HEPA filter means high efficiency particulate air filter.Air filter which can remove up to 99.95%(Europe) or 99.97%(America) suspended particles with size of 0.3um from air stream can be called HEPA.Our another article would tell why the pencentage is different,and omitted here.If interested about detailed air filter and HEPA classfication,you can click to read this article-HEPA filter rating.
HEPA is mechanical filter.filtration is classified into mechanical,chemical,and biological.Most air filters people can come into contact with in daily lives are mechanical filters.Chemical filters are filters like carbon filters,and biological type is not in this discusion.
So why HEPA has a higher filtration rate?It is because HEPA has a much large effective area to filter particulates.This is achieved by the deep and compact pleat structure of HEPA filter medium.The larger filtration area,the higher filtration rate and efficiency.
To increase the filtration area,people explored many ways.They found pleated structure is the best way at least for now,but there are still many difficuties need to resolve.The more pleats,the bigger size and the lower flow rate.These are still the big problems limiting mechenical air filtration development.
HEPA filter structure.The structure and apearance of a HEPA filter is determind by where it is adapted to.There are 2 main structure design of HEPA:box type HEPA and cylindrical HEPA.The box type can be divided into mini-pleat HEPA and deep-pleat HEPA filter.You can find your vaccum HEPA is always cylindrical filter,and in some other places like air purifier,mini pleated HEPA is often used.
How do I know if my filter is HEPA?Let’s talk about what’s true HEPA filters at first and you will know how to identify a filter is a HEPA or not.Firstly,you should make sure not decieved by the filter name sellers claim.Many filters claim to be “HEPA” sold in the market or online can’t really reach the HEPA standard.In fact,some sellers don’t know if their products is real HEPA either.If you really need a true HEPA filter,you’d better ask the seller if the filtration rate of this HEPA” can reach 99.97% in US or 99.95% in Europe.
What’s a true HEPA?In deed there shouldn’t come out this name.Cos there is fake HEPA there is true HEPA.But when you search online for what is true HEPA,you may find wrong answers.So let us tell you if your filter is true HEPA in the most easy way:All MERV filters including MERV 16 are not true HEPA filters,and all filters rating lower than H13 is not either.But if buying “HEPA filters” just for common use,actually you don’t need to be entangled.These filters can also resolve your common filtration task,as long as the quality is not too bad.True HEPA filters are much more expensive,and if you don’t really need critical filtration environment,buying true HEPA is also a waste of money.