Quick Tips for Fume Hood Exhaust Monitoring Part 2

Proper airflow is vital to personnel who are working with corrosive, hazardous, or volatile materials in a cleanroom. Safety hinges on proper fume hood exhaust monitoring; it alerts workers when the airflow drops below calibrated levels. In Part 1, we discussed some available options in fume hoods. With a fume hood selected, you can focus on maintenance, replacing equipment, and selecting the monitoring system.


Regular maintenance will likely be an annual or semiannual certification consisting of a velocity test with a thermal anemometer at predetermined points. The points depend on the size of the sash opening. The certification also includes calibrating the alarm and performing a smoke visualization test to prove airflow direction and smoke containment. In addition to certification, facility personnel should carry out scheduled checks on the blower motor belt.

Replacing Equipment

Your fume hood monitor does not need to be replaced until the system doesn’t function any longer or it doesn’t calibrate properly.

Selecting the Monitoring System

The monitoring system is obviously a critical part of the fume hood as it is what will tell you when levels are dangerous. Your choice will ultimately depend on how much data you want to receive. Some systems will set off an audible and visual alarm when velocity drops a set percentage; others will actually give a read out of the velocity. Your customer may require the read out for documentation. There are monitors that don’t give both alarms, but your safest bet is to go with one that has both the audible and visual alarms.

Remember that when installing your fume hood, you need to look at the layout of your lab. You don’t want supply vents or filters directly in front of the hood. It’s best to have a full ASHRAE 110 test at the initial certification. Additionally, it is best to have your fume hoods on dedicated exhaust systems. If one unit needs an adjustment, it usually requires a rebalance of any other hoods within a shared system.

For cleanroom certification and validation, contact the experts at Gerbig Engineering Company: 888-628-0056 or info@gerbig.com.

Quick Tips for Fume Hood Exhaust Monitoring Part 1

What kinds of options do you have available when selecting a fume hood for your cleanroom? What else do you need to know?

When working in a cleanroom with corrosive, hazardous, or volatile materials, sufficient airflow is critical to personnel safety. Calibrated exhaust monitors typically have audible and visual alarms to alert workers when the airflow drops below calibrated levels. In addition to monitoring this airflow, exhaust monitor alarms can also indicate that there is a problem with the pressure. As you can see, it is imperative to have calibrated exhaust monitors for your fume hoods. We offer some quick tips on choosing and maintaining your fume hoods. First, a few words about your options:

Selections in Fume Hoods

There are numerous options for fume hoods. Among these, you will find two different airflow valve setups:

Variable Air Volume (VAV) – This can be programmed to either adjust air velocity based on where the sash height is or regulate it regardless of where the sash height is.

Constant Volume Valve (CV) – The hood is designed so that it’s worked in at a specific velocity and a specific sash height. When the sash is raised past the set point, the velocity will drop; when the sash is lowered, velocity increases.

The other variations revolve around size, material, and sash opening setups. Some of the materials available include coated wooden units, polymer materials, and coated or raw stainless. Sizes vary greatly. You can find sash openings that are horizontal, vertical, a combination, and walk-in.

Knowing how many options you have available will help you understand exactly what you need to determine before selecting the fume hood itself. In next week’s post, we will continue with tips on maintenance, replacing equipment, and selecting the monitoring system.

For cleanroom certification and validation, Gerbig Engineering Company provides expert services. Call us at 888-628-0056 or email info@gerbig.com.

Optimal Type 2 Water Quality for the Cleanroom

You have numerous options for pretreatment methods for pure water, but what is the best combination to produce Type 2 water?

In our last post, we covered the six methods for pretreating water to make it pure for cleanroom purposes. This pretreatment is a vital stage in water purification, but it’s often overlooked. None of the methods will completely remove contaminants on its own, so it’s imperative that you find the right combination. While the exact best fit for you will depend on the application, there is one combination that is often the best to create Type 2 water: Reverse Osmosis (RO), and Electrodeionization (EDI).

To recap, RO is extremely useful in the first step of the purification process. It removes the majority of broad range of contaminants. Its efficiency, however, does vary among contaminant types.

EDI combines direct electrical current with ion exchange resins as well as selective semi-permeable anionic and cationic membranes. This technology deionizes water effectively, as the electric current continuously regenerates the ion exchange resins.

Using these methods together produces water with consistently low levels of ion and TOC. Having such a consistent quality makes it ideal for producing ultrapure water, as other methods tend to result in polished water that has fluctuating levels of contaminants. These kinds of fluctuations compromise any data that’s pulled using trace and ultra trace analyses.

Of course, once you have chosen your water purification methods, be sure to properly train personnel on use and maintenance of the technology and systems. Consistent monitoring will also ensure you are meeting compliance.

For cleanroom validation and/or certification, Gerbig Engineering Company provides quality services that will help you maintain the success of your business. Call us to discuss your needs at 888-628-0056 or reach out via email: info@gerbig.com.

6 Pretreating Methods for Pure Water in Cleanroom Labs

Here is a look at the 6 kind of methods used to pretreat water in the purification process necessary to use it in a cleanroom laboratory.

There’s water purification that produces Type 1, or ultrapure water, but equally important is the pretreatment step that results in Type 2 water. Pretreatment actually removes most of the contaminants in tap water. This step needs to be relied upon consistently, yet it is often overlooked. To ensure your water is purified to the highest possible standard, be sure to use a combination of the following technologies:

  1. Distillation. This removes a wide range of contaminants, but it requires large volumes of tap water and electrical energy. This method of purification is relied on much less today as contaminants are carried into the condensate.
  1. Reverse osmosis. The efficiency of this method varies among contaminants, but it is capable of removing the bulk of most of them.
  1. Ion exchange resins. This effectively removes dissolved inorganics (ions) and charged organics. It doesn’t remove neutral organics, bacteria, or particles, however.
  1. Electrodeionization. This process deionizes water while the ion exchange resins are continuously regenerated by the electric current in the unit.
  1. Activated carbon. There are two forms of this: natural and synthetic. Natural activated carbon has a high concentration of ionic contaminants. It’s only used as a preliminary step to remove chlorine from water. Synthetic activated carbon is much cleaner, and used to remove trace organics of low molecular weight.
  1. Germicidal UV. Ultraviolet radiation inactivates microorganisms and prevents microbial growth and contamination. This is a widely used germicidal treatment for water.

In our next article, we will discuss the best combination of methods to produce Type 2 water. If you have questions about cleanrooms or need certification or validation, contact Gerbig Engineering Company. We care about your success. 888-628-0056; info@gerbig.com

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