PED 97/23/CE Directive

The Pressure Equipment Directive, 97/23/EC, commonly known as the PED Directive, was issued by the European Union and implemented in Italy with Legislative Decree N° 93/2000. This Directive regulates the design and construction of pressure equipment subject to a relative pressure greater than 0.5 bar.

The main new features introduced by PED are: • The regulation of pressure equipment design and construction, including reference to European

Harmonised Standards (e.g. EN 13445 for flameless pressure vessels, EN 12952 for water tube boilers, EN 12953 for fire tube boilers, EN 13480 for piping), with a choice of which code is to be applied both in the engineering phase as well as the construction and monitoring phase. This is carried out by placing technical limitations related to the elastic properties, the efficiency of the welded joints and tenacity of the materials used.

• The identification of the manufacturer as the responsible for all construction phases, from design to manufacturing to final testing. The manufacturer must also ensure that the pressure risk is adequately addressed in all stages even after the final inspection, such as transport, installation, commissioning, operation, maintenance and disposal.

• The identification of a Notified Body, as the responsible for certain phases of Certification, depending on the Module of the Directive chosen by the Manufacturer

Each item of pressure equipment:

1. must be classified based on the pressure, the volume (or the diameter in the case of pipes) and the type of fluid contained.

2. must be subjected to an inspection of compliance with the minimum safety requirements with varying degrees of severity depending on the possible risk for safety purposes.

3. must be equipped with a user instructions manual wherein the manufacturer should: indicate any potential risks of their product; make the user aware of any precautions to be taken; indicate any inspections and maintenance that is required and how often in order to keep the product itself safe over time.

PRESSURE EQUIPMENT Pressure equipment are:

1. VESSELS Housing designed and built to contain fluids under pressure. This includes its direct attachments up to the coupling point connecting it to other equipment. A vessel may be composed by more than one chamber. The following examples of products are classified as vessels: • Compressors, pressure vessels, condensers, gas or steam vessels, reactors, heat exchangers,

LPG spheres • Tanks, reactors installed in production equipment, fire extinguishers • Steam Generators • Vessels for liquefied gases (cryogenic tanks)

2. PIPING

Piping components intended for the transport of fluids when connected together for integration into a pressure system. This includes a pipe or system of pipes, tubing, fittings, expansion joints, hoses, or other pressure-bearing components as appropriate; heat exchangers consisting of pipes for the purpose of cooling or heating air are considered as piping. For example: • dismantling joints, expansion joints • flanges, fittings, etc.

Not included are for example hydraulic tubing for oil or gas.

3. SAFETY ACCESSORIES

Devices designed to protect pressure equipment against the allowable limits being exceeded. Such devices include: • devices for direct pressure limitation, such as safety valves and bursting discs, buckling rods,

Controlled Safety Pressure Relief Systems and • limiting devices which either activate the means for correction or provide for shutdown or

shutdown and lock out, such as pressure switches, temperature switches or fluid level and equipment for Safety Related Measurement, Control and Regulation.

4. PRESSURE ACCESSORIES:

Devices with an operational function and having pressure-bearing housings. For example: • Valves (shut-off, regulator) • Vents, check valves

5. ASSEMBLIES:

Several pieces of pressure equipment assembled by a manufacturer to constitute an integrated and functional whole.

HAZARDS AND RISK ASSESSMENT PRINCIPLES The PED requires manufacturers to identify the risk level of the equipment built. They are required to assess hazards due to pressure and then to design and build the equipment with this analysis in mind. The danger level is related to the concept of energy stored in the equipment. The stored energy is evaluated using the following parameters:

• Maximum allowable pressure (PS): maximum pressure in bar for which the equipment is designed, according to the manufacturer specifications;

• dimensions: o volume V in litres in the case of containers (full volume including accessories attached

permanently, excluding the volume of permanent internal parts) o diameter DN in mm in the case of tubing

• minimum/maximum permissible temperature (TS): minimum/maximum temperatures for which the equipment has been designed, according to manufacturer specifications

• fluid type: gas, liquids, steam whether by themselves or mixtures thereof. These can be divided into o Fluid Group 1: dangerous media. The following fluids are included in this category:

Explosive Extremely flammable Highly flammable Flammable (where the maximum allowable temperature is above flashpoint) Very toxic Toxic Oxidizing media.

o Fluid Group 2: non-dangerous media. All other fluids not included in Fluid Group 1. • installation and operating conditions

Based on Annex II of the Directive, there are 9 tables through which it is possible to define the risk category (I, II, III, IV) depending on: the type of pressure equipment (piping, vessel, accessories); the fluid group (dangerous or non-dangerous fluids); the physical state of the fluid (gas, liquid); and the result of the PS x V calculation, for containers, or PS x DN, for pipes. The equipment acquires the category of highest risk from the risk characteristics of the components that are part of it, with the exception of the safety devices which are automatically classified in category IV, which is the maximum risk category.

RISK CATEGORY Low risk equipment In case of proven low hazard levels, (as provided in Article 3, paragraph 3 of the Directive), a formal assessment of compliance with minimum safety is not required, however, the equipment must still be designed and constructed in accordance with good engineering practice and must be accompanied by adequate user instructions clearly identifying the manufacturer. The manufacturer is still responsible for the safety of their product. Category I Equipment Low risk equipment and assemblies belong to this category. The formal assessment of compliance with the Directive is carried out by the manufacturer who signs a Declaration of Conformity (available to the client) and affixes the CE marking on the equipment or assembly. Products must be designed and manufactured in accordance with the minimum safety requirements of the Directive and must be accompanied by appropriate user instructions and bear an identification plate containing the data required by the Directive. Category II to IV Equipment Increased risk equipment and assemblies belong to this category. The formal assessment of compliance with the Directive is carried out by a Notified Body or a user inspectorate which, after the assessment, shall issue a Certificate of conformity to the manufacturer. Once the manufacturer has obtained the Certificate, he signs a Declaration of Conformity (available to the client) and affixes the CE marking on the equipment. Products must be designed and manufactured in accordance with the minimum safety requirements of the Directive and must be accompanied by appropriate user instructions and bear an identification plate containing the data required by the Directive. For assemblies, the conformity assessment is performed both on individual items making up the whole (each according to its category), and on the whole assembly. The category of an assembly is the maximum between those of the individual equipment that compose it.

APPLICATION MODULES For category I, which covers the less hazardous equipment, the CE certification is provided without the intervention of the Notified Body: indeed the PED allows "self-certification", i.e. the CE marking of the product according to the preparation of a technical file demonstrating how the essential requirements of Annex I of the Directive have been met and also justifying the product belonging to the category, accompanied by a Declaration of Conformity issued by the manufacturer and destined to the purchaser. The requirements are more onerous in the upper classes, up to class IV:

• Category II: the CE certification by a notified body is mandatory. Without considering the merits of design, the notified body shall carry out the monitoring of production and the methods chosen by the manufacturer;

• Category III: CE certification by a notified body is mandatory. If a manufacturer has not certified their quality system, including design, the execution of in depth testing on the prototype to be CE certification is mandatory;

• Category IV: requires the highest level of control on design and production. Reference is made to the safety equipment (automatically), and to assemblies consisting of vessels + pipes for the use with hazardous fluids at high pressures. Category IV is never reached by Group 2 fluids with a steam pressure lower than 0.5 bar (e.g. water at temperatures below 110 °C), regardless of the size of the equipment.

The application Modules according to the Category are summarised in the following table.

CATEGORY APPLICATION MODULE(S)

I A

Internal production control

II

A1 D1 E1

Internal production control and final monitoring inspection

Production quality assurance

Product quality assurance

III

B1+D B1+F B+E B+C1 H

CE EXAMINATION of design + Production Quality Assurance

CE EXAMINATION of production + Product inspection

CE TYPE EXAMINATION + Product Quality Assurance

CE TYPE EXAMINATION + Conformity of type

Full quality assurance

IV

B+D B+F G H1

CE TYPE EXAMINATION + Production Quality Assurance

CE TYPE EXAMINATION + Product inspection

Inspection of single product

Quality assurance with the final monitoring

REQUIRED DOCUMENTATION The PED requires stringent documentation of all equipment and pressure assemblies that exceed 0.5 bar.

DOCUMENT TYPE ISSUED BY MODULE CATEGORY

Declaration of Conformity Manufacturer A, A1, C1, D, D1, E, E1,

F, G, H, H1 I, II, III, IV

Certificate of CE type examination Notified Body B III, IV

Certificate of CE examination of design Notified Body B1 III

Certificate of CE examination of the project

Notified Body H1 IV

Certificate of Conformity Notified Body F, G III, IV

Quality system Assessment notification Notified Body D, D1, E, E1, H, H1 II, III, IV

A substantial part of the documentation required is collected in the "Technical File". We have listed some of the contents below. Regarding the design:

1. Risk analysis and assessment; 2. Report on design; 3. Drawings;

Regarding the materials:

1. Description of materials; 2. Specifications required; 3. Certification of materials; 4. Tests on the materials used;

Regarding the manufacturing:

1. Description of manufacturing processes; 2. Operator qualifications; 3. Welding qualifications; 4. Report on process control management;

Regarding the implementation:

1. Final inspection report; In addition to the technical dossier, the manufacturer must also draw up a user manual and a maintenance log for the user.

ASSEMBLY ASSESSMENT New assemblies New assemblies must follow the Directive and therefore must be subject to an assessment of conformity and bear the CE mark. Who builds and sells such assemblies is the manufacturer, pursuant to the Directive, and therefore is under all the obligations set out by the same. Assemblies pre-existing the Directive, which do not require any intervention These assemblies may continue to be operated without additional expense to the user except the re-classification according to the new categories of risk listed in the Directive and the execution of a series of checks to define the state of preservation. Assemblies pre-existing the Directive, which are subjected to modification The Directive states that, following any modification, the equipment should be subjected to a verification of compliance: therefore the party in charge of this modification (except in the case in which the product user assumes full responsibility) is the assembly manufacturer with all consequent obligations. Assemblies pre-existing the Directive, which are subjected to component replacement This is the most common and most complex situation. Notwithstanding the fact that the substitute component must be CE marked, the problem is represented by the inclusion of this component in the assembly. If the user does not assume full responsibility, the party responsible for replacement is required by the Directive to operate according to the Directive, and therefore we will be faced with two options:

1. CE mark the whole assembly (as in the case of a modification) 2. CE mark the individual substitution piece.

In the latter case, however, the Notified Body responsible must be provided with proper documentation attesting the fact that the existing part and the part replaced are mutually compatible; as a minimum, this will require a risk analysis of the whole. The choice of which path to take will depend on the specific case and the decision should be taken necessarily in agreement with the user of the assembly. ------------------------------------------------------------------------------------------------------------------------------------------------ CTAI, TÜV Rheinland Partner, Notified Body, can offer all services necessary for the application steps of the Directive and in particular:

- Technical File Examination - Inspections of materials and components - Special approvals of materials - Qualifications of working processes (e.g., permanent joints) and of the workers - Qualifications of operators of Non-Destructive Testing - Certificate for Modules A1, D1, E1 - Certificate for EC type examination, Module B - Certificate for EC design examination, Module B1 - Certificate of Conformity to Type, Module C1 - Certificate for production quality assurance, Module D - Certificate for product quality assurance, Module E - Single product verification, Module F - Single product EC verification, Module F - Certificate for full quality assurance, Module H - Full quality assurance certificate with production control, Module H1

We can also provide the manufacturer with support for the following services:

- Identification of the applicable requirements of the Directive, and the relevant harmonised and/or non-harmonised standards

- Choice of the application Modules of the Directive - Execution of compliance testing in affiliated laboratories - Consultancy for risk analysis and the development of the Technical File as required by the Directive - Training courses on the application of the Directive