Filtration grades
25 gsm meltblown: the layer that makes a mask a mask
The middle layer of a three-ply medical mask is meltblown, usually 25 gsm, and it carries the filtration performance the standard measures.
At a glance
Specification at a glance
| Property | 25 gsm typical range | Note |
|---|---|---|
| Fibre diameter | 1.2 to 2.5 µm | Finer than 20 gsm grades |
| BFE | 95 to 99 % when charged | EN 14683 method |
| Pressure drop | 30 to 45 Pa | Breathing resistance |
| Tensile MD | 10 to 16 N/5 cm | Needs support |
| Electret | Charged on request | Decays with time and humidity |
| Shelf life | 2 years typical when sealed | Charge retention dependent |
What the standard actually measures
EN 14683 sets bacterial filtration efficiency at 95 percent for Type I and 98 percent for Type II and IIR, with a pressure drop limit and, for IIR, splash resistance. The meltblown layer delivers the BFE; the spunbond layers deliver structure and splash resistance.
Charge decay is the hidden risk
An electret charged web loses efficiency over time, faster in humid storage. Two rolls meeting the same BFE on the day of production can differ after a year in a warehouse. Buyers should ask for the charged value and the storage condition, and test after accelerated ageing if the product carries a shelf life claim.
Respirator grades
Respirators use a heavier or multi-layer meltblown composite, because the required efficiency is higher and the pressure drop budget is larger. The 25 gsm single layer is a medical mask component, not a respirator filter.
Other weights in this range
This grade sits in the Meltblown range. Buyers comparing across weights usually ask for two or three of these at sample stage, because the decision is made on the converting line rather than on the data sheet.
- 20 gsm meltblown - 20 gsm meltblown is the light filtration layer: enough fibre density to catch .
- 30 gsm meltblown - 30 gsm meltblown trades airflow for capture. It is used as a pre-filter ahead .
Check the grade against your line
Send the application, the width and the monthly volume. We reply with the tolerance, the batch test values and a ship date.
Questions
Common questions
Does 25 gsm meltblown meet EN 14683?
It can, when charged and laminated correctly. The standard applies to the finished mask, not to the roll, so the mask has to be tested.
How long does the charge last?
Typically two years in sealed, dry storage. Humidity and heat accelerate decay, so storage conditions belong in the specification.
Is it the same as a respirator filter?
No. Respirators need higher efficiency and use a different structure. A single 25 gsm layer is a medical mask component.