Humidifiers for walk-in chambers

[rhondabayoudsnyder]

#5858

Our large walk-in chambers were installed with cold vapor misting humidifiers. While these humidifiers save energy, we have found algae growth and were recommended to place the humidifiers on a quarterly pm program. The water source is RO and is regularly serviced and constantly circulating. Our reach-in chambers are all installed with steam humidifiers. What are some of your recommendations for humidification systems, specifically for large room sized walk-in chambers, including pros and cons:
a. Misting ultrasonic humidifiers (ex., Humidifirst Mist-Pac)
b. Mist-free ultrasonic humidifiers
c. Steam/evaporative humidifiers

[John O’Neill]

#7166

Hi Rhonda,
Water sources and handling are a frequent topic in PSDG circles. I might take this opportunity to invite knowledgeable technicians, vendors and service providers to comment. While the StabilityHub Forum prohibits direct advertising, solicitation of business, of denigration of competitors in this segment, it welcomes the sharing of expertise in the spirit of advancing quality and efficiency in the medical product, nutraceutical and cosmetic industries. If someone from our technical stakeholders responds, you are welcome to pursue additional information or business arrangements off-line.
John O’Neill
Editor, StabilityHub

[PGC1977]

#7301

Hey Rhonda,

This may give a little more information.

Stability chambers bring in the opportunity of algae and other organic growth because most of ICH storage conditions do have a humidity component to the specification. Whether the humidification process is steam, ultrasonic, or saturator with dew point control – there will be wet surfaces somewhere in the conditioner or air plenums. Even some of the temperature only conditions like 5C and -20 will require a cold coil temperature with will also create water in the system.

Some of these humidification methods may require high purity water sources. While this “feed” water will generally not contain algae or contaminants, once the moisture is introduced into the air flow, it will generally cross over a cooler surface (DX coil or plenum) where temperature is lower than the dew point of the air. This will cause water to condense on the cooler surface. The air being circulated through system will pick up some contaminates either from inside the chamber or through the outside environment (fresh air make-up or chamber door openings) and growth will be more likely at the wetted surfaces.

Conditions (temperature/RH) of the chamber, temperature of the wetted surface, purity of make-up water, and the contents or activities of the chamber or surrounding area will determine growth potential of algae and other contaminants.

Best practices to reduce or even prevent growth include:

1. PMs that effectively clean and disinfect areas that are wet in the conditioner or chamber.
2. Preventing stagnate water from forming. Be sure the system has working condensate drains and that water is not forming in areas without drains.
3. If the chamber has a lot of corrugated boxes or paper, a return filter will help minimize the cellulose from the paper products which help feed growth in the wetted areas.
4. Reduce the possibility of introducing growth with the feed water by utilizing RO, chlorinated tap water (with filtered mineral content). DI water will also work but be careful that the purity level is not great to cause rapid deterioration in components.

Clay Hile
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