Therminol® LT Heat Transfer Fluid


Therminol LT is a synthetic aromatic heat transfer fluid. It can be used in both liquid phase and vapour phase, and has excellent heat transfer and fluid properties for low temperature applications.

Performance Benefits

  • Vapour Phase Operation—Therminol LT can be used in the liquid phase between -75°C (-100°F) and 315°C (600°F). With a boiling point of 181°C (358°F) at ambient pressure, Therminol LT can be used in the vapour-phase above 181°C (358°F).
  • Excellent Low-Temperature Performance—Therminol LT has the best low-temperature heat transfer coefficient of all coolant fluids. Therminol LT has excellent heat transfer properties to -75°C (-100°F).
  • Low Viscosity—Low viscosity at exceptionally low temperatures makes Therminol LT excellent for pumping extreme cooling applications.

Typical Properties

PropertyTest MethodTypical Value, Units
AppearanceClear, light yellow liquid
Composition Alkyl substituted aromatic
Recommended Bulk Temperature315 °C (600 °F)
Maximum Film Temperature345 °C (650 °F)
Normal Boiling Point181 °C (358 °F)
Pumpability @300 mm2/s (cSt)-75 °C (-103 °F)
Crystallization Point75 °C (-103 °F)
Autoignition TemperatureASTM E659
DIN 51794
412 °C (774 °F)
429 °C (804 °F)
Coefficient of thermal expansion @ 100°C0.001080 /°C (0.000600 /°F)
Minimum liquid temperatures for fully developed turbulent flow (NRe > 10000)
10 ft/s, 1-in. tube (3.048 m/s, 2.54-cm tube)
 20 ft/s, 1-in. tube (6.096 m/s, 2.54-cm tube)

-66 °C (-87 °F)
<-73 °C (-100 °F)
Minimum vapor temperatures for fully developed turbulent flow (NRe > 10000)
10 ft/s, 1-in. tube (3.048 m/s, 2.54-cm tube)
20 ft/s, 1-in. tube (6.096 m/s, 2.54-cm tube)

139 °C (283 °F)
116 °C (241 °F)
Heat of Vaporisationa223 kJ/kg (95.7 Btu/lb)
Viscosity, Kinematic
@ 40°C

ASTM D 445
ASTM D 445

0.48 cSt, mm2/s
0.81 cSt, mm2/s
Molecular Weight (Average)134
Pseudocritical temperature377 °C (710 °F)
Pseudocritical pressure34.5 bar (500 psia)
Pseudocritical density298 kg/m3 (2.49 lb/ft3)
Dielectric Constant @ 23°CASTM D-9242.3
Moisture Content, maximumASTM E-20380 ppm
Surface Tensionb @ 25°C28.0 dynes/cm
Properties reported here are typical of average lots.

Key Attributes

  • Vapour Phase Operation
  • Low Viscosity
  • Excellent Low Temperature Performance


  • htf – active pharmaceutical ingredients
  • htf – fine chemicals
  • htf – pharmaceutical processing
  • Environmental test chambers
  • Fibers
  • Formaldehyde
  • Specialty and batch chemical production
  • Specialty chemicals

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