Preparing a load for the autoclave means arranging instruments so that steam can touch every surface, every time. Get cleaning, drying, packaging, and chamber loading right and cycles become predictable; skip one step and you get wet packs, failed indicators, and reprocessing delays. This checklist covers the routine from the sink to the chamber door.
Print it, keep it near the sterilizer, and walk it with new team members until the steps are automatic.
Quick Facts
- Steam sterilizes only what it touches; steam contact is the whole game.
- Instruments must be clean and dry before packaging. Residue blocks steam and can bake onto surfaces.
- Pouches should fit the instrument with room to spare and stand on edge in the chamber.
- Vacuum sterilizers should see a Bowie-Dick test on the first cycle of the day.
Before packaging: clean and dry
- Flush lumens and open hinged instruments immediately after use so debris does not dry in place.
- Clean instruments with an appropriate detergent or ultrasonic bath, following the device manufacturer instructions.
- Inspect every item for debris, stains, rust, and residue before it is wrapped.
- Dry instruments completely; moisture trapped inside a pouch is the classic cause of wet packs.
- Confirm the instrument is steam-compatible and rated for the cycle you plan to run.
Choose the right pouch or roll
The package has two jobs: keep the instrument sterile after the cycle and let steam reach it during the cycle. Size and sealing decide both.
- Select a pouch that fits the instrument without stretching the seams or crowding the seal area.
- Leave a margin at the sealed end so tips do not push against the seal.
- Use sterilization pouches with clear chemical indicators, or cut sterilization roll to length with room to spare.
- Seal firmly and check the seal before loading; a weak seal can pop open in the chamber.
Load the chamber for steam contact
- Place hinged instruments open, never locked, so steam reaches the joint.
- Stand pouches on edge with paper facing paper and plastic facing plastic; this is what paper-to-paper means in practice.
- Avoid stacking pouches flat in piles. Flat stacks trap moisture between layers.
- Leave visible gaps between packs so steam circulates around each one.
- Follow the loading diagram in your sterilizer manual, including tray positions and maximum load size.
First load of the day and vacuum cycles
For pre-vacuum and Class B sterilizers, run a Bowie-Dick test on the first cycle before processing instruments. This is standard practice for vacuum cycles, in line with ISO 11140-4 and CSA Z314.8, and it catches air-removal faults while the day is still young.
| Loading mistake | Result | Fix |
|---|---|---|
| Instruments packaged wet | Damp packs, failed indicators | Dry thoroughly before wrapping |
| Pouch too large or overstuffed | Seal strain, poor steam contact | Match pouch size to the item |
| Pouches stacked flat | Moisture trapped between layers | Stand pouches on edge |
| Chamber packed to the brim | Air pockets and cool zones | Leave gaps between packs |
| Skipping the daily vacuum test | Undetected air leak | Run the Bowie-Dick test first cycle |
After the cycle: check before you trust
- Confirm every pack shows a colour change on its external indicator before it leaves the sterilizer area.
- Feel the packs: they should be dry, with no condensation inside the pouch.
- Check seals and paper for tears, then date or label the pack if your system requires it.
- For extra assurance on critical loads, add a Class 5 integrator inside the pack and check it before the item is used.
- Store processed packs in a clean, dry cabinet, away from sinks and traffic.
Frequently Asked Questions
Why does paper-to-paper matter?
Steam enters a pouch through the paper side. When pouches face paper to plastic, the plastic sheet of one pouch can block steam from reaching the paper of its neighbour. Facing paper to paper and plastic to plastic keeps the steam path open for both.
How full is too full?
When you cannot see space between packs, the chamber is too full. Steam needs room to circulate, so a loosely packed chamber often produces drier, more reliable results than one loaded to capacity.
Why must hinged instruments be open?
A locked or closed hinge is a shielded surface. Steam and heat reach it slowly, and any bioburden in the joint may survive the cycle. Opening the instrument lets steam contact the whole surface.
Is a daily Bowie-Dick test really necessary?
For vacuum sterilizers, yes, it is the standard practice for the first cycle of the day. Gravity-displacement sterilizers do not use a vacuum phase, so the test does not apply to them.
None of these steps is complicated on its own. Together they form the routine that keeps every load dry, every indicator honest, and every instrument ready for the next patient.
Related reading: browse the sterilization compliance hub for more spore-testing resources.
read the foundational SAL explainer before choosing your monitoring products.
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