Working near classrooms, offices, clinics, or food areas demands tighter control. The goal is simple: keep contaminants inside the work zone and return visibly and measurably cleaner air to occupied spaces.

Plan the air path and pressure

• Zone the work area with robust barriers; seal penetrations and edges.
• Set negative pressure in the work zone so air flows from clean to dirty areas.
• Provide make-up air from a clean source and exhaust to outside where possible.

Select equipment for the environment

• Use air scrubbers with H13 or H14 filters; choose H14 for fine or carcinogenic dusts such as RCS.
• Size by ACH and room volume, using under-load airflow. Aim 8–12 ACH for occupied-adjacent control, verified by monitoring.
• Consider noise and placement to avoid disruption; short, sealed duct runs reduce losses.
• Pair with local exhaust ventilation or on-tool extraction to prevent escape at source.

Operate, maintain, and evidence control

• Run units before shift to pre-clean, continuously during work, and 30–90 minutes after to purge.
• Use a particulate monitor to track PM trends; record readings with filter changes for COSHH evidence.
• Stage prefilters to extend HEPA life and watch differential pressure to time replacements.

Special considerations

• Avoid ionisers or ozone generators; stick to mechanical filtration.
• For food areas, manage dust migration routes and clean-down procedures with approved methods.
• Coordinate with building management on fire strategy when using barriers and ducting.

Practical takeaways

• Control the pressure gradient: clean to dirty, always.
• Specify H14 where fine or hazardous dusts are present.
• Prove performance with PM data, not assumptions.
• Integrate source capture, air cleaning, and disciplined housekeeping.

Keep the approach layered and measured. If the air leaving the zone trends cleaner and adjacent spaces remain undisturbed, your control strategy is working.