Autoclave Parts: What Each Component Does and What to Check

This page describes products and general use; it is not medical advice.

Who uses it: laboratory staff, clinic and sterile-processing teams, and buyers or students who need to know what each part of a steam autoclave does and what is checked on it before a run.

What an autoclave is

An autoclave is a self-locking, sealed chamber for sterilizing or decontaminating materials using steam under pressure (CDC REACH, Autoclave: Loading, Operating, and Unloading, checked 2026-10-31). In US device regulation a steam autoclave is a “Sterilizer, Steam”: FDA product code FLE, class 2, regulated under 21 CFR 880.6880, General Hospital panel (openFDA device classification database, checked 2026-10-31). For the machine as a whole, see what an autoclave is.

How it is built: the parts and what to check on each

A manufacturer description (Tuttnauer, a sterilizer maker, checked 2026-10-31) lists the main components of a steam autoclave. The CDC REACH job aid, which uses a jacketed autoclave with a gravity cycle, adds the checks staff make on several of them before a run. The table below joins the two; the third column is the CDC job-aid scenario and your own SOP and the manufacturer’s user guide take precedence.

Part	What it does	Check before a run (CDC job aid)
Pressure chamber	Stainless steel chamber that holds the load; the maker states it withstands 15-30 psi and 121-134 °C. Some models have a steam jacket.	Chamber pressure gauge: minimum of 15 psi during operation; it must read zero before the door is opened.
Jacket and jacket pressure gauge	The gauge displays the pressure inside the jacket.	Read it against the reading your manufacturer’s guide and SOP specify.
Door assembly and gasket	Seals the chamber from the outside atmosphere and prevents steam escaping; the maker adds safety interlocks.	Gasket and seals must not be ripped, torn or gouged; a damaged gasket can let steam and pressure escape.
Drain and drain screen	The maker describes condensate removal through a thermostatic trap or valve. The screen prevents debris entering the drain line.	Screen clear of debris. A clogged drain can lead to improper air removal and incorrect drying times, which may prevent correct pressure and temperature.
Emergency shutoff switch	A safety mechanism to turn the autoclave off in emergencies or when it cannot be shut down normally.	Verify it is in the “on” position.
Air removal system	Gravity displacement (Class N) or a vacuum pump (Class B/S), per the maker.	No separate check listed in the job aid.
Steam generator or supply	Internal boiler or external steam source, per the maker.	No separate check listed in the job aid.
Control system	Microprocessor managing time, temperature, pressure and cycle phases, per the maker.	Display checked during and after the cycle against the set values.
Safety devices	Pressure relief valves and alarms, per the maker.	No separate check listed in the job aid.
Drying system (optional)	Vacuum or heat to dry wrapped loads, per the maker.	No separate check listed in the job aid.

Parts and accessories with their own pages: autoclave gaskets and autoclave trays.

Types and variants

The main parts are the same across types; what changes is how air is removed from the chamber. The maker’s description names gravity displacement (Class N) and vacuum pump (Class B/S) systems. Autoclave types, sizes and the difference from other sterilizers each have a dedicated page, so they are summarised here only.

Question	Where it is covered
Autoclave types and sizes	Types of autoclaves
Gravity versus vacuum air removal	Gravity vs vacuum autoclave
Dry heat sterilizer versus autoclave	Dry heat sterilizer vs autoclave

Specifications that matter

Two values are sourced. The CDC job aid gives a chamber pressure of at least 15 psi (it also states 30 inches of mercury) during operation, with 121 °C in its gravity-cycle scenario, and says to check the manufacturer’s user guide and the laboratory’s SOP for the autoclave’s own settings. The maker states its chamber rating as 15-30 psi and 121-134 °C. Treat these as examples, not settings to copy.

Pre-run checks, in the order the CDC job aid makes them

1. Check the logbook for prior run errors, then log the run.
2. Confirm the emergency shutoff switch is on.
3. Read the jacket pressure gauge and the chamber pressure gauge.
4. Inspect the door gasket for nicks, gouges and tears.
5. Inspect the pans for cracks or punctures (a damaged pan is discarded and replaced per the SOP).
6. Confirm the drain screen is clear.

Safe use and handling basics

The CDC job aid lists burns, splashes and explosions as autoclave hazards. After the cycle, confirm the chamber gauge reads zero. Open the door no more than one inch and wait 10 minutes before opening it fully; if the door is opened wider or the wait is shortened, steam escapes rapidly and may cause a steam burn. The job aid’s PPE for the scenario is lab coat, safety glasses and nitrile gloves, plus a steam apron and heat-resistant thermal gloves for unloading. Always follow your laboratory’s SOP and risk assessment.

Common mistakes

• Opening the door while the chamber gauge is above zero, or opening it fully without the 10-minute wait.
• Running with a torn or gouged gasket.
• Skipping the drain screen check, which can mean improper air removal and incorrect drying times.
• Loading items so they touch the inner chamber walls; the job aid says items should be placed back to front and not touch them.

FAQ

What are the main parts of an autoclave?

Per the maker’s description: pressure chamber, steam generator or supply, air removal system, control system, door with gasket and interlocks, safety devices, sensors and gauges, drain and exhaust, and an optional drying system.

What is the difference between an autoclave and a sterilizer?

A steam autoclave is one kind of sterilizer; FDA files steam sterilizers under product code FLE. Other sterilizers use different methods, for example dry heat, compared on this comparison page.

What types and sizes of autoclave are there?

See types of autoclaves; this page does not give size figures.

Sources

• CDC REACH, “Autoclave: Loading, Operating, and Unloading” job aid (V26022): https://reach.cdc.gov/sites/default/files/job-aids-resources/Autoclave-Text-Version-UPDATED.pdf, checked 2026-10-31.
• Tuttnauer, “Key Components of Autoclaves for Effective Sterilization” (manufacturer description, not a standard): https://tuttnauer.com/knowledge-center/sterile-processing/autoclave/key-components-of-autoclaves-for-effective-sterilization, checked 2026-10-31.
• FDA openFDA device classification, product code FLE (data updated 2026-10-19): https://api.fda.gov/device/classification.json?search=product_code:FLE, checked 2026-10-31; 21 CFR 880.6880 “Steam sterilizer”: https://www.law.cornell.edu/cfr/text/21/880.6880.