Plant Engineering Infobase · Chapter 16 of 16
Fluids, materials and joints
Every pipeline starts with the fluid. Its properties – hazard to people and the environment, corrosion, pressure and temperature, purity – determine the material, and the material determines the possible joints. This chapter organizes the classifications of fluids, gives an overview of common piping materials and types of joints, and shows how building services and plant engineering differ. The result is summarized in the piping spec (Chapter 8).
Classifying fluids: hazard classes, fluid groups and fluid categories
A fluid is classified several times depending on the question. The classifications stand side by side – none replaces another. For the pipeline, these are the most important:
| Classification | Basis | Question | Meaning for the pipeline |
|---|---|---|---|
| Hazard classes and categories | CLPCLP – CLP Regulation (EC) No 1272/2008 EU regulation on the classification, labeling and packaging of substances and mixtures (hazard pictograms, H and P statements). Background and sources › Regulation (EC) No 1272/2008; safety data sheet, section 2 | What physical, health and environmental hazards does the substance have? | Basis for fluid group, risk assessment and labelling. The hazard class “corrosive to metals” is a direct indication for the choice of material. |
| Fluid group 1 or 2 | Pressure Equipment Directive 2014/68/EU, Art. 13 | How hazardous is the fluid in the pressure equipment? | The maximum allowable pressure PS and the nominal size DNDN – Nominal size (DN) Designation for the size of pipes, fittings and valves (Diameter Nominal). It is roughly the inside diameter in millimeters but is not an exact dimension. Background and sources › give the category according to Annex II (for piping, charts 6–9) and thus the scope of conformity assessment and testing (Chapter 15). |
| Water hazard class | AwSV | How severely does the substance endanger water bodies? | WGK 1WGK – Water hazard class Classes 1 to 3 according to the German Ordinance on Facilities for Handling Substances Hazardous to Water (AwSV): how strongly a substance endangers water bodies. The requirements for the facility depend on this. Background and sources › “slightly hazardous to water”, WGK 2 “hazardous to water”, WGK 3 “highly hazardous to water”, plus “not hazardous to water” and “generally hazardous to water”. The classification determines the requirements for facilities handling the substance. The officially published classifications in the database of the German Environment Agency are binding. |
| Fluid group 0–9 | DIN 2403,DIN – German Institute for Standardization “DIN” before a number means that the standard is published in Germany by the German Institute for Standardization. Background and sources › reproduced in TRGS 201TRGS – Technical Rules for Hazardous Substances Technical rules for the German Hazardous Substances Ordinance, drawn up by the Committee on Hazardous Substances. Background and sources › Annex 3 | Which identification color does the line have? | Identification of the pipeline; also suitable as a structure for the piping specs (Chapter 8, Fluids and fluid groups). |
| Fluid category 1–5 | DIN EN 1717EN – European Standard European Standard, developed by CEN (general) or CENELEC (electrical engineering). Background and sources › | How severely does backflow endanger the drinking water? | Building services: choice of the protection device between drinking water and connected installations. |
| Fluid Service | ASME B31.3ASME – American Society of Mechanical Engineers US engineering society. Its codes for piping, flanges and pipe dimensions apply in many plants worldwide. Background and sources ›B31.3 – ASME B31.3 Process Piping US code for process piping: materials, design, fabrication and testing of piping in chemical and process plants. Background and sources › | Which requirements apply to design, fabrication and testing? | Projects to American codes: Normal Fluid Service (standard case), Category D (non-flammable, non-toxic), Category M (toxic, even small leaks are dangerous), High Pressure, Elevated Temperature, High Purity. The assignment is defined by the owner. |
Fluid group 1 according to the Pressure Equipment Directive
Fluid group 1 comprises substances and mixtures classified under the CLP Regulation in one of these hazard classes:
Group 1 also includes fluids whose maximum allowable temperature is above their flash point. All other fluids – for example water, steam, air or nitrogen – belong to fluid group 2. If a pressure equipment item contains several fluids, the fluid that results in the highest category is decisive.
Since 2023, the CLP Regulation also includes the hazard classes endocrine disruption (environment and health), PBT/vPvB and PMT/vPvM. They apply to substances from 1 May 2025 and to mixtures from 1 May 2026. They are not in the list of fluid group 1; they nevertheless provide important information for risk assessment, tightness and material selection.
Fluid categories to DIN EN 1717 (building services)
| Cat. | Liquid | Example |
|---|---|---|
| 1 | Drinking water directly from the drinking water installation | Cold water line |
| 2 | no health hazard, only a change in taste, odor, color or temperature | Water in the domestic water heater |
| 3 | Health hazard from less toxic substances | Heating water without additives |
| 4 | Health hazard from toxic or very toxic substances | Heating water with additives, e.g. corrosion inhibitors |
| 5 | Health hazard from microbial or viral pathogens | Service water, waste water |
Pressure Equipment Directive 2014/68/EU, Art. 13 · German Environment Agency: CLP Regulation · Umweltpakt Bayern: water hazard classes (German) · TRGS 201 Annex 3 · IKZ: fluid categories to DIN EN 1717 (German) · ASME B31.3 Fluid Service (overview)
From fluid to material – why there are so many piping materials
No material meets all requirements at the same time. A steel that withstands high pressure and high temperature corrodes in water containing oxygen; a plastic that tolerates acid loses strength when heated. The variety of materials is the answer to the variety of fluids and operating conditions. These questions decide:
- Corrosion
- How does the material react with the fluid? Acids and alkalis require resistant materials according to the manufacturer's resistance list. Chlorides lead to local corrosion (pitting and crevice corrosion) in stainless steels. Unalloyed and low-alloy ferrous materials are resistant in closed heating systems because, after the initial operating period, there is no more oxygen in the water – their resistance is based on the absence of oxygen, not on the material itself. Acidic condensate attacks unalloyed steel (exhaust gas example in Chapter 8).
- Temperature
- At high temperatures, strength decreases; heat-resistant steels are used for this. At low temperatures, steel becomes brittle; low-temperature steels are used for this. Plastics have a much narrower temperature limit than metals.
- Pressure and strength
- The strength value of the material at operating temperature determines the wall thickness (Chapter 15, wall thickness per code).
- Purity and hygiene
- Drinking water, food, pharma and ultrapure media require materials that release nothing into the fluid and smooth, crevice-free surfaces. For drinking water, the assessment bases of the German Environment Agency apply.
- Abrasion
- Solids in the fluid erode the wall: wear allowance, hard or lined materials, bends with a large radius.
- Material pairing
- Different metals in the same system can promote corrosion; in heating systems, copper in mixed installations can increase corrosion when oxygen enters.
- Processing and economy
- Weldability, available joining technology, staff qualification, weight, delivery time and price over the service life.
Piping materials at a glance
The identification letters of the steels in the piping spec name are in Chapter 8, Materials. The following overview arranges the material groups by strengths, limits and typical use.
| Material group | Examples | Strengths | Limits | Plant engineering | Building services |
|---|---|---|---|---|---|
| Metallic materials | |||||
| Unalloyed steel | P235TR2P235GH – Steel name for pressure equipment Steel designation according to DIN EN 10027-1: P = steel for pressure vessels and pressure pipes, number = minimum yield strength in MPa, letters = properties (e.g. GH for elevated temperatures, NL for low temperatures). Background and sources ›, P235GH, P265GH | strong, easy to weld, inexpensive, for pressure and temperature | corrodes in water containing oxygen; corrosion allowance, coating or insulation with protection | Standard case for water, steam, condensate, oils, gases | Heating (closed systems), fire-fighting water, gas |
| Heat-resistant alloy steel | 16Mo3, 13CrMo4-5, 10CrMo9-10 | high strength at high temperatures | Welding to a qualified welding procedure specification with defined heat control | Steam and hot lines, power plants | – |
| Low-temperature steel | P355NL1, 12Ni14 | tough at low temperatures | Impact test at low temperature | Refrigeration and low-temperature lines | – |
| Stainless steel, austenitic | 1.43011.4xxx – Material number, stainless steel Material number according to DIN EN 10027-2. Numbers 1.4xxx are stainless steels, e.g. 1.4301, 1.4404 or 1.4571. Background and sources ›, 1.4404, 1.4571 | corrosion-resistant, hygienic, easy to clean | Chlorides can cause local corrosion; higher price | Chemicals, food, pharma, ultrapure media | Drinking water and heating, usually as a press-fit system |
| Stainless steel, duplex | 1.4462 | higher strength and better resistance to chloride-containing fluids than austenitic steels | More demanding to process | fluids containing chlorides, sea water | – |
| Nickel-based alloys, titanium | z. B. 2.4602, 3.7035 | resistant to highly corrosive fluids | very high price, special processing | Special case for particularly aggressive fluids | – |
| Cast iron | ductile cast iron, grey cast iron (SML) | robust, sound-absorbing, non-combustible | heavy; corrosion protection inside and outside | buried water lines (ductile, cement mortar lining) | Waste water inside buildings: SML pipe to DIN EN 877 |
| Copper | Cu-DHP to DIN EN 1057 | easy to process, many types of joints | Drinking water: not suitable for every water quality (pH, TOC) | rare, e.g. small auxiliary lines | Standard material for drinking water, heating, gas |
| Galvanized steel | hot-dip galvanized threaded pipe | inexpensive, threaded joint | Drinking water only cold and only with suitable water quality | Compressed air, cooling water (depending on piping spec) | Existing installations, cold water |
| Plastics and composites | |||||
| Polyethylene | PE 100,PE – Polyethylene Polyethylene, a thermoplastic for gas, water and wastewater pipes. “PE 100” indicates the strength class (MRS 10 MPa). Background and sources › PE-X | tough, corrosion-free, weldable (PE-X electrofusion only) | Temperature limit, change in length when heated | Water, waste water, cooling water, buried lines | Service connection water and gas (PE), heating and drinking water (PE-X) |
| Polypropylene | PP-HPP – Polypropylene Polypropylene, a thermoplastic for chemical, wastewater and hot water lines; more heat-resistant than PE. Background and sources ›, PP-R | chemically resistant, weldable | Temperature limit, UV sensitivity | Chemicals, water treatment, exhaust gas (PPs) | Drinking water (PP-R), waste water (HT pipe) |
| Polyvinyl chloride | PVC-UPVC – Polyvinyl chloride Polyvinyl chloride. PVC-U (rigid, without plasticizers) for water and chemical lines, PVC-C (post-chlorinated) for higher temperatures. Background and sources ›, PVC-C | chemically resistant, can be bonded | low temperature limit (PVC-C somewhat higher), impact-sensitive in the cold | Chemicals, water treatment | Underground drain (KG pipe) |
| Polyvinylidene fluoride | PVDFPVDF – Polyvinylidene fluoride Fluoroplastic with high chemical resistance, e.g. for acids and ultrapure water. Background and sources › | resistant to many aggressive fluids, higher temperature than PP, very pure | higher price | Chemicals, ultrapure water, semiconductors, exhaust gas | – |
| Multilayer composite | Plastic with aluminum layer | dimensionally stable, oxygen-tight, light | only in the system with matching fittings and tools | – | Drinking water, heating, underfloor heating |
| Glass-fiber reinforced plastic | GRP (thermoset with glass fiber) | corrosion-free, large nominal sizes, light | Joined by laminating or bonding; specialist staff | Cooling water and sea water, corrosive fluids | – |
| Lined and mineral materials | |||||
| Lined steel | PTFEPTFE – Polytetrafluoroethylene Fluoroplastic, very resistant to chemicals; in piping, used mainly for gaskets and linings. Background and sources ›/PFA, rubber, enamel, cement mortar | Steel carries the pressure, the lining protects against the fluid | not weldable after lining: flanged joints, define spool lengths in advance | Acids, alkalis, high-purity and abrasive fluids | – |
| Glass, stoneware, concrete | Borosilicate glass; stoneware and concrete for sewers | chemically very resistant | brittle, limited pressure | Special case glass (chemicals, laboratory) | Sewer outside the building |
Drinking water: materials in contact with drinking water must comply with the assessment bases of the German Environment Agency (UBA). Stainless steels in the passive state are approved for all product groups. Copper pipes are not suitable for every drinking water; the copper limits are generally met at pH ≥ 7.4 or at 7.0 ≤ pH < 7.4 with TOC ≤ 1.5 mg/l. Hot-dip galvanized ferrous materials are only approved for cold water and only with suitable water quality. Pipes and fittings bear a DVGWDVGW – German Technical and Scientific Association for Gas and Water Codes of practice for gas and drinking water installations (DVGW worksheets) and certification of components for these installations. Background and sources › or equivalent test mark.
Heating: plastic pipes in heating circuits are intended to be oxygen-tight to DIN 4726; if gas-permeable pipes are used, a heat exchanger made of corrosion-resistant material separates this circuit from the others. VDI 2035VDI – Association of German Engineers Association of German Engineers. Its VDI guidelines are regarded as generally accepted rules of technology. Background and sources › Part 2 requires that no continuous ingress of oxygen into the heating water is possible.
UBA: Assessment basis for metallic materials in contact with drinking water (German) (annex, sections 1.1, 1.2, 1.4) · BDH information sheet no. 3: Corrosion caused by heating water (German) · BauNetz Wissen: Waste water pipes (German) · Wikipedia: Pipeline (German) · Material groups to ISO 15608ISO – International Organization for Standardization “ISO” before a number denotes a worldwide standard of the International Organization for Standardization in Geneva. Background and sources › (Chapter 8)
Types of joints – and why there are so many
A joint must be tight, transfer the forces from pressure, weight and thermal expansion and suit the material. Then there are operational questions: does the point need to be detachable for maintenance or testing? How quickly and with which tool can it be made? Is hot work such as welding or soldering possible on site? Because these requirements differ by fluid, material and location, there are many types of joints. Permanent joints are permanently tight and have few crevices; detachable joints allow removal, maintenance and testing.
| Joint | Principle | detachable | Materials | Plant engineering | Building services |
|---|---|---|---|---|---|
| Material bond (permanent) | |||||
| Butt welding | bevelled pipe ends are welded; full strength, no crevices | no | Steel, stainless steel, non-ferrous metals | Standard case | Heating plants, large steel lines, gas |
| Orbital welding | mechanized welding around thin-walled pipes, uniform seam | no | Stainless steel | Standard case in food, pharma, ultrapure media | – |
| Socket welding (metal) | Pipe sits in a socket, fillet weld outside | no | Steel, stainless steel | small nominal sizes, auxiliary and instrument lines; not where crevice corrosion or hygiene requirements apply (gap at the socket base) | – |
| Soldering | Solder fills the capillary gap between pipe and fitting; soft below, hard above 450 °C | no | Copper | rare | widespread; drinking water in copper up to 28 × 1.5 mm soft soldering only, brazing only from 35 × 1.5 mm |
| Plastic welding | Butt fusion, socket fusion and electrofusion welding: the plastic is melted and bonds with the same material | no | PE, PP, PVDF; PE-X electrofusion only | Standard case for plastic lines in chemicals and water | PE service connection, drinking water PP-R (socket) |
| Bonding | Solvent cement joins pipe and fitting | no | PVC-U, PVC-C, ABS | Chemicals, water treatment | rare, cold water |
| Friction-locked and form-fitting, with gasket | |||||
| Press-fitting | Fitting with sealing ring is pressed; the pressing holds, the sealing ring seals | no | Copper, stainless steel, carbon steel, multilayer composite | Auxiliary systems such as cooling water or compressed air, if the system and sealing ring are approved for the fluid | Standard case for drinking water and heating |
| Flange | two flanges, gasket, bolts (sealing faces and gaskets in Chapter 8) | yes | all; for plastics with a loose flange | Standard case on valves, equipment, pumps, removal and test points, lined pipes | Heating plants, large nominal sizes, valves |
| Thread | taper external and parallel internal threads seal in the thread with sealant (DIN EN 10226-1); parallel threads to ISO 228-1 do not seal in the thread but on a sealing face | yes | galvanized steel, gunmetal, brass, stainless steel | small nominal sizes, instrument and auxiliary connections; use sparingly with hazardous fluids | Valve and device connections, existing installations |
| Compression and cutting ring | a ring is pressed onto the pipe or cuts into it when the union nut is tightened | yes | Steel, stainless steel, copper, composite pipe | Instrument, control and hydraulic lines (cutting ring DIN EN ISO 8434-1) | Valve connections, compression couplings |
| Screwed joint | union nut joins two halves, flat or cone sealing | yes | Brass, gunmetal, steel | Connecting pumps and devices | Radiators, pumps, valves |
| Hygienic union, clamp | crevice-free, detachable joints to DIN 11851, DIN 32676, DIN 11864 | yes | Stainless steel | Food, beverages, pharma (Chapter 8) | – |
| Push-fit socket | Spigot end in socket with lip seal | yes | PP, PE, PVC-U (HT and KG pipe) | unpressurized drainage | Standard case for waste water |
| Clamp coupling | socketless pipes with clamping sleeve or clamp and sealing sleeve | yes | Cast iron (SML) | Drainage | Standard case for SML waste water pipe |
| Grooved coupling | Housing coupling with sealing ring engages in grooved pipe ends | yes | Carbon steel | Cooling and fire-fighting water, large nominal sizes | Sprinkler and fire-fighting water lines (fittings to VdS 2100) |
What is standard, what is rare?
Plant engineering
- Standard case: welded line; detachable only where operation and maintenance require it – usually as a flange on valves, equipment and pumps. For fluid group 1, detachable joints are limited to what is necessary.
- Common: threads and compression or cutting-ring fittings on small instrument and auxiliary lines; welded plastics in chemicals and water treatment; orbital welding and hygienic joints in food and pharma.
- Rare: press-fitting (only if approved for the medium and operating conditions), bonding, soldering, grooved couplings.
Building services
- Standard case: press-fitting for drinking water and heating, push-fit sockets for waste water, threads on valves and devices.
- Common: soft soldering of copper, plastic welding (PP-R, PE), compression couplings, clamp couplings on SML pipe, grooved couplings in fire-fighting water.
- Rare: flange (large nominal sizes, heating plants), butt welding outside heating plants and gas lines.
This classification describes common practice. Which joint is permissible is determined by the piping spec, the code and the approval of the pipe system; the resistance of material and gasket must be checked for every fluid. The Piping Spec Calculator suggests materials and joints suitable for the application as preliminary sizing.
Wikipedia: Pipe joint (German) · SBZ Monteur 2008/02: Soldering and press-fitting copper pipes (German) (DVGW GW 2, GW 7) · DVS 2207-1: Heated tool welding of PE · DIN EN 10226-1 and DIN EN ISO 228-1 (pipe threads) · DIN EN ISO 8434-1 · VdS 2100 · BauNetz Wissen: Waste water pipes (German)
Building services and plant engineering – the differences
Both route pipes, but with different goals: building services supply buildings and their use, plant engineering carries substances through a process. This leads to different rules, materials, joints and documents.
| Characteristic | Building services | Plant engineering |
|---|---|---|
| Purpose | Drinking water, heating, cooling, waste water, gas, fire-fighting water for a building | Producing, converting, storing and transporting substances |
| Fluids | few, well-known fluids | many fluids, often hazardous (fluid group 1), mixtures and changing operating conditions |
| Pressure and temperature | usually low to medium, close to ambient or heating temperature | from vacuum to high pressure, from low temperature to superheated steam |
| Legal framework | Water networks and hot-water heating systems are excluded from the Pressure Equipment Directive (Art. 1(2)(b) and (t)); the German Drinking Water Ordinance, building regulations and the rules of good engineering practice are decisive | Pressure Equipment Directive, German Ordinance on Industrial Safety and Health, Hazardous Substances Ordinance, AwSV |
| Technical rules | DIN EN 806 and DIN 1988 (drinking water), DIN EN 1717, DIN EN 12056 and DIN 1986-100 (drainage), DVGW-TRGI (gas), VDI 2035 (heating water), VdS guidelines (sprinklers) | DIN EN 13480, AD 2000AD 2000 – AD 2000 Code German code for pressure vessels: calculation, materials and manufacture. Working to it meets the requirements of the Pressure Equipment Directive. Background and sources ›, ASME B31.3, DIN 21057 (piping specs) – see Chapter 14 |
| Material selection | Pipe systems from one system manufacturer (pipe, fitting and tool matched and approved); drinking water according to the assessment bases of the German Environment Agency | project-specific for each fluid in piping specs; material, wall thickness, gasket and valves defined and documented |
| Joints | press, push-fit, solder, clamp, screw | welding and flanging |
| Documents | Floor plans, riser diagrams, pipe network calculation, building model | P&IDR&I – Piping and instrumentation diagram Flow diagram showing all pipes, valves, equipment and instrumentation of a plant (P&ID, Piping and Instrumentation Diagram). Background and sources ›, piping specs, 3D plant model, isometric for each line, bills of materials |
| Testing | Pressure and leak test before commissioning, drinking water to DIN EN 806-4 | Pressure test to DIN EN 13480-5, non-destructive testing of the welds, tests before commissioning according to the German Ordinance on Industrial Safety and Health |
| Design | Specialist installation companies; for drinking water and gas registered in the utility's directory | Pipe construction with qualified welding personnel (DIN EN ISO 9606-1) and qualified welding procedures |
| CADCAD – Computer-Aided Design Computer-aided design and drafting. Background and sources › | Building services design software related to the building | Plant design with piping specs and isometrics, e.g. AutoCAD Plant 3D (Chapter 12) |
Transitions: in heating plants, steam and refrigeration systems, industrial buildings and laboratories, both worlds meet. The pipes of a hot-water heating system are excluded from the Pressure Equipment Directive; steam lines and pressure vessels, on the other hand, may fall under it. For every line it must therefore be clarified which legal framework and which rule apply – the result belongs in the piping spec.
Pressure Equipment Directive 2014/68/EU, Art. 1(2) · standards status in Chapter 14 · BDH information sheet no. 3
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Standards status for this page 13 standards · research October 2026
| Standard | Contents | Current edition | Replaced / successor |
|---|---|---|---|
| Directive 2014/68/EU (PED) | Pressure Equipment Directive (recast) | Directive 2014/68/EU of 15 May 2014 (OJ L 189 of 27 June 2014) | replaces Directive 97/23/EC (superseded on 19 July 2016) |
| AwSV | Facilities handling substances hazardous to water | AwSV 2017, amended 2020 | – |
| DIN 2403 | Identification of pipelines according to fluid conveyed | DIN 2403:2025-12 | replaces DIN 2403:2018-10 |
| ASME B31.3 | Process Piping | ASME B31.3-2024 | replaces ASME B31.3-2022 |
| DIN EN 1057 | Seamless round copper tubes for water and gas applications (plumbing/heating) | DIN EN 1057:2010-06 | replaces DIN EN 1057:2006-08 |
| DIN EN 10226-1 | Pipe threads sealing in the thread | DIN EN 10226-1:2004-10 | – |
| DIN EN ISO 8434-1 | Connectors for fluid power and general use – Part 1: 24° cone connectors | DIN EN ISO 8434-1:2018-11 | replaces DIN EN ISO 8434-1:2008-02; DIN EN ISO 8434-1 Corrigendum 1:2009-09; DIN 3859-2:1999-07 |
| DIN 11864-1 | Stainless steel valves for aseptic, chemical and pharmaceutical applications – Part 1: Unions | DIN 11864-1:2025-04 | replaces DIN 11864-1:2017-10 |
| DIN EN ISO 228-1 | Pipe threads not sealing in the thread | DIN EN ISO 228-1:2003-05 | – |
| DIN EN 13480 | Metallic industrial piping | DIN EN 13480-1 to -6 and -8:2024-12; Part 7 as DIN CEN/TR 13480-7:2022-08 | replaces the 2017-12 editions with amendments A1 ff. |
| DIN 21057 | Piping specs | DIN 21057-1:2023-08; Parts 5/6:2016-12; Parts 10–12:2026-04/-05 | replaces PAS 1057; DIN 21057-1:2016-12; DIN 21057-10 to -12:2017-04 |
| DIN EN 13480-5 | Metallic industrial piping – Part 5: Inspection and testing | DIN EN 13480-5:2024-12 | replaces DIN EN 13480-5:2017-12; DIN EN 13480-5/A1:2019-06; DIN EN 13480-5/A2:2021-12 |
| DIN EN ISO 9606-1 | Qualification testing of welders – steel | DIN EN ISO 9606-1:2017-12 | – |
Researched at DIN Media, ISO, IECIEC – International Electrotechnical Commission International Electrotechnical Commission in Geneva: worldwide standards for electrical engineering and for instrumentation and control. Background and sources › and ASME, as of October 2026. Before binding use, please check the current edition with the standards publisher. Overview of all standards: Plant Engineering Infobase · Standards status.
Technically responsible: A. Seitz, Managing Director of A. Seitz Ingenieur GmbH (plant design, AutoCAD Plant 3D).
Terms, background and sources 22 terms on this page
Brief explanations for reference. They do not replace the standard or code itself.
- CLP – CLP Regulation (EC) No 1272/2008
EU regulation on the classification, labeling and packaging of substances and mixtures (hazard pictograms, H and P statements).
- DN – Nominal size (DN)
Designation for the size of pipes, fittings and valves (Diameter Nominal). It is roughly the inside diameter in millimeters but is not an exact dimension.
Specified in DIN EN ISO 6708. Which outside diameter belongs to a DN is defined in the dimensional standards, e.g. DIN EN 10220 for steel pipes.
- WGK – Water hazard class
Classes 1 to 3 according to the German Ordinance on Facilities for Handling Substances Hazardous to Water (AwSV): how strongly a substance endangers water bodies. The requirements for the facility depend on this.
- DIN – German Institute for Standardization
“DIN” before a number means that the standard is published in Germany by the German Institute for Standardization.
DIN was founded in 1917 as the Standards Committee of German Industry. If “DIN EN” or “DIN EN ISO” precedes the number, a European or international standard has been adopted unchanged as a German standard.
- TRGS – Technical Rules for Hazardous Substances
Technical rules for the German Hazardous Substances Ordinance, drawn up by the Committee on Hazardous Substances.
- EN – European Standard
European Standard, developed by CEN (general) or CENELEC (electrical engineering).
Every member country must adopt an EN unchanged as a national standard – in Germany as “DIN EN …”. Conflicting national standards are withdrawn.
- ASME – American Society of Mechanical Engineers
US engineering society. Its codes for piping, flanges and pipe dimensions apply in many plants worldwide.
ASME was founded in 1880. Well-known codes: B31.3 (process piping), B16.5 (flanges), B36.10M and B36.19M (pipe dimensions).
- B31.3 – ASME B31.3 Process Piping
US code for process piping: materials, design, fabrication and testing of piping in chemical and process plants.
- P235GH – Steel name for pressure equipment
Steel designation according to DIN EN 10027-1: P = steel for pressure vessels and pressure pipes, number = minimum yield strength in MPa, letters = properties (e.g. GH for elevated temperatures, NL for low temperatures).
- 1.4xxx – Material number, stainless steel
Material number according to DIN EN 10027-2. Numbers 1.4xxx are stainless steels, e.g. 1.4301, 1.4404 or 1.4571.
- PE – Polyethylene
Polyethylene, a thermoplastic for gas, water and wastewater pipes. “PE 100” indicates the strength class (MRS 10 MPa).
Abbreviations for plastics according to DIN EN ISO 1043-1.
- PP – Polypropylene
Polypropylene, a thermoplastic for chemical, wastewater and hot water lines; more heat-resistant than PE.
Abbreviations for plastics according to DIN EN ISO 1043-1.
- PVC – Polyvinyl chloride
Polyvinyl chloride. PVC-U (rigid, without plasticizers) for water and chemical lines, PVC-C (post-chlorinated) for higher temperatures.
Abbreviations for plastics according to DIN EN ISO 1043-1.
- PVDF – Polyvinylidene fluoride
Fluoroplastic with high chemical resistance, e.g. for acids and ultrapure water.
- PTFE – Polytetrafluoroethylene
Fluoroplastic, very resistant to chemicals; in piping, used mainly for gaskets and linings.
- DVGW – German Technical and Scientific Association for Gas and Water
Codes of practice for gas and drinking water installations (DVGW worksheets) and certification of components for these installations.
- VDI – Association of German Engineers
Association of German Engineers. Its VDI guidelines are regarded as generally accepted rules of technology.
- ISO – International Organization for Standardization
“ISO” before a number denotes a worldwide standard of the International Organization for Standardization in Geneva.
ISO was founded in 1947. Its members are the national standards bodies; for Germany, this is DIN.
- AD 2000 – AD 2000 Code
German code for pressure vessels: calculation, materials and manufacture. Working to it meets the requirements of the Pressure Equipment Directive.
- R&I – Piping and instrumentation diagram
Flow diagram showing all pipes, valves, equipment and instrumentation of a plant (P&ID, Piping and Instrumentation Diagram).
Symbols and drawing rules: DIN EN ISO 10628-1 and -2. Identification letters for instrumentation: DIN EN 62424 or ISA-5.1.
- CAD – Computer-Aided Design
Computer-aided design and drafting.
- IEC – International Electrotechnical Commission
International Electrotechnical Commission in Geneva: worldwide standards for electrical engineering and for instrumentation and control.
IEC was founded in 1906. IEC standards adopted in Europe are called “EN IEC …” or “EN 6xxxx”.
Sources and origins
- Regulation (EC) No 1272/2008 (EUR-Lex) (for CLP)
- ISO 6708 – Pipework components, definition and selection of DN (for DN)
- DIN – German Institute for Standardization (for DN, DIN, P235GH, 1.4xxx)
- German Environment Agency – substances hazardous to water (for WGK)
- Federal Institute for Occupational Safety and Health (BAuA) – Technical Rules (for TRGS)
- CEN and CENELEC – European standardization (for EN, P235GH, 1.4xxx)
- ASME – American Society of Mechanical Engineers (for ASME, B31.3)
- ISO – International Organization for Standardization (for PE, PP, PVC, PVDF, PTFE, ISO, R&I)
- DVGW – German Technical and Scientific Association for Gas and Water (for DVGW)
- VDI – Association of German Engineers (for VDI)
- VdTÜV – TÜV Association (for AD 2000)
- IEC – International Electrotechnical Commission (for R&I, IEC)
- Wikipedia – Computer-aided design (for CAD)