Three-Door Interlocking for a Medical Device Cleanroom
Three linked passage doors needed to fit a prepared cleanroom structure and operate as one coordinated system. SEPPES supplied compact internal-motor doors, connected the three-door interlock and commissioned the door-state indication on site.
- Door package
- 3 high-speed doors
- Opening size
- 2,000 × 2,000 mm
- Control arrangement
- Three-door interlock
- Project handover
- June 2026
A passage package with three doors and one operating relationship.
The project was located in China. Its central requirement was coordinated access: when one of the three doors was open, the other two were held closed.
The Site Challenge
The passage served a medical-device assembly area and connected with air-shower and material-transfer facilities. The installation had to work within a prebuilt steel framework.
- Three openings required coordinated access.
- Available side space influenced the drive layout.
- The contractor needed the mechanical and control work to fit the wider cleanroom programme.
The SEPPES Response
SEPPES combined the door assemblies with the required interlock connections and status indication, then installed and commissioned the package on site.
- Internal-motor PVC doors for the compact opening layout.
- Brush and rubber sealing details at the guides.
- Door travel, protective-device and interlock checks at handover.
Keep the essential functions together when comparing door proposals.
The selected package focused on the functions needed at these openings: compact installation, visibility, guide sealing and door-to-door coordination. These are useful comparison points when reviewing another proposal.
| Design consideration | Selected for this project | Why it matters to a buyer |
|---|---|---|
| Installation space | Internal drive within the door assembly. | Compare the complete head and side-clearance drawing, including access for servicing, rather than comparing clear opening dimensions alone. |
| Passage visibility | Grey PVC curtains with transparent viewing sections. | Specify the viewing position around the actual people, trolley and load route. Confirm sight lines from both approaches. |
| Guide sealing | A combination of brush and rubber seals. | Match the sealing detail to the environmental brief. If the specification requires a declared leakage class, request the relevant test evidence for the offered configuration. |
| Multi-door control | Three-door interlock and door-state indication. | Include the relationship between doors in the quotation scope. A set of separate motorised doors does not define a coordinated operating sequence. |
| Contractor interfaces | Mounting at a prepared steel framework and site control connections. | Agree who supplies the fixing structure, cable routes, power and interface terminations before manufacture. |
Working within a prepared frame? Review the door installation and retrofit checklist for mounting and service clearances.
One open door keeps the other two waiting.
In this project, the control arrangement prevented normal simultaneous opening of the three doors and provided door-state indication. For another passage, start by marking every opening and the areas it connects.
Define the Signals
For a similar system, agree which signal means a door is closed, which signal permits another door to open and how a waiting request is shown to the operator. Write the sequence before the control connections are finalised.
Define the Exceptions
Ask the responsible controls and facility teams to agree the response to lost signals, power interruption, alarms and emergency access. These conditions need their own design review and commissioning checks.
An interlock manages the opening sequence; cleanroom environmental performance also depends on ventilation, pressure relationships and enclosure sealing. Review those requirements with the facility designer. ASHRAE’s clean-spaces guidance explains these wider design relationships.
To prepare the complete control brief, use the industrial door automation and interlocking guide.
Mechanical fit and control commissioning were handled together.
SEPPES’s scope covered door supply, mechanical installation and interlock commissioning. Treating these interfaces as one coordinated package helped keep responsibility for the door functions clear.
Confirm the Opening and Package
The team agreed the three 2,000 × 2,000 mm doors, internal-motor arrangement, curtain details and interlock requirement before supply.
Coordinate the Supporting Structure
Door assemblies were fitted to the contractor’s prepared steel framework. Guide position, door travel and sealing interfaces were addressed as part of installation.
Complete the Control Connections
Dedicated interlock cabling and door-state indication were connected to establish the required relationship between the three openings.
Check the Operating Functions
The site checks covered door movement, the protective devices and the three-door interlock. Installation and commissioning were completed for handover in June 2026.
When does a passage need a different specification?
Use this project as a starting point for a brief, then compare it with the conditions at your own facility. The items below identify where another design or additional evidence may be needed.
| Your requirement | What to review | What to request |
|---|---|---|
| A compact internal passage | Drive position, headroom, side clearances and maintenance access. | An installation drawing showing the complete door envelope and fixing positions. |
| A defined pressure or cleanliness requirement | Sealing design, leakage characteristics and the facility’s qualification criteria. | Applicable configuration-specific test information and an agreed division between door checks and room qualification. |
| Materials larger than the clear opening | Largest load, trolley envelope, turning area and the transfer route. | A layout review using the actual loaded trolley or equipment dimensions. |
| Additional equipment interlocks | Air-shower, conveyor or process-equipment interfaces and ownership of the control logic. | An input/output list, operating narrative and responsibility list for integration testing. |
Prepare the site brief before requesting a firm quotation.
The following checklist is for planning a new project. It helps SEPPES and your contractor review the complete passage before a door configuration and integration scope are agreed.
Opening and Installation Information
- Clear opening width and height for every door, labelled to match a layout.
- Headroom, side space, steelwork details and photographs of nearby services.
- Wall or panel construction and the fixing structure provided by the contractor.
- Expected site-readiness date, power provision and agreed cable routes.
Process and Control Information
- Which rooms and transfer areas each door connects.
- The normal opening sequence and required activation method.
- Existing equipment interfaces and the person responsible for the control logic.
- Environmental targets and the documents required for project acceptance.
A marked layout is more useful than a list of three door sizes. Label the openings A, B and C, show the direction of travel, and identify where an operator may need to wait.
Agree the handover information as well as the test sequence.
For a similar installation, define these deliverables early so the facility team receives a usable system and a clear route for future support.
Commissioning Checklist
Agree a witnessed test plan covering normal requests at each door, waiting-door indication and the approved responses to exceptional conditions. Record the final settings and the parties responsible for each interface.
Handover and Ongoing Support
Request the operating instructions, door identification, approved control drawings, cleaning guidance and service contact. Set inspection arrangements around the operating duty and manufacturer’s instructions; keep changes to the sequence under control.
Clarify the door package before ordering.
Does an interlock establish the cleanroom classification?
No. It controls the door-opening relationship. Room classification and pressure performance depend on the complete facility and its testing. Include the facility’s requirements in the brief so the door package can be reviewed against them.
Why select an internal-motor layout?
In this project, the internal drive avoided a projecting side-drive arrangement at the passage. For your site, compare the full installation dimensions and the access needed for inspection and service.
Can more doors or process equipment be connected?
Describe the proposed equipment and operating relationship for review. The final interfaces, control ownership and commissioning scope need to be agreed for that system rather than assumed from the number of doors.
Can seals be selected without pressure information?
Provide the environmental brief before final selection. If leakage or pressure performance is specified, ask for the appropriate supporting data and agree how the door functions and wider room performance will be verified.
What is the most useful first enquiry?
Send a labelled passage layout, door dimensions, clearance photographs, traffic details and a short description of the required sequence. Identify the contractor or integrator who will coordinate the site interfaces.
Planning a linked production or cleanroom passage?
Send a marked passage layout, opening dimensions, clearance photographs and the door relationship you need. SEPPES can help review the door package, installation interfaces and control-coordination scope.
