The Pressure Equipment Directive (PED) 2014/68/EU is a European Union directive that sets out safety requirements for the design, manufacture, and placing on the market of pressure equipment. The PED harmonized material lists (HMLs) are a set of standards that specify the materials that can be used in pressure equipment.
The ASME Boiler and Pressure Vessel Code (BPVC)
The ASME BPVC is a set of American standards that are used for the design, construction, and inspection of pressure vessels. The BPVC is not explicitly referenced in the PED, but many of the materials listed in the BPVC are also listed in the PED HMLs.
Materials in the PED HMLs
The PED HMLs list a wide variety of materials, including:
Carbon steel
Stainless steel
Nickel alloys
Copper alloys
Titanium alloys
Aluminum alloys
Magnesium alloys
Plastics
Composites
The choice of materials for pressure equipment is important for ensuring its safety. The materials must be able to withstand the pressure and temperature conditions to which they will be exposed. They must also be resistant to corrosion and other forms of degradation.
How to Use the PED HMLs
The PED HMLs are divided into two parts:
Part A: Materials for pressure vessels
Part B: Materials for piping
Each part of the HMLs lists the materials that can be used for a particular type of pressure equipment. The lists also specify the minimum requirements for the materials, such as their mechanical properties and corrosion resistance.
To use the PED HMLs, you first need to identify the type of pressure equipment that you are designing or manufacturing. Once you have identified the type of equipment, you can then consult the appropriate part of the HMLs to find the list of approved materials.
Particular Material Appraisal (PMA)
If the material you want to use is not listed in the PED HMLs, you may need to obtain a Particular Material Appraisal (PMA) from a notified body. A PMA is a one-time evaluation and approval of a material as it relates to the pressure equipment's parameters it will be used in. The PMA will consider the material's properties, the design of the pressure equipment, and the intended operating conditions.
The PMA process can be costly and time-consuming, but it is necessary to ensure the safety of the pressure equipment.
The PED HMLs are an important resource for designers and manufacturers of pressure equipment. The lists ensure that the materials used in pressure equipment meet the required safety standards. By using the PED HMLs, you can help to ensure the safety of your pressure equipment.
Other Standards for Pressure Equipment Materials
In addition to the ASME BPVC and the PED HMLs, there are a number of other standards that can be used to specify the materials for pressure equipment. These standards include:
EN 13445:2004 - Pressure Equipment - Materials and Design
API 579:2016 - Fitness for Service
NACE MR0175/ISO 15156:2015 - Petroleum and Natural Gas Industries - Materials for Use in H2S-Containing Environments in Oil and Gas Production
The choice of which standard to use will depend on the specific application. However, the PED HMLs are a good starting point for most applications.
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