How to Validate a Sterilizer – A 7-Step Checklist for Tuttnauer Autoclaves

Who Needs This Checklist (And When)

If you're suddenly facing a JCI or ISO audit next week – or your lab's new Tuttnauer unit needs its initial qualification report – this list is for you. I've been in your shoes: March 2024, a dental chain called at 4 PM on a Friday needing validation docs for a Monday survey. Normal turnaround? Two weeks. We pulled it off by following a tight protocol, and I've refined that process over 40+ rush validation jobs since.

(Should mention: this applies to tabletop models like the EZ9 and T-Edge, as well as the M Series and larger washer-disinfectors. The principles are the same, but always double-check your specific model's manual – I'll flag where the dre tuttnauer m series manual and tuttnauer ez9 autoclave manual differ.)

Step 1: Gather the Documentation First

You'll need the manufacturer's operation manual, installation qualification (IQ) report, and any previous validation records. For the Tuttnauer M Series, the manual includes specific cycle parameters for wrapped and unwrapped instruments. If you're using an EZ9, the manual has a separate section for the liquid cycle – don't confuse them.

Action item: Pull up the PDF of your model. I want to say the EZ9 manual has a table on page 43 listing the required chamber drain test frequency, but don't quote me on that page number – it might be 47 in the latest revision.

Step 2: Perform the Physical Installation Check

This is often rushed. Check water quality (distilled or RO? Tuttnauer recommends conductivity < 5 μS/cm). Verify steam supply pressure – my notes from a recent site visit: the M Series needs 40-60 psi, while the smaller EZ9 works on 30-50 psi. Oh, and make sure the drain line has an air gap – I once saw a direct connection that caused backflow risk. The installation qualifications template in the Tuttnauer manual covers all these points.

Step 3: Run the Leak Test (Chamber Integrity)

A standard leak test holds vacuum for 15 minutes. Per AAMI ST79, the chamber leak rate should be ≤ 1.3 mbar/min. For Tuttnauer autoclaves, I've found that the M Series often achieves 0.5 mbar/min brand new, but older units might drift. If you're seeing > 1.0, check door gaskets and drain valve. The tuttnauer ez9 autoclave manual states the leak test must be done weekly – I'd argue that for validation, you do it before every test run.

Step 4: Validate with Chemical Indicators

Use a Class 6 (emulating) chemical indicator for the specific cycle you're validating. Place it in the most challenging location – typically the center of the load, wrapped in a towel pack. The indicator must change to the specified color within the tolerance window.

Here's where many people trip: the indicator placement. I once had a client place indicators only on the top shelf. After 3 years of validation, they failed a challenge by an inspector who put one at the bottom. Now I always use 5+ locations: top, middle, bottom, front, back. It's tempting to think you can skip the bottom because 'steam rises,' but air removal isn't perfect – especially in gravity-displacement cycles like some older Tuttnauer models.

Step 5: Run Biological Indicators (BIs)

This is the core of validation. Use Geobacillus stearothermophilus spores (ATCC 7953) for steam sterilization. Place BIs in the same locations as chemical indicators. After the cycle, incubate for 24-48 hours at 56-60°C.

Important: the M Series manual recommends a 30-minute exposure at 134°C for porous loads. But if you're sterilizing mammography compression paddles or parts of a mechanical ventilator, check the device manufacturer's IFU – those might require a different cycle. (I learned this the hard way when a client's ISO auditor questioned the 134°C cycle for a ventilator component rated for 121°C. We had to re-run everything.)

Step 6: Document All Results – Including the Failures

Your validation report should include: date, operator, cycle parameters, load configuration, indicator results, any deviations, and corrective actions. The Tuttnauer validation template (available from their service portal) has a section for 'non-conformances' – don't leave it blank. If a BI failed on your first attempt, write it down and explain the root cause.

After 5 years of doing this, I've come to believe that a perfect first-run validation report is less credible than one with a small issue and a clear fix. It shows you actually looked.

Step 7: Repeat and Trend

One successful run isn't validation. Per ISO 17665, you need three consecutive successful runs for initial qualification. For ongoing monitoring, I recommend re-validation every 6 months for high-use autoclaves, or after any major repair (new door seal, heater replacement). The EZ9 manual suggests a monthly Bowie-Dick test – that's a good routine minimum.

Common Mistakes to Avoid

• Using expired BIs – check the lot number and expiration date on the ampoule. I've seen labs use indicators that were 18 months past expiration because they were 'stored properly.' The spore population can degrade.
• Overloading the chamber – the M Series manual has a maximum load diagram. Exceeding it can cause wet packs and failed sterility.
• Forgetting the printer paper – if your Tuttnauer unit has a chart recorder or thermal printer, make sure paper is loaded and the printout is legible. I once had to re-run a cycle because the printout was too faint to read.
• Ignoring the pre-vacuum phase – for prevac cycles, the chamber must reach a deep vacuum (typically -0.8 bar) before steam injection. Check the manual for your specific model's pre-vacuum requirements.

When to Call Tuttnauer Support (Don't Wait)

If your leak test consistently fails, or your BIs come back positive after three attempts, it's time to involve the manufacturer's technical team. I've had instances where a client tried to 'fix' a stuck valve themselves and voided the warranty. The dre tuttnauer m series manual includes a troubleshooting section – but some issues require a qualified technician.

Also: if your facility also processes items from other areas like mammography or respiratory therapy (mechanical ventilators), make sure you have separate validation protocols for each device type. A single cycle doesn't fit all loads.

Final Thought

What was best practice in 2020 may not apply in 2025. Biological indicators are faster now, wireless data loggers are replacing paper charts, and some regulators are accepting remote validation audits. But the fundamentals haven't changed: good documentation, rigorous testing, and a willingness to admit when something went wrong. Follow this checklist, and you'll pass even the most unexpected audit.