Technical Data A Division of Lubrizol
Thermal Fluid System Leakage Rev. 716
Heat transfer oils are formulated insufficient — vapor can accumulate be located so that they cannot be to move fast and carry maximum and cause a potential fire hazard. accidentally removed with a fork heat at high temperatures. But The key to preventing safety truck. Leaking pump seals should the properties that will optimize problems from leaks is to make be replaced before they flush out these performance characteristics sure thermal fluid systems are not the bearing grease. The expansion — low viscosity and high density operated in enclosed areas without tank level should be checked — also complicate efforts to keep adequate ventilation. Ensure before startup. the fluids’ molecules contained at adequate fresh air flow in any operating temperatures. The very location (valves, flanges, instrument Flash, Fire, and Autoignition properties that make them good ports, pumps, expansion tanks, for Points Demystified heat transfer media also make them example) where the potential exists Three major technical terms prone to leakage. for a significant leak. describe flammability conditions in hydrocarbon liquids and their Leak Detection To Minimize Leaks vapors; flash point, fire point, and One of the simplest leak detectors 1. System Maintenance: Hot metal autoignition temperature. for thermal fluid is the smoke increases in length (and diameter). that shows up when the hot fluid Bolts stretch. Piping runs increase Flash Point Defined is exposed to air. The amount of up to 4” per 100’ of length. Hot The lowest temperature at which a smoke depends on the size of the fluid is also much thinner than heated liquid’s vapor/air mixture can leak, the temperature of the fluid cold (above 400°F, less viscous be ignited (“flashed”) by a flame or and to some extent the airflow in than water at room temperature). spark, or other ignition source placed the area. Small oozing leaks can In new and old systems, the above the liquid surface. produce an exaggerated amount biggest sources of leaks are of smoke because there isn’t flanges. Leaking flanges should Fire Point Defined enough fluid to form a drop. This be re- torqued. If you have to The lowest temperature at which a steady weeping smokes and then remove the insulation to get to the heated liquid’s vapor/air mixture will cooks onto the metal near the leak, flange, make sureyoureadabout burn continuously when combustion leaving dark stains, or — in time — insulationfires in Paratherm’s Fire is supported by ignition sources a carbon crust. Prevention in Thermal Oil Heat such as the above. With larger leaks, the fluid Transfer Systems technical data usually cools quickly as it drips sheet. Use fluoro- carbon based Autoignition or sprays into the air. Since smoke thread sealant or Teflon tape on Temperature Defined is actually the reaction of the heat threaded fittings and tighten The temperature at which the vapor transfer fluid’s volatile low-boiling them down. formed by a heated liquid will flash portions (smaller molecules) with without a source of ignition. oxygen in the air, this cooling 2. Prevent Operator Error: All of reduces the vaporization of fluid the drain valves should be closed (Continued on reverse side) which helps lessen the amount of before adding fluid. All of the block smoke. However, if the leak is large valves should be closed before enough that its oxidation uses up opening a line. Pressure gauges all the fresh air — or if ventilation is should have isolating valves and
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Flash Point and Fire vapor/air mixture, causing a pop. in the container, that temperature Point Testing The observed temperature when is the Auto Ignition Temperature. IF The liquid to be tested is heated the flame momentarily ignites the no flash is observed after a period in a cup and the rising liquid vapor/air mixture is the Flash Point. of time, the flask temperature is temperature is continuously The ignitions repeat as the liquid increased and the test repeated. measured. A small flame is temperature continues to rise. The This method (ASTM E659-78) mechanically passed back and observed temperature when the is valid only for fluids that are forth just above the surface of the burning becomes continuous is the completely vaporized at the test liquid. As the liquid gets hotter, Fire Point. temperature since the degradation more of it evaporates causing the products formed by any remaining fuel/air mixture above the liquid to AutoIgnition liquid will affect the test result. gradually become richer. When the Temperature Test lower flammability limit is reached, A sample is injected into a flask the ignition source will ignite the which is heated to the test temperature. If a “flash” is observed
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Note: The information and recommendations in this literature are made in good faith and are believed chantability or fitness for a particular use or purpose (recommendations in this bulletin are not intended to be correct as of the below date. You, the user or specifier, should independently determine the nor should be construed as approval to infringe on any existing patent). The user’s exclusive remedy, suitability and fitness of Paratherm heat transfer fluids for use in your specific application. We warrant and Paratherm’s sole liability is limited to refund of the purchase price or replacement of any product that the fluids conform to the specifications in Paratherm literature. Because our assistance is furnished proven to be otherwise than as warranted. Paratherm will not be liable for incidental or consequential without charge, and because we have no control over the fluid’s end use or the conditions under which damages of any kind. Some product names of companies found in Paratherm literature are registered it will be used, we make no other warranties—expressed or implied, including the warranties of mer- trademarks. This statement is in lieu of individually noting each.
© Paratherm 2016 Rev. 716