Three Tests for Disinfectants for Cleanroom Validation

You need to control fungal contamination in your cleanroom, and you need to test the disinfectants for validation. Here are three to consider.

Controlling fungal contamination in your cleanroom requires cleaning and disinfection procedures. Your disinfectant application is a critical step that needs validation. Since many agents that are effective against vegetative fungi aren’t effective against fungal spores, it’s necessary to conduct a series of tests to demonstrate your agent’s efficacy. Here are three testing methods to consider.

  1. Suspension tests. These are especially valuable for finding how much time is needed to reduce organisms to an acceptable level. However, they don’t reveal any variations in efficacy that happen when disinfectants are applied to different surface types. The test procedure is to suspend the microorganism in an appropriate dilution of the test disinfectant. At designated time intervals, samples are removed for viable counts. The test is conducted at room temperature.
  1. Carrier tests. These are specific to hard-surface disinfection agents, and they’re performed under the conditions that match your facility’s specific application. Typical cleanroom surfaces are stainless steel, but can also include terrazzo flooring, vinyl, epoxy, and glass.
  1. Statistical comparisons. While both of the above tests are quite reliable in evaluation a disinfectant’s efficacy under lab conditions, they guarantee results in your actual cleanroom environment. To address this, you need to perform statistical comparisons of the frequency of isolation and the numbers of organisms isolated before and after a new disinfection program is implemented. Trend the environmental data over the course of a year to find seasonal variations that may cause facility or maintenance issues.

When it’s time for cleanroom validation, trust the experts at Gerbig Engineering Company. We’ve provided cleanroom validation, certification, and construction for thirty years. Contact us at 888-628-0056 or

Methods for Testing Container Closure Integrity : Cleanroom Products – Part 2

Container closure integrity is a must for drug manufacturers. Here are the last 2 of 5 common methods to test this integrity

As mentioned in part 1, container closure integrity (CCI) is paramount for the entirety of the shelf life of any drug product. There are numerous ways to test CCI. In part 1, we discussed dye ingress testing, vacuum decay, and headspace analysis. Here we will wrap up with the final two most popular methods: helium leak and high voltage leak detection.

Helium Leak. While the previous methods discussed are not extremely sensitive, this test is the most accurate, giving the most reproducible results. Helium is one of the safest gases to use for such a test, and the vials or syringes can be filled manually or arrive with helium in them.  A mass spectrometer that only detects helium ions picks up the rate of helium leaking from a container. Vials can contain liquids or lyophilized product; syringes must be empty. The helium does destroy the product, but this test can pinpoint a leak, and it can be conducted in cold temperatures.

High Voltage Leak Detection (HVLD). This method is very practical for stability studies, biologics, and containment systems holding liquid with no headspace. A high-voltage current is applied to the liquid in the container, and a voltage differential identifies an integrity breech. It’s a non-destructive method that produces rapid results and requires little operator skill.

The right CCI test will depend on your specific application and needs. For cleanroom validation or certification, contact Gerbig Engineering Company. We have thirty years of experience in the cleanroom industry: 888-628-0056;

Methods for Testing Container Closure Integrity: Cleanroom Products – Part 1

There are a number of alternative methods to test container closer integrity for drug products. Start comparing these methods here.

Container closure integrity (CCI) of a drug product must be preserved throughout its entire shelf life. There are a number of ways to conduct a CCI test, each with its pros and cons.  Here is a rundown of the most familiar methods.

  1. Dye Ingress Testing. This is probably one of the most popular tests used. Some of the benefits are that being a visual test, the drug can be in its final configuration (syringe or vial.) It also only requires an observation of the dye to see whether the container has been compromised. This is a basic and efficient means of testing; however, it should only be used as a gross analysis of cracks and misalignment. There are much more sensitive tests available for a full analysis.
  1. Vacuum Decay. This test uses a rise in chamber pressure to expose leaks. While the previous test destroys the product, this test is non-destructive and can be used on solid products. Additionally, it can be performed in vials of any color, whereas the dye ingress test requires a clear container. On the other hand, the method is labor-intensive, requires specific instrumentation, and only offers a pass/fail result as opposed to isolating the source of the problem.
  1. Headspace Analysis. This is a highly-sensitive, non-destructive test. It uses frequency modulation spectroscopy to determine the pressure inside the vial. It’s a rapid test that can be conducted on varying container sized. It’s more accurate than the previous two tests. However, the containers do need to be transparent, the test can’t be done on syringes, and you cannot pinpoint the source of a leak

In part two, we will evaluate a couple of methods that are more sophisticated in their sensitivity. If you need assistance with compliance for your cleanroom, Gerbig Engineering Company can help. We offer cleanroom validation and certification. Our experts also build hardwall and softwall Airecell cleanrooms. For more information, call 888-628-0056 or email

3 Ways to Sterilize Cleanroom Apparel

Sterility is a major part of every cleanroom, be it the equipment, the tools, the product, or the structure. In aseptic cleanrooms, the garments must also be sterile. Most companies require all components in an aseptic cleanroom – including garments – to be terminally sterilized to 10-6SAL.  There are three methods of achieving this: autoclaving, ethylene oxide (EtO), and ionizing radiation (gamma or electron beam.)


1. Steam Autoclaving

As the name suggests, sterility is attained in this method using steam and pressure. The garment is wrapped in a vapor-permeable bag and placed under a high temperature. The steam carries heat to every surface of the garment. So long as the object in the autoclave isn’t heat, pressure, or moisture-sensitive, this method is reasonably efficient and convenient. However, it typically shrinks garments up to two sizes. Aside from the obvious problem here, it degrades the material more quickly. Wrinkles also set in, making the garments unsightly.

2. EtO

This is a gas that kills microorganisms, and this sterilization method was used widely for years. It works by using a vacuum chamber to evacuate the air from wrapped objects and replace it with EtO. After sterilization, the gas is evacuated and air replaced. The greatest downside to this is EtO’s dangerous effects on humans. Items sterilized with this method had to be quarantined up to two weeks while the EtO dropped to a safe level. For this reason, extra garments need to be on hand to use while other garments are outgassing.

While both methods have their upsides, neither is considered the most advantageous given the culture and needs of today’s cleanroom. This brings us to the third, most preferred method of garment sterilization…

3. Ionizing Radiation

This includes two forms, though gamma irradiation is the only one being successfully used in cleanrooms. The electromagnetic radiation of gamma rays has great penetrating power, like an x-ray, but with a shorter wavelength. Sterilization with these rays occurs after the garments have been laundered and packaged. Before gamma irradiation, however, you must follow validation protocol to determine the dosage required to obtain the desired sterility. Since this kind of radiation is destructive, it’s important to use the lowest possible dose, which may be lower than the 25 kilograys we know are sufficient. This will help extend the garment’s life significantly.

Liability also plays a role in using the lowest possible dosage. Garment service providers undergo extremely rigorous customer audits because if the process drifts out of control or the dose has not been set properly, it can put a person’s life at risk. Therefore, the calculated sterilization dose for gamma irradiation will be included in the customer specifications for the product.


When it comes to cleanrooms, every aspect of sterilization and sanitation affects compliance and validation. Gerbig Cleanrooms knows how vital every detail is the overall process. If you need cleanroom validation or certification, or if you need cleanroom construction, reach out to us. We know what you need to achieve and maintain success: 888-628-0056;

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