Cleanroom Cleaning (A)

When to design cleanrooms, how to prevent contamination shall be taken into account. However, the contamination may be generated from process equipment, maintenance work, production process and workers themselves within cleanroom, and is dispersed and finally settled on the surface of cleanroom. Therefore, it’s necessary to do cleanroom cleaning at regulate interval so as to keep contamination away from production process.

How to do cleanroom cleanning? Let’s get started.

Cleaning Surface Grading

First, we shall classify surface grading according to how much it will effect on the product and process within cleanroom. The cleaning surface grading will be helpful to set up right cleaning measures.

No.	Surface Grading	Typical Area	Description
1	Principal Surface	Product manufacturing area and surroundings	1.The contamination directly spoil product or production process 2.Keep these surfaces at most cleanest state 3.Isolation devices can be used, such as unidirectional flow device, clean bench or booth, to control the cleanliness of these surfaces
2	“Normal”Surface	Non-manufacturing area or not the surface under unidirectional flow	To clean these surfaces at regular interval to prevent the contamination from moving onto principal surface
3	Surfaces in Change Room and Buffer Room	Change Room and Buffer Zone	These areas are so frequently occupied that the surfaces are the most contaminated.The surfaces must be cleaned frequently so as to minimize the generation of contamination and their diffusion into cleanroom

Cleaning Method Classification

1 Basic Cleaning

Based on current conditions of surfaces and what cleanliness is required after cleaning, the cleaning work can be classified into three categories: Coarse Cleaning, intermediate cleaning and fine cleaning.

No	Classification	Cleaning Object	Cleaning Area
1	Coarse Cleaning	Particle Dia. >50µm	Floor, Change Room and Buffer Area; Waste, Broken or Overflown Material in the process of production; Big-particle contamination generated in the process of equipment maintenance;
2	Intermediate Cleaning	10µm < Particle Dia.<50 µm	Wall, Work Surface and Clean Corridor; The particle will remain there after coarse cleaning and can achieve higher cleanliness class after intermediate cleaning;
3	Fine Cleaning	Particle Dia. < 10µm	The principal surfaces or the surface around of stored products and processing products

2 Vacuum Cleaning

As a normal and first step for principal surface, as well as a necessary step before wiping and wet wiping; big particles and other scraps like glass flakes can be removed.
Cleaning shall be done unidirectionally to prevent turbulent airflow at floor and working height.
Use HEPA/ULPA-equipped vacuum cleaner. Vacuum cleaning can accelerate surface drying after wiping

3、Half-dry Cleaning

Use cleanroom wiper. The wiper is used with suitable cleaning solvents.
Cleaning shall be done unidirectionally in an overlapping wiping route.
Fold the wiper after one-way wiping and use clean side for another route
Change the wipers regularly to prevent other cleanroom surfaces from contamination.

4 Wet Cleaning

Use liquid on the surfaces of cleanroom and do cleaning by wiping or vacuum cleaning. Every cleaning phase can adopt wet-cleaning. The wet cleaning is done as follows:

No	Classification	Description
1	Scrubbing	Scrub stains or seriously dirty areas mechanically or manually. Control the contamination generated possibly by scrubbing device or materials. After scrubbing, do mopping or wet vacuum cleaning
2	Mopping	Mopping is an effective way to remove contamination for coarse and intermediate cleanings, as well as for liquid remains; For small or local area, to use wet cleanroom wipers; for floor or big area, to use mop; Use filtrated water hold in bucket and replace the water often. The more principal surface, the more times water shall be changed. Use TWO or more buckets to reduce the replacement of water; Squeeze mop to prevent from water stains. The half-dry surface cleaned by half-dry mop become try more faster; To mop surface in an overlapping way and ensure all surfaces are covered; Flush and rotate mop surface often to prevent cleaned floor from contamination; The head of mop shall be flushed always to prevent from re-contamination.