Company

AD2000

AD2000 Code from the German Working Group for Pressure Vessels (Argeitsgemeinschaft Druckbehälter – AD) sets forth all essential safety requirements that must be met according to the European Pressure Equipment Directive (97/23/EC).

AGFW

The German Energy Efficiency Association for Heating, Cooling and CHP (Energieeffizienzverband für Wärme, Kälte und KWK e.V.), formerly the German Heat and Power Association (Arbeitsgemeinschaft für Wärme und Heizkraftwirtschaft). AGFW Code for district heating supply, heat generation and heat distribution.

ASCE7‐10

The American standard for design data for buildings and other structures containing also statements for seismic design / seismic loads and wind loads. The standard is published by the American Society of Civil Engineers (ASCE).

ASME B31.1

American standard for piping in power stations. Governs the dimensioning and calculation of pipelines; includes material characteristics / permissible stresses. Applicable in power plant engineering.

ASME B31.3

American standard for piping in processing plants. Governs the dimensioning and calculation of pipelines; includes material characteristics / permissible stresses. Applicable in chemical plants and refineries.

CAESAR II

Software by Intergraph Corporation. Program for static and dynamic structural analysis of piping systems.

Converting Fahrenheit

Unit of temperature used in American codes.

TC = (TF-32) x (5/9)  – TC: Temperature in degrees Celsius (°C)
TF = TC x 1,8+32  – TF: Temperature in degrees Fahrenheit (°F)

Converting inches

Unit of length used in American codes. Pipe dimensions are often given in inches.

1 inch = 25,4 mm

Converting PSI

Unit of pressure or stress used in American codes.
Pound-force per square inch (psi)
1 psi = 6,8948 x 10³ pascals or N/m² (exponential representation rounded to four decimal places)

DIN EN 1591-1

European standard for flanges and flange joints. Part 1 (DIN EN1591-1) deals with the calculation of flange joints with circular flanges. It covers proof of tightness and compliance with permissible stresses for flanges, bolts and seals, and also contains calculations for the required bolt forces and tightening torques.

DVGW

German Technical and Scientific Association for Gas and Water (Deutscher Verein des Gas- und Wasserfaches – DVGW). DVGW Code for piping systems for gas and water supply.

EN13445

European standard for Unfired pressure vessels. Part 3 (EN13445‐3) deals with design and calculation, Appendix C describes the method of analysis, basis for the calculation of thin‐walled shells by FEM analysis

EN13480

European standard for metallic industrial piping. Part 3 (EN13480-3) deals with design and calculation, including bracing.

EN1991‐1

European Standard for the design of structures against wind loads and snow loads published in 2010.

EN1998‐2010

European standard for the design of structures for earthquake resistance published in 2010.

Eurocode 3

The Euro code 3 (short EC3) is a series of European standards (EN) for the design of steel structures, consisting of 20 documents EN1993

FDBR

German Association of Steam Boiler, Pressure Vessel and Piping Manufacturers (Fachverband Dampfkessel-, Behälter- und Rohrleitungsbau). Association for plant construction in the energy and environmental process industries. FDBR directives and FDBR information sheets for piping and other subjects. Organizes the annual FDBR Expert Symposium on Piping Technology (FDBR-Fachtagung Rohrleitungstechnik). CPG is usually among the exhibitors at this event.

FEM

Finite Element Method (FEM): a numerical method for calculating partial differential equations. In piping technology, FEM is used for 3D calculations of stresses and deformations in components and shaped pieces. It is based on the generation of a network structure.

GRP

Glass fiber reinforced plastic (GRP). GRP piping is used primarily for chemical transport as well as for cooling water lines and in flue gas desulphurization systems in power plants. Calculation of GRP lines was also the subject of a CPG employee’s graduate thesis.

Internal pressure reaction force of axial expansion joints

Onaxial expansion joints without tie rods, the internal pressure reaction force acts axially on both sides of the connecting pipe system. The value of this force is depend on the effective bellows cross-sectional area of the expansion joint and the overpressure in the system. If not specified by the manufacturer, the effective bellows cross-sectional area can be calculated approximately with the middle bellows diameter of the largest wave. A calculation of the internal pressure reaction force is possible on our website „TOOLS„. Furthermore, forces must be taken into account which result from the spring rates of expansion joints.

ISO14692

European standard for glass fiber reinforced plastic piping (GRP). Part 3 (ISO14962-3) covers system design / calculation.

Joukowsky surge

Named for the scientist Joukowsky. A simplified method for calculating the maximum pressure surge in a fluid-filled pipeline, depending on the closing time of valves or overrun time of pumps (e.g. in case of mains failure) as well as the flow rate, density and wave propagation speed of the fluid and the length of the pipe. Used in pipe structural analysis to determine, for example, the forces of directional changes resulting from a pressure surge.

KMR

Plastic-jacketed pipe (Kunstoffmantelrohr – KMR): composite pipe composed of a core pipe (usually steel), an insulating layer of hard polyurethane foam and a jacket pipe of polyurethane. Used for underground district heating lines that also have a moisture-leakage warning system.

KTA

The Nuclear Safety Standards Commission (Kerntechnische Ausschuss ‐ KTA) create safety rules for nuclear power plants.

Natural frequency

The frequency of an oscillatory system whereby the system can oscillate on its own after a single stimulus. Resonance occurs if the excitation frequency (for example, when starting the pumps) matches the natural frequency. This can damage the pipelines. Influence variables and calculations were the subject of a CPG employee’s graduate thesis, which came about in connection with a CPG project.

PED

European Directive 97/23/EC. Referred to in German as „Druckgeräterichtlinie“ (DGRL) and in English as „Pressure Equipment Directive“ (PED). Its scope includes pipelines and containers with a positive internal pressure of more than 0.5 bar.

Pipe stress analysis

Part of the pipe structural analysis. Proof of whether the permissible temperature-dependant and load-dependent stresses of the material in use are not exceeded. Piping is modelled as a beam model, and mounting parts are assigned stress intensification factors. Calculation regulations: EN13480-3, ASME B31.1, ASME B31.3, ISO14692, KTA…

Rohr2

Software by  SIGMA Ingenieurgesellschaft. Program for static and dynamic structural analysis of piping systems.

RStab

Software by Dlubal (www.dlubal.com). Structural analysis program for beam structures, including steel structures.

SMR

Steel-jacketed pipe (Stahlmantelrohr – SMR): between the core pipe and the jacket pipe, there is a built-in area of negative pressure / vacuum, which serves as an isolator / thermal insulator. Used for underground district heating lines and steam lines.

TA Luft

German Technical Instructions on Air Quality Control (Technische Anleitung zur Reinhaltung der Luft). This general administrative regulation governs requirements on the tightness of valves and flange joints.

Tightening torques

Especially important when ensuring the tightness of flange joints in pipelines. The required value can be affected by factors such as the minimum sealing surface compression (depending on the tightness class), the maximum permissible temperature-dependant surface compression of the seal and the friction factor between the bolt and the nut. The required tightening torque can be determined mathematically with the aid of DIN EN1591-1.

TRD

German Technical Rules for Steam Boilers (Technische Regeln für Dampfkessel) – superseded by new European standards.

UBC1997

American standard (Uniform Building Code – UBC). UBC 1997 contains statements relating to seismic design / seismic loads and wind loads.