Physical Properties

The physical properties described below are tested on antifreeze solutions sent to Dyne Technologies. The physical properties are not a measurement of performance and as such will not cause the sample to FAIL. If the value is outside of the specification, it is simply noted as OUT OF SPEC.

Physical Property Test Type Definition Possible Reasons Why Value is Out of Spec
Appearance  Appearance is the description of the color, consistency and the visible presence of sediment or particles.

The appearance can indicate the type of antifreeze.

The appearance is often OUT OF SPEC and can indicate several things such as:

  • A different type of antifreeze than indicated on the report
  • Interaction of the tank or piping with the antifreeze solution – indicated by rust-coloring (corrosion)
  • Sediment or particulates which is often also the result of corrosion
Refractive Index The refractive index is a measurement of the angle in which light bends as it passes through the sample.

The refractive index is proportional to the amount of antifreeze in the sample and will increase as the concentration of antifreeze increases.

Please note the refractive index of tap water is approximately 1.3330 at 20 degrees Centigrade.

Density (Specific Gravity) The density is a measurement of the weight of a specified volume and is reported in grams per milliliter. Some labs report this as specific gravity, which is the relative density compared to water.

The density is proportional to the amount of antifreeze in the sample and will increase as the concentration of antifreeze increases.

Please note the density of tap water is approximately 0.998 grams/milliliter at 20 degrees Centigrade.

pH The pH value determines the acidity/basicity (ion activity) of the sample.

The acceptable pH range limits are 6.0-9.5:

  • A pH below 6.0 means that the sample is acidic
  • A pH above 9.5 means the sample is basic
  • A pH outside of 6.0-9.5 often indicates corrosion within the sprinkler piping or degradation of the antifreeze


Performance Properties

The type and concentration of the antifreeze solution is the only property which can fail. It is the responsibility of the system owner to ensure the freeze point of the antifreeze solution is low enough to remain a liquid under all the anticipated environmental conditions.

Performance Test Type Definition
Estimated Concentration by Weight and by Volume

The type of antifreeze solution and the concentration - by volume and weight - is determined by the physical properties of the solution in addition to the freeze point verification test. The acceptable concentration of the various antifreeze materials is determined by the National Fire Protection Standard 25, 2014 Edition - Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems:

  

Antifreeze SolutionWhen Can it be Used?
Diethylene Glycol Prohibited in any system
Ethylene Glycol Prohibited in any system
Propylene Glycol

Prohibited for use in chlorinated polyvinyl chloride (CVPC) piped systems

 Allowed in non-CVPC piped systems installed prior to September 30, 2012 and meeting the following conditions:

 Cannot exceed 40 percent by volume

  • Systems with concentrations greater than 30 percent but less than 40 percent by volume will be permitted based upon an approved deterministic risk assessment prepared by a qualified person approved by the authority having jurisdiction.
Glycerine

Allowed in both chlorinated polyvinyl chloride (CPVC) and non-CPVC piped systems installed prior to September 30, 2012 and meeting the following conditions:

  • Cannot exceed 50 percent by volume
  • Systems with concentrations greater than 38 percent but less than 50 percent by volume shall be permitted based upon an approved deterministic risk assessment prepared by a qualified person approved by the authority having jurisdiction.
All antifreeze solutions introduced after September 30, 2012

Must have factory premixed antifreeze solutions

For systems installed prior to September 30, 2012

Systems have until September 30, 2022 to become compliant in regards to listed premix antifreeze solutions

  • For additional details, see NFPA 25 Section 5.3.4
Estimated Freeze Point in Degrees Celsius and Degrees Fahrenheit

The estimated freeze point in degrees Centigrade and degrees Fahrenheit indicates the temperature at which the solution will begin to freeze. It is not recommended that systems be exposed to temperatures below this freezing point for any extended time period.

Freeze Point Verification

The estimated freeze point of the antifreeze solution is verified by placing a sample of the antifreeze solution into a freezer.