Hospitals, day surgery and diagnostic centres

Why hospital-scale sizing is a different problem

A single clinic buys one or two units and tests them in one room. A hospital, day surgery centre or diagnostic group buys across dozens of bays and wards, usually through a tender, and has to defend every specification to a facilities auditor months later. The question is rarely whether it works — it is how many units, at what air-change target, and whether the working can be shown on paper. Scoping a hospital-wide rollout covers how to survey an entire facility and phase the purchase across wards rather than buying everything in one order.

The sizing logic, worked through a real ward bay

Required clean-air delivery is floor area (m²) × ceiling height (m) × target air changes per hour (ACH). A 96 m² ward bay at a 2.8 m ceiling, sized to 6 ACH, needs roughly 1,613 m³/h (96 × 2.8 × 6 = 1,612.8). One Pro 800S unit delivers 800 m³/h of CADR, so this bay needs two units, not one — a common miscalculation when a specification is written off floor area alone without checking the CADR total against unit output. At 6 ACH, the bay reaches 99% clearance of an airborne contaminant in about 46 minutes; at the US CDC's minimum of 5 ACH that stretches to around 55 minutes. Our breakdown of ward unit counts runs this same calculation across a general ward, nurse station and isolation bay, which each need separate sizing rather than one figure covering the whole floor.

Different areas, different targets

A ward bay, a day-surgery recovery bay and a health-screening waiting hall do not share a specification, even at similar floor areas, because occupancy time and patient vulnerability differ. The table below is a starting point; each area type has its own guide with the detail behind it.

A portable unit is not isolation-room engineering

A negative-pressure isolation room is engineered ventilation, designed to hold a pressure differential that keeps air from moving out of the room. A portable H13 unit adds clean-air delivery to a bay or waiting area; it does not create that pressure differential and does not replace HVAC design. Where an isolation bay or its waiting area needs a unit added quickly ahead of a review, treat it as additional clean-air delivery, not a redesign of the room's ventilation.

Choosing equipment and comparing suppliers at scale

Across a hospital-wide rollout, the units in play are usually the Pro 800S for larger bays (56–96 m², CADR 800 m³/h, dual intake, castors, 26 dB in sleep mode with a PM2.5 sensor) and the Classic 400S for mid-sized rooms (31–54 m², CADR 480 m³/h). Marketing across suppliers tends to sound interchangeable at this scale too — HEPA, quiet, hospital-grade — so what "best for hospital wards" actually means sets out coverage area, verifiable certifications and noise as the things actually worth comparing between tender submissions. In independent chamber testing, over 99.99% of tested organisms (E. coli, Staphylococcus albus and Influenza A) were eliminated within 60 minutes under chamber-test conditions, against a plain-HEPA comparison unit's passive decay of roughly 4 hours 23 minutes; results in an occupied ward will differ from a sealed chamber.

What drives cost, and procurement at scale

For a day surgery centre specifically, cost tracks recovery bay count and the CADR each bay needs, not patient headcount — what actually drives day surgery centre costs sets out how a site survey turns bay count into a specification. Across many wards, the purchase-versus-rental decision changes shape again: a serviced rental bundles filters, parts, preventive visits and two-way delivery into one contract covering dozens of units rather than one, and phased quotes let a facility roll units out ward by ward against budget cycles. Renting versus buying across many wards covers how that servicing and phasing works in practice. There is no public price list for either route; every quote follows a site survey, and a one-month rental pilot is available for a single ward before a wider commitment.

What we will not claim

We do not claim fewer infections, fewer sick days or any other health outcome from an air purifier, and we do not describe a bay as "sterile," its air as "safe," or a specification as "MOH-" or "HSA-approved." What we do provide is verifiable: an H13 HEPA specification, CE and RoHS marks, ISO 9001 and 14001 management systems, and an FDA Class 2 medical device listing held by the manufacturer. A portable unit is one input into a facility's air quality; it sits alongside your HVAC design and infection-control protocols rather than replacing either.

The next step for any of the areas above is the same: a Clinic Air Report at S$150 per site visit (minimum two rooms), with every room measured on site and a report emailed within two working days, carrying a sized-right guarantee — if a specified unit does not reach the report's air-change figure, we upgrade or add a unit at no extra cost. For a multi-ward rollout, the same report scales to a phased survey across the facility.