AD 2000 code: series, W data sheets and ordering practice
Anyone building pressure vessels or pressure-bearing pipework sooner or later runs into an abbreviation such as “AD 2000-W 2”. It appears on certificates, in specifications and on orders – and it helps decide whether a material may be used at all. This article explains how the code is structured and which part of it you actually need when purchasing.
What the AD 2000 code is
AD 2000 is a technical code for pressure vessels, published by the German Pressure Vessel Association (Arbeitsgemeinschaft Druckbehälter). It is not legislation but a recognised code of practice: building to it demonstrably satisfies the essential safety requirements of the European Pressure Equipment Directive 2014/68/EU.
The code is not a single document but a collection of data sheets. Each sheet carries a letter for its series and a number – together they form references such as “HP 0”, “B 1” or indeed “W 2”.
The series at a glance
| Series | Content | Example of a question it answers |
|---|---|---|
| G | Principles | Scope, structure of the code |
| A | Equipment, installation, marking | Which safety devices are required? |
| B | Design calculation | How thick does the wall have to be? |
| HP | Manufacture and testing | Who may weld, how is it inspected? |
| W | Materials | Which steel is approved for which temperature? |
| S | Special cases | Cyclic loading, unusual operating modes |
| N | Non-metallic materials | Plastics, linings |
For purchasing piping material the W sheets matter most – they define which materials may be used in which product form and temperature range.
The W sheets: materials
| Data sheet | Covers | Typical materials |
|---|---|---|
| W 0 | General principles for materials | applies to all |
| W 1 | Plate in unalloyed and alloy steels | P235GH, P265GH, P355GH |
| W 2 | Austenitic and austenitic-ferritic steels | 1.4404, 1.4571, 1.4462 |
| W 4 | Tubes in unalloyed and alloy steels | 16Mo3, 13CrMo4-5, 10CrMo9-10 |
| W 7 | Bolts and nuts | 25CrMo4, 21CrMoV5-7 |
| W 9 | Flanges | P250GH, forged grades |
| W 10 | Materials for low temperatures | fine-grain normalised and nickel-alloyed grades |
The list names the sheets most often met in procurement, not the complete series. The current edition of the respective data sheet always governs.
What this means for your order
The practical core: “to AD 2000-W 2” on a certificate means the manufacturer holds the corresponding qualification and that the material meets the requirements of that data sheet in addition to those of the material standard. It is an additional requirement – it does not come automatically.
In practice that means three things:
- State it before ordering. AD conformity has to be on the order. A tube from running production cannot be “rewritten to AD” afterwards.
- Quote it together with the certificate type. AD 2000 and EN 10204 are two different things: one says which rules the testing followed, the other who confirms the result. The usual combination is “AD 2000-W 4, certificate 3.1 to EN 10204”.
- Order the marking with it. So that parts can be identified on site, material, heat number and data sheet should be marked on the item, not only on the paperwork.
AD 2000 and the Pressure Equipment Directive
Since the Pressure Equipment Directive came into force, AD 2000 is no longer mandatory – there are other routes to conformity, such as the harmonised standards EN 13445 for pressure vessels or EN 13480 for industrial piping. In practice, especially in German-speaking markets, AD 2000 remains the most frequently specified basis.
For materials covered neither by a harmonised standard nor by a European approval for materials, the route is a particular material appraisal (PMA). That takes time – one more reason to settle the choice of material early.
The short version
AD 2000 is the code, EN 10204 is the evidence, the Pressure Equipment Directive is the law. For an order one line is usually enough: material, standard, AD data sheet, certificate type. We supply pipes, flanges and fittings and power plant and boiler parts with the matching documentation – an overview of the grades is available under Materials.
Frequently Asked Questions
Is the AD 2000 code mandatory?
No. AD 2000 is a recognised code of practice, not a law. What is mandatory is the Pressure Equipment Directive 2014/68/EU. Building to AD 2000 demonstrates that its essential safety requirements are met. Alternatives are harmonised standards such as EN 13445 or EN 13480.
What does AD 2000-W 2 on a certificate mean?
W 2 is the data sheet for austenitic and austenitic-ferritic steels. If it appears on the certificate, the material meets the requirements of that sheet in addition to the material standard – for example on heat treatment, scope of testing and manufacturer qualification.
What is the difference between AD 2000 and EN 10204?
AD 2000 defines the technical rules for manufacture and testing. EN 10204 defines how the test result is certified – as declaration of compliance 2.1, test report 2.2 or inspection certificate 3.1 or 3.2. The two are normally ordered together.
Can AD conformity be confirmed retrospectively?
As a rule no. The requirements concern manufacture and testing themselves, not just the paperwork. Material produced without an AD specification cannot be reassigned afterwards. The requirement therefore belongs in the enquiry, not in the acceptance.
Which W sheets matter for piping?
W 4 governs tubes in unalloyed and alloy steels, W 2 austenitic and duplex grades. Add W 7 for bolts and nuts, W 9 for flanges and W 10 where low temperatures are involved.
Do you need exactly these parts?
Grade, size, pressure rating and quantity are enough – you usually receive your quote the same day, with an inspection certificate 3.1 on request.
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