ASME STS

An alternative criterion is given in ASME STS-1-2000, Steel Stacks. This standard is written specifically for stacks. The criterion listed in this standard calculates a critical vortex... 

This procedure is for cylindrical stacks or vessels only, mounted at grade. It is not appropriate for tapered stacks or vessels. There is a detailed procedure in ASME STS-1 for tapered stacks. Multidiameter columns and stacks can be evaluated by the methods shown. This procedure also does not account for multiple vessels or stacks in a row. 

ASCE 7-95 Major Oil Co ASME STS-1 NBC Misc. Papers Gupta Compress... 

Ip = importance factor, 1.0-1.5 L = overall length of vessel, ft Ml = overturning moment due to force Fl, ft-lb Ms = overturning moment due to seismic, ft-lb Mr = resultant moment, ft-lb Mw = overturning moment due to wind, ft-lb MwD = modified wind moment, ft-lb qH =wind velocity pressure, psf, per NBC q = external wind pressure, psf per ASME STS-1 S = Strouhal number, use 0.2 T = period of vibration, sec t = shell thickness, in. 

Vco = critical wind speed for ovalling of stacks, ft/sec Vr = reference design wind speed, mph, per ASME STS-1... 

Vj, = mean hourly wind speed, ft/sec Vzcrit = mean hourly wind speed at % L, ft/sec W = overall weight of vessel, lb w = uniform weight of vessel, Ib/ft Wr = uniform weight of top third of vessel, Ib/ft a, b = topographic factors per ASME STS-1 8= percent critical damping, damping factor jSa = aerodynamic damping value... 

Step 5 To evaluate v ortex shedding loads, refer to ASME STS-1, Appendixes E-5 and E-6. 

Steel Stacks, ASME STS-1-2000, American Society of Mechanical Engineers, 2001. 

The ASME STS-1 Steel Stacks [2] governing standard used in the design of steel stacks is important, and everyone should be familiar with it. In Example E.7 in the standard, the mass damping parameter is used as a... 

TABLE 3.2 ASME STS-1 Representative Structural Damping Values... 

Lining must consist of a minimum 2 in. thick, nominally lOOpcf density liner material for stack to beconsidered lined for the use of this table. (Reprinted from ASME STS-1-2006, by permission of the American Society of Mechanical Engineers. All rights reserved.)... 

Now look at the sixth criterion the mass damping parameter. According to Table 3.2 (from Table 5.2.1 of ASME STS-1 [2]), an unlined stack has a structural damping value, x, of 0.004, which Findlay [3] states is commonly used. According to Note 3 of this table, a structural damping value of 0.006 can be used only when the stack has a lining of a minimum of 2 inches thick... 

The phenomenon of ovaling is predominant with stacks. ASME STS-1, Paragraph 5.2.2(b) [2], gives guidelines for ovafing. Eor unlined steel stacks, the ovaling natural frequency is computed as follows ... 

If Vco is less than 1/, the mean hourly wind speed (ft/sec), the unlined stack should be reinforced with ring stiffeners meeting the requirements of Table 3.3 (Table 4.4.7 in ASME STS-1 [2]). 

ASME STS-1-2006, American Society of Mechanical Engineers, New York, NY, 2006. Findlay, Matt, Improved Screening Criteria for the Prediction of Wind Induced Vibration of Tall Process Vessels Arising from Recent Field Experience, ASME, New York, NY, November 2001. 

ASME STS-1 [1] follows the latest ASCE 7 standard series— presently ASCE 7-2005 [2]. We will develop a general guideline of this standard that can be used throughout the world in various locations that do not have wind codes. If you are located in a country that has such a standard, it is advised that you follow that document. However, for operational applications, the methodology proposed here should be adequate. 

T. Asayama, Update and improve subsection NH — alternative simplified creep-fatigue design methods, ASME ST-LLC, STP-NU-041 (2011). 

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