Performance Comparison: PP vs SMS vs SMMS vs Microporous

Choosing the right disposable apparel – industrial coveralls or hospital gowns – is critical. Wrong fabric: poor protection, staff heat stress, or high costs. Right fabric: optimal barrier, Breathable, and cost-efficiency – tailored to your job.

This article gives you a clear, data-driven comparison of four common nonwoven materials used in disposable protective clothing. Review: PP, SMS, SMMS, microporous film – making, performance, uses.

What Exactly Is Nonwoven Fabric? – A Simple Explanation

• Spunbond (S): Continuous filaments of polypropylene are extruded, laid into a web, and then thermally bonded. Strong, durable, breathable fabric – but poor filter for particles/liquids alone.
• Meltblown (M): Here, high-speed hot air turns PP into 1–5 μm fibers. These dense, tangled microfibers create a tortuous path that traps particles and resists liquid penetration. This is the filtration layer you find in SMS, SMMS, and SMMMS fabrics.

Material 1: PP Spunbond – The Basic Choice

Structure: PP spunbond is a single-layer fabric made entirely from continuous spunbond filaments that are thermally bonded together. There is no meltblown layer at all.

Key Performance Data (typical values):

• Basis weight: 25–50 gsm
• Hydrostatic head (water resistance): < 10 cm H₂O
• Particle filtration efficiency (0.3–10 µm): < 10%
• Moisture vapour transmission rate (MVTR): > 5000 g/m²/24h (very breathable)
• Tensile strength: good (but barrier is minimal)

Strengths:

• The most cost-effective option on the market – ideal when budget is tight
• Excellent Breathable, which reduces heat stress and keeps wearers comfortable
• Soft and gentle against the skin, making it pleasant for short-term wear
• Suitable for low-risk, low-exposure environments where no real hazard exists

Limitations:

• No meaningful fluid resistance – liquids pass through on contact
• Minimal particle filtration – only effective against very large dust or fibres
• Not suitable for any standard Type 5 or Type 6 chemical protective coverall application

Best for: visitor gowns, patient gowns, dust covers, and dry food areas.

Material 2: SMS – The Balanced Workhorse

Structure: SMS: spunbond outer, meltblown middle, spunbond inner. These layers are hot-rolled together into one unified fabric.

Key Performance Data (typical values):

• Basis weight: 35–50 gsm
• Hydrostatic head: 30–60 cm H₂O
• Particle filtration efficiency (0.3–10 µm): 40–65%
• MVTR: 3000–4500 g/m²/24h (moderately breathable)

Strengths:

• Significantly higher filtration than PP alone – the meltblown layer is the game-changer
• Maintains reasonable Breathable despite the added filtration layer
• Offers a balanced cost-to-protection ratio, making it very popular
• The industry standard for general medical isolation gowns (AAMI Level 2)

Limitations:

• The single meltblown layer limits fluid resistance to light-to-moderate splash only
• Not suitable for high-fluid-exposure surgical or critical care settings
• Under pressure or extended contact, particle penetration is still possible

Material 3: SMMS – Double the Filtration, Higher Protection

Structure: SMMS is a four-layer composite: spunbond → meltblown → meltblown → spunbond. Meltblown ×2 between outer spunbond, hot-rolled for barrier.

• Basis weight: 40–60 gsm
• Hydrostatic head: 70–110 cm H₂O
• Particle filtration efficiency (0.3–10 µm): 65–80%
• MVTR: 2000–3500 g/m²/24h (noticeably less breathable than SMS)
• Tensile strength: very good
• SMMS vs SMS: extra meltblown layer → double barrier. Same weight: +40–60% water, +3–5 pp filtration (0.3–10 µm); dual filters block more.
• AAMI PB70: SMS=L2, SMMS=L3, Micropores + PE=L4.
• Type 5/6: microporous for particle-tight (EN 13982) & splash (EN 13034) suits.
• ASTM F1670/1671: blood/viral tests for surgical gowns.

Limitations:

• Lower Breathable than SMS – heat stress can become an issue in warm environments or during heavy physical work
• Slightly higher cost than SMS, but still less expensive than microporous

Best Applications: Emergency departments, intensive care units, trauma settings (medium to high fluid risk). Gowns include isolation (AAMI Level 2–3) and surgical gowns (Level 3, sterilized).

Material 4: Microporous Membrane – The High-Performance Specialist

Microporous membrane: PP/PE film laminated onto spunbond/SMS. The pores in the film are extremely small – typically 0.2 to 5 micrometres. These pores are large enough to let water vapour (sweat) escape, but small enough to block liquid droplets and solid particles. High-end variants also have an outer PE coating for extra fluid resistance.

• Basis weight: 50–70 gsm
• Hydrostatic head: > 150 cm H₂O (often > 200 cm)
• Particle filtration efficiency (0.3–10 µm): 85–99% (comparable to or better than meltblown)
• MVTR: 4000–6000 g/m²/24h (surprisingly high for such a strong barrier)
• Tensile strength: good, but film can be stiff

Strengths:

• This microporous film offers unmatched Breathable and barrier. It blocks liquids/particles and lets vapor out – critical for extended use.
• Its pore structure gives particle filtration that rivals meltblown and beats SMS for solids.
• Certified for Type 5 (particle-tight) and Type 6 (limited splash) protection per EN ISO 13982-1 and EN 13034 standards.
• High MVTR cuts heat stress — comfy in hot/humid, ideal for long shifts.

Limitations:

• Higher cost than PP, SMS, and SMMS – sometimes double or more
• The film can feel stiff if the microporous layer is thick; softer versions are more expensive
• Without a PE outer lamination, fluid resistance under sustained pressure may not reach AAMI Level 4

Type 5/6 coveralls: chemical, cleanroom, pest, asbestos, painting, and other particle/splash/moisture risks.

Head-to-Head Comparison Table (Quick Reference)

This tradeoff is best illustrated by MVTR data. Microporous membranes excel here because their 0.2–5 µm pores block liquid droplets but release vapour. That makes them ideal for long-wear industrial tasks where both barrier and comfort are essential.

GSM vs. Performance – A Common Misunderstand

Many buyers assume that higher GSM always means better protection – but that is not true. The relationship is more nuanced:

• PP Spunbond: GSM affects durability/opacity, not barrier – no meltblown, weight won't filter.
• SMS: GSM adds thickness/barrier, but gains drop >50. Filtration = meltblown, not weight.
• SMMS: Meltblown = barrier; over 55 gsm, added weight stiffens and reduces comfort, not protection.
• Microporous Membrane: GSM = backing fabric; barrier = film pore size, not weight.
• AAMI PB70: Classifies gowns into Levels 1–4 based on fluid resistance. SMS typically meets Level 2; SMMS meets Level 3; microporous with PE coating can meet Level 4.
• EN ISO 13982-1 (Type 5): Regulatory bodies commonly certify microporous membranes for particle-tight coveralls.
• EN 13034 (Type 6): Limited splash protection – again, microporous is a top choice.
• ASTM F1670 / F1671: Tests resistance to synthetic blood and viral penetration – relevant for surgical gowns.

Choose PP Spunbond if:

• Your primary need is coverage and modesty, not real protection
• There are no fluid or particle hazards
• Cost is the dominant factor
• Wear time is short and exertion is low in a controlled environment

Choose SMS if:

• AAMI Level 2 isolation gown compliance is required
• You face moderate fluid splash risk (routine patient care, ER triage)
• Comfort and Breathable remain important alongside protection
• The environment is temperature-controlled

Choose SMMS if:

• High fluid exposure is expected (surgical procedures, trauma care, recovery)
• AAMI Level 3 performance is specified
• Longer wear duration is expected (2–3 hours) without major heat stress concerns
• You need ultrasonic or heat-sealed seams for integrity

Choose Microporous Membrane if:

• EN ISO 13982 Type 5 and/or Type 6 certification is required
• You need both particle and liquid splash protection simultaneously
• The environment is hot, humid, or physically demanding
• Regulatory bodies (e.g., for medical, biotech, or nuclear sectors) mandate this level
• Extended-duration wear (4+ hours) is expected

References & Further Reading

1. ANSI/AAMI PB70:2012 — Healthcare gowns/drapes: liquid barrier rating. Association for the Advancement of Medical Instrumentation (AAMI). https://www.aami.org
2. EN ISO 13982-1:2004+A1:2010 — Type 5 full-body chemical suit — Part 1: specs against airborne solids. International Organization for Standard (ISO). https://www.iso.org/standard/52539.html
3. EN 13034:2005+A1:2009 — Type 6 suit specs — limited liquid chemical protection. European Committee for Standard (CEN).
4. ASTM F1671/F1671M-13 — Penetration resistance test for protective clothing against bloodborne pathogens (Phi-X174 phage method). ASTM International. https://www.astm.org
5. EN 14126:2003 — Performance requirements and test methods for protective clothing against infective agents. European Committee for Standard (CEN).
6. USEON — SMS/SMMS Spunmelt Nonwoven Fabric Manufacturer (performance specifications). https://www.useon.com/spunmelt-fabric/
7. Sogou Baike — SMS Nonwoven Fabric (SMS无纺布) (Chinese technical reference). https://baike.sogou.com/v183097.htm

Note: For education. Material choice = hazard assessment + local rules. Standards compliance = test finished garment, not swatches. Seams/design/cuffs affect certification.