Table 8.8.

Recommended differential pressure

Purpose		Difference between turbulent flow cleanroom and the adjacent room with air cleanliness level lower by one Class level (Pa)	The same as the left condition but with air cleanliness level lower by more than one Class level (Pa)	Difference between unidirectional flow cleanroom and the adjacent communicating room (Pa)	Difference between cleanroom and outdoors (or the space communicating with outdoor air)
General	To prevent infiltration through gap	5	5–10	5–10	15
Strict	To prevent entrance of pollution during door opening	5	40 or it is 5 relative to buffer chamber	10 or it is 5 relative to buffer chamber	It is 10 relative to buffer chamber
	Sterile cleanroom	5	It is 5 relative to buffer chamber	It is 5 relative to buffer chamber	It is 10 relative to buffer chamber