T/AQB 14-2022 Active Group standards

T/AQB 14-2022 Testing methods for filter performance of polypropylene melt-spun nonwoven used in masks

Publish Date: 2022-03-18 Implement Date: 2022-03-18 For services related to genuine standard inquiry, procurement, translation, and other related services in China, please Contact Us

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Basic Information

Standard Code: T/AQB 14-2022

Standard Type: Group standards

Standard Status: Active

is_force_gb: no

CCS Name: Chemical fibers

ICS Name: Textiles

Publish Date: 2022-03-18

Implement Date: 2022-03-18

Scope

Main technical content: 1. Basic filtration principle The filtration principle of filter materials is very complex. It cannot be simply regarded as a sieving effect, where particles larger than the pores are intercepted and smaller ones can pass through. This is because the inhalable particles targeted by respiratory protection filter materials are at the micron level, which is much smaller than the pores of the filter materials. A simple sieving effect cannot explain the high filtration efficiency of the filter materials and the high respiratory resistance. The filtration principle is also related to the particle size, including diffusion, interception, inertia, gravity settling, and electrostatic adsorption, as shown in Figure 1. Rational utilization of these filtration principles not only improves filtration efficiency but also reduces respiratory resistance, ensuring a good coordination and unification of various filtration performances. The basic principle of interception is to idealize the particles as having only volume and no mass. When the gas flows through the various fiber layers, the intricately arranged fibers in the fiber layers form numerous pores of different sizes. When a particle of a certain size reaches the surface of the collector just as the gas flow reaches it, and the radius of the particle is greater than the distance between the streamline and the collector, the particle is adhered to the collector and deposited on its surface, which is called interception. When the particle diameter is greater than the pores of the filter material, it is called sieving effect, which is also considered a special type of interception. It is generally believed that interception is ineffective for particles smaller than 0.05 micrometers, and it is obvious that particles with larger diameter and rougher surface are more easily intercepted by the collector. The efficiency of interception is shown in Figure 2. Large particles do not have significant diffus