Cleanroom

A cleanroom (or clean room, usually abbreviated to C/R) is an enclosed room that has equipment which controls the amount of particulate matter in the air by using air pressure and filters. It is a facility ordinarily utilized as a part of specialized industrial production or scientific research, including the manufacture of pharmaceutical items and microprocessors.

Definition: A manufacturing room with an extremely low level of particles.
Particles: Dust, airborne organisms, or vaporized particles.

Basic Design Principles

Prevention of dust accumulation
Prevention of dust occurrence
Exclusion of dust
Prevention of carrying dust into room
Dehumidification of A/C
Controlled temperature, humidity and room barometric pressure

Other Design Considerations

Removal of harmful vapors
Reduction static electricity
Prevention of electromagnetic interference
Air tightness of structures
Power Spare Solution
Convenience of management and expandability
Budget

Cleanroom Classifications

Cleanrooms are classified by how clean the air is. To say more precisely, they are classified according to the number and size of particles permitted per volume of air. Depending on what industry your company is in, and what product being manufactured, the cleanroom will have to comply with certain standards.

ISO 14644-1 & US FED S209E

Both ISO 14644-1 and US FED S209E classifications are most widely used standards. ISO 14644-1 are non-governmental standards developed by the International Organization for Standardization (ISO), and US FED-STD-209E is a United States federal standard.

Class		Maximum Particles
Class		0.1 µm		0.2 µm		0.3 µm		0.5 µm		1 µm		5 µm
US F. S209E	ISO 14644-1	(m³)	(ft³)	(m³)	(ft³)	(m³)	(ft³)	(m³)	(ft³)	(m³)	(ft³)	(m³)	(ft³)
	ISO 1	10		2		0		0		0		0
	ISO 2	100		24		10		4		0		0
C-1	ISO 3	1,000	35	237	8	102	3	35	1	8	0	0	0
C-10	ISO 4	10,000	350	2,370	75	1,020	30	352	10	83	2	0	0
C-100	ISO 5	100,000	3,500	23,700	750	10,200	300	3,520	100	832	24	29	0
C-1K	ISO 6	1,000,000	35,000	237,000	7,500	102,000	3,000	35,200	1,000	8,320	236	293	7
C-10K	ISO 7	*	*	*	*	*	*	352,000	10,000	83,200	2,360	2,930	70
C-100K	ISO 8	*	*	*	*	*	*	3,520,000	100,000	832,000	23,600	29,300	700

PIC/S and EU GMP Guides

PIC/S GMP (Pharmaceutical Inspection Convention and Pharmaceutical Inspection Co-operation Scheme), also the GMP EU classifications, are more stringent than others, requiring cleanrooms to meet particle counts at operation and at rest. Because it also applies the recommended tolerance for microbes, these classifications are widely used in pharmaceutical-related industries.

Grade	Maximum Particles/m³				Recommended Limits for Microbial Contamination
	At Rest		In Operation		Air Sample	Settle Plates (Diameter 90 mm)	Contact Plates (Diameter 55 mm)	Glove Print 5 Fingers
	0.5 µm	5 µm	0.5 µm	5 µm	cfu/m³	cfu/4hr	cfu/deska	cfu/glove
A	3,520	20	3,520	20	<1	<1	<1	<1
B	3,520	29	352,000	2,900	10	5	5	5
C	352,000	2,900	3,520,000	29,000	100	50	25	--
D	3,520,000	29,000	*	*	200	100	50	--

Air Flow Design

Based on different clean room levels, different airflow is designed. It is popularly divided as follows: vertical laminar flow (class 1~100), horizontal laminar flow (class 1~1,000), turbulent flow (class 1,000~100,000). This difference is namely as here below table.

	Vertical Laminar Flow	Horizontal Laminar Flow	Turbulent Flow
Air Flow Chart
Air Flow Direction	Clean air flows from the ceiling to the floor.	Clean air flows from one wall to the opposite wall.	Clean air flows in an unidirectional way.
Outlet Vent	Blow out: 80%-100% on ceiling area.	Blow out: over 80% on wall.	Blow out: outlet of filter is better.
Intake Vent	Suck in: over 40% on floor area.	Suck in: over 40% on wall, also promote on ceiling.	Suck in: on neighboring floor area.
Clean Level	Used in class 1 - 100	Used in class 1 - 10,000	Used in class 1,000 - 100,000
Air Change Rate	300 - 600 times/hr	C-100: 250 - 350 times/hr C-1K: 60 - 120 times/hr	C-1K: 60 - 120 times/hr C-10K: 35 - 45 times/hr
PRO	Fully taken effect. Clean level may not easily affected by employee working operation and state. After operating, it will enter a stable condition in a moment. Less dust accumulating and floating. Easy to control.	After operating, it will enter a stable condition in a moment. Simple construction.	Simple construction. Lower equipment costs. Easier to expand the room. Clean booth can be used to increase clean level.
CON	Needs to reduce turbulent effect from lamps. Extended overhead clearance means changing filters or servicing may require a step-ladder. Higher equipment costs. Harder to expand the room.	Large samples obstruct laminar air flow, may contaminate downstream samples. Designing equipment and operator layout should be careful. Higher equipment costs. Harder to expand the room.	After operating for a while, it will enter a stable condition. Designing equipment and operator layout should be careful.

Testing and Certification

The purpose of testing or validating an air-conditioning system is to ensure that the system continuously and steadily controls the air quality at the workplace, so that products can be manufactured at a high quality and free from contamination.

Testing Timing

There are three timing for testing a cleanroom, which are as-built, as-rest, and operational.

As-Built
The empty room.
As-Rest
The room fitted with machinery but no personnel present.
Operational
The room fitted with machinery and persons in operation.

Testing and Validation Items

Not every testing needs to be preformed at these three testing timing as above. It depends on its type and requirements in design.

Wind speed and air volume testing
Air laminarity testing
Particle counting
Microbes counting
Temperature and humidity readings

Differential pressure measurements
Filter leak testing
Room integrity testing
Recovery performance testing
Light and noise level readings

Differential pressure testing

Air volume testing

Air flow testing

HEPA leak testing

Particle count testing

Return-air windspeed testing

Temperature and humidity testing

Validation Plan and Process

For industries involved in pharmaceutical and health care products, or even laboratories, product quality is paramount and minute inconsistencies can have disastrous results. Design Qualification (DQ), Installation Qualification (IQ), Operational Qualification (OQ) and Performance Qualification (PQ) are essential parts of quality assurance of a HVAC system validation.