The air change rate method of calculation is commonly used in cleanrooms with lower cleanliness requirements usually iso 6 to 9 with the air change rate largely based on the level of particles generated by people and processes.
Clean room hvac design calculations.
Cleanrooms and hvac systems design fundament.
Rooms having 60 air changes per hour will have 60 times air supply then the volume of the room.
During this technical presentation ashrae fellow and distinguished lecturer wei sun discusses the following.
If any form of variable air volume or load shedding system is used for energy conservation it must not compromise the corridor to room pressure balancing relationships or the minimum air changes required by the table.
If the supply of the air by hvac system in one hour is equal to the volume of the room then it will be one air change per hour.
The hvac system requirements include.
Design of the ventilation system shall provide air movement which is generally from clean to less clean areas.
A lot of aspects are not taken into consideration for the calculation including but not limited to heat gain number of people the use of a fume hood etc.
The above suggested air changes per hour are only a design rule of thumb.
Supplying airflow in sufficient volume and cleanliness to support the cleanliness rating of the room.
Ashrae clean spaces technical committee tc9 11 chairman 07 10 healthcare facilities technical committee tc9 6 member laboratory systems technical committee tc9 10 member iest working group cc012 cleanroom design chairman president.
Fda recommends maintaining the minimum 20 air changes per hour for clean rooms.
The bigger the room the more air you need.
Hvac systems design fundamentals karachi pakistan february 22 2011 wei sun p e.
The bigger the room the more air you need.
The width length and height of the classified rooms and their layout must be used for hvac calculations.
If you want help with the design of your cleanroom fill out a request for quote and one of our experts will contact you.
The volume of air in the cleanroom will influence the amount of airflow needed.
This is achieved by supplying more air to the room than is extracted from it.
People often forget that the height of the room directly impacts the airflow.
The width length and height of the classified rooms and their layout must be used for hvac calculations.
They should be computed by an hvac cleanroom expert as many aspects must be taken into consideration such as the size of the room the number of people in the room the equipment in the room the processes involved the heat gain etc.
2 the hvac system the integrity of the cleanroom environment is created by the pressure differential compared with adjacent areas through heating ventilation and air conditioning system.
