PP vs SMS vs Microporous Coveralls: Which Is Right for Your Cleanroom?

When setting up a cleanroom or controlled environment, one of the most common questions is surprisingly simple:

“Which coveralls do we need?”

The answer can quickly become confusing. Disposable coveralls may look very similar, yet polypropylene (PP), SMS and microporous materials provide different levels of barrier protection, breathability and liquid resistance. There is also a considerable difference in cost.

More importantly, cleanroom classification alone does not determine which coverall you should wear.

An ISO Class 7 cleanroom, for example, does not automatically require an SMS coverall, just as an ISO Class 5 room does not automatically require a microporous coverall. Garment selection should form part of the facility’s overall contamination-control and gowning program and consider the process being performed, contamination risk, whether the product or worker needs protection, particle shedding, liquid exposure and whether sterile garments are required. ISO 14644-5:2025 specifically includes personnel management and a gowning programme within cleanroom operational controls.

TIDDOX is a cleanroom garment specialist and has compiled this guide to explain the differences between the polypropylene, SMS and microporous disposable coveralls, and the factors to consider when deciding which is appropriate for your application.

Why Are Coveralls Worn in Cleanrooms?

It is easy to think of a coverall simply as PPE protecting the person wearing it.

In a cleanroom, there is another equally important consideration:

“Protecting the cleanroom, process and product from the person.”

People are significant potential sources of contamination. Hair, skin particles, fibres and other contamination can be released as people move and work. Cleanroom clothing therefore forms a barrier between personnel and the controlled environment.

The International Society for Pharmaceutical Engineering (ISPE), a global professional association for the pharmaceutical and life-sciences industries, notes that cleanroom garments help protect products and processes from human-sourced contamination. Its technical guidance also highlights that garment selection and correct use can have a significant impact on cleanroom performance.

Depending on the workplace, a coverall may therefore have one or both of two jobs:

• Product/process protection: helping prevent contamination generated by personnel from entering the controlled environment.
• Personnel protection: helping protect the wearer from dust, particles, limited liquid splashes or other hazards associated with the task.

Understanding which of these matters, or whether both matter, is an excellent starting point when selecting a garment.

What Is the Difference Between PP, SMS and Microporous Coveralls?

Although all three are disposable coveralls, their construction is different.

Quick comparison

Feature	Polypropylene (PP)	SMS	Microporous
Product Illustration
Construction	Single-layer polypropylene	3-layer Spunbond/Meltblown/Spunbond	PE film laminated to PP nonwoven
TIDDOX garment	Lightweight PP	55 gsm SMS	PE/PP microporous laminate
Breathability	Excellent	Very good	Good*
Dust barrier	✓	✓✓	✓✓
Liquid resistance	Low	Moderate	Higher
Type 5 certified	N/A	Yes	Yes
Type 6 certified	N/A	Yes	Yes
Weight/comfort	Very light	Medium	Lightweight
Typical cost	$	$$	$$$
General use	Basic contamination/dust control	Balanced protection & comfort	Greater barrier requirement
Relative price	Lowest	Mid-range	Highest
Colours	White, Blue	White, Blue, Orange	White with Orange Stripes
Sizes	S–3XL	M–3XL	M–3XL

*Breathability varies substantially between microporous laminates and garment constructions.

The specifications above for garments come from the individual product data available on the TIDDOX website. The PP coverall is a lightweight single-layer polypropylene garment; the SMS version uses 55 gsm three-layer spunbond/meltblown/spunbond material; and the microporous version uses polyethylene laminated to polypropylene nonwoven material.

Let’s look at what those differences mean in practice.

1. Polypropylene (PP) Coveralls

Polypropylene coveralls are generally the simplest and most economical of the three options.

The PP coverall is manufactured from lightweight polypropylene and provides a single-layer hygienic dust barrier. It has an elasticised hood, wrists, waist and ankles and is designed to remain lightweight and breathable.

Where does PP make sense?

PP can be a practical choice where the primary objective is basic contamination control rather than substantial protection from liquids or hazardous particulate matter.

Typical applications can include general manufacturing, food processing, maintenance, visitor garments, automotive environments and some less-critical controlled environments where the garment has been assessed as appropriate under the site’s contamination-control procedures.

The major advantage is straightforward: “PP provides basic coverage at a relatively low cost”.

This can become significant when dozens or hundreds of disposable garments are being used every week.

However, inexpensive does not mean that PP is automatically the best-value garment. If the process requires better particle containment or protection against liquid splash, moving to SMS or microporous construction may be appropriate.

PP is generally worth considering when:

• The main requirement is basic dust or contamination control.
• Liquid exposure is unlikely.
• Maximum breathability is desirable.
• Garments are being changed frequently.
• Visitors require disposable protective clothing.
• Cost per garment is an important consideration.

TIDDOX supplies PP coveralls in white and blue colours and in all sizes from Small to 3XL.

2. SMS Coveralls

SMS stands for: Spunbond – Meltblown – Spunbond.

Rather than using a single layer of polypropylene, SMS combines three layers.

The outer spunbond layers provide strength, while the meltblown middle layer contributes filtration/barrier properties. This construction gives SMS an effective compromise between protection, durability and breathability.

TIDDOX supplies 55 gsm SMS coveralls made from three-layer lint-free and breathable SMS material. The coveralls include elastic wrists and ankles, a two-way zipper and a three-layer hood designed to accommodate goggles and respirators.

This makes SMS an attractive option where PP does not provide sufficient protection but a laminated garment may not be necessary.

“The big advantage of SMS: Balance”

SMS occupies a useful middle ground.

It offers greater barrier performance than basic single-layer PP while retaining good wearer comfort.

That matters more than it might appear.

People working long shifts in protective clothing generate heat and perspiration. A garment that provides significantly more protection than the application requires but makes workers excessively uncomfortable is not necessarily the most appropriate solution.

An important difference between TIDDOX’s polypropylene and SMS coveralls is the level of certified protective performance. TIDDOX SMS coveralls are classified as Category III protective clothing and provide Type 5 and Type 6 protection. We’ll explain what those classifications mean shortly. TIDDOX supplies SMS coveralls in white, blue and orange colours and in all sizes from Small to 3XL.

3. Microporous Coveralls

Microporous coveralls introduce another type of construction.

TIDDOX supplies garments made from a lightweight polyethylene (PE) layer laminated to polypropylene nonwoven material.

The film changes the barrier characteristics of the garment.

The result is a soft, lightweight coverall offering water repellency and resistance to hazardous dust and limited liquid chemical spray.

Like the SMS garment, the microporous coverall is Category III and Type 5/6.

Why choose microporous?

Microporous material becomes particularly interesting when the application involves a greater possibility of liquid, spray, dust or contamination reaching the wearer.

Typical applications can include pharmaceutical and laboratory work, painting, maintenance, industrial processing and other operations where additional barrier performance is required.

“The trade-off is cost.”

Microporous garments typically sit above PP and SMS in the disposable-coverall price hierarchy.

That doesn’t make microporous “better” for every cleanroom.

It simply makes it different.

If the additional barrier is unnecessary for the task, purchasing it may provide little practical benefit. TIDDOX supplies Microporous coveralls in white with orange stripes and in all sizes from Medium to 3XL.

SMS vs Microporous: Which Is Better?

This is probably the most useful comparison for many buyers.

Both garments provide Type 5 and Type 6 protection, but they achieve their performance through different material constructions.

SMS = Breathability + protection + comfort

SMS tends to be attractive when workers need a protective garment for extended periods and breathability remains important.

Microporous = Enhanced surface barrier + water repellency + protection

Microporous laminate is attractive when the environment involves liquids, spray or contamination where a laminated outer barrier is desirable.

Industry guidance commonly identifies the trade-off between barrier performance and wearer comfort when comparing disposable cleanroom materials. ISPE also recommends evaluating fabric performance, construction quality and particle-emission performance rather than selecting garments from material name alone.

That last point is important.

Not every SMS garment performs identically, and neither does every microporous garment.

Fabric weight, construction, seams, closures, hood design and manufacturing quality all matter.

What Do Category III, Type 5 & Type 6 Protection Actually Mean?

These classifications are often misunderstood, particularly when protective coveralls are being selected for cleanroom use.

Category III, Type 5 and Type 6 relate to PPE classification and protective performance; they are not cleanroom classifications.

What does Category III mean?

Category III applies to PPE designed to protect against risks that may cause very serious consequences. For disposable coveralls, the Category III designation indicates that the garment is protective clothing intended for higher-risk applications and is subject to the applicable PPE conformity assessment requirements.

Category III does not indicate a cleanroom class or level of cleanroom cleanliness.

What does Type 5 mean?

Type 5 = protection against airborne solid particles.

ISO 13982-1 specifies requirements for full-body chemical protective clothing providing protection against penetration by airborne solid particulates.

For TIDDOX SMS and microporous coveralls, the Type 5 classification is relevant where protection against hazardous dry particles is required.

What does Type 6 mean?

Type 6 = limited protection against liquid chemical spray.

Type 6 protective clothing is intended for applications where there may be exposure to light spray, liquid aerosols or low-volume splashes and where a complete liquid-permeation barrier is not required.

It is important to remember that Type 6 does not mean the garment provides protection against every chemical or every type of liquid exposure. The specific chemical, concentration, exposure and garment performance should always be considered.

Type 5/6 is not the same as ISO Class 5/6

This distinction is particularly important when purchasing garments for cleanrooms.

A Type 5 coverall is not automatically suitable for an ISO Class 5 cleanroom, and a Type 6 coverall does not correspond to an ISO Class 6 cleanroom.

The numbering is coincidental.

Type 5 and Type 6 describe the protective performance of the garment, whereas ISO cleanroom classes describe the airborne particle cleanliness of the cleanroom environment.

Cleanroom garment suitability should therefore be assessed separately according to the cleanroom classification, process, contamination risks, sterility requirements and facility gowning procedures.

What Coveralls Do I Need for an ISO Class 5, 6, 7 or 8 Cleanroom?

This is where garment selection is frequently oversimplified.

ISO cleanroom classification primarily concerns the concentration of airborne particles within the cleanroom. ISO 14644-5:2025 then establishes operational requirements covering areas such as personnel, training, entry and exit procedures, cleaning and a gowning programme.

However, it does not create a simple universal rule linking a particular cleanroom class to a particular coverall material.

COMMON MISCONCEPTION

❌ ISO Class 8 = PP
❌ ISO Class 7 = SMS
❌ ISO Class 6 = Microporous
❌ ISO Class 5 = Sterile suit

These are not universal cleanroom garment rules.

For example, two ISO Class 7 facilities may carry out completely different processes and consequently require very different gowning systems. One might assemble non-sterile industrial components, another might manufacture medical devices, while another might handle powders or hazardous chemicals.

The cleanroom classification is therefore one input into garment selection, not the entire decision. The process, contamination risks, product requirements, personnel protection, sterility requirements and the facility’s gowning procedures should also be considered.

A Better Way to Select Cleanroom Coveralls

When choosing disposable coveralls, ask the following questions.

1. What cleanroom classification applies?

Determine the ISO classification and any industry-specific requirements applying to the room.

2. What are you protecting?

Is the priority:

• the product/process from the operator,
• the operator from the process,
• or both?

The answer can substantially change the garment required.

3. What does the operator actually do?

Consider the task rather than simply the room.

Someone briefly inspecting equipment may present a different risk from an operator leaning over exposed product for eight hours.

4. Are liquids involved?

Consider water, cleaning solutions, chemicals, sprays and process liquids.

Where liquid exposure exists, the additional barrier provided by SMS or microporous garments may become important.

5. Are hazardous dry particles present?

If hazardous airborne solid particulates are part of the risk assessment, a certified Type 5 garment may be required.

6. Does the garment need to be sterile?

This is a completely different question from whether a garment is clean, disposable or described as lint-free.

Non-sterile and sterile are not interchangeable terms.

7. How much does the garment shed?

In contamination-sensitive applications, consider documented particle-shedding and particle-retention performance.

ISPE specifically identifies particle-emission testing, fabric performance and construction quality as relevant garment-selection criteria.

8. How long will it be worn?

Comfort becomes increasingly important during long shifts.

9. What other PPE is required?

Coveralls form only part of the gowning system.

Gloves, masks, goggles, hoods, overshoes and boots may also be required.

10. What is the actual cost per use?

The cheapest garment is not automatically the lowest-cost solution.

Neither is the most expensive garment automatically the safest or most appropriate.

Cleanroom Class vs Garment Selection

The following table is intentionally a guide to the decision process rather than a garment prescription.

Environment	Typical considerations	Garment selection approach
ISO Class 8	General contamination control, process requirements, visitor access	PP, SMS or other qualified garment depending on process
ISO Class 7	Greater contamination-control requirements	Consider garment particle performance, process and gowning protocol
ISO Class 6	More stringent contamination control	Assess low-shedding performance, process requirements and the need for documented garment qualification
ISO Class 5	Highly controlled environment	Garment system should be specifically selected/qualified for the application
GMP Grade D	General protective clothing and contamination controls	Follow applicable GMP/site gowning requirements
GMP Grade C	Low-shedding clothing with appropriate hair/facial-hair coverage	Site-specific GMP gowning procedure required
GMP Grade A/B	Sterile operations	Dedicated qualified sterile cleanroom garment system

Australian cleanroom garment guidance similarly recommends considering cleanroom grade, whether the manufacturing process is wet, static risk, whether the product is hazardous, physical abrasion and whether garments must be sterile.

A Special Warning for Pharmaceutical Cleanrooms

Pharmaceutical cleanrooms operating under GMP require additional consideration.

For sterile medicinal-product manufacture, EU GMP Annex 1 provides specific garment expectations for Grades A/B, C and D.

For Grade B, including access or interventions into Grade A, the requirements include sterilised garments, sterile headgear, facemask, eye coverings, gloves and sterilised footwear. Garments must also minimise fibre/particle shedding and retain particles shed by the body. Grade C and D have their own gowning requirements.

Consequently:

“A disposable garment should not be assumed to be suitable for Grade A/B simply because it is called “lint-free”, “cleanroom”, SMS or microporous.”

Sterility, garment qualification, particle performance, gowning procedure and the facility’s contamination-control strategy all matter.

This is particularly important when establishing a pharmaceutical, biotechnology or aseptic manufacturing facility.

Cost: When Is It Worth Paying More?

Cost matters, especially when disposable garments are used every day.

Using the current TIDDOX pack pricing supplied on its website at time of writing, the price difference is illustrated below:

TIDDOX Coverall	Pack of 5	Approx. Garment Cost*
Polypropylene	$18.95	$3.79
SMS	$22.50	$4.50
Microporous	$44.95	$8.99

*Based on the supplied list prices; check current product pricing before ordering.

At first glance, PP looks like the obvious choice.

But imagine a facility using 100 coveralls per week.

Selecting a garment that costs several dollars more creates a significant annual difference. Conversely, saving a few dollars on a garment that does not meet the facility’s actual contamination-control or PPE requirements is false economy.

The objective should therefore be:

“Use the garment appropriate to the risk, not simply the cheapest or most expensive garment available.”

PP vs SMS vs Microporous: The TIDDOX Selection Guide

As a practical starting point, use the TIDDOX selection guide:-

• For a basic hygienic barrier with minimal liquid exposure, start by assessing PP.
• For a stronger balance of particle protection, limited splash protection and breathability, assess SMS.
• For an application requiring a laminated, water-repellent barrier against hazardous dust and limited liquid spray, assess microporous.

For critical cleanrooms, sterile manufacturing, hazardous chemicals or specialised processes, don’t choose solely between these three materials. Determine the regulatory, contamination-control and PPE requirements first and then select a garment that has been specifically qualified for them.

Once you’ve selected your coverall, don’t forget that it forms part of a complete gowning system.

Disposable vs Reusable Cleanroom Coveralls

There is another decision worth considering.

Not every cleanroom should necessarily use disposable garments.

Reusable cleanroom garments are commonly made from specialist continuous-filament fabrics and processed through controlled cleanroom laundering systems. Disposable garments can make sense where contamination, hazardous materials, limited garment volumes, logistics or other operational considerations make laundering less practical.

ISPE notes that choosing reusable versus disposable garments can depend on the manufacturing process, access to suitable cleanroom laundry services and the number of garments required.

This is particularly relevant when a facility grows.

A start-up cleanroom using relatively small quantities of disposable clothing may eventually reach a point where a validated reusable garment program deserves consideration.

The Coverall Is Only One Part of Cleanroom Gowning

Choosing the correct coverall is important, but a coverall is only one component of a cleanroom or controlled-environment gowning system.

Depending on the cleanroom classification, process and contamination-control requirements, personnel may also require appropriate head and hair coverings, beard covers, face coverings, gloves and footwear protection. The purpose is to reduce potential contamination pathways from the wearer while also providing any personal protection required by the task.

For example, a gowning system may include:

Coverall + hood or hair covering + beard cover (where required) + face covering + gloves + shoe covers or cleanroom footwear.

TIDDOX supplies a range of complementary disposable gowning products, including disposable shoe covers, polypropylene balaclavas, polypropylene hoods, hoods with integrated masks, disposable beard covers, disposable hair caps and bouffant caps. These provide different levels of coverage for footwear, hair, facial hair, head and neck containment.

The correct combination should be determined by the facility’s gowning procedure and contamination-control requirements rather than simply adding every available disposable item.

The gowning procedure itself is equally important. Appropriate garments can still become a source of contamination if they touch the floor during gowning, are handled incorrectly, are worn between incompatible areas or are reused contrary to the site’s procedures.

Choosing the Right Coverall

The difference between PP, SMS and microporous coveralls ultimately comes down to what you need the garment to do.

Polypropylene provides lightweight, breathable and economical basic contamination and dust protection.

SMS adds a three-layer construction and, in TIDDOX’s range, certified Type 5/6 protection while maintaining good breathability.

Microporous adds a polyethylene laminate to the polypropylene substrate, providing a water-repellent barrier and Type 5/6 protection for applications requiring a greater level of protection.

But material should never be selected in isolation.

For cleanrooms, the appropriate garment needs to work with the cleanroom classification, process, contamination-control strategy, gowning procedure and applicable regulatory requirements.

When establishing a new cleanroom, that distinction is far more important than simply asking:

“Which coverall is the best?”

The better question is:

“What are we protecting, what are we protecting it from, and what garment performance does our process actually require?”

That question usually leads to the right choice.

Need Help Selecting Cleanroom Garments or Consumables?

TIDDOX is an Australian supplier of cleanroom garments and contamination-control consumables for pharmaceutical, biotechnology, medical, laboratory, electronics, manufacturing and other controlled environments.

In addition to disposable coveralls, TIDDOX supplies a comprehensive range of cleanroom supplies, including sterile and non-sterile cleanroom wipes, polyester and foam cleaning swabs, cleanroom paper, sticky mats, nitrile gloves and disposable gowning products. The range includes products designed for low-lint and contamination-sensitive applications, with options available for different cleanroom environments and process requirements.

Selecting cleanroom consumables should consider more than ISO classification alone. Material construction, particle generation, chemical compatibility, sterility, process risks and site-specific contamination-control procedures can all influence product selection.

If you are establishing a new cleanroom, reviewing your gowning requirements or consolidating your cleanroom consumables, contact TIDDOX for assistance with product selection and supply.

Frequently Asked Questions