Immersion Cooling Myths Debunked
See what our experts have to say about some common myths surrounding immersion cooling and 3M fluids. Have a question of your own?
Are 3M fluids considered harmful to human health?
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No. 3M engineers fluids for immersion cooling to be safe in their intended uses with wide margins of safety. The margin of safety is assessed by comparing anticipated exposure to recommended exposure guidelines, such as the eight-hour time weighted average (TWA) exposure guideline.
Test results demonstrate that Novec Engineered Fluids and Fluorinert Electronic Liquids are relatively low in acute toxicity; as a result, they are not classified as hazardous under the Global Harmonized System of Classification and Labeling of Chemicals (GHS).¹ All 3M fluids have undergone rigorous toxicity testing in accordance with global standards and have been accepted for use in targeted applications by the U.S. EPA and other global regulatory bodies.
[ ¹ The hazards of a materials are routinely characterized by conducting single and repeat exposure studies. Hazards are categorized by using the GHS (Globally Harmonized System of Classification and Labeling of Chemicals) classification scheme, which can be found at unece.org.]
The exposure guidelines for 3M fluids are included in the product Safety Data Sheet (SDS). 3M customers have the responsibility to understand worker exposure in their facilities. 3M is available to provide information on exposure analyses.
Do 3M fluids leave a dew after condensation from a vapor?
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No. 3M fluids used for single-phase and two-phase cooling will evaporate cleanly from any surface and should never reach airborne concentrations at which they could condense on these surfaces. 3M fluids—both Novec Engineered Fluids and Fluorinert Electronic Liquids—are low in toxicity. Please refer to each product’s SDS for more comprehensive information on fluid composition.
Are 3M™ Novec™ Engineered Fluids and 3M™ Fluorinert™ Electronic Liquids oil-based?
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No. Both Novec fluids and Fluorinert liquids are based on proprietary fluorine technology. These fluids and liquids are neither oils nor oil-based, and they have different physical, chemical and performance properties than oils sold by 3M for specific targeted applications.
Should one be concerned with the high volatility of 3M fluids for two-phase immersion cooling applications?
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No. Volatility is a material quality which describes how readily a substance vaporizes. 3M fluids are 100% volatile, a quality that is essential if they are to boil and condense in a heat transfer application or evaporate cleanly from wetted hardware.
When immersion cooling equipment functions as intended in data center deployments, loss rates (and therefore airborne breathable concentrations) are anticipated to be well below occupational exposure guidelines.
Are 3M fluids for immersion cooling available for purchase and use globally?
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Both 3M™ Fluorinert™ Electronic Liquids and 3M Novec™ Engineered Fluids are registered in and/or compliant with the inventory requirements of numerous countries for a variety of industrial applications. Contact 3M for further details.
The conditions of evaluation, selection, and use of a 3M product can vary widely and affect the use of the 3M product in the intended application. Because many of these conditions are uniquely within the user’s knowledge and control, it is essential that the user evaluate the 3M product to determine whether it is fit for a particular purpose and suitable for the user’s method of application, and complies with all local applicable laws, regulations, standards, and guidance. These fluids are not intended for use as a medical device or drug.
Are 3M fluids 2-3 times denser than water? Are there concerns regarding floor loading with 3M fluids?
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Yes. 3M fluids are approximately 1.5 - 2 times denser than water. To minimize weight, if that is a concern, 3M recommends optimizing the amount of fluid used to cool the hardware (target fluid usage is around 5 liters per kW). Immersion-cooled servers do not require traditional air-cooled infrastructure such as raised floors for cold air distribution for cooling IT equipment. Hence, immersion-cooled data centers can be built on slab/hard floors, reducing cost and eliminating the complexities of air-cooled systems.
Does the boiling action of two-phase systems create micro-cavitation that erodes metals on electronic devices?
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No. In countless deployments over the past six decades, 3M and its customers have not observed this phenomenon. Boiling is not cavitation. The creation of a bubble when a liquid starts to boil, and then the bubble’s return to liquid form is a gentle, constant pressure phenomenon. This in contrast to the violent, often supersonic creation or collapse of a bubble on a pump impeller or boat propeller that we commonly associate with cavitation.
Do fluids for two-phase immersion cooling produce high pressures in systems because they must transition to gas and then be re-condensed to remove heat from a system?
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No. While pressure would build in a rigid sealed tank, two-phase immersion cooling systems are most commonly designed and controlled to operate at atmospheric pressure with control systems in place to manage and help prevent modest pressure increases.
Do two-phase cooling systems require high pressure water to be brought into a data room, risking failure?
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No. In the way that two-phase immersion is commonly practiced, facility water is flowed through condensers integrated into the tank. These condensers are built with the same time-proven technologies used in industrial chiller condensers. In this sense, they are analogous to the plate heat exchangers through which that same water would flow for a single-phase immersion or cold plate system.
Do two-phase fluids evaporate or boil away unless they are fully contained, leading to significant fluid replacement costs?
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No. Two-phase immersion tanks are sealed when access is not needed. They “breathe” through controlled systems that capture vapor and return it to the tank. Because they are maintained at atmospheric pressure, parasitic losses should be limited, mostly to those encountered during servicing operations. Target loss rates today are around 1-2% per year and should improve with technology refinement.
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