Vertiv Liebert XD Series, System Design Manual

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When mishandled, glycol products pose a threat to the environment. Before using any glycol products,
review the latest Material Safety Data Sheets and ensure that you can use the product safely. Glycol
manufacturers request that the customer read, understand and comply with the information on the
product packaging and in the current Material Safety Data Sheets. Make this information available to
anyone responsible for operation, maintenance and repair of the drycooler and related equipment.
No chemical should be used as or in a food, drug, medical device, or cosmetic, or in a product or process in
which it may contact a food, drug, medical device, or cosmetic until the user has determined the suitability
and legality of the use. Since government regulations and use conditions are subject to change, it is the
user's responsibility to determine that this information is appropriate and suitable under current,
applicable laws and regulations.
NOTICE
Risk of using the wrong type of glycol. Can cause piping damage, coolant fluid leaks, and substantial
building damage.
Automotive antifreeze is unacceptable and must NOT be used.
Typical inhibited formula ethylene glycol and propylene glycol manufacturers and suppliers are Union
Carbide (Ucartherm) and Dow Chemical (Dowtherm SR-1, Dowfrost). These glycols are supplied with
corrosion inhibitors and do not contain a silicone anti-leak formula. Commercial ethylene glycol and
propylene glycol, when pure, are generally less corrosive to the common metals of construction than water
itself. Aqueous solutions of these glycols, however, assume the corrosivity of the water from which they are
prepared and may become increasingly corrosive with use when not properly inhibited.
There are two basic types of additives:
• Corrosion inhibitors and
• Environmental stabilizers
The corrosion inhibitors function by forming a surface barrier that protects the metals from attack.
Environmental stabilizers, while not corrosion inhibitors in the strictest sense of the word, decrease
corrosion by stabilizing or favorably altering the overall environment. An alkaline buffer, such as borax, is a
simple example of an environmental stabilizer, since its prime purpose is to maintain an alkaline condition
(pH above 7).
The percentage of glycol to water must be determined by using the lowest design outdoor temperature in
which the system is operating. Table 6.19 below indicates the solution volume of inhibited glycol required
to provide freeze protection at various ambient temperatures.
Coolant Type
Temperature, °F (°C
20 (-7) 10 (-12) 0 (-18) -10 (-23) -20 (-29) -30 (-34) -40 (-40) -50 (-46)
Propylene Glycol
% by Volume
18 * 29* 36 42 46 50 54 57
Ethylene Glycol
% by Volume
17 * 26* 35 41 46 50 55 59
Based on Dowfrost™ (PG) and Dowtherm™ SR-1 (EG) product literature.
* Inhibitor levels should be adjusted to properly protect the system if solution concentrations are less than 30%.
Table 6.19
Glycol concentrations for freeze protection by ambient temperatures
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