Cleanroom door Manufacturer

In cleanroom systems, doors are not merely passageways for personnel and materials — they are critical nodes for maintaining pressure differential gradients, preventing particle ingress, and stopping cross-contamination. The clear conclusion is: A qualified cleanroom door must simultaneously meet four requirements — airtightness (air leakage ≤0.3 m³/(h·m²) @100Pa), cycle life (≥500,000 operations), antibacterial/corrosion resistance, and intelligent interlock control — and failure in any of these areas can lead to loss of cleanliness, often with consequences more severe than wall panel leakage. The following provides in-depth technical reference from six dimensions: core performance indicators, door construction and materials, sealing systems, viewing window design, hardware selection, and installation acceptance.

Core Performance Indicators: Four Key Technical Parameters for Cleanroom Doors

The performance of cleanroom doors can be directly quantified and evaluated. The following are four industry-recognized core indicators:

Door Construction and Materials: Performance Comparison of Three Mainstream Types

Cleanroom doors are primarily divided into three types based on application scenarios and cleanliness levels:

Sealing System: Five Lines of Defense to Ensure Airtightness

The sealing performance of a cleanroom door is its core value. A complete sealing system consists of the following five layers:

1. Three-sided magnetic sealing strip: Installed on the top and both sides of the door frame, made of medical-grade silicone or EPDM, with magnetic attraction ≥3 kg/m. Seal compression of 2-3mm when the door is closed ensures sealing without making closing difficult;
2. Bottom automatic drop seal (sweep strip): Automatically lowers to contact the floor tightly when closed (drop height ≥15mm, gap to floor ≤1mm), and automatically lifts when opening. A dual-row brush + rubber scraper combination is recommended for both sealing and wear resistance;
3. Concealed bottom sealing mechanism: For aseptic areas, pneumatically or electromagnetically driven concealed sealing strips are recommended to avoid exposed components that accumulate dust, while meeting GMP no-dead-corner requirements;
4. Threshold design: Cleanroom doors should prioritize threshold-free or ramp-type threshold designs (height ≤15mm) for easy cart passage. For threshold-free designs, the floor must be continuously flat with the bottom seal directly contacting the floor;
5. Viewing window sealing: The window perimeter must have dual seals — inner silicone sealant (continuous fill) and outer EPDM gasket — to ensure no gaps between glass and door panel.

Airtightness acceptance standard: At 50Pa differential pressure, the entire door's air leakage shall be ≤0.3 m³/(h·m²). Semi-annual smoke tracer testing using a smoke tube is recommended to check seal aging and installation defects.

Viewing Window Design: Condensation Prevention and Structural Reliability

The viewing window of a cleanroom door is not just a window — it is also a vulnerable point for airtightness. Design standards for high-quality viewing windows are as follows:

• Glass configuration: Double-layer tempered glass with single-layer thickness ≥4mm and total thickness ≥20mm. Tempered glass has 3-5 times the impact strength of ordinary glass and breaks into blunt particles for safety;
• Condensation prevention design: A 6-12mm air gap between glass layers, with the cavity filled with argon gas (concentration ≥90%) and molecular sieve desiccant, ensuring no internal condensation under temperature differences ≥15°C. For cold storage cleanrooms, electrically heated glass (50-100W/m²) is recommended;
• Sealing process: Continuous silicone sealant filling between the glass perimeter and door panel, with joint width 8-12mm and depth ≥5mm. The use of trim strips + gaskets is prohibited due to micro-gaps that accumulate dust;
• Corner treatment: Window frame inside corners should have R≥5mm rounded transitions or 45° mitered corners to avoid 90° corners that accumulate dust and are difficult to clean;
• Safety accessories: For high-impact areas such as logistics passages, stainless steel mesh or transparent polycarbonate guard plates should be installed on the outside of the glass, capable of withstanding 50 joules of impact energy without breaking.

In cleanrooms with relative humidity >75% or temperature differences ≥15°C, standard double glazing may develop internal condensation — argon-filled + Low-E coated glass must be selected. Desiccant typically lasts 3-5 years, after which replacement or maintenance is required.

Hardware and Accessories: Details Determine Reliability

The hardware of cleanroom doors must simultaneously meet requirements for durability, cleanability, and corrosion resistance. Key component selection recommendations are as follows:

Intelligent Control and Interlock Systems

In high-level cleanrooms (ISO 5-7), intelligent door control is a key technology for preventing cross-contamination. Main features include:

• Electronic interlock: Both doors of an airlock cannot be opened simultaneously, with interlock response time ≤0.5 seconds. When one door opens to ≥90°, the other automatically locks to prevent pressure gradient disruption;
• Access control integration: Integrated with BMS, supporting card swipe, fingerprint, or facial recognition. Recognition time ≤1 second, with antibacterial coating on recognition device surfaces;
• Differential pressure monitoring: Miniature differential pressure sensors can be integrated into the door frame, displaying real-time pressure differences between adjacent rooms (range 0-125Pa, accuracy ≤±1Pa). Audible/visual alarm when differential pressure falls below setpoint (e.g., 5Pa);
• Timer control: Logistics doors can be set with an opening delay (10-30 seconds); if the door remains open beyond the set time, the system automatically closes it or triggers an alarm to prevent pressure differential loss;
• Seal status monitoring: High-end intelligent doors can be equipped with magnetic switches or proximity sensors to send alarm signals to the central control room when the door is not fully closed, logging events via BMS.

Interlock logic requirement: For material airlocks, the outer door must be opened first, materials placed, outer door closed, and only then can the inner door be opened — both doors must never be open simultaneously. Electronic interlock system reliability should achieve MTBF ≥50,000 hours. Monthly interlock function testing is recommended to ensure safety and reliability.

Installation and Acceptance: Nine Key On-Site Control Points

The installation quality of cleanroom doors directly affects their long-term performance and cleanliness effectiveness. The following are nine key inspection points for on-site acceptance:

1. Door frame plumbness: Vertical deviation ≤2mm/m, horizontal deviation ≤1.5mm/m;
2. Gap between door leaf and frame: Uniform and ≤3mm, gap variation ≤1mm;
3. Seal compression: When door is closed, seal compression is 20%-30% of original thickness (typically 2-3mm measured);
4. Bottom seal test: With door closed, use a 0.1mm feeler gauge to check gap between door bottom and floor — should be unable to insert or insert depth ≤50mm;
5. Airtightness test: Use a smoke tube to release smoke around the door gap perimeter — no smoke penetration should be visible on the inside (tracer method); or use differential pressure leak detection, with air leakage ≤0.3 m³/(h·m²) at 50Pa;
6. Opening/closing force test: Use a force gauge — opening force ≤50N, closing force ≤30N;
7. Interlock function test: Simulate two-door interlock scenario to verify that when one door is fully opened, the other indeed cannot be opened;
8. Emergency egress test: With power off, open the door from inside — opening force ≤67N, egress path unobstructed;
9. Surface quality: No scratches, dents, or rust spots on door panel surface; coating adhesion ≥Grade 1 (cross-cut test); stainless steel panel Ra≤0.4μm.

A quarterly inspection system is recommended, focusing on seal aging/cracking, hinge looseness, door closer speed adjustment, and interlock system sensitivity. Address issues promptly through repair or replacement to ensure cleanroom doors remain in optimal sealing condition.