Self-accelerated decomposition temperature SADT

UN Recommendations on the Transport of Dangerous Goods, Part II, Test Methods for Determining the Self-Accelerating Decomposition Temperature (SADT) of Organic Peroxides and Other Thermally Unstable Substances," ST/SG/AC. 10/11/Rev. 1, United Nations, New York, NY (1990). 

Self-Accelerating Decomposition Temperature (SADT) the lowest ambient temperature at which a runaway decomposition is observed within seven days the test is run with unstable substances, such as a peroxide, in its commercial shipping container, and the reported result applies only for the container used. 

The decomposition of some materials into smaller, more stable molecules can be initiated by mechanical shock alone, and they are known as shock-sensitive. Many commercially important chemicals are thermally sensitive and decompose with the addition of heat. For storage situations, the critical temperature at which the thermal energy is sufficient to start an uncontrolled reaction in a particular storage configuration for a specified time is known as the self-accelerating decomposition temperature (SADT), as described in NFPA 49. 

Self-accelerating decomposition temperature (SADT), screening methods, 56 Self-reactive materials chemical reactivity hazard, 1,2 screening methods, 54-58 Seveso, Italy incident, 4 Seveso II Directive, 5-6,27 Shelf life... 

Self-Accelerating Decomposition Temperature (SADT) means the lowest temperature at which self-accelerating decomposition may occur with substance as packaged ... 

Self-reactive substances need to be subjected to temperature control if their self-accelerating decomposition temperature (SADT) is less than or equal to 55 °C. Test methods for determining the SADT as well as the derivation of control and emergency temperatures are given in the UN Recommendations for the Transport of Dangerous Goods, Manual of Tests and Criteria, Part II, section 28. The test selected shall be conducted in a manner which is representative, both in size and material, of the package. 

Mixtures of organic peroxides may be classified as the same type of organic peroxide as that of the most dangerous component. However, as two stable components can form a thermally less stable mixture, the self-accelerating decomposition temperature (SADT) of the mixture shall be determined. 

Organic peroxides are prone to violent decomposition. Safety must be of utmost importance in handling these products. Decomposition can be caused by several factors, but overheating and exposure to metallic impurities (which catalyze decomposition) are the most common. Suppliers of organic peroxides have published "self-accelerating decomposition temperature" (SADT) data. SADT is defined as the lowest temperature at which self-accelerating decomposition may occur. Supplier recommended maximum storage temperatures are typically 15-20 °C below the SADT. 

M. Aral, N. Mochizuki, M. Itoh, Y. Hara and T. Yoshida, Self-Accelerated Decomposition Temperature (SADT) of Explosive Substances (in Japanese), Kogyo Kayaku, 43, 101 (1982). 

Self-accelerating decomposition temperature (SADT) Organic peroxides or other synthetic chemicals that decompose at ambient temperature, or react to light or heat, resulting in a chemical breakdown. This releases oxygen, energy, and fuel in the form of rapid fire or explosion. To ensure stabilization, these materials must be kept in a dark or refrigerated environment. 

Bubble columns for the cumene oxidation maybe equipped with internals such as trays [29] or an inner shaft for airlift loop operation [18, 20, 30]. However, the impact of any internals on the so-called self-accelerating decomposition temperature (SADT) and on an effective emergency cooling must be considered carefully (see Section 2.3.4). 

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