What means the “maximum allowable pressure PS”?
The Term “PS = maximum allowable pressure” is specified in PED. “PS” is the pressure at a specific point on the pressure equipment for which the pressure equipment as a whole was designed. The specified location is usually the highest point on the pressure equipment, where the safety devices for pressure limitation are usually also […]
Suitable Standard-Duplex and Super-Duplex steels for Pressure Equipments
This article provides an overview of duplex material specifications for pressure equipment applications. Compared with some other materials, Standard Duplex Steels and Super Duplex Stainless Steel are less costly material of construction offering high mechanical strength, good weldability, good toughness and good corrosion resistance even in highly demanding applications. These qualities have led to acceptance […]
Stainless steel materials with high resistance to chloride-induced stress corrosion cracking (SCC)
Stress corrosion cracking (SCC) is characterized by cracks propagating either transgranularly or intergranularly (along grain boundaries). Chlorides are widely present in many industrial and natural environments, such as seawater. When metal alloys are exposed to these environments, they can become vulnerable to Chloride-induced SCC. This type of corrosion is particularly common in materials like stainless […]
Duplex stainless steels – Classification in four groups
The PREN (Pitting Resistance Equivalent Number) for duplex steels is an important parameter for classifying duplex steels also from the point of view of corrosion resistance, such as chloride stress corrosion cracking (SCC). Duplex materials have evolved in recent decades and are now classified into 4 groups: This classification is not officially standardised, but it […]
Is Design Approval by a notified body required under Modul G?
Module G does require that a notified body must examine the design of the pressure equipment and it is considered reasonable to expect the notified body to inform the manufacturer of the results of the examination. Module G does not contain any explicit requirement for approval of the design by the notified body. However, it […]
Which documents have to be available for the final inspection of a Pressure Equipment?
Pressure equipment shall undergo a final inspection to assess visually and by examination of the accompanying documents compliance with the requirements of this Directive. Test carried out during manufacture may be taken into account. As far as is necessary on safety grounds, the final inspection shall be carried out internally and externally on every part […]
Weldolet – Integral reinforced forged branch outlets
Weldolet fittings – the Branch Connection Fittings are also named as Outlet fittings. Outlets are a family of forged products used to make 90 degree or 45 degrees integrally reinforced branch connections from a header pipe or run pipe to an outlet pipe or branch pipe. When stress concentrations and cyclic loads are a concern, detailed analysis is required. […]
What means ISO 5208 leakage rate A?
The ISO 5208 rate A specify a leakage by internal tightness seat test (or often also called closure test) of valves. Usually one side (valve inlet) shall be subjected to the test pressure and amount of leak shall be measured on the opposite side of the valve to atmosphere. ISO 5208 specifies valve closure tests of an […]
High temperature hydrogen attack (HTHA) of steels
Carbon steel process plant that operates with hydrogen at elevated pressure and temperature can be weakened by a phenomenon known as high temperature hydrogen attack (HTHA). The effect of hydrogen on carbon steel and its alloys has been known for some years, whereby at elevated temperatures and pressures, atomic hydrogen enters the microstructure of the steel, and reacts with […]