The hydrostatic pressure of a liquid column under horizontal water pressure in a vertical container

It’s messy – the static pressure used in the operation and the precise pressure head used in the hydrostatic test have been mixed up.

I haven’t done any research, but my first impression is that you’re right.

GB150 stipulates that when performing a hydraulic test on vertical containers in a horizontal position, the test pressure shall include the hydrostatic pressure of the liquid column that would be present during a vertical test.

The 5% design pressure of the liquid column hydrostatic pressure P in medium refers to the selection of the value for the liquid column hydrostatic pressure, based on the calculated load (the pressure value used in the calculations). . . .

1. Since the MAWP in ASME VIII-1 already takes into account the hydrostatic pressure of the liquid column, is it not necessary to add additional hydrostatic pressure due to the liquid column when conducting a hydrostatic test, whether it is done vertically or horizontally? A: For vertical installations, just proceed as normal, using the smallest value from the calculations (excluding the hydrostatic pressure of the liquid column) ； For horizontal installations, the static pressure of the liquid column is not considered, with a threshold of 5%. 2. In GB150, if the static pressure of the liquid column P represents 5% of the design pressure of the medium, then for vertical containers undergoing horizontal hydrostatic testing, the pressure P = (1.25 * design pressure at the bottom * stress ratio); is it not necessary to add the static pressure of the liquid column again? A: Hydrostatic pressure of the liquid column.

The last edit to this post was made by yonglishiwo on 2022-3-24 at 16:55. 1. The requirement of 5% for the static pressure of the liquid column and the design pressure is intended for calculating the wall thickness of the tank, and it has nothing to do with the pressure resistance test； The clause is derived from clause 4.3.2 b) of GB/T150.1-2011. If the medium in the container is a gas, there is no hydrostatic pressure from a liquid column, and this is not taken into account in the calculations ； 2. During the hydrostatic test, the pressure used for the stress test is the pressure at the top of the tank; at this point, whether the tank is tested in an upright or horizontal position, the pressure at the bottom of the tank is greater than the pressure used for the stress test ； The provision is derived from GB/T150.1-2011, Clause 3.1.5: 3. During the hydrostatic test, the static pressure of the liquid column is used to verify the strength at the test pressure; regardless of its magnitude, it must be taken into account in the strength assessment to prevent accidents ； The provisions are derived from: GB/T150.1-2011, Clause 4.6.3(4); for vertical vessels, a horizontal pressure testing is carried out, and the pressure required for the strength test is 1.25 times the design pressure multiplied by the allowable stress ratio, with the additional static pressure of the liquid column in the vertical position also taken into account. The clause is derived from: GB/T150.1-2011, Clause 4.6.2.1(a). The purpose of this is to ensure that, during hydraulic testing of the tank while it is in use, the tank does not collapse under pressure; since the pressure at the bottom of the tank is higher in such situations, the strength tests conducted during manufacturing are carried out using this pressure level, thereby ensuring the safety of the container during use.

When considering the calculated pressure, the static operating pressure of the medium needs to be added to the design pressure as the calculated pressure. Vertical and horizontal configurations take into account the hydrostatic pressure of water, which is the testing medium used in the final pressure resistance test

This post was last edited by zjq1962 on 2022-3-25 08:51. 1. Since the MAWP in ASME VIII-1 already takes into account the hydrostatic pressure of the liquid column, is it not necessary to add an additional hydrostatic pressure for the hydraulic test, whether it is conducted vertically or horizontally? 2. In GB150, if the static pressure of the liquid column P represents 5% of the design pressure of the medium, then for vertical containers undergoing horizontal hydrostatic testing, the pressure P = (1.25 * design pressure at the bottom * stress ratio); is it not necessary to add the static pressure of the liquid column again? 1. The ASME code does not specify the need to apply a hydrostatic head pressure, but it requires that the pressure at any part of the vessel during the pressure testing shall not be lower than the specified test pressure. It depends on the position of the pressure gauge during the test; if it is at the top, there is no need to consider it, but if it is not at the top, then it needs to be taken into account. For example, if the pressure gauge is not located at the top during pressure testing, then when the specified test pressure is reached, the actual pressure at the top of the container has not been attained. Then the hydrostatic pressure of the liquid column corresponding to the height from the top to the pressure gauge needs to be added. 2, 3: When determining the design pressure, the static pressure of the liquid column is not taken into consideration; however, during pressure testing, the static pressure of the liquid column must be accounted for whether the vertical container is tested in an upright position or in a horizontal position.

The hydrostatic head used in calculating thickness and the hydrostatic pressure of the liquid column considered during testing serve different purposes and should not be confused.