What is the acceptance standard of clean room engineering installation?

The acceptance of clean room project is based on gb 50591-2010 code for construction and acceptance of clean rooms, supported by gb 51110-2015 code for construction and quality acceptance of clean factories and industry-specific standards (such as medicine, electronics and food). it is divided into four stages: acceptance of construction process, system debugging, third-party testing and completion acceptance, and the core is cleanliness, pressure difference, airflow, sealing and acceptance.

i. core basis and process of acceptance

1. core standards

gb 50591-2010: the mandatory national standard for clean room construction and acceptance, including a number of mandatory provisions.

gb 51110-2015: special code for construction and quality acceptance of industrial clean workshop.

supporting standards: gb 50073 (design), gb/t 25915 (cleanliness classification), industry-specific (pharmaceutical gmp, electronic gb 50472, food gb 14881).

2. acceptance process (four steps)

acceptance of construction process: self-inspection and supervision acceptance after each process (decoration, air duct, equipment and electricity) is completed, and concealed works are recorded.

joint debugging of the system: the air conditioning system, automatic control system, exhaust system and differential pressure system run continuously for ≥12h, and the air volume/differential pressure/airflow balance is completed.

third-party special testing: testing by institutions with cma qualification and issuing reports.

completion acceptance: complete data+site+test report, and organize joint acceptance of design/construction/supervision/owner/quality supervision.

second, the construction process acceptance (key working procedure standard)

1. acceptance of envelope (decoration)

wall/ceiling: color steel plate/glass-magnesium plate is spliced in a tongue-and-groove manner, and the joint width is ≤2mm, and the neutral silicone sealants is continuous without breakpoints; the angle of yin and yang shall be an arc with r≥50mm, and there shall be no dead angle of dust accumulation.

floor: epoxy/pvc flatness ≤ 1 mm/2m; gap with wall/column/equipment base ≤0.3mm, sealed with stainless steel batten.

doors and windows (clean doors/windows):

vertical/horizontal error of door frame ≤2mm, diagonal difference ≤2mm.

the sealing strip is complete, and the wind speed of air leakage at the crack of the door is ≤0.2m/s after closing.

the glass window is firmly sealed, free of glue stains and even in light transmission.

wall-penetrating/ceiling-penetrating pipeline: stainless steel sealing sleeve+sealant double seal, with a gap ≤0.5mm, no leakage and no dust accumulation.

2. acceptance of purified air conditioning system

duct fabrication and installation:

the galvanized steel plate has no scratch and the zinc layer is complete; the bite is tight, and the surface is concave and convex ≤ 5 mm.

the levelness of the horizontal air duct is ≤3mm/m (the total deviation is ≤ 20 mm); verticality of vertical air duct ≤2mm/m (total deviation ≤20mm).

light leakage detection: there is no obvious light leakage point in dark environment; air leakage is ≤ 10% of the design value.

high efficiency filter (hepa/ulpa):

before installation, the system shall run continuously for more than ≥12h, and the room shall be thoroughly cleaned.

scan for leak detection after installation: the filter frame/gasket has no leakage; efficiency ≥ design value.

the layering torque is ≤ 10n m, and the stress is uniform.

tuyere/air valve: smooth installation and flexible opening and closing; air volume deviation ≤5%.

3. electrical and automatic control acceptance

lamps/switches/sockets are dust-proof and clean, and there are no exposed pipelines in the dark.

the differential pressure sensor and the temperature and humidity sensor are installed in correct positions, and the calibration is qualified.

automatic control system linkage is normal (fan start and stop, air valve adjustment, differential pressure interlock).

third, system debugging and third-party testing (core indicators)

1. air volume/wind speed/air exchange times (required)

unidirectional flow (laminar flow): the wind speed of vertical laminar flow is 0.36–0.54 m/s, and that of horizontal laminar flow is 0.3–0.5 m/s; uniformity deviation ≤15%.

non-unidirectional flow (turbulent flow):

iso 5 (class 100): ≥300 times /h

iso 6 (thousands of grades): ≥100 times /h

iso 7 (10,000 grades): 50–60 times /h

iso 8 (class 100,000): 20–30 times /h

the deviation of air volume at each tuyere is ≤5%.

2. static pressure difference (mandatory standard)

clean area to unclean area: ≥10pa.

adjacent areas with different cleanliness levels: ≥5pa (high level versus low level).

core clean zone (iso 5) to buffer zone: ≥10pa.

the pressure difference is stable, and the fluctuation is ≤±1pa.

3. cleanliness (core judgment)

according to the classification of iso 14644-1/gb/t 25915, the particle concentrations of **≥0.5μm and ≥5μm** were detected:

form

cleanliness grade ≥ 0.5 μ m (grains/m) ≥ 5 μ m (grains/m)

iso 5 (class 100) ≤ 3520 ≤ 29

iso 6 (thousands of grades) ≤ 35200 ≤ 293

iso 7 (10,000) ≤ 352,000 ≤ 2930

iso 8 (class 100,000) ≤ 3520000 ≤ 29300

the sampling points are evenly arranged, and the test is up to standard for three consecutive times.

4. temperature and humidity and noise/illumination

temperature: 20-26℃ in general clean room; the process requires design (e.g. electronic 18-22℃).

relative humidity: 40%–60% (medicine/electronics can be 5%).

noise: ≤60db(a) (dynamic).

illumination: the main operating area is ≥300lx, and the auxiliary area is ≥ 150lx; uniformity ≥0.7.

5. other key tests

self-purification time: the time to recover from pollution to cleanliness standard, ≤ design value (usually ≤ 15–30 min).

air flow pattern: one-way flow without vortex and short circuit; non-unidirectional flow has no dead angle and conforms to the design flow pattern.

micro-vibration: the vibration speed in the precision equipment area is ≤0.1mm/s (according to the process requirements).

four, the completion acceptance data and judgment

1. necessary information

construction drawings, design changes, materials/equipment certificates and test reports.

process acceptance records, concealed works records and debugging records (air volume/pressure difference/temperature and humidity).

third-party cma test report (cleanliness, pressure difference, wind speed, etc.).

as-built drawings, operation manuals and maintenance plans.

2. acceptance judgment

qualified: all processes are qualified; the third party detects that all indicators meet the standard; the information is complete and complete.

unqualified: rectification within a time limit, re-inspection/acceptance, until reaching the standard.

five, common unqualified acceptance points and rectification points

cleanliness is not up to standard: leakage of high efficiency filter, seal failure, short circuit of air flow; rectification: leak detection, replacement, re-sealing and air distribution adjustment.

insufficient pressure difference/large fluctuation: unbalanced air volume, air valve failure, air leakage at the door; rectification: air volume debugging, sealing strip replacement and interlocking control.

poor decoration and sealing: glue joint break point, no circular arc at the angle of yin and yang, and large pipeline gap; rectification: glue filling, arc treatment and casing sealing.

insufficient wind speed/ventilation: small fan selection, air leakage in the air duct and blocked air outlet; rectification: leak detection, blockage removal and adjustment of fan frequency.