Surgical Mask: Types, Manufacturing Process and Uses

Introduction:
I know you have a lot of question about mask. Either it protects us from airborne diseases, or it just protects us from pollution. Which surgical mask should I buy or there are many things to know? We will find out everything in this article.

What is surgical mask?
This thing is also known as procedure mask, medical mask but most commonly known as face mask. This kind of mask is widely used by the health professionals during surgery. Surgical face masks are an important component of surgical apparel. It is a product of medical textiles. Masks function as filters for the mouth and the nose area, usually covering most of this area, and are expected to block the dual contamination and protect both the patients and healthcare workers. In Paris surgical mask first use was recorded in 1897. It was used by French surgeon Paul Berger. These masks are designed to catch microorganisms shed in liquid droplets and aerosols from the wearer’s mouth and nose. Therefore, surgical masks minimize the risks of contaminations from secretion of nose and mouth during operation time in operation theaters or clinics. But we shouldn’t be confused between surgical mask and respirator. This mask is not designed to inhale you from airborne bacteria or virus particles. This is less effective than respirators. Surgical masks are abundantly used in this coronavirus pandemic.

surgical mask
Fig: Surgical mask

Different types of surgical mask:
Not every mask protects us from everything. There are 4 classifications depending on its protection level. They are:

1. Minimum protection:
This face mask is made for minimum protection. This are for short procedures and exams. This do not include fluid, spray or aerosol.

2. Level 1:
This mask is advance then the previous one. This often offers loops. This is standard for surgical and procedural application. This thing has a barrier for 80mmHg fluid. This thing is used when the risk is low and spray, fluid and aerosol are not included.

3. Level 2:
These masks have higher level of protection for wearer than level 1 mask. This mask has 120mmHg fluid protection. This mask can handle light or moderate fluid, spray and aerosol.

4. Level 3:
These masks can handle more critical situation than other. It can handle 160mmHg fluid. It can give you protection from heavy fluid, spray and aerosol.

Surgical mask design and manufacturing process:
Design of a surgical mask depends on various modes. In general, this mask has three or four layers. Which give better protection and more air permeability. This thing is made from non-woven fabric. Because this non-woven fabric gives better bacteria filtration remaining less slippery than woven cloth. Also, non-woven fabric is cheaper to make and has a disposable nature. This three-level ply is made from a melt blown material. Melt blown material is placed between non-woven fabrics. This melt blown material act as a filter which stops microbes entering and exiting mask. The outer layer of mask generally uses long fiber nonwoven materials, which in turn, are made from spunbonding.

The most common material which is used for mask is polypropylene. Other materials like polystyrene, polycarbonate, polyethylene, or polyester are also used to make both 20 and 25 grams per square meter (gsm) in density. 20 gsm and 25 gsm mask making process are similar. In 20 gsm first extruding melted plastic on a conveyor. Plastic are extruded in web for that they stand in bond as they cool. 25 gsm making is also similar. Here also extruded through a die with hundreds of nozzles and blown by hot air to became tiny fiber. Filtration ability of a mask on many things such as fiber it uses, manufacturing process, web structure, the fiber’s cross-sectional shape etc. Generally, surgical masks produced via fabric forming technique
are shown in Fig.

Surgical masks (A) woven, (B) nonwoven, and (C) knitted
Fig: Surgical masks (A) woven, (B) nonwoven, and (C) knitted

Aspects of best fitting surgical mask:
Proper adjustment of surgical mask is needed to allow the wearer to breathe appropriately. A properly fitted mask involves several aspects. The first aspect is the form of the mask. The shape of mask depends on the surfaces of the two sides of the nose, the cheeks, the under surface of the chin and the confluence of these three surfaces. Some products are constructed in a round-shape; some are in an egg-shape. Fiberglass, nylon, heat-stable moldable plastic and resin-impregnated cotton have been used as the frame of masks to support the curved shape of the mask and maintain reasonable weight and durability. The second aspect of mask fitting is the adaptability of the mask to the irregular and various contours of faces. The third aspect is the need to restrict air leakage around the mask when inhaling and exhaling. Silk, cotton, nylon, polyethylene and polystyrene complexes, various synthetic esters, rubber in different forms (solid, foam and inflatable) and polyurethane foam have been studied for their effectiveness in the adapter ring.

Surgical mask test:
After making of a surgical mask it goes through different test:

1. Bacteria filtration efficiency in vitro (BFE):
Shooting an aerosol with staphylococcus aureus bacteria on mask at the rate of 28.3 litters per min to ensure either it can catch the amounts of bacteria it should.

2. Flammability:
It tests how slowly and how long the material takes to burn.  Level 1,2,3 all need level 1 flame resistance.

3. Breathing resistance:
This test is shooting air flow on mask then measure the air pressure both the side of the mask. So that when wearer breathes that mask can hold its shape and filter properly.

4. Splash resistance:
In this test simulated blood is splashed to mask at the similar speed of human body to ensure liquid cannot contaminate wearer.

5. Particle Filtration Efficiency:
To ensure if the mask can filter the size of particle it should this test spray an aerosol of polystyrene microspheres.

Uses of surgical mask:
Surgical masks are widely used by the health care workers. Simple surgical mask protects us from being splashed by the body fluid of other or prevent transmission of body fluid from the wearer to others. Surgeons wear them during surgery. Surgical mask is also worn by the general people. They wear these masks to protect them from air pollution, bacteria and infection.

Surgical mask vs respirators:
There are many questions in people mind. Like, what is surgical mask for? When we should use it? Can it filter airborne disease? Let’s answer these questions. In previous paragraph we knew about is surgical mask. Now we will know what respirator is.

Respirators:
Respirators are designed to protect you from airborne disease. Respirators come in different size. So, you should choose which one fits you. Because it provides a tight seal between wearer’s face. Which force air to pass through filter of the respirator?

surgical mask vs Respirator

Now we can say that respirators are more suitable for blocking airborne diseases.

Conclusion:
Now you know about type of surgical mask, its usage, and difference with respirator and test. I hope it was helpful for you to choose perfect surgical mask in this COVID-19 pandemic.

References:

  1. Improving Comfort in Clothing Edited by Guowen Song
  2. Polyolefin Fibres: Structure, Properties and Industrial Applications, Second Edition Edited by Samuel C. O. Ugbolue
  3. https://en.wikipedia.org/wiki/Surgical_mask
  4. https://textilelearner.net/spunbonding-method-for-nonwoven-fabric-production/
  5. https://www.thomasnet.com/articles/other/how-surgical-masks-are-made/
  6. https://www.osha.gov/Publications/respirators-vs-surgicalmasks-factsheet.html

Author of this Article:
Md. Sadman Nafe
B.Sc. in Textile Engineering
Textile Engineering College, Noakhali.
Email: nafe2290@gmail.com

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  1. Spunbonding Method for Nonwoven Fabric Production
  2. Spunbonding Technology with Types, Application (Bags) and Market Future
  3. Melt Blown Non-Woven Technology – An Overview
  4. Characteristics of Nonwoven Fabric | Uses and Specialty of Nonwoven Products
  5. Personal Protective Equipment (PPE): Blessings of Medical Textile

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