The term HEPA (High Efficiency Particulate Air) denotes a high-efficiency filtration system, which is used for microparticles, fine dust and oil mists. This category of filter assumes a key role within vacuum cleaners, as it allows them to capture contaminants before they can affect machine’s head. In this way, it is possible to ensure high vacuum cleaner efficiency and, at the same time, safeguard operators’health by putting filtered and purified air back into the environment.
Classification of dusts and filters
Before listing the technical features and functionality of the HEPA filter, we want to examine how dust and filtration classes are divided.
Classification of dusts
We can classify dusts according to the risk they may cause to operators and according to its granulometric size.
- Class L
This class includes dusts representing a moderate risk for operators’health and distinguish by a particle size of less than 3 microns.
- Class M
Class M includes dusts that represent a medium risk for operators’health, their particle size is less than 2 microns.
- Class H
Dusts classified within Class H are dusts that are very harmful for operators’health, falling into the category of high-risk dusts. Their particle size is less than 1 micron and they also include carcinogenic dusts.
Classification of filters
There is a classification for filters too, it is made according to their filtering capacity.
- L-type filter
Vacuum cleaners with an L-type filter are able to vacuum up to 99% of dust with a size of 3 microns. These filters are usually used for vacuum cleaners employed for general cleaning, where they come into contact with dust that doesn’t cause a high risk to operator’s health.
- M-type filter
M-type filter captures 99% of dust that is up to 1 micron in size. In this case, it is mounted on vacuum cleaners used in different industries that require high filtration efficiency.
- H-type filter
In this classification we find filters that can offer the highest suction and filtration capabilities. These filters capture up to 99.995% of dusts that has a size as small as 0.18 microns.
What is HEPA filter
HEPA filter is also known as “absolute filter” because of its high filtration efficiency and is essential for all areas where harmful dusts is produced. This filter falls under the classification of H–type filters due to its 99.995% filtering capacity of 0.18 micron dust.
The composition of a HEPA filter
HEPA filter consists of microfiber filter sheets assembled in several layers and separated by aluminum septa. The filter sheets block pollutant particles that are present in the area to be treated. Because of their versatility, HEPA filters can be applied upstream, downstream or on other locations in the filter path of an aspirator, or can even be mounted in series.
The types of HEPA filter and its functionality
In accordance with the UNI EN 1822 standards, HEPA absolute filters are characterized by high filtration efficiency and can be classified into 5 classes (from H10 to H14) based on their 0.3 micron particle filtration capacities:
- H10: retains up to 85% of particles
- H11: retains up to 95% of particles
- H12: retains up to 99,5% of particles
- H13: retains up to 99,95% of particles
- H14: retains up to 99,995% of particles
The particles that the HEPA filter is able to trap are particles that are invisible to the human eye, just think that the size of a grain of sand has a diameter of 90 microns. The smaller these particles are, the more dangerous they are to the health of the operators because they are able to enter deep into the lungs, eventually entering the bloodstream.
In terms of operation, the HEPA filter blocks particles in 3 different ways:
Large particles, once they come into contact with the filter, can not cross the filter structure, in this way they remain trapped outside.
Airborne particles become trapped within the intricate fiber structure.
Diffusion is the mode that succeeds in trapping smaller particles, these collide with each other until they change direction and quickly lose speed.
HEPA filtration in industrial vacuum cleaners
HEPA filtration fitted in industrial vacuum cleaners is essential for all those companies working in industries where fine and harmful dust is generated. In fact, this filter is the most suitable tool for:
- Retaining pollutant particles that could be dispersed into the air;
- Slow down the wear and tear of the vacuum cleaner, as it prevents micro-dust from coming into contact with the engine head, risking to affect its efficiency.
In addition, some industries are required by law to use industrial vacuums with absolute HEPA filters, since they must comply with strict air quality requirements.
The sectors concerned are:
In all these areas, it is extremely important that the filtered air is completely free of any residual pollutants, viruses or bacteria potentially toxic to workers or the success of the final product. Thanks to the HEPA filter, it will be possible to avoid both pollution of the external environment and toxic contamination of the internal air breathed by workers.
Contact us to find out more about the most suitable filter for your industrial vacuum cleaner!
HI-TECH VACUUMHEPA is the acronym used for the definition “High Efficiency Particulate Air”. It ‘a kind of filter for vacuum cleaner with a particular system of filtering with high efficiency for fluid, liquid or gas. It has the ability to trap a very high amount of particles of very small size, ability that other filters for vacuum cleaners do not have. Indeed, there are different categories of filters (L / M / H), and different categories of HEPA filters, that has made according to the material more efficient to inhale. The HEPA filter is composed from microfiber filter sheets (generally borosilicate) assembled in multiple layers, and separated by aluminum septa. The microfiber filter sheets have the task to block the polluting solid particles (or particulate). The solid particles are very small and can be harmful to health or may affect the quality of the final product to be obtained. HEPA filters are part of the category of the “absolute filters”, justified by the fact that these filters have a high efficiency of filterign. In particular, HEPA filters introduce an efficiency of filtering between 85% (H10) and 99.995% (H14). The filtration efficiency of particles of 0.3 µm, is regulated by the UNI EN 1822.
HI-TECH VACUUMThe classification filters for vacuum cleaner and powders emissions into the environment, is assigned by the type of powders and the degree of danger to health. For its suction devices such classification is regulated by IEC 60335-2-69 worldwide. This classification provides several categories of powders, such as: • Category of powders L (low/moderate): fall into that category powders with MPC values (maximum permitted concentration in the work place) > 1 mg / m³Are retained at least 99% of particles aspirated.The disposal of the collected material must be made trying to raise a few powders. • Category of powders M (medium): fall into that category powders with MPC values (maximum permitted concentration in the work place) > 0.1 mg / m³ and wood powdersAre retained at least 99.9% of particles aspirated.The disposal of the collected material must be made trying to raise a few powders. • Category of powders H (high): fall into that category powders with MPC values (maximum permitted concentration in the work place) < 0.1 mg / m³, with carcinogenic and pathogenic powdersAre held at least 99.995% of particles aspirated.The disposal of the collected material must be done without raising powders. On each iVision vacuum cleaner is applied a label indicating the hazard class of the dust in the environment allowed.
HI-TECH VACUUMStrongly recommended whenever possible, the pre-filter is positioned between the vacuum and the chip-generating machine, as the first point of collection of the collected material. It is specially used to preserve the life of the filter inside the vacuum unit. It retains most of the collected material and can have a cone or cylindric shape and serves as a mechanical filter. Through a tangential entry the collected material is centrifuged into its interior until its speed gradually decreases and the material gradually falls to the bottom of the collecting unit due to the force of gravity. Such a process ensures that only a relatively low percentage of collected dust or chips manages to actually reach the real filter positioned in the upper part of the vacuum cleaner. The cyclonic pre-filter can be combined with a: • 160 L tank • 500 L tank • 1000 L tank The cyclonic pre-filter becomes almost mandatory for fine or very fine powders, which are very likely to clog the filter quickly, compromising the smooth operation of the entire system, but are only recommended for large, heavy chips. The main advantage of the cyclonic pre-filter is to protect the filter of the vacuum cleaner from quickly clogging, thus extending its life before replacement and significantly reducing the maintenance of the entire system.