Sizing air purification for a busy imaging centre waiting hall

Key takeaways

• Imaging centre patients often wait longer than at a typical GP clinic
• Sub-waiting areas outside MRI and CT rooms usually need separate sizing from the main hall
• The CADR formula applies room by room: floor area times ceiling height times target ACH
• Clinics generally target 5 or more air changes per hour
• A floor-wide survey avoids under-treating smaller linked spaces

Why an imaging centre waiting hall differs from a GP waiting room

A GP clinic waiting room usually turns patients over fairly quickly, often within a fairly short window of time between arrival and being seen by the doctor. An imaging centre operates on a different rhythm. Appointments for MRI, CT and other scans often run longer, and patients frequently arrive earlier than needed to complete preparation steps such as changing or fasting confirmation.

That combination, longer individual appointments and earlier arrivals, means more people sitting in the same waiting space for longer stretches at any given time compared with a typical GP clinic of similar size.

Longer dwell times before MRI and CT appointments

Dwell time matters for air purification because it changes how much shared air a group of patients is exposed to during a single visit. A waiting room with fast turnover naturally refreshes its occupant group more often; a waiting hall with longer average visits holds a more stable, extended sharing period between patients.

This doesn't call for a different technology, but it does support sizing on the higher end of the recommended range for clinical waiting areas rather than the lower end, given how much longer people are likely to be sitting there.

Peak morning slots, when several appointment types often bunch together, are usually when the hall is fullest and dwell time longest, so it's worth sizing for that busier period rather than an average across the whole day.

Sizing the main hall and sub-waiting areas separately

Many imaging centres have a large central waiting hall feeding into smaller sub-waiting areas just outside each MRI or CT suite, where patients wait once called forward. These sub-waiting spaces are usually much smaller in floor area than the main hall, and a single central unit sized for the hall alone will not adequately cover them.

Treating each of these as its own zone, sized to its own floor area, avoids the common gap of a well-treated main hall next to an under-treated sub-waiting pocket right outside the scanning room.

Applying the CADR formula across several linked spaces

Required clean-air delivery rate is calculated as floor area in square metres multiplied by ceiling height in metres multiplied by target air changes per hour, generally 5 or more for a clinical setting. Apply this formula separately to the main hall and to each sub-waiting area, rather than dividing one whole-floor figure evenly across every unit.

Our size calculator runs this calculation directly and maps the result to a specific model, whether that's a larger unit for the main hall or a smaller unit for each sub-waiting pocket. Running the numbers for each zone separately usually reveals that a single centrally placed unit undersizes at least one of them.

Getting a floor-wide survey instead of estimating

Because an imaging centre typically has several distinct spaces feeding into and out of the main waiting hall, an accurate specification usually needs a proper floor-wide survey rather than an estimate based on total square footage alone. A survey captures each zone individually, including ceiling heights that can vary between the main hall and smaller adjoining rooms.

This is exactly the kind of multi-room layout our clinic waiting room guide was written for, and it's worth requesting a free room-by-room Air Report rather than sizing each area by guesswork. A single visit can usually cover the whole floor in one pass.

Budgeting a multi-zone rollout across the floor

An imaging centre weighing a floor-wide air purification upgrade can plan it in stages rather than committing to every zone at once. Starting with the main waiting hall, where the largest number of patients spend the most time, and following with the sub-waiting areas once the first phase is running, is a reasonable way to sequence a rollout without a single large commitment upfront.

Flexible rental across multiple zones, with servicing coordinated on one schedule, also tends to suit a phased rollout better than separate purchases made at different times, since it keeps every unit on the same maintenance cycle from the start.

Next step

Use our size calculator to check the main hall and each sub-waiting area against the recommended air changes per hour for a clinical setting, or request a full survey if the floor has several linked zones to cover.

Frequently asked

Why do imaging centre patients typically wait longer than at a GP clinic?

MRI, CT and other scan appointments often run longer than a typical GP consultation, and patients frequently arrive earlier to complete preparation steps such as changing or confirming fasting requirements. The combination of longer appointments and earlier arrivals means more people sharing the same waiting space for extended periods.

Should sub-waiting areas outside MRI and CT rooms be sized separately from the main hall?

Generally, yes. Sub-waiting areas are usually much smaller than the main waiting hall, and a single unit sized for the hall alone will not adequately cover these smaller adjoining spaces. Applying the clean-air delivery rate formula to each zone separately avoids leaving these pockets under-treated.

What does a floor-wide survey cover for an imaging centre?

A floor-wide survey measures the main waiting hall and each sub-waiting area individually, including differences in ceiling height between zones, so an accurate specification can be built for the whole floor rather than estimated from total square footage alone.

Can an imaging centre roll out air purification in stages?

Yes. Starting with the main waiting hall, where the largest number of patients spend the most time, and following with sub-waiting areas afterward, is a reasonable way to sequence a floor-wide rollout without committing to every zone in a single order.

Related reading

• Clinic Waiting Room Air Purifiers: What Actually Works