Design factor of safety

With aflame length of 13.9 m, the jet flame will impinge on the steel structure overhead. Consequently, the steel will see high convective and radiative heat fluxes on the order of 200 kW/m. Since the structure will be exposed to direct flame impingement, the expected failure time would be 3-4 minutes (Table 5-7) or less due to the high heat flux from the jet fire, depending on the type of steel structure and design factor of safety. 

Safety, as always, is a prime consideration for any changes in a winder system especially where the operation of ropes is concerned. The amount of offset that would be available should not cause any concerns at the bottom of the shaft, if applied in error by a faulty control system, given that the nominal value of 2.5 tonnes of offset would be on a base load of 22.26 toimes of rope and half of the 45 tonnes of total skip load, or -5.6%. Whilst this will likely exceed the design factor of safety for the hoist during the event, it will not be by a large amount Even at the tip the base load would be half of an empty skip, which would be some 8.6 toimes. 

Design Safety Factor A factor used to account for uncertainties in material properties and analysis procedures. It is often referred to as design factor of safety or simply safety factor. 

A difference between tank cars and most pressure vessels is that tank cars are designed in terms of the theoretical ultimate or bursting strength of the tank. The test pressure is usually 40 percent of the bursting pressure (sometimes less). The safety valves are set at 75 percent of the test pressure. Thus, the maximum operating pressure is usually 30 percent of the bursting pressure. This gives a nominal factor of safety of 3.3, compared with 4.0 for Division 1 of the ASME Pressure Vessel Code. 

NASA Engineering Management Council (EMC) 1995 Preliminary NASA Standard, General Requirements for Structural Design and Test Factors of Safety. 1 August (http // amsd-www.larc.nasa.gov/amsd/refs/fac saf.html). 

One of the key elements in laminated composite structures design is the ability to tailor a laminate to suit the job at hand. Tailoring consists of the following steps. We want to design the constituents of the laminate, and those constituents include the basic building blocks of the individual laminae and as well how they are oriented within the laminate. We design those constituents to just barely meet (with an appropriate factor of safety) the specific requirements for, say, strength and stiffness. 

The problem must be simplified considerably to permit solution in the context of this book. Suppose an equilateral triangle is subjected to some loads in the vertical direction as in Figure 7-22. A load P of 100 lb (445 N) is applied to the top joint, and that load can go in either the downward or upward direction (in the diagram, not in space ). This truss must take its reversible load with, say, a factor of safety of two against whatever event would cause it to fail. What material, size, and weight of truss element would you select to satisfy the design requirements that include building the structure for the lowest cost ... 

Safety as it is reflected in factors of safety in design of pressure vessels, pressure testing of piping and vessels, etc. Use of A.P.I., A.S.M.E. and ASA Codes Code Stamps on equipment. 

In the example the manufacturer has been specified from available performance curves, and the details of construction must be obtained. The pump is selected to operate at 22 GPM and 196 to 200 feet head of fluid, and must also perform at good efficiency at 18 GPM and a head which has not been calculated, but w hich will be close to 196 to 200 feet, say about 185 feet. Ordinarily the pump is rated as shown on the specification sheet. This insures adequate capacity and head at conditions somewhat in excess of normal. In this case the design GPM w as determined by adding 10 percent to the capacity and allowing for operation at 90 percent of the rated efficiency. Often this latter condition is not considered, although factors of safety of 20 percent are not unusual. However, the efficiency must be noted and the increase in horsepower recognized as factors w hich are mounted onto normal operating conditions. 

Scope, 52 Basis, 52 Compressible Flow Vapors and Gases, 54 Factors of Safety for Design Basis, 56 Pipe, Fittings, and Valves, 56 Pipe, 56 Usual Industry Pipe Sizes and Classes Practice, 59 Total Line Pressure Drop, 64 Background Information, 64 Reynolds Number, R,. (Sometimes used Nr ), 67 Friction Factor, f, 68 Pipe—Relative Roughness, 68 Pressure Drop in Fittings, Valves, Connections Incompressible Fluid, 71 Common Denominator for Use of K Factors in a System of Varying Sizes of Internal Dimensions, 72 Validity of K Values,... 

The summary of HETP values of Vital [142] for various types and sizes of packings are believed to be referenced to typical industrial distributors for the liquid. This variation can influence the value of HETP in any tabulation the effect of distributor design is discussed in an earlier section of this chapter. Porter and Jenkins [143] developed a model to improve the earlier models of Bolles and Fair from about 25% deviation to about a 95% confidence using a 20% factor of safety [139]. 

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