TABLE OF CONTENTS Areas of flat surfaces under internal pressure which are not supported have the tendency while under pressure to deform, bulge, and try to form a circle. An example of this phenomenon can be seen by blowing air into a cereal box. As pressure is applied to the box, the box becomes tubular in shape, and if one could blow hard enough, the box would rupture. The Code recognizes this problem and has included requirements for adding bracing or stays between these flat surfaces. Table 2.14 states the equations for braced and stayed surfaces and gives the Code references which apply.
| Equations | Remarks | Code reference |
|---|---|---|
 | Measurement of pitch p and values for C | Par. UG-47(a) |
 | Minimum thickness of plate that is stayed is 5/16 in except in welded construction and cylindrical or spherical outer shell plates | Pars. UG-47(b) UW-19 |
| where t = minimum plate thickness, in P = allowable pressure, psi p = maximum pitch, in S = allowable stress, psi C = a factor depending upon the plate thickness and type of stay | If stayed jackets extend completely around a cylindrical shell or spherical vessel or completely cover a formed head, the required thickness shall meet the requirements of par. (a) and the applicable requirements of UG-27(c) and UG-31. For any nozzles one should consult UG-37(d)2. | Par. UG-47(c) |
| If... |
