Guide to Applying a Vacuum or a Vacuum and Gas Flush to a Pouch

Pouch Sealing

Your Step-by-Step Guide to Applying a Vacuum or a Vacuum and Gas Flush to a Pouch

Many manufacturers have questions about applying a vacuum only or a vacuum and gas flush to a pouch. In this blog post, we’ll explain:

  • The most common applications for applying a vacuum or a vacuum and gas flush to a pouch
  • How pouch materials impact which application is optimal and the best methods for working with common pouch material combinations
  • The process for using a nozzle to apply a vacuum or a vacuum and gas flush to a pouch
  • The process for using a chamber to apply a vacuum or a vacuum and gas flush to a pouch

Understanding these fundamental concepts and best practices will help you determine which application is optimal for your use case.

How to apply a vacuum or a vacuum and gas flush to a pouch

A vacuum or a vacuum and gas flush can be applied to a pouch in one of two ways—either by using a nozzle sealer or by placing the pouch in a chamber sealer. The optimal method is dependent on the type of pouch materials being used, whether vacuum only or vacuum and gas flush is required, and other factors.

A nozzle sealer is most commonly used for:

  • Volume reduction. The goal of volume reduction is to remove enough air from the pouch to prevent it from popping during high altitude shipments or so that it can fit into a box or secondary container. Because volume reduction applications are considered a “gross” vacuum process, either time-based or level-based programs can be used; however, a time-based mode is the most popular. Product sensitivity can play a role in how much volume should be drawn out of the pouch.
  • Product immobilization. In certain cases, it is critical to remove air from the pouch so that the product being packaged is immobilized. Product immobilization applications are considered a “gross” vacuum process so either time-based or level-based programs can be used; however, since the final internal volume in the pouch is a function for immobilizing the product, operating in level mode provides greater reassurance that the appropriate internal pressure has been achieved to restrain the product in the pouch. Product sensitivity can play a role in how much volume should be drawn out of the pouch.
  • Reducing O2 or relative humidity (RH). Multiple vacuum/flush cycles can be programmed to progressively reduce the O2 or RH in the pouch. While modifying the atmosphere in the pouch can be programmed as a time-based function, vacuum and flush levels are critical in adequately and repeatedly reducing oxygen or relative humidity. That is why most applications requiring reduced O2 or RH operate in level mode. The flexibility of the pouch materials and their ability to conform around the geometry of the nozzle can affect the achievable goal, even with multiple cycles.

A chamber sealer is most commonly used for:

  • Achieving ultra-low residual O2 Vacuum and gas flush applications requiring an extremely low residual oxygen level (below 1%) require a chamber sealer. A nozzle sealer cannot be used for these applications because of the “leak points” around the nozzle while it is processing the pouch. For ultra-low residual O2 level applications, the entire chamber atmosphere is modified and level setpoints as low as 1mbar can be programmed. A dwell time at each step can be programmed to maintain the level for the specified amount of time and allow the product to acclimate.
  • Sealed header pouches. Sealed header pouches that need to be vacuumed and/or flushed must use a chamber sealer because it is physically impossible to insert a nozzle into a hermetically sealed and terminally sterilized pouch. In these cases, the atmosphere inside the pouch is modified by vacuuming and/or flushing through the Tyvek window on the pouch. For this type of application, a program that has the flexibility to allow multiple steps in either direction (vac-vac-vac-flush-vac-flush-flush, for example) with programmable dwell times at each step will provide the control required to vacuum the pouch without bursting it or to flush the pouch without crushing the product or pinching off the header. The atmosphere inside the chamber can change significantly faster than the interior of the pouch because the header acts as a filter, hampering the flow of air and/or gas into and out of the pouch. A dwell time at each vacuum or flush step can provide the necessary time for the pouch to acclimate to the chamber atmosphere before the next process step begins.

Pouch materials impact whether a nozzle or chamber should be used for applying a vacuum or a vacuum and gas flush

The pouches used for vacuum (no gas flush) and vacuum and gas flush applications are typically made from laminated or mono-layer flexible materials including—but not limited to—Tyvek, coated foil, and film. The specific materials used impact whether a nozzle or chamber is optimal, and these are the most common pouch material combinations and the method that works best for applying a vacuum and/or gas flush to each one:

  • Foil/Foil: Nozzle or chamber
  • Film/Foil: Nozzle or chamber
  • Film/Film: Nozzle or chamber
  • Foil/Tyvek Header: Chamber
  • Film/Tyvek Header: Chamber
  • Film/Tyvek: Nozzle

Other factors to consider before deciding to use a nozzle to apply a vacuum or a vacuum and gas flush to a pouch

A number of different factors should be considered before deciding to use a nozzle sealer to apply a vacuum or a vacuum and gas flush to a pouch. Here is a sampling of the top concerns:

  • Headspace. Since using a nozzle involves employing a clamp between the guarding and the sealing die, the pouch must have sufficient “free” material (i.e., headspace) for loading into the sealer.
  • Nozzle length. In order to be able to load the pouch over the nozzle, the nozzle must extend out of the sealer at least ½” resulting in nozzle penetration into the pouch of typically at least 1½” for constant heat sealers.
  • Product sensitivities. If the nozzle must not come into contact with the product, the pouch length must be sized appropriately to allow the product to remain safely distant from the nozzle.

Other factors to consider before deciding to use a chamber to apply a vacuum or a vacuum and gas flush to a pouch

Before deciding to use a chamber to apply a vacuum or a vacuum and gas flush to a pouch, it is important to consider factors such as:

  • Immobilizing the pouch. It is critical to immobilize the pouch during the vacuum and flush process. The air inside the chamber can become turbulent, and if the pouch shifts out of alignment with the seal bar, the pouch will not be sealed correctly.
  • Cycle time. The cycle time when using a chamber sealer will always be longer than when using a nozzle sealer because of the volume of air that is being modified. A nozzle sealer is modifying only the interior of the pouch. By contrast, a chamber sealer is modifying the volume of the entire chamber and the pouch. Additionally, processing a header pouch for a low residual oxygen level application requires the most time and may require multiple vacuum/flush steps with dwell times at each step.
  • Window for visibility. Using a chamber sealer that has a window for viewing the pouch as it is being processed can have enormous benefits. A window allows visibility into the process and enables the operator to monitor how the pouch is behaving during the vacuum, flush, sealing and repressurizing process.

The process for using a nozzle sealer to apply a vacuum or a vacuum and gas flush to a pouch

Using a nozzle sealer to apply a vacuum or a vacuum and gas flush to a pouch is a relatively straightforward process involving eight distinct steps:

  1. Bring the nozzle into the load position
    The nozzle used to apply a vacuum or a vacuum and gas flush to a pouch is like a snorkel or “straw.” In the first step of this process, the operator presses a foot switch that brings the nozzle into the load position.
  2. Load the pouch over the nozzle and slide it into the seal area
    With the nozzle in the load position, the operator places the pouch over the nozzle and slides it into the seal area.
  3. Close off the pouch around the nozzle
    Next, the operator presses the foot switch a second time, bringing a soft-faced clamp down to close off the pouch around the nozzle.
  4. Initiate the vacuum process, followed by gas flush, if needed
    Once the pouch is closed off around the nozzle, the vacuum process can begin. If a gas flush process is programmed, the gas will flush the pouch upon completion of the first vacuum process. Additional vacuum and gas flush cycles can be programmed depending on the application requirements.
  5. Apply final cycle
    The cycle can be programmed to end after a flush step, leaving a “pillow effect” in the pouch, or it can be programmed to end after a vacuum step, drawing the pouch down around the product.
  6. Retract nozzle while clamp is still engaged
    Once the vacuum/flush cycle has fully completed, the nozzle retracts from the pouch while the clamp is still engaged.
  7. Actuate seal bar and seal the pouch
    After the nozzle is clear of the seal area, the seal bar actuates and seals the pouch.
  8. Releasing the pouch from the sealer
    In the last step of the process, the seal bar and the clamp open, releasing the pouch from the sealer.

The process for using a chamber sealer to apply a vacuum or a vacuum and gas flush to a pouch

Using a chamber sealer to apply a vacuum or a vacuum and gas flush to a pouch is a relatively straightforward process involving eight distinct steps:

  1. Load the pouch onto a platform in the chamber
    When a chamber sealer is used to apply a vacuum or a vacuum and gas flush to a pouch, the process begins when the operator loads the pouch onto a platform inside the chamber sealer.
  2. Close the lid and apply the vacuum
    Next, the operator closes the lid of the chamber sealer and initiates application of the vacuum. The entire volume inside the chamber is vacuumed until the programmed level is reached.
  3. Initiate the gas flush
    The gas flush process begins after the initial vacuum step(s) are completed and flushes the entire chamber to the programmed setpoint.
  4. Apply additional vacuum and gas flush cycles as needed
    Additional vacuum and gas flush steps can be programmed to achieve even lower residual oxygen levels.
  5. Shuttle the pouch into the seal area and apply the seal
    Once the vacuum/gas flush process is completed, the pouch is shuttled into the seal area and the seal bars close, sealing the pouch.
  6. Shuttle the pouch back to the load position
    After the seal dwell timer has elapsed, the pouch is shuttled back out into the load position.
  7. Repressurize the chamber and open the lid
    Next, the chamber repressurizes back to atmosphere and the lid opens.
  8. Remove the pouch from the chamber
    Finally, the operator removes the pouch from the chamber.

This blog post covered several of the primary issues you need to consider when determining how best to apply a vacuum or a vacuum and gas flush to pouch. For more information and to discuss the details of your particular application, please contact us.

Pouch Sealer Frequently Asked Questions

How does a CeraTek pouch sealer create a seal?

A CeraTek pouch sealer is designed to seal a package made from laminated or mono-layer flexible materials, and it creates a seal by applying heat and pressure to the pouch for a set amount of time. A pouch like this is created by bringing two webs of material together and sealing them on three sides, leaving the fourth side open. The product that needs to be packaged is inserted into this opening and then the pouch is inserted into the sealing machine. The CeraTek pouch sealer applies the temperature, pressure, and time required to activate a sealing adhesive which bonds the two layers of material together, creating a seal.

What are the main process variables associated with pouch sealing using a CeraTek sealer?

The main process variables associated with pouch sealing using a CeraTek sealer are time, temperature, and pressure. All three of these process variables are required to seal a pouch effectively.

How are time, pressure, and temperature controlled and monitored?

The three process variables—time, pressure, and temperature—are controlled through the CeraTek pouch sealer’s HMI. An operator can use the setup screens to program the time, temperature, and pressure based on the desired sealing process. These parameters can be changed for different materials and/or different pouch sizes.

What is the maximum temperature that a CeraTek pouch sealer can be set to?

The maximum temperature that a CeraTek pouch sealer can be set to is 400 degrees Fahrenheit for the top and bottom heat. Some pouch sealer models only use bottom heat, while others apply heat from both the top and bottom dies. If the pouch sealer has internal sensors, then the bottom heat maximum is 200 degrees Fahrenheit. Using temperatures that exceed these maximums can accelerate the wear of parts and increase maintenance costs.

What type of pouches can be sealed on CeraTek pouch sealers?

CeraTek pouch sealers can seal pouches made from a variety of different materials, including LDPE, nylon, Tyvek, foil, and many others. Our sealers are compatible with gusseted pouches, as well as with those that have headers or ones that are made from two different types of materials. If there are any question about compatibility, the experts at CeraTek are happy to test your materials and pouch designs on our equipment at our factory. The main requirement to keep in mind is that the pouch being used must be sealed on three sides. Then, the CeraTek sealer creates the fourth and final seal on the pouch.

When is Tyvek a better choice than foil?

Tyvek is a better choice than foil for products that must undergo additional sterilization processes after packaging. Tyvek is made of 100% high density polyethylene fibers, and it is manufactured to be “breathable,” yet impervious to microbes. That means Tyvek pouches can undergo sterilization processes using EtO gas, gamma radiation, electron beams, hydrogen peroxide, and steam. For example, in the case of a medical pouch made of Tyvek, the EtO gas passes through the Tyvek material, killing any contaminating microorganisms that are inside the package. Then, the pressure is relieved, as regular air is pumped back into the chamber, dispersing the EtO gas. As long as the medical pouch remains sealed, the contents are sterile. Foil is a non-breathable material, and pouches made from foil cannot be sterilized in this way.

Are CeraTek pouch sealers able to be validated?

Yes, CeraTek pouch sealers are validatable. Sealing parameters such as time, temperature, and pressure can be validated through the output ports on the side of the machine. The operator can use these ports to plug in a calibrated test instrument and retrieve the readouts of time, temperature, and pressure and confirm that the machine is functioning properly.

Are CeraTek pouch sealers ISO 11607 compliant?

Yes, CeraTek pouch sealers are ISO 11607 compliant. This compliance means that the accuracy and repeatability of the sealing process can be verified. For example, pouch sealing parameters such as time, temperature, and pressure can each be validated through their own specific output ports on the side of the machine. Each individual thermocouple has an output port for validation of the temperature readings. Likewise, there is a pressure output port and a timer output port.

Does CeraTek perform testing on pouch samples?

CeraTek has an in-house tensile tester which collects data on the strength of the seal, and we are happy to use this for testing customer samples at no cost. We can also help customers connect with others who can perform additional assessments, such as creep, burst, and dye penetration tests.

Does CeraTek offer different width sealing dies?

Yes, CeraTek offers sealing dies of different widths. The most common width is three-eighths inch, but we also offer standard one-eighth, one-fourth, one-half, and one inch sealing dies. We can also custom-make dies for requirements outside of our standard widths. Each sealing process has its own die requirements and validation parameters, so it is critical to make sure the die being used is the correct width.

When is it important to vacuum air out of a pouch prior to sealing it?

There are a few different reasons why it may be important to vacuum air out of a pouch before sealing. One of the most common reasons is to accommodate altitude changes for packaged products that are going to be shipped by air. If the pouch is sealed with too much air in it, and the altitude increases, the pouch could potentially burst. Another common reason to remove air from a pouch is to reduce its bulkiness so that it fits better into secondary packaging. CeraTek sealers can vacuum out air from a pouch through a nozzle that extends from the machine. The operator simply loads the pouch around the nozzle, initiates the cycle, and the nozzle vacuums out the air. Once the vacuum cycle is complete, the nozzle retracts and the sealing cycle begins.

How much compressed air needs to be supplied to a CeraTek pouch sealer?

For optimal pouch sealing, CeraTek recommends supplying 15 PSI above the desired pressure set point, up to a maximum of 125 PSI. For example, if the desired pressure set point is 50 PSI, we recommend supplying at least 65 PSI to the CeraTek pouch sealer. There are onboard air accumulator tanks within the CeraTek machine that reduce the risk of any pressure drops during the sealing cycle.

How is compressed air used on a CeraTek sealer?

The manufacturing facility supplies air to the CeraTek sealer’s onboard air accumulator tanks, and a pressure regulator on the machine ensures that the pressure supplied is accurate (i.e., it is not under- or overpowering). The air accumulator tanks initiate and perform the sealing cycle, driving the cylinders up and down to create the pressure applied to the seal. Incorporating these tanks into the sealer’s design helps mitigate the risk of fluctuation in the air supply. For instance, if the manufacturing facility has multiple machines on the same airline, the pressure flow across that line could vary. The CeraTek sealer’s air accumulator tanks significantly mitigate that risk.

How to Find the Right Vendor

How to select a vendor for heat sealers for medical pouches

With so many types of heat sealers and ancillary features available today, the process of choosing for the right vendor can seem a bit daunting. Here are the key capabilities you need to look for:

First, it’s important to find a heat sealer vendor that has the ability to customize their equipment to meet your specific medical pouch sealing needs. Look for a company that can handle the design engineering in house so that they can tailor a solution to fit your production flow.

Second, it’s critical for you to find a heat sealer vendor that understands the industry requirements of validation and package testing. They should also be involved at the industry level through ASTM, AAMI, and other organizations such as the IoPP medical packaging subcommittee. The vendor you choose needs to understand not only where the industry is today, but also where it’s going, so that you can rest assured that you are getting the most up to date technology to meet your needs.

Third, look for a heat sealer vendor that has a strong field service engineering team. They need to be able to handle both remote and on-site service support, regardless of where your packaging operations are located throughout the world. Look for a vendor that will partner with you as your equipment supplier, complete with a field service engineering network that offers rapid support for all your medical pouch heat sealing needs.

Validating Heat Sealers

Validation of heat sealers using IQ, OQ, and PQ

Heat sealers must be validated before they can be used in production. This validation is a three-phase process.

The first phase is the IQ, which stands for installation qualification. During the IQ, the medical device manufacturer verifies that the heat sealer was built to spec, has the needed utilities, and was installed properly.

The second phase is the OQ, or operational qualification. For the OQ, the medical device manufacturer must walk through all the control processes of the heat sealer and verify that it operationally functions every time as it should. The temperature control, pressure control, time control, recipe control, alarms and all other operational aspects must be verified.

The final phase is process qualification, or PQ. The PQ phase involves observing the heat sealer in combination with the medical pouch it’s going to seal, i.e., the actual heat sealing process. The IQ and the OQ are focused on the heat sealer itself. The PQ phase verifies that the heat sealer is delivering a repeatable process and that the medical pouch is sealing in a repeatable fashion. It confirms that the output is what it’s supposed to be.

Any heat sealer used for medical pouch sealing should be ISO 11607-compliant. ISO 11607 is a guidance document that is used to define many different aspects of sterile packaging. For example, for a piece of sealing equipment to be ISO 11607-compliant, it must have the ability to verify and alarm temperature, pressure, and time.

FDA approval of medical pouches

Just as medical products require FDA approval, medical packaging must also be FDA approved. Medical device manufacturers need to have their manufacturing and packaging processes regularly audited to ensure that they are using the proper equipment and that it has been validated and maintained properly. The FDA offers approval guidelines for medical manufacturers to follow, but it does not provide instructions.

The types of heat sealer options

Today’s heat sealers can come equipped with options that help with compliance and risk mitigation. Traditionally, medical pouch sealing has been mostly a manual operation. However, more and more medical device manufacturers are implementing automation and other features to minimize operator error and mitigate other risks.

For example, some heat sealers are not enabled to cycle until the product which is put into the package is confirmed by weight. Others are equipped with barcode readers, vision cameras, or other sensors that detect certain markings on a pouch to verify that it has been positioned correctly for sealing. The cycle will only begin if the medical pouch is properly oriented and located. In some cases, heat sealers come equipped with alarms to alert the operator of errors and that a pouch needs to be put into a quarantine bin before the next cycle can start. They can also have outputs designed to control conveyors that move a pouch to the next process based on whether or not there was a good or a bad cycle.

Features for printing are also becoming more popular. For example, inkjet printers or embossing type systems can be added to continuous band or a rotary band sealers so that the medical pouches are printed on as they are sealed. Embossers can also be added to jaw type heat sealers to emboss a fixed imprint into the pouch.

In addition, other ancillary equipment can be added to heat sealers to help operators work more efficiently. For instance, some heat sealers have a pouch opening system that will pull a pouch out of a magazine and present it to the operator in an open format. After the operator places the product into the pouch, the pouch opener releases the package so that the operator can seal it. Since operators working in a clean room are typically gloved, this type of pouch opening system can significantly increase throughput. Efficiency can also be improved using static elimination options, which range from an overhead ionizing fan blowing down on the assembly area to reduce the static field to static elimination chambers for the medical pouches to pass through.

How to Optimize Heat Sealers

Medical pouch seals must be optimized to maintain sterilization

In the medical device manufacturing field, sterility is a fundamental concern. If a medical device needs to be sterile for use, it must be delivered to the end user in a sterile condition. Otherwise, the product is worthless. The pouch materials and the heat sealing conditions must be carefully determined so that the seal can both sustain and maintain sterilization.

Heat seals are created by delivering a specific temperature, under a specific pressure, for a specific amount of time. When designing a package and defining its optimal sealing parameters, manufacturers run a DOE (Design of Experiments) to determine what the low and high points are for temperature, pressure, and dwell time.

Then, they use this data to create a 3D matrix, where the center point marks the optimal temperature, pressure, and time. They also identify a process that has a range above and below the temperature set point, time set point, and pressure set point, where an acceptable, although not optimal, seal can still be achieved. This creates a window for alarming around the optimal seal parameters where the heat sealer can operate.

The more consistent a heat sealer is in delivery of temperature, pressure, and time, the more repeatable the seal strength will be—and the more repeatable the seal strength is, the tighter the manufacturer’s statistical control over that packaging process. Tight statistical control is important. If a manufacturer has to defend their packaging process during an FDA audit, tight statistical control will give the FDA more confidence in the development of the packaging process.

Manufacturers need to validate their heat sealers to verify that they deliver the same seals in a repeatable manner cycle, after cycle, after cycle. These processes must be minimally affected by operators, and they need to deliver the designated temperature, pressure, and dwell time repeatedly and reliably.

How to measure medical pouch heat seal integrity

There are a few different ways to verify seal integrity and quality. The most common way is to measure peel strength using a tensile tester. This process involves clamping a sample of the seal into the two plates/grippers of a tensile tester, and then measuring the force required to separate the seal. The goal is to achieve a repeatable seal strength, so this test will typically be conducted multiple times. Another way to test seal integrity is to use a burst test, where the inside of the pouch is increasingly pressurized until it bursts and/or the sterility is compromised. Medical device manufacturers use a Process Capability Index called CpK, to describe how accurate and repeatable the seal strength is over the course of a sample lot.

Recently, the FDA has begun to focus more than ever before on the statistical control that medical device manufacturers have on their processes. This means medical device companies are being driven to have a higher process capability, or Cpk. CpK indicates how accurately a medical device manufacturer can control medical pouch seal strength, and how repeatable their processes are. It is imperative for medical device manufacturers to identify the sources of variability in their heat seal processes, and then control those variables with precise and reliable systems for temperature, pressure, and timing.

Different heat sealers run differently. For example, in an impulse sealer, heat can build up in the bar that supports the wire, and that can change the amount of heat that packages is exposed to over the course of a production run. This type of variability can result in peel strengths that change throughout the production run. This is one of the reasons why it is more difficult to achieve a high CpK with an impulse sealer compared to a constant heat sealer. With a constant heat sealer, the seal heat is stable, leading to a high CpK.  

Keep in mind that temperature, pressure, and dwell time are all interrelated. Of these, the two most critical factors in seal strength are temperature and dwell time. Pressure is the least impactful, because once intimate contact is achieved, increasing seal force, or seal pressure, will not have a big impact until the pressure level increases to the point of squeezing the adhesive layer out of the seal. So seal force is the least impactful, once you’ve achieved intimate contact.

Throughput objectives can be a factor, as well. If a medical device manufacturer wants to maximize throughput, they may increase temperature and decrease dwell time, because they want to get more medical pouches sealed faster. Another manufacturer may want more process stability, and so they may opt for a lower temperature with a longer seal time. The ultimate goal of either throughput or stability will drive the sealing process toward low temperature with high time, or low time with high temperature.

The Materials Used to Make Medical Pouches

Medical pouches can be made from various materials, including Tyvek ®, nylon or mylar-based materials, metalized films, different types of coated foils, LDPE or LLDPE and medical grade papers. Manufacturers choose which kind of material is best based on the specific barrier properties required and the type of sterilization method that will be used after the packaging process is complete.

Tyvek® and film is the most common material combination used for medical pouches. Tyvek® is made of 100% high density polyethylene fibers, and it is manufactured to be “breathable,” and yet impervious to microbes. Often, medical pouches are made from Tyvek® on one side and another material on the other side.

The characteristics of the product being packaged can impact what type of material should be used for the medical pouch. For instance, if a manufacturer is packaging bulky product that could potentially put a strain on the inside of the pouch, it may be optimal to use a pouch made from a linear low-density material that is elastic and puncture resistant. If it is human bone or tissue that needs to be packaged for transplant purposes, the medical pouch is likely to be made from Polytetrafluoroethylene (PTFE) or Teflon, materials that can withstand the cryogenic conditions required for transportation.

Medical device packaging occurs in clean rooms

Typically, medical device packaging happens in either a class 10,000 clean room (ISO class 7) or a class 100,000 clean room (ISO class 8). The numbers 10,000 and 100,000 refers to how many parts per million of particulate are allowed to be in the clean room atmosphere.

The ISO classifications for clean rooms should not be confused with the ISO designation for sterile packaging. ISO 11607 is a guidance document that is used to define many different aspects of sterile packaging. For example, for a piece of sealing equipment to be ISO 11607-compliant, it must have the ability to verify and alarm temperature, pressure, and time.

How products in medical pouches are sterilized

The products that are packaged in medical pouches are not sterilized beforehand. Instead, they are sterilized post-packaging, using either ethylene oxide (EtO) sterilization, electron beam (e-beam) sterilization, radiation sterilization or steam sterilization.

EtO sterilization

EtO sterilization is the procedure most commonly used to sterilize medical products packaged in pouches; however, it does require that at least one side of the pouch be made from a breathable material, such as Tyvek®. Generally speaking, here’s how EtO sterilization works:

After the product is sealed into a medical pouch, the pouches are packaged in boxes and cartons, palletized and sent to a sterilization facility (the entire pallet of products can be moved into a sterilization chamber all at once). Then, ethylene oxide (EtO) gas is pumped into the chamber under pressure.

In the case of a medical pouch made of Tyvek®, the EtO gas passes through the Tyvek® material, killing any contaminating microorganisms that are inside the package. Then, the pressure is relieved, as regular air is pumped back into the chamber, dispersing the EtO gas. As long as the package remains sealed and dry , the contents should remain sterile for the shelflife of the package.

Many medical products are packaged in linear, low density materials with a small Tyvek® window, or header, on one end of the pouch. These “header bags” can reduce costs, but because of the Tyvek® window, the products within them can still be sterilized using EtO sterilization.

Electron beam (e-beam) sterilization and radiation sterilization

Unlike the EtO sterilization process, electron beam (e-beam) sterilization and radiation sterilization do not require medical pouches made from breathable material. Typically, these types of sterilization processes are used for medical pouches consisting of non-breathable films or coated foils. As the names imply, e-beam sterilization uses electron beams to sterilize the medical product after packaging, and radiation sterilization uses radiation, usually in the form of high energy gamma rays.

Steam sterilization

Steam sterilization, as accomplished in an autoclave, exposes each item to direct steam contact at the required temperature and pressure for the specified time. There are four parameters of steam sterilization: steam, pressure, temperature, and time.  Typically, Tyvek/film pouches are used for this application but the pouch is specifically designed to withstand the sterilization process.  Typically, steam sterilizable pouches have a higher sealing temperature and a narrower processing window than pouches used for ETO sterilization.