Cleanroom class calculation An ISO 146441-1 Class 2 cleanroom is 3 m high with a total floor area of 100 m², what is the maximum amount of particles that are larger than 100 nm in diameter?

Question

Cleanroom class calculation
An ISO 146441-1 Class 2 cleanroom is 3 m high with a total floor area of 100 m², what is the maximum amount of particles that are larger than 100 nm in diameter?

Accepted Answer

Substitute
[latex]d^{*}_{p}[/latex] = 100 nm = 0.1 μm; N = 2

into Eq. (14.2), we get
[latex]c^{*}_{p}=10^{N}\left(\frac{0.1}{d^{*}_{p}} \right)^{2.08}=10^{2}\left(\frac{0.1}{0.1} \right)^{2.08}=100 /m^{3} [/latex]

Since the volume of the room is 300 m³, the total number of particles larger than 100 nm in diameter cannot exceed 30,000 in total. That is an extremely clean room!

For the ease of practice, the cleanroom classes and their corresponding maximum particle number concentrations are computed using Eq. (14.2) and they are summarized in Table 14.3. In this table, the values are the maximum concentrations for the particles size or greater. The greater the class number, the higher allowable particle concentration can be.
For a given class, all limits for all particles sizes must be satisfied. For a Class 1 clean room, the concentration of particles greater than 0.2 μm should be 2 or less particle/m³. Meanwhile, the particles ≥0.1 μm should not exceed 10 #/m³.
Cleanroom is important to the quality of many industries, such as medical, manufacturing, and packaging. Cleanrooms were first developed for aerospace applications to manufacture and assemble satellites, missiles, and aerospace electronics. Most applications involve clean airspaces of large volumes with cleanliness levels of ISO Class 9 or cleaner. Recent advances in electronics industries continue to drive the design of cleanrooms. Most recently designed semiconductor clean rooms are ISO Class 5 or cleaner. In addition, preparation of pharmaceutical, biological, and medical products all require clean airspaces to control airborne bacteria and viruses to prevent contamination. Furthermore, some operating rooms in hospital may be classified as cleanrooms, but their primary function is to limit particular types of contamination rather than the quantity of particles.

Table 14.3 Cleanroom classes

ISO class number (N)	Maximum particle number concentration (#/m³) for particle size [latex]c^{}_{p}=10^{N}\left(\frac{0.1}{d^{}_{p}} \right)^{2.08}[/latex]
ISO class number (N)	0.1 μm	0.2 μm	0.3 μm	0.5 μm	1 μm	5 μm
ISO Class 1	10	2
ISO Class 2	100	24	10	4
ISO Class 3	1,000	237	102	35	8
ISO Class 4	10,000	2,370	1,020	352	83
ISO Class 5	100,000	23,700	10,200	3,520	832	29
ISO Class 6	1,000,000	237,000	102,000	35,200	8,320	293
ISO Class 7				352,000	83,200	2,930
ISO Class 8				3,520,000	832,000	29,300
ISO Class 9				35,200,000	8,320,000	293,000

Question 14.2: Cleanroom class calculation An ISO 146441-1 Class 2 cleanroo...

Related Answered Questions

Transient indoor air pollutant concentration Consider a commercial kitchen with a volume of 80 m³ where natural gas is used as a cooking fuel. Assume that after cooking the indoor fume concentration is 1,000 μg/m³. The HVAC system works with a fresh air flow rate of 10 m³/s and an internal ...

Verified Answer:

Ventilation rate calculation There are 20 people in a dinning room, each produces 200 W total heat. The carbon dioxide concentration in the supply air is 500 ppmv. Assume the supply air temperature is 15 °C and relative humidity 50 %. The room air is to be maintained at 22 °C and 60 % relative ...

Verified Answer:

Threshold limit value In a welding shop, the measured concentrations of CO, CO2 and welding fumes are 10, 1,500 ppmv and 3.5 mg/m³, respectively, all below the recommended TLV-TWA. Is this working environment safe to the workers daily based on normalized concentration? ...

Verified Answer: