Standard Set for Judging the Material of the Observation Window Glass of Ultra-clean Workbench (On-site Self-inspection + Professional Acceptance)
Compliance Standards: 5mm or thicker tempered float glass. All 3C, non-tempered, thin ordinary glass are all unqualified. The judgment is divided into four parts: visual inspection, practical operation, certificates, and usage compatibility.
I. First step: Check the 3C mandatory marking (the most basic determination basis)
Qualified glass requirements
On the lower right corner / corner of the glass, there should be a permanent etched 3C mark + factory code, which cannot be erased or scraped off;
Complete marking example: CCC + E0XXXX (glass factory code).
Unqualified situation
Only a sticker 3C, which falls off when torn: laterally pasted fake marking, not tempered glass;
Complete absence of 3C etching: ordinary flat glass, prone to cracking, does not comply with laboratory safety regulations;
Printed ink 3C, which can be scraped off with fingernails: counterfeit marking.
II. Second step: Thickness measurement (industry hard standards)
The minimum thickness of the observation window of the ultra-clean bench is 5mm tempered glass. GMP / pharmaceutical factory priority 6mm:
Tools: ruler, vernier caliper, measure the exposed thickness of the glass on the side;
Avoidance points:
4mm or less thin glass: poor impact resistance, prone to cracking due to collision, temperature difference, etc.;
Merchants’ interlayer with plastic pads to imitate thickening, need to directly measure the thickness of the glass itself.
III. Third step: Visual + tactile differentiation of “tempered glass VS ordinary glass”
1. Look for the unique wave pattern (core feature)
Facing the light / natural light at a 45° angle, observe the surface of the glass. Qualified tempered glass will show a slight, uniform water wave pattern, rainbow patterns (formed by high-temperature cooling of tempering, which is a normal process trace);
Ordinary flat glass is completely flat, without wave patterns.
2. Edge and corner process inspection
Compliant tempered glass: all four sides are finely ground into round corners, smooth and round, no sharp cutting edges;
Poor quality ordinary glass: right angles, burrs, sharp edges, easy to scratch hands during cleaning and operation.
3. Knocking sound identification
Lightly tap the middle of the glass with your finger:
Tempered glass: clear and bright sound;
Thin ordinary glass: dull and muffled sound.
4. Breakage test (only for theoretical identification, not recommended to destroy on site)
After the tempered glass breaks, it will break into countless small particles without sharp edges, without forming long, sharp fragments;
Ordinary glass breaks into large, sharp corners, easily cutting the operators.
IV. Fourth step: Environmental adaptability test (specific requirements for laboratories)
The ultra-clean bench is in long-term contact with ultraviolet lamps, 75% alcohol, 84 disinfectant, high-temperature fumigation, the glass must be able to withstand:
Resistant to ultraviolet aging
Long-term exposure to ultraviolet rays does not cause whitening, fogging or cracking;
Low-quality ordinary glass will become cloudy and yellow after long-term exposure, blocking the operation view.
Chemical resistance
Repeatedly wiped with alcohol and sodium hypochlorite, there are no corrosion spots, peeling or scratches on the surface;
Ordinary float glass has low hardness and is prone to scuffing and blurring with frequent disinfection.
Cold and hot tolerance
The cabinet undergoes ultraviolet sterilization heating, and there is no cracking when there is a temperature difference between the room temperature and the ambient temperature; When the temperature difference of thin non-tempered glass is large, there is a risk of self-explosion.
VII. Fifth step: Verify the supporting qualification documents (audit, GMP required)
The original factory 3C certification test report, indicating the thickness and type of tempering;
The material list of the complete machine, clearly stating “5mm tempered glass observation window”;
The manufacturer’s test data on the glass’ resistance to ultraviolet rays and chemical corrosion.
VIII. Common identification of glass counterfeiting / reduced specification
Common white glass imitating tempered glass: no 3C marking, no waves, sharp corners;
4mm thin tempered glass imitating 5mm: the measured thickness with a caliper is insufficient, and the safety factor is insufficient;
Semi-tempered / annealed glass: the fragments have large sharp corners, no complete 3C marking;
Acrylic organic glass replacing glass:
It is easily corroded by alcohol and turns white, and is quickly aged and cracked under ultraviolet long-term exposure. It is strictly prohibited from being used in the laboratory.
IX. On-site rapid acceptance steps (check in order)
Check the permanent etched 3C mark at the corner of the glass;
Measure the glass thickness with a vernier caliper ≥ 5mm;
Observe with side light if there is any tempered wave pattern;
Touch the four sides to confirm that all corners are rounded and there are no burrs;
Wipe with alcohol repeatedly and observe after standing still for 10 minutes if there is any whitening or corrosion;
Request the 3C certification report of the glass for archiving.