Chapter 5 Cleanroom Design Flashcards
(15 cards)
What is a cleanroom and its purpose?
How does it achieve its purpose?
A room that controls particulate contamination and minimize:
1. Introduction
2. Generation
3. Retention of particles
By controlling:
1. Temperature
2. Humidity
3. Pressure
What is the purpose and function of an Air Handling Unit (AHU) or HVAC system?
Ventilation - To prevent ingress, dilute and flush contaminants from the room by sucking air through a series of progressively smaller filters
Heating, Ventilation and Air Conditioning (HVAC)
Why is the function of the AHU important?
To prevent staff sweating and shedding of more particles
To avoid proliferation of microbes in humid environments
What is HEPA?
High Efficiency Particulate Air Filters - Very small pore size that can retain 99.995% of particulates when air enters the cleanroom via the ceiling
What is a damper and why is it found in the AHU?
To control air intake and balance the amount of air reaching each leg of the system or room
Automatically closes in the event of a fire to prevent air from feeding it
What is the average rate of clean airflow which purges the room from contaminants that built up?
20-30 room air changes per hour dependent on room grade
What’s the purpose of balancing flaps and extracts?
Pressure stabilisation - To allow air pressure differential between rooms to be tightly controlled
What should the minimum pressure difference between classified zones and between unclassified zones?
10 Pa and 15 Pa
Why is pressure differential important?
Critical rooms have a positive pressure (higher pressure) than adjacent rooms like gowning rooms and support rooms to prevent dirty air from entering the critical rooms
What alarm and monitoring systems should be fitted in the facility?
Fire alarm, smoke alarm, air supply alarm
If the air supply alarm is activated, what should not be done?
- Do not commence work
- Do not open doors if possible to prevent dirty air ingress
- Do not just resume work once the airflow is back because depending on the total period of air supply failure, the rooms and equipment should be cleaned
What are the 2 air distribution types in the cleanroom? How are the filters distributed?
Unidirectional airflow
- Vertical (HEPA filter from ceiling to perforated flooring/grilles mounted on flooring)
- Horizontal airflow also possible
Non-unidirectional airflow
- Filters distributed at equal intervals throughout the room or grouped over critical areas
- More turbulent airflow in nature
Which air distribution type is more common in pharmacy aseptic units?
Non-unidirectional airflow
How are clean room classification grades based on?
Maximum permitted number of particles in a defined volume of air ( per metre squared)
- At rest
- In operation
