Safe operating temperature

This is useful in verifying whether a diode s junetion temperature is within its safe operating temperature. 

Where flammable gases or combustible dusts are or may be present at the same time, the simultaneous presence of both shall be considered when determining the safe operating temperature of the electrical equipment. 

Equipment that is approved for Class I and Class II shall be marked with the maximum safe operating temperature, as determined by simultaneous exposure to the combinations of Class I and Class II conditions. 

In general, adiabatic calorimeters are more sensitive than TPA techniques. The induction time can be u.sed for direct evaluation of boundaries for safe operation. Obviously, the time of a corrective action must be less than t d. The fully safe operational temperature is that corresponding to tad = 24 h and is denoted as ADT24 (Adiabatic Decomposition Temperature for 24 hours). 

An understanding of how chemicals are used in your facility needs to occur before any detailed testing is performed. Quantitative reactivity testing need only be performed when data, such as heat of reaction and safe operating temperatures, are not available from other sources. For example, in a warehouse where no chemical or physical processing is being done, material suppliers may be able to pro-... 

A particularly critical case is the exothermal decomposition immediately following the endothermal melting peak. In such cases, the decomposition is faster in the liquid than in the solid state. In an industrial environment, this could mean that a hot spot may melt a small part of the solid, which begins to decompose and the decomposition may propagate through the entire volume of the product. In such cases, the definition of a safe operation temperature becomes critical. 

Also, as polymerization temperature increases, the quality of the polymer begins to suffer, and 160-170 °F is generally considered the maximum safe operating temperature. If a still lower molecular... 

Achieving the required separation of solvent from residue at the safe operating temperature is likely to involve the use of reduced pressure, particularly towards the end of a batch when the mole fraction of volatile solvent becomes low and that of the involatile residue becomes high. Because this situation is present all the time in a continuous operation, it is likely to be under vacuum. This presents no insuperable problem for handling solvents with high boiling points since it is still possible to condense their vapours with cooling water or ambient air with an adequate temperature diiference in the condenser. 

The graph shows that the region of polymer/monomer ratio smaller than 3 will not be safe. In other words, if higher monomer concentrations are used and the cooling system fails there is a risk of exceeding the Tiim temperature (T ork + AT > Tiim). Above the limit polymer/monomer = 3, the process can be operated safely because the operating line [T oik + AT] does not exceed the limit of the safe operation temperature. These data must be included in the optimization as a constraint to correctly compute safe profiles of the manipulated variables (monomers, CTAs and initiators) that would ensure the production of the polymer with the required quality under safe process conditions. 

Safe operating temperatures. Synthetic web slings of polyester and nylon shall not be used at temperatures in excess of 180° F (82.2° C). Polypropylene web slings shall not be used at temperatures in excess of 200° F (93.33° C). 

Insulation class standard insulation classes are B, F, and H, which establish the maximum safe operating temperature for the motor. 

It is valid for thicknesses of less than 2 in. Larger thicknesses require special evaluation and it has been proposed that the FTE temperature for thicknesses over 6 in. should be taken as NDT + 120 F rather than NDT + 60 F. The FTP temperature should be NDT + 210°F instead of NDT + 120°F. This indicates that for thick sections. Fig. 4.14 is on the unconservative side and the safe operating temperature should be greater than those indicated by the figure. 

Example 4.2. A low-carbon steel material with NDT temperature of 15°F is used in a pressure vessel. What is the minimum safe operating temperature for such material ... 

Solution. Because no stress level is given, the minimum stress is assumed at yield. Entering Fig. 4.14 at yield stress, the CAT curve is intersected at the FTE point. Moving vertically, a temperature of NDT + 60 F is obtained. Thus, the minimum safe operating temperature is 75°F. 

If stress concentrations are assumed in the vessel and the stress level is beyond yield at some areas, then a conservative design is at the FTP point. In this case, the safe operating temperature is NDT + 120 F, or 135°F. ... 

In order to determine carbon deposition on the anode and catalyst a new technique has been introduced, temperature-programmed oxidation (TPO). This technique is beneficial in determining a safe operating temperature for avoiding carbon deposition at low oxidant/carbon ratios. The technique allows determining the quantity of carbon deposited on the anode or catalyst with respect to operating time. 

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