PED

Introduction to PED Certification for Pressure Equipment

　　The EU Pressure Equipment Directive was updated from 97/23/EC to 2014/68/EU, and the new directive will be enforced on July 19, 2016. The 2014/68/EU "Pressure Equipment Directive" (hereinafter referred to as the PED Directive) is a directive for pressure equipment among many EU directives. It stipulates the basic safety requirements (ESRs) of pressure equipment and maintains the EU pressure equipment Existing security level. It is suitable for the design, manufacture and qualification assessment of pressure-bearing equipment and complete sets of equipment with a maximum working pressure greater than 0.5 bar.

　　The specific content update date is as follows:

　　2014/6/27: released;

　　2014/7/17~2015/2/28: Article 13 transition period;

　　2015/2/28~2015/6/1: Article 9 of the old directive and Article 13 of the new directive can be used at the same time;

　　2015/6/1: Cancel Article 9 of the old directive and use Article 13 of the new directive;

　　2016/7/19: Cancel 97/23/EC, implement 2014/68/EC.

　　Authentication mode changes:  

1. Basic safety requirements (according to Appendix I of the PED Directive)

        Appendix 1 of the PED Directive is the basic safety requirements, the main contents are:

        Design (for example: strength, reliability);

        Processing (for example: processing of components);

        Inspection (for example: pressure test, acceptance);

        Marking/acceptance mark (manufacturer's acceptance mark);

        Operation guide;

        Materials: materials that comply with European harmonized standards, materials that have obtained European material approval (EMA), and materials that have passed special assessments (PMA)

Basic binding requirements:

        The manufacturer shall, in accordance with the requirements of the PED, conduct a risk analysis responsibly at the beginning of the design in order to find out the hazard of the pressure device under pressure. To this end, it is necessary to prevent the danger caused by mechanical failure of the component or container shell, and the overflow of the medium due to this. Therefore, risk analysis is the basis of component design.

        The safety of the pressure device should first be considered when designing, especially when the manufacturer expects or pre-specified operating conditions, the following issues should be considered:

Risk reduction or elimination (overall structural design, material selection, processing);

The application of protective measures (mainly using safety devices) when the hazard cannot be eliminated;

Explanation about operation in residual hazard (explained in the operation guide);

        The standards used must comply with the following requirements:

       -Tested standards;

       -European materials allowed or

       —Expert appraisal permission regulations.

        The PED directive gives the minimum requirements for materials, such as the corresponding performance and toughness indicators. The higher value range of the necessary test pressure in the regulations for finding pressure vessels is:

—1.43 times the maximum allowable pressure at room temperature;

-1.25 times the maximum load of the component at the design temperature.

 
2. Divided according to the risk level of pressure-bearing equipment in Appendix II of the PED Directive

        According to the provisions of PED Appendix II, pressure equipment can be divided into four qualified assessment levels: I, II, III, and IV. For pressure-bearing equipment with low hazard, it can be operated in accordance with sound engineering practice.

In order to achieve the classification of pressure equipment, manufacturers need to understand the following knowledge.

1) Device type

Pressure vessel

steamer

pipeline

2) Fluid status: gas or liquid. At the highest working temperature of the equipment, if the saturated vapor pressure (gauge pressure) of the fluid does not exceed 0.5 bar, it is regarded as a liquid, otherwise it should be regarded as a gas.

3) Fluid group

Group 1-Hazardous fluids: flammable, explosive, toxic, and highly oxidizing

Group 2-non-hazardous fluids: fluids outside of group 1 include steam

4) The maximum allowable pressure PS and volume V/nominal size DN of the equipment

5) The highest working temperature TS of the equipment

        Based on the above information, the manufacturer can determine the relevant classification chart in Appendix II of the PED by referring to the "Basis of Risk Level Classification", and then mark it according to the maximum allowable pressure PS and volume V/nominal size DN of the equipment in the selected classification chart Coordinate points to determine the category of pressure-bearing equipment.

         Pressure-bearing accessories can be classified according to pressure vessels or pressure pipelines, whichever is related. When both volume and nominal size are considered relevant, the category of pressure-bearing accessories shall be the highest category.

        Safety accessories are generally classified as Category IV, but as a special list, the safety accessories of some special equipment can be in the same category as the equipment they protect.

Risk classification basis

 3. Conformity assessment method in accordance with Appendix III of the PED Directive

I-IV equipment evaluation mode selection:

1) Mode A: Internal production control

This mode requires manufacturers to prepare technical documents, including: general description of pressure-bearing equipment, design drawings, strength calculations, list of adopted standards, inspection results, test reports, etc. The manufacturer puts the CE mark on each pressure-bearing equipment and submits a written declaration of conformity. This mode does not require an authorized body (Notified body) to perform the review.

2) Mode A1: Internal manufacturing inspection with final assessment supervision

In addition to the requirements of Mode A, the manufacturer performs the final assessment (final inspection and pressure test), and the authorized agency conducts irregular supervision and spot checks on the pressure equipment being manufactured or completed. In addition to the CE mark and the declaration of conformity, the authorization is reflected The responsibility of the agency is to mark the identification number of the authorized agency on each pressure-bearing equipment.

3) Mode B: EC type approval

The authorized agency certifies that the representative samples produced by the manufacturer meet the requirements of the directive.

In addition to the requirements of Mode A, the content of the manufacturing process has been added. The authorized body will perform review and check the certificate issued by the material manufacturer for materials that do not meet the European harmonized standards or European approvals; approve the permanent connection (welding) process; verify that the welding and NDT personnel have been qualified and approved as required; at the same time , Verify that the sample manufacturing complies with the technical documents. The authorized institution will issue an EC type approval certificate with a validity period of 10 years.

4) Mode B1: EC design approval

The authorized agency certifies that the design of a pressure-bearing equipment product meets the requirements of the directive. Except that it is not necessary to verify that the samples meet the requirements of the technical documents, the evaluation items of the authorized institution are the same as those of mode B. The authorized institution will issue an EC design approval certificate with a validity period of 10 years.

5) Mode C1: Type conforms

The manufacturer guarantees that the pressure equipment conforms to the type described in the EC Type Approval Certificate and meets the requirements of the directive. Authorized agencies conduct irregular supervision and spot checks on pressure-bearing equipment being manufactured or completed, mark each product with the CE mark, authorized agency identification number, and issue a written declaration of conformity.

6) Mode D: Production quality assurance

The manufacturer conducts production, final inspection and testing in accordance with the approved quality system to ensure that the pressure-bearing equipment conforms to the type described in the EC type approval certificate or the EC design approval certificate and meets the requirements of the directive.

The authorized institution will review the quality system to determine whether it meets the requirements, and must conduct regular audits and complete a comprehensive review every 3 years. The authorized agency will also perform irregular supervision and inspection on the manufacturer to verify the normal operation of the quality system. Each product is marked with the CE mark, the authorized agency identification number, and a written declaration of conformity is issued.

7) Mode D1: Production quality assurance

Compile technical documents according to mode A. The manufacturer conducts production, final inspection and testing in accordance with the approved quality system to ensure that the pressure-bearing equipment meets the requirements of the directive. The rest is the same as mode D.

8) Mode E: product quality assurance

The manufacturer conducts final inspection and testing in accordance with the approved quality system to ensure that the pressure-bearing equipment conforms to the type described in the EC type approval certificate and meets the requirements of the directive. The rest is the same as mode D.

9) Mode E1: product quality assurance

Compile technical documents according to mode A. The manufacturer conducts final inspections and tests in accordance with the approved quality system (ISO9003) to ensure that the pressure-bearing equipment meets the requirements of the directive. The rest is the same as mode D.

10) Mode F: product verification

The manufacturer guarantees that the pressure equipment complies with the EC type approval certificate or the EC design approval certificate and the requirements of the directive.

Authorized agencies perform inspections and tests on each product to verify that its type meets and meets the requirements of the directive. The key is to verify that the welding personnel and NDT personnel have been qualified and approved in accordance with the regulations; the certificate issued by the material manufacturer; the final inspection and verification test (pressure test) of the product and the inspection of the safety device. Each product is marked with the CE mark, the identification number of the authorized organization, and a written declaration of conformity is issued. The authorized agency issues the conformity certificate of the product.

11) Mode G: Single unit verification

The manufacturer compiles technical documents according to mode A. The authorized agency inspects the design and structure of each pressure-bearing equipment, and conducts inspections and tests in accordance with relevant standards during manufacture. The inspection content includes final inspection and verification test (pressure test) and inspection of safety devices, in addition to the items in Mode B. Each product is marked with the CE mark, the identification number of the authorized organization, and a written declaration of conformity is issued. The authorized agency issues the conformity certificate of the product.

12) Mode H: Total Quality Assurance

The manufacturer implements the approved quality system including design, manufacturing, final inspection and testing to ensure that the pressure-bearing equipment meets the requirements of the directive.

The review, regular review and irregular supervision and inspection of the quality system by the authorized institution are the same as Mode D. Each product is marked with the CE mark, the identification number of the authorized organization, and a written declaration of conformity is issued.

13) Mode H1: Comprehensive quality assurance with specific supervision of design approval and final assessment

In addition to the requirements of Mode H, it is also necessary to add:

1) The manufacturer submits an application for design approval to the authorized agency, and after the review meets the requirements of the directive, the authorized agency will issue an EC design approval certificate;

2) The authorized agency conducts supervision and inspection on the final assessment (final inspection and pressure test) performed by the manufacturer through irregular visits.