Areas of special consideration

The following are special considerations for the AVEVA Unified Engineering Default Configuration:

Safety System – Setpoints

The following information outlines the Safety System setpoints:

Setpoints and alarm in the Control System

Protective instruments and alarms in industrial plants are provided with adjustable setpoints where specific actions are either automatically initiated, prohibited, or alarmed. Provide care when you identify setpoint attributes on instruments datasheets.

Setpoints on pressure, differential pressure, flow, level, and temperature devices correspond to certain provisions of technical specifications and datasheets that have been incorporated into the system.

Setpoints and alarm attributes

To standardize the setpoint attributes within the AVEVA Unified Engineering Default Configuration, the following attributes are assigned to the required instruments and mechanical equipment.

Setpoints and alarm attributes data type

These attributes use multi-measure value data types, such as mixed measure that includes flow, pressure, and temperature. The Data Type should be Double. You do not require a unit of measure (UoM) list of values for these attributes.

To cover the UoMs for the set point attributes, a specific attribute called SetPoint Units is available with a comprehensive list of values that cover all measure UoMs.

Safety System – Hazardous areas

The following information outlines the Safety System hazardous areas:

Hazardous attributes in the Class Library

Hazardous attributes are used where a piece of equipment is in an area in which an explosive gas atmosphere is present or maybe expected to be present in quantities, such as to require special precautions for the construction, installation, and use of apparatus. Some examples of explosive gas atmospheres are the following:

• Flammable gases or vapors

• Combustible dust

• Flammable liquids

• Ignitable fibers

Based on the National Electrical Code (NEC) and International Electrotechnical Commission (IEC) standards, you should associate flowing attributes to any electrical or non-electrical equipment that requires hazardous attributes.

Hazardous area classification guide

The two widely used systems which are followed in the Oil and Gas for hazardous area classification are the following:

• The Class/Division system

• The Zone system

While Canada and the United States predominantly use the class/division system, other parts of the world use the zone system of Hazardous area classification.

The following standards covers these concepts:

• International Electrotechnical Commission (IEC) 60079

  Standard IEC 60079 is a suite of standards that cover a wide standard relating to different types of equipment and protection measures in explosive atmospheres.

• ATmosphères EXplosibles (ATEX) 114 Directive

  The ATEX 114 legislation (formerly known as ATEX 95) provides the relevant information for safeguarding the safety of devices intended for use in potentially explosive atmospheres.

  ATEX 114 also relates to the safety, control, and control devices that are not directly in an explosion hazardous zone, but which are required for the safe operation of devices and systems in such a zone.

• National Electrical Code (NEC) 500/NEC 505/NEC 506

  Articles 500 to 506 of the NEC constitute the fundamental reference document in the United States for installation of electrical equipment in hazardous locations. Article 500 defines the classification of hazardous areas in broad terms in accordance with the nature of the hazard and the degree of hazard. Subsequent articles stipulate specific requirements for equipment and installation practices to be used in hazardous locations of a particular classification.

  Hazardous Standard	Attribute Name	Look Up List Value
  IEC 60079 and NEC 505, NEC 506	Area Classification	Zone 0, Zone1, Zone 2, Class 1 Div1, Class1 Div2, Non-classified
  IEC 60079 and NEC 505	Temperature Class	T1, T2, T3, T4, T5, T6
  IEC 60079 and NEC 505,NEC 506	Equipment Sub-Group (or Gas Group)	I, IIA, IIB, IIC, IIIA, IIIB, IIIC
  IEC 60079	Type of protection	Ex d, Ex e, Ex de, Ex n, Ex p, Ex ia, Ex ib
  IEC 60079 NEC 505 NEC 506	Equipment Protection Level	Ga, Gb, Gc, Da, Db, Dc
  IEC 60079 and NEC500, NEC 505, NEC 506	Hazard Area Certificate	N/A
  IEC 60079	IEC Standard	N/A
  National Electrical Manufacturers Association (NEMA)	NEMA CLASS	NEMA 1, NEMA 2, NEMA 3, NEMA 4, NEMA 5 , NEMA6, NEMA 7, NEMA 9, NEMA 12, NEMA 12K, NEMA 13,
  ATEX 114	ATEX Category	1, 2, 3
  ATEX 114	ATEX Equipment Group	I, II
  ATEX 114	ATEX Environment	G, D
  ATEX 114	ATEX Code	N/A
  NEC 500	Temperature Code	T1, T2, T2A, T2B, T2C, T2D, T3, T3A, T3B, T3C, T4, T4A, T5, T5A
  NEC 500	NEC Gas Group	Group 1, Group 2, Group 3
  NEC 505, NEC 506	Protection Concept Code	AEx da, AEx db, AEx dc, AEx eb, AEx ec, AEx ta, AEx tb, AEx tc, AEx ia, AEx ib, AEx ic, AEXpxb, AEX pzc, AEx pyb, AEx mb, Aex mc, AEx o, AEX q, AEx nA, AEx nC, AEx nL, AEx nR
  NEC 500	Hazard Class	Class 1, Class 2, Class 3
  NEC 500, NEC	NEC Standard	N/A

Process Simulation – Stream structure

Stream structure from simulation, by its nature, is complex and may have up to four basic phases:

• Vapour — The gaseous phase above the liquid.

• Liquid 1 — Maybe only one liquid phase.

• Liquid 2 — Maybe another liquid phase, such as oil on water.

• Solids — Possibly particulates.

  

Depending on requirements, it may be required to show varying degrees of detail.

• Bulk Phase — The overall stream (Vapour + Liquid 1+ Liquid 2 + Solid).

• Bulk Liquid — the overall liquid (Liquid 1 + Liquid 2).

• Individual phases — Vapour, Liquid 1, Liquid 2, or Solid.

Each phase set is made up of individual flowing components (parts), which can be the following:

• Pure components [1-n]

• Grouped components [0-n] made up of pure components (parts)

Within each flowing component, there is common thermodynamic (part), and two content data (parts) that varies with phase. With this combination, any component flow phase can be described in a standard manner:

• Thermodynamic conditions (part) — Characteristic features of a material. For example:

  • Viscosity

  • Density

  • Enthalpy

• Material fractions, % (part) — Giving the proportion of each component. For example:

  • Mole %

  • Mass %

  • Volume %

• Material rates, rates per unit of time (part) — giving the throughput. For example:

  • Molar flowrate

  • Mass flowrate

  • Volumetric flowrate

The combination of the options means that inheritance and parts give the minimum discrete sets whilst providing all the combination.

The structure needs understanding for usage and should not require modification.

These structures are combined in a material flow specification which is attached to a stream or a pipe. The idea being that one specification may be applied to multiple streams/pipes. By altering one specification, it alters multiple items in the same way a pipe specification is used against pipes.

Summary

A stream is composed of two main aspects (parts):

• Design Conditions

• Material flow specification

A material flow specification may have a combination of six phase sets:

• Four true phases [1-n] Vapour/Liquid 1/Liquid 2/Solid

• Two overall phases Overall Stream (Vapour + Liquid 1+ Liquid 2 + Solid) and Overall Liquid (Liquid 1 + Liquid 2)

Each phase set is made up of individual flowing components (parts) which can be the following:

• Pure components [1-n]

• Grouped components [1-n] made up of pure components

Within each phase you have a common thermodynamic (part) and content data (parts) that varies with the phase:

• Thermodynamic conditions

• Material fractions

• Material rates