: controls at the source, respiratory protection, exposure monitoring and health monitoring for the workers involved.

That is a worker health requirement independent of whether anybody outside the area notices the dust, and it is managed through the safe work method statement for the activity rather than through the site clean.

Shut down the air conditioning

The mistake that spreads dust through a whole building.

A ducted or central system running during demolition or cutting will draw dust into the return and distribute it to every room on the system. So the system is isolated or shut down for the affected zone, the returns in the work area are sealed, and the filters are changed before it is brought back on.

Which has to be coordinated with whoever operates the building, because shutting down a system in summer has its own consequences. That coordination sits with [mechanical and air conditioning upgrades](/answers/mechanical-and-air-conditioning-upgrades) and with the operational interface in [how do you carry out construction while a school stays open](/answers/how-do-you-carry-out-construction-while-a-school-stays-open).

Clean properly, every day

**Filtered vacuums** rather than brooms, because sweeping puts settled dust back into the air.

**Wet wipe down** of hard surfaces in and around the work area.

**Daily rather than weekly,** at the end of each shift, so the building is handed back clean each day.

**The route in and out** cleaned as well as the work area, which is where most of the visible dust complaints originate.

Older buildings change the controls entirely

Dust from a pre-1990 building may contain asbestos fibres, and dust from a pre-1970 painted surface may contain lead.

Neither is managed with a dust control plan. Both stop the work until the material is identified and handled under its own regime, which is the subject of [asbestos in school refurbishment](/answers/asbestos-in-school-refurbishment) and [lead paint in heritage buildings](/answers/lead-paint-in-heritage-buildings).

Monitoring and response

Dust is visible, which means the occupants will tell you about it before any monitoring does.

So there is a named contact, a daily walk of the interface with the facility manager, and a response that changes the method rather than promising to try harder. The environmental controls around it are in [environmental controls on a construction site](/answers/environmental-controls-on-a-construction-site).

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