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BioTherm fluids® AF (Formerly IceClear® AF)

Biobased Glycerin Antifreeze / Heat Transfer Fluid HT1 Approved For Incidental Food Contact Applications (Inhibited)

BioTherm Fluids® AF is a non-toxic, non-glycol, biobased anti-freeze / heat transfer fluid with a food grade multi-metal corrosion inhbitor which, as is, meets ASTM D1384. Made with highly refined glycerin, AF is NSF registered with an HT1 rating, allowing use where incidental food contact is possible. AF is specifically formulated as an alternative to petroleum derived 50% propylene glycol (PG) based anti-freeze fluids for industrial low temperature, non-automotive applications, especially those with environmental concerns:

  • RV Toilet & Water System Winterizer
  • Fountain/Water Line Winterizer
  • Directional Drilling Fluid
  • Pressure Testing
  • Ballast Fluids
  • Chiller Fluids
  • All Season Dust Suppressant


AF is also supplied without the corrosion inhibitor package under the name BioTherm Fluids PGX.

For Heavy Duty, Heated and/or Engine Related Applications, Use BioTherm Fluids AI.

Derived from agricultural materials or bio-based processes, this environmentally friendly product is engineered to match the freezing point performance of conventional antifreeze products based on glycols, but with the following advantages:

  • Biobased / BioPreferred
  • NSF Registered (HT1)
  • Tested to ASTM D1384
  • Lower BOD/COD
  • No Glycols
  • Readily Biodegradable
  • Non-Toxic
  • Designed for Environmentally Sensitive Applications



nsf logoNSF Registered
This product is acceptable for use as a heat transfer fluid where there is possibility of incidental food contact (HT1). 

Won’t Dry Out
Due to its viscous nature and hygroscopic character, AF will not dry out after initial application, making it effective for extended periods of time as an antifreeze and a dust suppressant.


Environmentally Friendly

biopreferred logoBioTherm Fluids® AF is a 100% certified USDA Biobased Product as tested by ASTM D6866 through the USDA BioPreferred® Program. AF is non-toxic, non-corrosive and is fully biodegradable, offering a lower BOD/COD than glycol. 

BioTherm Fluids® AF has been tested to OECD 310 with results showing it is "readily biodegradable" meaning that there is unequivocal evidence that AF is rapidly mineralized to inorganic components and biomass. AF also meets the definitions of "inherently biodegradable" and "ultimately biodegradable" meaning that there is a reasonable expectation that they will eventually be completely mineralized in aerobic environments.



BioTherm Fluids® AF is formulated from complex carbohydrates derived from renewable resources and/or process side streams that facilitate cost-effective and not subject to the market swings of glycols.


HI96801 Refractometerglycerin freeze point testerAF is a glycerin based product, DO NOT use testers designed for glycols. Freeze point range can quickly be determined by a special tester (pictured left) available from Orison or more accurately by a refractometer (Brix pictured right) - Brix Value Chart below.

AF is slightly more viscous than conventional antifreeze materials. As such, it adheres to particle surfaces and clings to transportation and conveying equipment with little run-off and settling. This prevents freezing, clumping and sticking, and keeps product moving freely.




Although no negative effects are expected, mixing antifreeze/coolants is not recommended due to varying freeze point depressants and corrosion inhibitor technologies which leads to difficulties determining actual freeze point protection and corrosion inhibition properties. Use only BioTherm Fluids® AF in the system.

The chart below is supplied as a guide for diagnostic / maintenance purposes. The values are calculated values and are only approximations. AF is ready-to-use and not recommended to be diluted as the result would weaken the corrosion inhibitor package. Custom blends are available.


*Addition of TRAMFLOC® 1142 FOAM CONTROL AGENT may be beneficial for some applications. TRAMFLOC® 1142 FOAM CONTROL AGENT is a nonionic, nonsilicone, food grade defoamer. TRAMFLOC® 1142 FOAM CONTROL AGENT performs well in a wide range of pH and temperatures. All ingredients used in the manufacture of TRAMFLOC® 1142 FOAM CONTROL AGENT are either GRAS or listed in the Code of Federal Regulations: Title 21, Section 173.340. Recommended use at 1 oz/ 10 - 20 gallons of system fluid.


Maintenance / Information Chart (information only)

IceClear AF % (weight)
Brix Value (Refractometer)
Freeze Point F/C
Boiling Point F/C
Specific Heat @35F
ViscositycSt @68F (20C)


Note: BioTherm Fluids® AF is designed as a ready-to-use. It may be diluted, however, it may weaken the corrosion inhibitor package. Diluting this product more than 20% with water may be subject to bacterial contamination.

Downloads & Links

IceClear AF antifreeze heat transfer fluid

PDF Downloads

Product Data Sheet

SDS - IceClear AF

NSF HT1 Registration Letter

FDA Letter of Guarantee




Typical Properties

  • Clear Liquid
  • Mild/No Odor
  • pH: 9
  • Specific Gravity: 1.15
  • Freeze Point: -34 °C (-30 °F)
  • Viscosity: 11 (@ 20C cSt)
  • Conductivity: 1.7 mS



US Patents
One or more claims of US Patent No. 6,890,451 and 7,270,768.

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FREE Shipping to lower 48 states!
55 Gallon Drums and 275 and 330 Gallon Totes are only shipped to Commercial Business locations. We will not ship drums or totes until the address has been verified as a commercial business address. If you require delivery to a residential address (or farm), please call 800-460-2403.