A question that comes up more often than most ASC administrators expect: if the operating room already has HEPA filtration built into the air handling system, why would anyone bring in a portable air scrubber at all? And on the flip side, if a scrubber is sitting in the hallway running, does that mean the room's air is being handled correctly?
Both questions come from the same place. "HEPA filtration" gets used as a single idea, when in a surgical environment it actually describes two very different things doing two very different jobs. One is engineered into the building and runs continuously as part of the room's certified air handling design. The other is portable equipment that gets wheeled in for a specific task and wheeled back out when that task is done. Treating them as interchangeable, or assuming one makes the other unnecessary, is where ORs and ASCs end up with gaps that don't show up until someone asks a harder question than "is there HEPA in here."
This is a look at what each one is actually built to do, where the confusion between them creates real inefficiency, and how to know which one a given situation in a surgical environment actually calls for.
When someone says an OR has "HEPA filtration," they're almost always talking about the room's engineered air handling system: terminal filtration integrated into the HVAC design, delivering a fixed, code-driven number of air changes per hour and maintaining the room at positive pressure relative to adjacent corridors and support spaces. Depending on how the space was designed and commissioned, that terminal filtration may be true HEPA media or a lower, still code-compliant efficiency rating. Either way, it's built into the room, sized, tested, and commissioned as part of it, and it's expected to run continuously, case after case, without anyone thinking about it.
A portable air scrubber is not a smaller version of that system. It's a separate category of equipment entirely: a mobile, recirculating HEPA unit that pulls air from a defined space, filters it, and returns it to that same space. It doesn't tie into the building's air handling design, doesn't affect the OR's engineered pressure relationship, and isn't meant to run indefinitely as a substitute for it. It's brought in for a bounded purpose and removed when that purpose is finished.
Framed that way, the comparison isn't "which one is better." It's "which job is actually in front of you," because the two pieces of equipment were never designed to compete for the same role.
The OR's central air handling system exists to maintain a continuous, verified environment for every case scheduled in that room, not just the one happening today. That means holding a specific air change rate and outdoor air percentage set by the applicable ASHRAE 170 or FGI guideline for that space, and maintaining positive pressure so that air moves out of the OR into the surrounding corridor rather than the reverse. The exact filtration efficiency and air change requirement varies by facility type and how the room was classified during design, which is a reason to confirm the room's actual rated requirement rather than assume it matches a number from a different project.
This system is inspected, tested, and recommissioned on a schedule, not assumed to be working because nothing has gone visibly wrong. It's the infrastructure the entire surgical schedule depends on, and it's built to handle the baseline bioburden of normal case activity, not an unplanned load introduced from outside the room.
A HEPAFORCE® air scrubber exists to solve a narrower, temporary problem: reducing airborne particulate concentration in a specific space for a specific window of time. It recirculates and filters air within the room it's placed in, which makes it effective at pulling down particulate load quickly, but it does not change that room's pressure relationship to the spaces around it and does not replace the engineered air changes the central system is responsible for delivering.
That distinction matters because a scrubber's job is bounded by the task it was brought in for. Once that task is finished, either the room returns to relying entirely on its built-in system, or the scrubber gets repositioned to the next space that needs the same kind of temporary support.
The cleanest way to keep these two straight isn't a side-by-side spec comparison. It's knowing exactly where each one's responsibility stops.
The built-in system's job ends at the room's own walls, and it's not designed to react to anything. It holds its rated air changes and pressure relationship whether the corridor outside is quiet or whether there's a demolition crew working on the other side of the wall. That consistency is the point. It's also the limit. The system wasn't engineered to absorb an unplanned particulate load introduced from outside the room, and it won't flag that it's being asked to.
A portable scrubber's job ends the moment the task it was brought in for is finished. It has no ongoing obligation to the room the way the built-in system does, no maintenance schedule tied to the facility's commissioning cycle, and no responsibility for the room's pressure relationship at all. What it does have is the ability to respond to a specific, temporary condition that the built-in system was never asked to handle, which is exactly the gap that shows up when construction, a service window, or an elevated-risk turnover puts a load on the room the permanent system isn't built to cover.
Put those two boundaries next to each other and the failure mode on each side becomes obvious. A facility that leans on a scrubber to quietly cover for air changes that have never actually been verified is asking temporary equipment to do a permanent system's job. A facility that skips a scrubber during nearby construction because the room already has a rated central system is asking a permanent system to absorb a load it was never sized for. Both mistakes look reasonable in the moment. Neither one holds up when someone actually checks.
The built-in versus add-on question isn't just a facility-level decision. It shows up one level down, in how a portable isolation module itself is equipped, and AnteRoom and HEPAROOM™ are a direct illustration of it.
AnteRoom is a portable isolation vestibule without filtration built into the module itself. It's designed to be paired with a separate HEPAFORCE® air scrubber or negative air machine, sized independently to whatever the specific job requires. That separation is a genuine advantage on projects where dust load, room volume, or duration varies from one deployment to the next, because the filtration capacity gets matched to the job instead of being fixed at the point of manufacture.
HEPAROOM takes the opposite approach. It's the same category of portable isolation vestibule, but with a HEPA-filtered negative air machine and digital pressure monitoring built into the unit itself. There's no separate scrubber to source, connect, or verify at setup, which cuts a step out of deployment and reduces the chance that a crew shows up with the vestibule but the wrong filtration unit to go with it.
Neither is the better product across the board, and it isn't honest to claim otherwise. AnteRoom's independently sized filtration is the right call when a facility's projects vary enough in scope that a fixed, built-in unit would be over- or undersized for some of them. HEPAROOM's integrated filtration is the right call when a facility runs frequent, similarly scoped isolation setups and values a faster, simpler deployment over that per-project flexibility. And the same caveat that applies to a room's central system applies here too: HEPAROOM's built-in unit is sized for its typical vestibule application, and a job with a heavier dust load or a larger adjoining space may still call for an additional scrubber running alongside it. Built-in filtration removes a setup step. It doesn't remove the need to confirm the equipment actually matches what the job requires.
The inefficiency rarely looks like an obvious mistake. It shows up in a handful of specific, recurring decisions.
A portable scrubber gets treated as a workaround for a central system that's falling short. If an OR's air changes per hour have never been independently verified, or verification happened years ago during initial commissioning, a scrubber can end up doing quiet, unofficial compensation work for a gap nobody has formally acknowledged. That's not what the equipment is built for, and it doesn't fix the underlying engineering issue.
Construction near or inside a surgical space skips supplemental scrubbing because "the room already has HEPA." The central system is sized for the room's normal bioburden, not for the dust load generated by drilling, demolition, or renovation work happening in or next to it. Portable HEPA filtration doesn't have to slow down an OR when it's brought in correctly for exactly this kind of situation, but it has to actually be part of the plan, not assumed unnecessary because the room's engineered system is functioning normally.
A running scrubber gets read as proof the space is protected. A scrubber pulling particulate out of the air is doing real work, but it isn't evidence that the room's pressure relationship or engineered air changes are intact. Those are separate questions that need separate verification, a pattern that shows up just as often with negative air machines treated as a standalone fix rather than one piece of a larger system.
Scrubber sizing gets estimated instead of calculated. A unit chosen because it fit the last job, rather than the actual volume and contamination load of the current space, either underperforms or adds more equipment and noise than the task requires. Running the room's numbers through an air changes per hour calculator before deployment avoids both outcomes.
A few situations come up repeatedly across ASCs and hospital ORs where a portable scrubber is the correct call, not an overreaction:
Just as important is recognizing when a scrubber adds equipment and noise without adding protection. Standard case-to-case turnover in a room with a verified, functioning central system doesn't need supplemental scrubbing added as a matter of habit. Deploying one anyway doesn't create risk, but it does add setup time and floor space to a room that's already operating within its engineered parameters, and it can create a false sense that extra equipment is compensating for a gap that doesn't exist. The better response, when a team feels the need to add a scrubber "just in case," is to verify the central system's actual performance first rather than layering equipment on top of an unconfirmed baseline.
Before deciding whether a portable air scrubber belongs in a given surgical space, work through these questions rather than defaulting to habit:
If the answer to the second, third, or fourth question is yes, a portable scrubber is doing a job the built-in system isn't positioned to cover. If none of those apply, the room's engineered filtration is almost certainly enough on its own, and the more useful step is confirming that system's performance rather than adding equipment around it.
Does adding a portable air scrubber mean the OR's built-in filtration isn't good enough? Not on its own. A scrubber deployed for a specific, bounded reason, such as adjacent construction or a service window, is a supplemental response to a temporary condition, not an indictment of the room's engineered system. The concern only applies when a scrubber becomes a standing fixture covering for air changes that have never actually been verified.
Can a portable scrubber affect the OR's pressure relationship to the corridor? A standard recirculating air scrubber doesn't establish or change pressure differential on its own. If a project requires actual pressure control rather than particulate reduction, that's a different piece of equipment and a different conversation, and how negative air pressure works in healthcare construction environments covers that distinction directly.
How do we know if our OR's central filtration is actually performing to spec? Independent verification against the room's required air changes per hour and pressure differential, not just a maintenance log that says the system was last serviced on schedule. Infection control equipment that holds up under audit applies to permanent systems just as much as portable ones, and a gap here rarely surfaces until someone asks for the documentation. Standardizing infection control risk assessment across teams is what keeps that verification consistent regardless of which facilities lead is handling the review.
Is it ever appropriate to run a scrubber continuously in an OR as a permanent addition? It can be, in specific cases where infection prevention protocol calls for it, such as ongoing supplemental filtration during a phased renovation elsewhere in the facility. What matters is that the decision is documented and tied to a defined reason, not left running indefinitely because someone added it once and nobody removed it.
The gap between a surgical space's built-in HEPA filtration and a portable air scrubber isn't a technicality. One is infrastructure the entire surgical schedule depends on every day. The other is a tool for a specific, temporary condition. Confusing the two in either direction, leaning on a scrubber to cover for an unverified central system, or skipping supplemental filtration because the room already has HEPA on paper, is how dust escapes containment in a hospital in ways nobody planned for.
Getting this right starts with knowing which question is actually in front of the team: is this about the room's engineered performance, or is it about a temporary condition the room wasn't designed to absorb on its own. Once that's clear, the equipment decision tends to follow without much debate, and it almost always comes back to the same underlying number: the air changes per hour the space actually requires, not an assumption carried over from a similar room or a previous job. Run your space's numbers through HEPACART's Air Changes Per Hour Calculator before deciding whether the built-in system covers it, a portable scrubber needs to join it, or a self-contained option like HEPAROOM is the simpler fit.