Thermal Stability and Thermal Hazards Testing
Often material safety data sheets refer to the thermal stability as an intrinsic property of a substance or mixture. In fact, this is an oversimplification of a concept that must be defined in a more comprehensive way.
Thermal stability testing aims at collecting reaction rate data and applying that data to assess whether a specified quantity of material can be used in a way such that runaway reactions are avoided. This is important when considering processing, long-term storage, or shipping of a material.
Accurate determination of safety parameters:
- Onset Temperature
- Kinetic Parameters
- Time to Maximum Rate
- Critical Temperature / Temperature of No Return
- Self Accelerating Decomposition Temperature
Testing Services
Differential Scanning Calorimetry (DSC)
Measures the heat flow to or from a sample under controlled heating conditions. DSC data can be used to assess the thermal hazard potential as well as evaluate material properties of a given sample. ASTM Standards commonly used for such evaluations are as follows:
- ASTM E 537-12: Standard Test Method for the Thermal Stability of Chemicals by Differential Scanning Calorimetry
- ASTM E 698-11: Standard Test Method for Arrhenius Kinetic Constants for Thermally Unstable Materials Using Differential Scanning Calorimetry and the Flynn/Wall/Ozawa Method
- ASTM E 793-06: Standard Test Method for Heats of Fusion and Crystallization by Differential Scanning Calorimetry
- ASTM E 794-06: Standard Test Method for Melting and Crystallization Temperatures by Thermal Analysis
- ASTM E 928-08: Standard Test Method for Purity by Differential Scanning Calorimetry
- ASTM E1269-11 Standard Test Method for Determining Specific Heat Capacity by Differential Scanning Calorimetry
Fauske & Associates specializes in performing DSC tests on reactive chemical samples. High pressure crucibles are used to accommodate pressure generation due to both vapor and non-condensable gas. DSC data provides an excellent screening tool with which to identify the thermal hazard potential of a sample.
Thermogravimetric Analysis (TGA)
Measures the change in mass of a sample under controlled heating conditions. TGA data can be used to assess the thermal hazard potential as well as evaluate material properties of a given sample. ASTM Standards commonly used for such evaluations are as follows:
- ASTM E 1131-08: Standard Test Method for Compositional Analysis by Thermogravimetry
- ASTM E 1641-07: Standard Test Method for Decomposition Kinetics by Thermogravimetry
- ASTM E 1868-10: Standard Test Method for Loss-On-Drying by Thermogravimetry
- ASTM E 2008-08: Standard Test Method for Volatility Rate by Thermogravimetry
- ASTM E 2550-11: Standard Test Method for Thermal Stability by Thermogravimetry
Accelerating Rate Calorimeter (ARC)
The high thermal inertia adiabatic calorimeter that is used to obtain data regarding the relationships between time, temperature, and pressure for exothermic reactions. The following safety parameters are attained, or can be evaluated, from Accelerating Rate Calorimetery:
- Onset temperature
- Temperature rise rate dT/dt as a function of temperature
- Pressure rise rate dP/dt as a function of temperature
- Adiabatic temperature rise (ATR)
- Heat of reaction
- Adiabatic time to maximum rate (TMR)
- Temperature of no return (TNR)
- Self-accelerating decomposition temperature (SADT)
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Thermal Activity Monitor (TAM)
An isothermal microcalorimeter designed to monitor a wide range of chemical and biological reactions. The TAM is commonly used in the following studies:
Kinetics of Chemical Reaction
- Activation Energy
- Rate Law
- Autocatalytic Behavior
- Assure Safe Transport- Self Accelerating Decomposition Temperature
- Quantify Shelf Life
- Evaluation of Fermentation Rates
- Oxidation or Corrosion Rates
- Interaction Tests
Fauske & Associates Thermal Activity Monitor (TAM) contract testing service test protocol conforms to the operational recommendations made by the instruments manufacturer. A sample size of 0.5 to 2 grams is typically required for each test.
AKTS - Thermokinetics Software
Critical process safety and thermal stability parameters (TMRad, SADT, etc.) can be determined quickly and reliably from a modest amount of calorimetry data by using AKTS-Thermokinetics software. This software utilizes an advanced differential is conversional kinetic technique for the precise modeling of runaway chemical reactions. AKTS-Thermokinetics software package facilitates kinetic analysis of DSC, DTA, TGA, and TAM data for the study of raw materials and products within the scope of research, development and quality assurance.
Advanced kinetic analysis:
- Automatic baseline construction and use of the differential isoconversional method of Friedman (model-free) for advanced baseline optimization
- Smoothing of data (Savitzky-Golay)
- Differential isoconversional method of Friedman (model-free)
- Integral isoconversional method of Ozawa-Flynn-Wall (model free)
- Standard ASTM E698 procedure
- Model fitting method applying common reaction models
Prediction of the reaction progress and thermal stability of materials under any temperature mode:
- Isothermal and non-isothermal, stepwise
- Modulated temperature or periodic temperature variations
- Rapid temperature increase (temperature shock)
- Real world temperature profiles (up to 7000 climates)
Fauske & Associates, has experience utilizing AKTS-Thermokinetics software for kinetic analysis and is also an authorized distributor. A series of Differential Scanning Calorimetry (DSC) tests on a small sample size (roughly 1-10 mg per test) can be sufficient to provide data for analysis.
The use of ATKS-Thermokinetics software does not require knowledge of the reaction mechanism. The model-free approach to kinetics ensures proper modeling of materials subject to autocatalytic or multi-stage reactions.
C80, Manufactured By Setaram
The C80 is a reaction, thermal and scanning calorimeter that operates like a larger version of a DSC which accommodates a larger sample size and bigger test cells — 10 ml test cells, as opposed to 20-50 µl test cells.
This is especially advantageous when dealing with heterogeneous or multi-component samples that come in and are not uniformly mixed and cannot be uniformly mixed (think different colored M&Ms) as the larger size allows a more representative sample to be tested. Some of the key benefits include:
- It has a wide range of vessels that can be used with it which makes it flexible
- A lot of the other instruments primarily use metal cells, but the C80 can use glass-lined cells which is beneficial when dealing with peroxides or other chemicals that are highly sensitive/reactive to metals
- The C80 offers a unique level of sensitivity to thermal events and also the ability to design cells and vessels to simulate almost any potential condition
- Temperature ramp measures heat flow as a function of time and temperature
- Temperature range is from ambient to 300mC
As you can see, the C80 is a fantastic addition to our toolkit here at FAI as it nicely complements other instruments in our lab and enhances the ability of our engineers to offer practical and customized solutions to unique process safety issues dealing with thermal hazards and thermal stability. When you are considering a provider for your own process safety needs in this area make sure that they too have a robust toolkit with which to effectively address your concerns.
Training
Our team is happy to help train your staff in the understanding of technical issues, process safety programs or audits, regulations and more. We perform process safety audits as part of a comprehensive hazards analysis and can work with you to make sure your staff is supplied with skills training needs in many ways including:
- Level I - Gap Analysis
- Level II - training & consulting
- Level III - Program Development and Implementation
Partial List of Services Offered:
- Reviews and upgrades of all your safety process systems and regulatory requirements
- VPP Consulting
- Audits, reviews, and upgrades of all your Operating, Safety, and Maintenance Procedures
- Training program evaluations for both completeness and effectiveness (from technical skills to professional development) and upgrades where
needed - Reviews and upgrades of your program elements such as Employee Participation and Process Safety Information for effectiveness and completeness
- Work process effectiveness evaluations and upgrades
- Overall organizational development (e.g., motivation, work processes)
- Stress reduction
- Evaluations of the effectiveness of communication
We design, custom develop and deliver any site specific training materials needed by your organization. Our Consultants, Engineers and Technical Specialists are available to deliver the classroom, lab or on-the-job training your staff needs. In addition, we will assist with the identification and procurement of commercially available training materials where available.