Isolation Gowns for Aerosol-Generating Procedures: A Canadian Clinic Decision Guide

Isolation Gowns for Aerosol-Generating Procedures: A Canadian Clinic Decision Guide

A dental office in Ontario moved to a Level 2 gown for scaling appointments after a hygiene team raised a simple point: the spatter pattern on the assistant's forearms was visible at the end of a long afternoon, and the gowns on the hook were the lightest tier the practice could buy. Nothing had gone wrong. Nobody had been exposed. The practice changed its order anyway, because the gap between what was being worn and what the room was actually producing had become obvious.

That is the useful way to think about gown selection for aerosol-generating procedures. It is not a compliance ritual and it is not a marketing category. It is a match between the fluid load a procedure creates and the barrier a garment can document.

What is an aerosol-generating procedure, and why does the gown matter at all?

In a Canadian clinical setting, the term covers the procedures where powered instruments, pressurised irrigation or suction turn fluid into a fine suspension that travels further than the immediate treatment site. Ultrasonic scaling, air polishing, high-speed handpiece work and surgical suction in a small operatory all qualify. So does airway suctioning in a care home, for the same reason: a spray is created and it lands on surfaces, on equipment and on people.

The gown matters because a gown is what stands between that spray and the clothing and skin of the person generating it. A wet sleeve carried from room to room is a transport route, and a gown that wets through in the first ten minutes of a procedure is not doing the job it was bought for. Both provincial infection prevention guidance and the dental colleges treat gown selection as part of routine practices, which means the decision belongs in a written procedure rather than in a preference.

How do the four AAMI PB70 levels differ in what they test?

The four-level scale in AAMI PB70 is a performance ranking, not a description of fabric. The lower levels are judged on impact penetration, which approximates a splash hitting the material at speed. As the level rises, the requirement includes hydrostatic pressure, which approximates fluid sitting against the material under load. Level 4 adds viral penetration testing under ASTM F1671, and there is an equivalent international route through ISO 16603 and ISO 16604, which use synthetic blood and bacteriophage respectively.

Two consequences matter to a purchasing manager. First, the level describes a tested result, so a gown cannot be called Level 2 because of its grammage or its fibre. Second, a supplier who prints a level on a carton without being able to name the test behind it is telling you something about documentation, not about protection.

Which level fits an AGP in a Canadian dental or clinic setting?

For most AGP appointments in a dental practice or a community clinic, Level 2 is the defensible default and Level 1 is the tier that gets practices into trouble, because it is the lowest-priced case on the shelf and it looks identical when worn. The practical test is a wet forearm at the end of the appointment: if the sleeve is damp, the gown was under-specified for the task, regardless of what the carton says.

There is a second consideration that clinics rarely write down: duration. A barrier that holds for a ten-minute procedure may not hold for a forty-minute scaling appointment with continuous coolant spray. Level 2 in a four-layer SMMS construction is chosen for exactly that reason, because the meltblown layer in the middle is what resists wicking while the outer spunbond layers carry the mechanical load.

Why should the decision be written down rather than left to the room?

Because the person selecting the gown is usually the person working under time pressure, and the safe choice has to be the default one on the cart. A one-page table that names the tasks in your facility, the gown level for each, and the change points, removes the decision from the moment. It also gives an auditor something to read, which no amount of good intentions can substitute for.

ISO 14971 frames this as risk management, and the framing is useful even outside a manufacturer's quality system: identify the hazardous situation, decide the control, and record that you decided it. A clinic that can point to a written rule and a cart stocked to that rule is in a very different position from one that can only describe what staff usually do.

How should a gown be put on and taken off around a procedure?

Put the gown on before gloves, so the cuffs sit under the glove cuff and no bare wrist is exposed when you reach. Fasten the neck tie, then the waist tie, and check that the back closure actually covers the back rather than hanging open between the ties. If the gown is short enough that the front of the trousers is exposed when seated, it is the wrong size, and no tie will fix it.

Removal is the step that carries the contamination risk. Untie the waist, then the neck, then peel the gown away from the shoulders by touching only the inside of the fabric, turning it inside out as it comes off. Gloves come off last, and hands are cleaned after. The detail that clinics skip is the pause: doffing in a hurry is how a contaminated cuff ends up against a wrist.

What breaks a gown barrier during a procedure?

How many gowns does an AGP day actually need?

Count change points. One gown per patient is the floor for an AGP room, and the floor is not the number to stock, because the moments that force a change are not evenly distributed. Add a spare for each splash-prone task, a spare for the room where suction canisters are changed, and a spare per practitioner so nobody leaves an operatory to fetch one.

A single-operatory practice running eight AGP appointments typically wants twelve to fifteen gowns in the working stock plus a sealed reserve. At about a dollar a gown in a 50-gown case, that is a supply decision measured in tens of dollars a day, which is why gown level is a poor place to save money and a good place to standardise. The same arithmetic applies in a care home that runs airway suctioning on a unit: the cart should be stocked for the worst shift, not the average one.

What should a purchase order specify?

Name the level and the test behind it, not just the fabric. Ask for the grammage, the layer construction, the closure type, the cuff type and the case pack, and ask whether the level claim is supported by a test report for the material rather than a general statement about the product family. For a facility buying across several sites, ISO 2859-1 sampling discipline is worth asking about, because it tells you how the supplier decides a lot is acceptable.

Where a facility wants a lower-impact option for low-exposure tasks, a compostable gown has a place, provided it is kept in that place. The PLA Level 1 isolation gown belongs on the cart for reception and low-splash work in a facility with an industrial composting route, not in the AGP room. The full range sits in the isolation gowns collection, where level and construction are listed side by side so the cart can be stocked to the written rule rather than to whatever arrived last.

A practice that writes the rule once, stocks to it, and checks the cart at the start of the day stops having this conversation. The gown on the hook stops being a habit and becomes a decision with a document behind it.

References

1. ISO 13688:2013 — Protective clothing: general requirements (checked 27 October 2026)
2. ISO 16603:2004 — Clothing for protection against contact with blood and body fluids: determination of the resistance of protective clothing materials to penetration by blood and body fluids using synthetic blood (checked 27 October 2026)
3. ISO 16604:2004 — Clothing for protection against contact with blood and body fluids: determination of resistance of protective clothing materials to penetration by blood-borne pathogens using bacteriophage phi-X174 (checked 27 October 2026)
4. ASTM F1671 — Standard Test Method for Resistance of Materials Used in Protective Clothing to Penetration by Blood-Borne Pathogens (checked 27 October 2026)
5. ISO 10993-1:2018 — Biological evaluation of medical devices, Part 1 (checked 27 October 2026)
6. ISO 10993-10:2021 — Biological evaluation of medical devices, Part 10: tests for skin sensitization (checked 27 October 2026)
7. ISO 10993-23:2021 — Biological evaluation of medical devices, Part 23: tests for irritation (checked 27 October 2026)
8. ISO 15223-1:2021 — Medical devices: symbols used with information supplied by the manufacturer (checked 27 October 2026)
9. ISO 13485:2016 — Medical devices: quality management systems (checked 27 October 2026)
10. ISO 14971:2019 — Application of risk management to medical devices (checked 27 October 2026)
11. ISO 2859-1:1999 — Sampling procedures for inspection by attributes, Part 1 (checked 27 October 2026)
12. ISO 9001:2015 — Quality management systems: requirements (checked 27 October 2026)
13. ISO 31000:2018 — Risk management: guidelines (checked 27 October 2026)
14. ISO 45001:2018 — Occupational health and safety management systems (checked 27 October 2026)
15. Personal Protective Equipment — Canadian Centre for Occupational Health and Safety (checked 27 October 2026)
16. Routine Practices and Additional Precautions — Public Health Ontario (checked 27 October 2026)
17. Infection Prevention and Control — Royal College of Dental Surgeons of Ontario (checked 27 October 2026)

Printable companion: the PPE and room turnover SOP template gives you a column for gown level, one for change points, and one for who checked the cart at the start of the day.

Estimate what a full AGP day consumes before you set a par level with the clinic supply planner, then put the case quantity on the bulk quote form so the price reflects the volume you actually use.

Buying for a facility? Open a wholesale and institutional account for case pricing, purchase-order billing and a named account contact.

Related Reading

• Isolation gown levels for Canadian buyers: CSA and AAMI explained
• Which medical isolation gown do community health centres in Ontario order
• Buying medical isolation gown for group purchasing organizations in Montreal

Frequently Asked Questions

Is an aerosol-generating procedure only a dental thing?

No. Dentistry is where the language is used most, because ultrasonic scalers, air polishers and high-speed handpieces put a fine mist of coolant, saliva and blood into the air in a small operatory. But the same physics applies to any clinic procedure that uses powered instruments, high-pressure irrigation or suction that aerosolises fluid, and to airway work in a care home. If a procedure can throw a spray beyond the immediate treatment site, it belongs in the conversation about gown level and room turnover.

Does a higher gown level replace an N95 or a fit-tested respirator?

No, and treating the two as substitutes is the most common PPE error in this area. A gown is a barrier against fluid that reaches your body; it does nothing about particles you inhale. Gown level and respiratory protection are chosen on separate grounds, and a Level 2 gown worn without appropriate respiratory protection offers no respiratory protection at all. Decide the respiratory side from your provincial guidance and your procedure list, then decide the gown level from the fluid volume you expect.

Can staff wear the same gown for a whole AGP session?

Only if the gown stays visibly clean and dry, and only if your policy says so. Once a gown is wet, soiled, or has been worn through a room change, the barrier is compromised and the gown is spent. In practice, the change points that matter are between patients, after any splash, and whenever the gown has been doffed. A gown worn through a morning of scaling and then hung on a hook is not protection; it is a stored contamination risk for whoever handles it next.

What does AAMI PB70 actually test?

It places gowns into one of four levels based on how the fabric resists liquid under defined conditions, using an impact penetration test for the lower levels and a hydrostatic pressure test as the requirement rises. Level 4 adds a viral penetration test rather than a fabric weight, which is why Level 4 is bought for surgery and not for routine clinic work. The important consequence for a buyer is that level is a performance result, not a material: two 40gsm gowns from different mills can land in different levels.

Is a 40gsm gown better than a 25gsm gown?

Grammage tells you how much fabric there is per square metre, and more fabric usually means more barrier and more strength, but the number alone does not set the level. A 40gsm SMMS gown tested to Level 2 is a better buy than a heavier single-layer gown that has never been tested at all, because the tested product carries a claim you can point to in an audit. For an AGP room where splatter is routine, the four-layer SMMS construction is the part worth paying for.

What should a clinic do with a compostable isolation gown?

Use it where the exposure is low and the waste stream supports it. A PLA gown certified to a compostability standard belongs in a facility that has an industrial composting route and a policy that names which tasks may use it. It should not be offered as a substitute for a Level 2 barrier in an AGP room, because compostability says nothing about fluid resistance. Keep both products, and label the cart by task so the choice is made before the patient is seated.

How many gowns should be on the cart for a full procedure day?

Count the change points, not the patients. One gown per patient is the floor; add a spare for every splash-prone task, a spare for the room where suction lines are changed, and a spare per practitioner so nobody leaves a room to fetch one. A single-operatory practice running eight AGP appointments in a day usually needs a working stock of twelve to fifteen gowns plus a sealed reserve, which is why a 50-gown case at roughly a dollar a gown is a reasonable unit to hold.

How should gowns be stored and inspected?

Keep them in the closed case, off the floor, away from the room where chemicals are mixed, and inspect before use. Check the ties, the cuff seams and the shoulder seam, because those are the three places a gown fails first. A gown with a torn tie or a separated cuff seam is not a gown with a cosmetic defect; it is a gown that will open at the back during the procedure. Discard it at inspection rather than in the operatory.

Last updated: October 2026. CliniEco Medical is a licensed medical device establishment (MDEL #35334).