Body coverall and medical gowns are worn by front-line medical staff who have constant contact with patients.

According to WHO, the coveralls (or gowns) should be of AAMI-PB70 standards. [1]

American National Standards Institute (ANSI) and the Association of the Advancement of Medical Instrumentation (AAMI) describe AAMI-PB 70 as protective apparel and drapes intended for use in health care facilities that are resistant to the pathogen, Infectious diseases (non-airborne), and large amounts of fluid exposure over long periods.

 

Understanding Global PPE Standards and Their Impact on Workplace Safety

As an experienced compliance consultant and expert in the field, we deeply understand that high-quality protective equipment is not merely a piece of clothing—it is the ultimate lifeline for frontline workers. When evaluating procurement options, it is critical for EHS personnel, hospital material directors, and procurement managers to strictly adhere to global ppe standards. Standards such as AAMI-PB70 are not just technical certificates; they are directly tied to workplace safety and risk management. Procuring reliable gear ensures compliance, minimizes cross-infection risks, and protects organizations from unforeseen occupational liabilities.

Coverall Raw Material Requirements for Broad-Spectrum Protection

Fabric and seam integrity are the cornerstones of high-quality protective coveralls. Their performance is strongly associated with the overall protection level against a wide range of modern occupational hazards—from emerging infectious diseases in healthcare to hazardous chemical exposure in industrial settings. To meet stringent global regulations, procurement teams should evaluate materials based on the critical tests within the EN 14126 framework:

• ISO 16604: Resistance to penetration by contaminated liquids under pressure. (Crucial for trauma units and heavy-duty ppe for manufacturing where high-pressure fluid exposure is a significant risk).
• EN 14126 Annex A: Resistance to penetration by infective agents due to mechanical contact. (Essential for preventing cross-contamination from high-touch surfaces like bed rails or factory machinery).
• ISO 22611: Resistance to penetration by contaminated liquid aerosols. (Vital for environments with airborne pathogens or aerosolized hazardous chemicals).
• ISO 22612: Resistance to penetration by contaminated solid particles. (Important for industrial cleanrooms, pharmaceutical manufacturing, and dusty environments).

 

The ISO 16604 Test: The Gold Standard for Pathogen and Fluid Resistance

The ISO 16604 test is widely considered the ultimate benchmark for evaluating an impervious gown or coverall. It uses synthetic blood infected with a Phi-X174 bacteriophage to assess penetration. Because this bacteriophage is incredibly small (0.027 microns)—significantly smaller than most common viruses (such as Influenza, Hepatitis, and Coronaviruses)—passing the ISO 16604 test at a high class guarantees that the fabric provides a robust, future-proof barrier against aggressive microscopic threats.

Buyer’s Guide: Matching Protection Level to Workplace Hazards

To assist EHS managers and hospital procurement directors in choosing the right disposable coverall, we have summarized the protection standards into a quick-reference decision matrix:

Workplace Hazard Level	Primary Risk Exposure	Required Fabric Standard	Ideal Application Scenario
Basic / Low Risk	Dry dust, minimal fluid splash	ISO 22612	Routine cleaning, basic factory visitors, general patient care.
Moderate Risk	Aerosolized liquids, mechanical contact	EN 14126 Annex A / ISO 22611	Outpatient clinics, janitorial services, standard ppe for manufacturing.
High / Extreme Risk	Bloodborne pathogens, high-pressure fluids	ISO 16604 (AAMI Level 4 equivalent)	Surgical theaters, ICU, hazardous material handling (Hazmat), viral outbreak response.

Selecting the Best Materials for Protective Coveralls: SMS vs. Microporous Film

The foundation of any reliable disposable coverall lies in its fabric. To effectively block viral transmission and safeguard against hazardous fluids, the material must achieve the rigorous status of an impervious gown. When manufacturing protective coveralls, we evaluate fabrics against stringent pressure tests. It is not just about fabric weight; it is about ensuring that the microscopic barriers remain uncompromised under pressure, providing true impervious protection for both clinical and demanding industrial environments.

Common Types of fabric types are

1. SMS (Spunbond-Meltblown-Spunbond tri laminate)
2. PPSB + PE coating
3. PPSB + Microsporous PE Film

As a first step, you should choose a fabric that conforms to all four tests of EN 14126. There are a few fabric manufacturers that claimed to manufacture fabrics specifically for body coveralls that conforms to acceptable standards. ViroSēlTM Breathable viral barrier (BVB) fabric is a lightweight tri-laminate fabric from Ahlstrom that comes with polypropylene spunbond (SB) or polypropylene spunmelt (SMS). Pure/Armor TM is another tri-laminate fabric from Ahlstrom Munksjo that is made with bi-component spunbound (PE/PET) outerlayers and a monolithic breathable film. The other players in this field are Surya Textech and Shiva Texyarns limited fabric that can be used in the construction of surgical gowns. These fabrics are nonwoven based and typically 50 to 62 gsm and come in 160 cm width and are suitable for single use.

There are different ways of making patterns for body coverall, the objective is to have least number of seams thereby minimising risk, as well as cost of manufacturing. Pictures shown here depict one of the options without flap at centre front. However, most of the options are made with centre front zip flap as additional protection.

While cutting of fabric can be done using straight knife or CNC cutter, and does not require any special machine, it is utmost important to remember not to use any pins or stapler while handling of the fabric. We need to remember that fabric has inbuilt membrane layer, which gives the vital protection against the penetration of virus and contaminated liquids and should not be ruptured or punctured at any cost.

Plant and machinery

There is a lot of confusion in the industry about fabric joining methods to make AAMI 4 level compliant coverall, i.e. the seam also should be resistant to penetration by contaminated liquids. Theoretically, if the joining happens by high frequency or ultrasonic welding, then the joint (seam) is naturally sealed. But this process requires special dedicated infrastructure and is not commonly available. The commonly used method in the sewn product industry is that the traditionally stitched seam is sealed by overlaying tape. This process is called “seam sealing” and requires special machinery called “hot air seam sealing machine”. These machines are also used for making high end outerwear or workwear and therefore selected garment manufacturers may already have it. While stitching can be done by either single needle lockstitch or 4/5 thread overlock, seam sealing can be done by hot air seam sealing machine. In this document, we will elaborate making of coverall by classical method.

The hot air seam sealing machine uses adhesive tape as consumable. The machine produces hot air with precisely controlled temperature to directly heat up the adhesive of seam tape. The heated tape and the fabric are feeding into two oppositely rotating rollers under pressure called nip rollers. The seam sealing tapes are multi-layered adhesive films and are applied to the sewn seams to prevent water from leaking through those seams. The tape roll is mounted on top of the machine and a digital tape tensioning device controls the consistent feeding of tape. The nozzle supplying hot air at maximum temperature up to 800 degrees centigrade can be positioned accurately using three-axis positioning system. However, the nozzle temperature should be set as per fabric and tape material and generally found to be around 260-350 degrees centigrade.

There are numerous brands of hot air seam sealing machines globally, some of the popular brands available in Asia are Pfaff, H&H, Macpi, Ardmel, etc. These hot air seam sealing machines typically have an outward slanted post bed for easy maneuvering of seamlines by the operator. Apart from the hot air seam sealing machine the organization also requires a hydrostatic tester, which should be used to test the sealed seams randomly and maintain a report (similar to a quality inspection report). It is important to note that both hot air seam sealing, as well as a hydrostatic tester, requires compressed air connection to operate.

Please note that it is not  possible to make coverall from one continuous piece of material, there will be joints; therefore, along with fabric being tested, the seam also should be separately tested for resistance to penetration by contaminated liquids under pressure.

For a medical PPE, a 2 layer seam sealing tape can be appropriate, which is designed to seal the seams on light to medium weight, PP, and PE fabrics. According to fabric type, we can use tape made out of fabric + Ethylene Vinyl Acetate Copolymer (EVA) or Polyethylene (PE) + EVA. Application of tape can be either inside surface or outside surface of seam depending on fabric characteristics. A typical two-layer seam sealing tape should have a total thickness of 0.15 mm, a weight of approximately 0.95 gm/square cm, and an inner layer melt index (ASTM D1238) of 200 gm/10 min.

 

The Critical Role of Seam Sealing in Protective Equipment Manufacturing

Even the highest-grade fabric is vulnerable if the seams fail. In the realm of ppe for manufacturing and advanced healthcare defense, seam sealing is a critical process that separates standard garments from true life-saving shields. Applying the correct coverall tape requires absolute precision. Calibrating hot air seam sealing machines exactly between 260-350 degrees Celsius to bond a 0.15mm multi-layered adhesive film is a testament to top-tier manufacturing capabilities. This meticulous attention to detail ensures that the seam is completely sealed against contaminated liquids, guaranteeing the highest level of structural integrity.

Right fabric, right tape, right machinery and correct processing parameters, all are equally important for making a AAMI level 4 body Coverall. We should not compromise on any of these, as it is going to jeopardise the safety of our health workers.

The operation flow chart above shows the sewing and seam sealing steps. The representative SAM value of a representative style of coverall will be approx. 11.81 standard minutes with sewing amounting to 6.41 minutes and seam sealing 5.40 minutes. The total consumption of seam sealing tape is around nine meters.

 

The manufacturing organizations should organize machinery and equipment depending on the target production they would like to achieve.

The views expressed in this article entirely belong to the author/s and need not represent organizational viewpoint. While this article is an attempt to collate information and guide manufacturers attempting to make body coverall of AAMI PB70 Level 4 standard, it should not be taken as a prescriptive document for same. The reader of the report is advised to conduct an independent evaluation and form conclusions with respect to the information provided.

 

WHO is urging governments to increase the production of PPE by 40% to meet the rising demand, but the reality is that the industry is lacking manufacturing know-how, raw material, and machinery infrastructure.

 

Conclusion: Elevating Safety Through Manufacturing Excellence

In an era of evolving biological and industrial hazards, the value of high-quality protective equipment extends far beyond basic compliance—it is a cornerstone of organizational resilience and worker trust. As we have explored, the transition from raw fabric to a high-performance disposable coverall involves a sophisticated synergy of material science, precise engineering, and rigorous testing.

For B2B procurement managers and EHS directors, the decision-making process should focus on three strategic pillars:

• Verified Standards: Always prioritize ppe standards like AAMI-PB70 and ISO 16604. These are the only objective measures that guarantee a barrier is truly an impervious gown capable of blocking microscopic pathogens.

• Total Integrity: A coverall is only as strong as its weakest seam. Ensure your ppe manufacturers utilize advanced coverall tape and hot-air sealing technology to maintain 100% protection across every joint.

• Operational Reliability: Technical expertise must be backed by a stable supply chain. Partnering with a proven supplier of ppe ensures that your facility remains protected, even during global surges in demand.