Pass-Through Chamber or Material Airlock - Which to Pick?
A material airlock lets you move parts into the cleanroom without anyone opening a door between zones. This guide explains passive versus dynamic designs, mechanical or electrical interlocks, and the criteria for material and cleanability.
View pass-through chambersWhat is a material airlock for?
A material airlock - also called a pass-through chamber or pass box - moves parts, tools and samples into the cleanroom without a single door leading straight from the dirty into the clean zone. The principle relies on two mutually interlocked doors: only one side is ever open, so no air short circuit can form.
This keeps the pressure cascade between zones intact so that every transfer does not disturb the cleanroom class per DIN EN ISO 14644‑1. Without an airlock, doors would have to be opened, dragging particles and uncontrolled airflow across the boundary.
Passive or dynamic - which design?
A passive chamber is a pure pass box with no airflow of its own: material is handed through, the doors interlock, that is all. A dynamic chamber adds a filter-fan unit that blows HEPA-filtered air (H13/H14) over the goods and actively flushes off loose particles.
- Passive: ideal for already-packaged or non-critical material and lower cleanroom classes.
- Dynamic: required when open parts are transferred and particles must be actively removed.
- An H14 filter stage retains at least 99.995 % of particles at 0.3 µm (MPPS).
- For toxic or sterile processes, versions with UV or positive/negative pressure can make sense.
What matters for interlock and material?
Interlocks come mechanical (Bowden cable, bolt) or electrical (magnetic lock with status display, releasing only after a purge time has elapsed). Electrical interlocks can be tied into the building management system with a status light, emergency release and signal contact.
For material, stainless steel 1.4301 (304) dominates, or 1.4404 (316L) for aggressive media, with a ground surface of Ra ≤ 0.8 µm. Rounded corners, welded rather than screwed joints and a crystal-clear viewing window make cleaning and wipe disinfection easy.
Frequently asked questions
What is the difference between a passive and a dynamic material airlock?
A passive chamber only hands material through under interlock, with no airflow of its own. A dynamic chamber additionally flushes the goods with HEPA-filtered air (H13/H14) and suits higher cleanroom classes and open parts.
Why must both doors never be open at the same time?
Opening both at once would create an air short circuit, collapse the pressure cascade and carry particles into the cleanroom. The interlock therefore keeps one of the two doors locked at all times.
Which material is best for a material airlock?
Stainless steel 1.4301 (304), or 1.4404 (316L) for aggressive media, with an Ra ≤ 0.8 µm surface, rounded corners and welded joints. That keeps the chamber gap-free, cleanable and disinfectant-proof.
Do I strictly need a dynamic chamber for ISO 5?
For critical, open parts in class ISO 5‑6 a dynamic chamber with HEPA filtration is usually required. Packaged material in lower classes often manages with a passive chamber.
Looking for a pass-through chamber for your cleanroom?
We supply passive and dynamic stainless-steel material airlocks with mechanical or electrical interlocks - matched to your cleanroom class.
Standard-compliant
Designed for cleanroom classes per DIN EN ISO 14644.
Safely interlocked
Interlock prevents both doors being open at once.
Fully cleanable
Stainless Ra ≤ 0.8 µm, rounded and gap-free.
Expert advice
Cleanroom specialists support your selection.