This Day in History (1986): New sound power level technology predicts possibility of pipe fatigue

From the Aug. 27, 1986, edition of The Arabian Sun

Very few gas plants in the world have the high volume and pressure that are intrinsic to Aramco gas facilities, as well as the large relief valve systems that protect against potential ruptures during upset plant conditions.

Recently Aramco process engineers analyzed these relief systems and devised sophisticated procedures to incorporate sound power level technology acquired from Exxon.

This technology helps determine whether relief systems would suffer pipe fatigue from acoustically induced vibrations called by "a relief" during an upset condition and offers approaches to prevent fatigue or failure.

"When a relief valve lifts to offset pressure caused by an upset like a blockage or fire, the resulting high gas velocities can produce sonic flow (flow at the speed of sound) and high noise levels that — depending upon the individual system and the duration the system is operating — can cause serious damage," says Frank Hollis, engineering specialist within the Process and Control Systems Department.

In the past, a major stumbling block to gauging sound power levels with the system's piping — sometimes consisting of thousands of meters between flare and relief valve — was the inability to quantify the levels at critical pipe locations as well as their potential impact.

Hollis developed several sophisticated computer programs for the IBM mainframe -- by incorporating pertinent data such as physical properties of the gas and safety valve capacities -- that calculate pressure drops and predict sonic shock waves at critical points in the relief system. These programs allow a process engineer to sit down at a terminal and in a short time produce a pressure profile of a particular relief system.

Caption for top photo: Frank Hollis, engineering specialist with Process and Control Systems, refers to one of his IBM computer programs that calculate pressure drops and predict sonic shock wave occurrences in relief valve piping.

Also on this date

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1991 — The European Community recognizes the independence of the Baltic states of Estonia, Latvia, and Lithuania

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1962 — The Mariner 2 unmanned space mission is launched to Venus by NASA

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1933 — The first Afrikaans bible is introduced during a Bible Festival in Bloemfontein

1928 — The Kellogg-Briand Pact outlawing war is signed by 15 nations, with 61 nations eventually signing it

1908 — China is transformed from a dynasty to a constitutional monarchy with the Qinding Xianfa Dagang

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