Understanding SMS Coveralls: The Science, Material, and Applications in Protective Clothing

In the world of Personal Protective Equipment (PPE), the SMS coverall stands out as one of the most versatile and widely used garments. Whether in a high-tech laboratory, a medical facility, or an industrial manufacturing plant, SMS material provides a critical balance between protection, breathability, and cost-effectiveness.

What is SMS Material?

The acronym SMS stands for Spunbond-Meltblown-Spunbond. It is a trilaminate non-woven fabric designed to combine the mechanical strength of spunbond polypropylene with the barrier properties of meltblown polypropylene.

To understand why this material is so effective, we must look at its three-layer construction:

1. Spunbond Layer (Top): This layer consists of continuous filaments that provide high tensile strength and durability. It protects the inner layers from abrasion and tearing.
2. Meltblown Layer (Middle): This is the “filter” of the fabric. It is composed of extremely fine microfibers that create a complex, tortuous path. This structure is small enough to block bacteria, particles, and fluid splashes while remaining porous enough for air to pass through.
3. Spunbond Layer (Bottom): The base layer provides additional structural integrity and a soft touch against the wearer’s skin or inner clothing.

The Evolution: SMMS and SMMMS

In recent years, manufacturers have introduced SMMS or SMMMS, which add extra meltblown layers. These variations enhance the filtration efficiency and fluid resistance without significantly increasing the weight of the garment.

Key Features and Benefits of SMS Coveralls

SMS coveralls are preferred in many environments over traditional cotton or simple polyethylene suits due to several distinct advantages:

1. Superior Breathability

Unlike “microporous” films or solid plastic aprons, SMS material allows for high air permeability. This is crucial for workers performing physical labor in warm environments, as it helps regulate body temperature and reduces the risk of heat stress.

2. Effective Barrier Protection

The meltblown core acts as a highly efficient filter. SMS coveralls are particularly effective against:

• Dry Particles: Such as dust, fibers, and powders.
• Light Liquid Splashes: Such as water-based aerosols or minor chemical sprays.

3. Durability and Strength

The outer spunbond layers make the garment resistant to punctures and tears. This ensures that the protective barrier remains intact even when the wearer is moving, bending, or working around sharp equipment.

4. Low Linting

SMS is a non-woven material that does not shed fibers easily. This makes it ideal for “cleanroom” environments or paint-spraying applications where fiber contamination could ruin a product or process.

Industry Applications

Because of its balanced properties, the SMS coverall is a staple in several sectors:

Medical and Healthcare

In hospitals, SMS is used for surgical gowns and isolation coveralls. It provides a barrier against blood-borne pathogens and fluids while keeping surgical staff comfortable during long procedures.

Industrial Manufacturing and Maintenance

Workers involved in fiberglass processing, power plant maintenance, or general factory cleaning use SMS coveralls to protect their skin and personal clothing from grime and hazardous dust.

Asbestos and Lead Abatement

For Type 5 and Type 6 protection levels (European Standards), SMS coveralls are frequently used during the removal of hazardous materials like asbestos, where preventing fiber inhalation and skin contact is paramount.

Pharmaceutical and Laboratory

In environments where cross-contamination must be avoided, SMS garments provide a reliable, disposable solution that ensures both the wearer and the product remain protected.

Understanding Protection Standards

When selecting an SMS coverall, it is essential to look for specific certifications. In the European market, these are categorized by “Types”:

• Type 5 (EN ISO 13982-1): Protection against hazardous dry particles.
• Type 6 (EN 13034): Protection against light spray and splashes of liquid chemicals.

Most high-quality SMS coveralls are rated as Type 5/6, meaning they offer a dual defense against both dust and light liquid threats.

SMS vs. Microporous Film: Which to Choose?

A common question in PPE procurement is whether to choose SMS or Microporous Film (MPF).

 

The Verdict: If the environment involves heavy liquid exposure or hazardous oils, Microporous Film is superior. However, for general dust protection and light splashes where worker comfort and heat management are priorities, SMS is the gold standard.

Conclusion

The SMS coverall represents a triumph of textile engineering. By layering different types of polypropylene, manufacturers have created a garment that is tough enough for the factory floor, clean enough for the lab, and breathable enough for all-day wear. When choosing protective clothing, understanding the “SMS” construction ensures that you are selecting a material designed for both safety and performance.