A Pre filter is an essential component in air filtration systems and the air supply systems of AHUs. What exactly is a Pre filter? What are the characteristics of pre filters such as G1, G2, G3, and G4?
In this article, Vietnam Cleanroom will explore these questions in detail.

What is Pre Filter?

A pre filter, also known as a primary dust filter or air conditioner filter, is used in air filtration systems. This filter is designed to capture dust particles from the external environment before they enter clean rooms or factories through air conditioning or ventilation systems.

High-filtration products, such as coarse dust filters rated G3 or G4, are highly effective for filtering air from the external environment into AHU system. They are particularly effective as paint dust filters.
pre filter
In addition to its cotton-like form, this product can be manufactured in various shapes to accommodate a wide range of air filtration applications.

Structure and Classification of Pre Filter

According to the EN 779 standard for clean room air filtration, Pre filter is classified into filtration levels ranging from G1 to G4. These Pre filters are primarily made of synthetic fibers compressed into sheets.
The filter unit consists of two main components: the filter and the filter frame. The filter is made by compressing fibers into a unified mass, with interwoven fibers enhancing filtration efficiency. The frame is typically constructed from durable materials such as aluminum or zinc, providing resistance to environmental factors and physical impacts.
Structure and Classification
Pre filters are available in thicknesses of 5mm, 10mm, 15mm, and 20mm, with filtration efficiencies ranging from 65% to 95%. The weight of the filter increases with filtration level, from G1 (170 g/m²) to G4 (350 g/m²).
Among the Pre filters, G4 has the greatest thickness and filtration efficiency, making it the most widely used.
Read more: G4 Filter

G1, G2, G3, G4 Specifications

Filter (according to EN779 standard) Weight (g/m2) Thickness (mm) Breathability (m3/h) Head pressure difference (Pa) Replacement pressure difference (Pa). Efficiency (%) Size (m) Color
G1 170 5 5400 12 150 65%
G2 250 10 17 250 75% 2x20 white
G3 300 15 26 250 85%
G4 380 20 42 250 95%

Advantages of Pre filter G1, G2, G3, G4

Pre filter G1, G2, G3, and G4 are made of synthetic fibers designed to filter and retain a large amount of dust, providing clean air for working and living spaces. Additionally, the lightweight synthetic fibers of this Pre filter make transportation and installation convenient.

Advantages of Pre filter

Applications of Pre filter G1, G2, G3, G4

Pre filter is a coarse filter material with filtration efficiency that increases progressively from G1 to G4. Therefore, Pre filter G1, G2, G3, and G4 are suitable for various air purification applications, including hospitals, schools, factories, and industrial parks.

However, the application of Pre filter varies depending on the specific field. For environments with moderate air quality requirements, G1 and G2 Pre filter are sufficient. For environments requiring stricter air quality, such as hospital clean rooms, research laboratories, or pharmaceutical and cosmetic production facilities, G3 and G4 Pre filter are necessary to meet the standards.

Tags: