What is “Static Head” in ASME Section VIII Vessels? In designing the Pressure Vessels according to the ASME Section VIII Division 1, aside from not only considering the design pressure that will occur within the Pressure Vessel, but we also need to consider the weight of the Liquid within the Vessel acting on it. The pressure caused by the weight of Liquid in Vessel is the “Static Head” which is based on the density of the liquid (Liquid Density called the p) and will have greater value as the height of the liquid from the bottom of the tank or Bottom of … Continue reading What is Static Head of vessel
External Evidence of Caustic Leaking; Carbon Steel Piping used for Caustic Service (NaOH content) may be damaged by Caustic Cracking, especially in areas with welded and discrete areas that have high stress. Caustic leaks or leaks from the cracks will look like White salt, which can be seen with the naked eye. Therefore, when doing an external visual inspection for Caustic Piping, don’t forget to look for “White Salt” which is an Evidence that indicates that our Caustic pipe is leaking. External Evidence of Caustic Leaking – Caustic Cracking on Socket Welded Piping; Example of Caustic leakage from Caustic (NaOH) Injection Piping … Continue reading What is Caustic corrosion cracking
Circumferential vs Longitudinal Stress of a Cylindrical Shell in ASME VIII Vessels; Let’s look at the formula for calculating the Cylindrical Shell thickness of the ASME Section VIII Pressure Vessel. We can see that the Minimum Thickness calculated from Circumferential Stress is approximate twice the thickness calculated from Longitudinal Stress. This is because the Circumferential Stress is twice as much as Longitudinal Stress. Therefore, when calculating Shell thickness, use the formula of Circumferential Stress. Refer to: What is Hoop Stress in pressure vessel? Continue reading Circumferential vs Longitudinal Stress
Soil to Air Interface – Zone of Corrosion on API 570 Piping; The area where the pipelines fall underground, or soil-to-air interface, is the area that has a high chance of external corrosion if Wrapping or Coating is damaged. Due to the difference in temperature, humidity and oxygen in the area, the API 570 stipulates that 6 inches above and 12 inches below the soil surface is the Soil-to-air Interface zone that should be Reviewed. Inspection of Soil-to-air Interface for Underground Piping; For example, to monitor underground pipes ( Underground, Piping) in a pipe underground or Soil-to-air Interface by digging tube down … Continue reading What is Soil Corrosion
Vessel and Tank Inspection – Rubber Lining Inspection; Within the Piping, Vessel or Tank, some will be done with Lining or Coating to Prevent Corrosion and Erosion. During inspection (in-service), damages that will occur to the Lining, such as separation, breakage, swelling. If we find that Lining damage. We have to dismantle the lining to check for damage to the metal surface of the Vessel beneath the lining (in the picture is an example of the Rubber Lining inside the tank that is very cracked and swollen, and the Corrosion that occurs on the metal surface of the tank under the Rubber Lining) Continue reading Vessel rubber lining inspection
Hydrostatic Test Pressure vs MAWP of Section VIII Vessels; An example of Hydrostatic Test Pressure compared to the MAWP of Pressure Vessel ( in the form of Shell & Tube Heat Exchanger) designed according to ASME Section VIII Div.1. What is Hydrostatic Test Pressure for Section VIII Vessels; The Hydrostatic Test of Pressure Vessel according to the ASME Section VIII Div.1 must be done at a pressure not less than 1.3 times of the Maximum Allowable Working Pressure (MAWP) of the Vessel multiplied by the Stress Ratio to compensate for the strength of the material. In case of use at high temperatures ( when Hydrotest is made at Ambient Temp.) , The Stress Ratio is the ratio of the Allowable Stress of the material to … Continue reading Test Pressure vs MAWP (ASME VIII)
PRV Testing – Trevitest (Principle); Trevitest Test Set Pressure of the Pressure Relief Valve (PRV) with On-Line while PRV are In-Service without adding (Build up) the pressure in the whole system approaching the Set Pressure. The Trevitest test kit uses the Hydraulic Lift Assist Device to help push the spindle of the PRV to overcome the spring force without increasing the pressure in the system and calculate the set pressure of the PRV using the pressure in the system. PRV Testing – Trevitest (Tools Setup); Examples of tools and installation of Trevitest test kits installed on the Pressure Relief Valve at the site: PRV Testing – Trevitest (Result Interpretation); Interpretation of Trevitest test results is done by using the software that comes with … Continue reading What is PRV valve Trevitest ?
PRV Testing – Field Test; Test Set Pressure and Seat Tightness Test of Pressure Relief Valve (PRV) at the venue (Field Test) can be performed using a kit for compressed inward, Inlet performed on Nozzle of PRV, which will make the case that PRV is large, located on a high ground, difficult to transport. Refer to: What is PRV pop test? (Popping test) Continue reading What is PRV Field Test?
PRV – Set Pressure Tolerances per ASME Section I; Pressure Relief Valve (PRV) is designed to be opened to release pressure (Relief Overpressure) at Set Pressure is set, which follows the Requirement of ASME Section I Power Boiler to Pressure Relief Valve (PRV) is a deviation ( of Tolerance) of Opening. Pressure from Set Pressure not exceeding the value in the table divided by Set Pressure of the PRV. Refer to: What is PRV pop test? (Popping test) Beside this term, there’s Blowdown and Overpressure Tolerance for PRV testing: Refer to: What is PRV blowdown? Continue reading What is PRV Set Pressure Tolerance