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The corner treatment methods for purification boards in clean decoration projects
2025/11/12
01 Core Processing Principles (Prerequisites)
Before choosing a specific treatment method, it is necessary to first clarify three core principles to ensure that the treatment effect meets the standards of purification engineering:
No blind spot design: There must be no right angles, gaps or depressions in the corners of the walls to prevent dust accumulation and microbial growth (a core requirement for clean rooms, especially for clean grades of 10,000 and above).
Sealing continuity: All joints must be filled with special sealants (such as silicone sealant, polyurethane sealant) to ensure airtightness and prevent the penetration of external contaminants.
Impact resistance and easy cleaning: The corners of the walls should have a certain strength (such as by installing corner guards), and the surface should be smooth and flat to withstand wiping with cleaning reagents such as alcohol and disinfectants.
02 Specific treatment methods for different types of corners
1. Inner corner (The purification board is connected at a right Angle to the interior of the purification board
2. Outer corner (connection between the purification board and the outdoor wall
The outer corner of the wall needs to take into account both sealing and waterproofing as well as structural insulation to prevent the outdoor temperature, humidity and pollutants from affecting the internal environment of the clean room. The common treatment methods are as follows
Thermal insulation sealing layer + metal corner guards
The first step is to fill the gap between the purification board and the outdoor wall with fireproof and thermal insulation cotton (such as rock wool, which must meet the fire protection grade of the purification project) to ensure thermal insulation.
Step 2: Use galvanized steel plates (or aluminum alloy plates) to make "L-shaped" corner protectors on the outside of the gap to cover it. Fix the corner protectors to the purification board and the outdoor wall with expansion screws (the screws need to be waterproof treated, such as adding waterproof gaskets).
Step 3: Apply weather-resistant sealant (such as silicone weather-resistant sealant, which can withstand high and low temperatures and rain erosion) to all the joints between the corner guards and the purification board and the wall to prevent water seepage.
Integrated corner parts (Industrial-grade purification engineering)
For large-scale purification projects (such as electronic factories and pharmaceutical workshops), factory-prefabricated purification board special corner parts (with the same material as the purification board, such as color steel composite corner parts) can be used and directly spliced with the purification board.
The joints are sealed with structural adhesives (such as polyurethane structural adhesives), and metal corner guards are added to the outside of the corner parts (to enhance impact resistance). This is suitable for scenarios with extremely high sealing requirements.
3. Connection corners of different material purification boards (such as color steel purification boards and magnesium oxide purification boards)
When the corner is joined by different material purification boards, the problem of "gaps caused by the difference in material shrinkage rates" needs to be solved. The core of the treatment is "flexible transition + sealing buffer"
First, install elastic sealing tape (such as butyl rubber sealing tape) at the junction of the two types of purification boards to counteract the stress caused by the thermal expansion and contraction of the material.
U-shaped aluminum alloy transition strips are installed on the outside (with a width covering the joint of the two plates), and the transition strips are fixed to the two plates with self-tapping screws (screw spacing ≤250mm).
Apply neutral silicone sealant to the gap between the transition strip and the purification board (to prevent acidic sealant from corroding some materials, such as magnesium oxide board), ensuring no dead corners in the seal.
If the cleanliness level is relatively high (such as Class 100 or Class 1,000), an additional layer of PE protective film specifically designed for cleanrooms should be attached to the inner side of the transition strip to further reduce the adhesion of contaminants.
03 Selection of Key Supporting Materials (The Core Affecting Treatment Effect)
The material selection for corner treatment directly determines the sealing performance and durability. The following three types of materials need to be given special attention:
Sealant
Indoor corner: Select neutral silicone sealant (odorless, no release of harmful substances, in compliance with GB/T 14683-2017 standard) to prevent acidic sealant from corroding metal parts or releasing volatile substances.
Outdoor corner: Select weather-resistant silicone sealant (resistant to high and low temperatures -40 ℃ to 80℃, UV and rain, such as GB/T 16777-2008 standard products);
Food/pharmaceutical cleanroom: Food-grade silicone sealant (FDA-certified, suitable for direct contact with food or pharmaceutical environments) must be selected.
Corner guard strip
Material: Prefer aluminum alloy corner protectors (high strength and impact resistance) or food-grade PVC corner protectors (lightweight and easy to clean).
Specification: Thickness ≥1.2mm (aluminum alloy), radius R50-R150 (the higher the cleanliness level, the larger the radius), length consistent with the height of the purification board (avoid splicing).
Thermal insulation/cushioning materials
Exterior corner insulation: Select fireproof rock wool (A-level fireproof, thermal conductivity ≤0.04W/(m · K)) or extruded polystyrene board (good moisture resistance, suitable for humid areas);
Joint buffer: Choose butyl rubber sealing tape (with good elasticity and aging resistance) or foam silicone strip (with strong sealing performance, suitable for small gaps).
04 Post-construction acceptance Criteria (Ensuring Compliance with purification Requirements)
After the corner treatment is completed, it should be inspected and accepted according to the following standards to avoid rework later:
Visual inspection: The surface should be smooth and flat, without protrusions, depressions or bubbles. The arc transition is uniform without any sharp edges or corners. The sealant shows no cracking or peeling, and the width of the sealant surface is uniform (usually 8-12mm).
Sealing test: The air tightness is detected by the "smoke test method" or the "pressure test method" - the cleanroom is pressurized to 50Pa, and the pressure drop within 30 minutes is ≤5Pa (in compliance with GB 50591-2010 "Code for Construction and Acceptance of Cleanrooms").
Impact resistance test: A 1kg heavy hammer (wrapped in soft cloth) was used to vertically strike the corner guard from a height of 1m. The corner guard did not deform and the sealant did not crack.
Cleanliness test: Wipe the corner surface with 75% alcohol. There is no residue, no discoloration, and the surface is easy to clean without dust accumulation.
Through the above standardized treatment, it can be ensured that the corners of the purification board meet the core requirements of the clean room, while enhancing the structural stability and the convenience of later maintenance. The specific requirements of different cleanliness grades (such as Class 100, Class 10,000, and Class 100,000) and industries (such as electronics, pharmaceuticals, and food) may vary. The plan should be adjusted in accordance with the actual needs of the project.
