HG/T 20549-1998Design Standard Piping Layout for Chemical Plant (English PDF)

1.1 Composition and brief description of piping layout design documents

1.1.1 Composition of piping layout design documents

The main documents of piping layout design for chemical plants are:

1 List of design documents;

2 Design description;

3 Piping layout drawings;

4 Piping isometric drawings and their index;

5 Pipe segment lists and their index.

1.1.2 Brief description

1 List of design documents

Only the finished design documents to be issued to the construction site are listed; intermediate products of the design process are not listed in the list.

2 Design description

Requirements are stated for matters that are not described in the finished documents, or are difficult to describe clearly in them, but which the owner or the construction organization needs to understand and implement, such as: design scope, area division of the plant, installation requirements for equipment and piping, construction acceptance standards, composition of the design documents, unified legend symbols and abbreviations, static grounding requirements.

3 Piping layout drawings

1) Piping routing drawing (initial edition for short)

It shall be completed in the basic engineering design stage. It is drawn on the basis of the PID editions "A", "B", "C", "D" of the process system discipline [see Process System Engineering Design Regulations for Chemical Plants (HG 20557~20559-93), hereinafter the same] and of the equipment layout drawing editions "A", "B", "C", "D" of the equipment layout discipline [see Design Regulations for Equipment Layout of Chemical Plants (HG 20546-92), hereinafter the same]; its content and depth requirements are given in 1.2 of this chapter.

2) Piping layout drawing

The study edition (also called detail edition 1, E edition for short, hereinafter the same), the design edition (also called detail edition 2, F edition for short, hereinafter the same) and the construction edition (G edition for short) of the piping layout drawing shall be completed in sequence in the detailed engineering design stage; they are drawn on the basis of the PID editions "E", "F", "G" of the process system discipline and of the equipment layout drawing editions "E", "F", "G" of the equipment layout discipline respectively, of which editions "E" and "F" are intermediate products and shall not be issued externally. The content and depth requirements of edition "E" are given in Chapter 2 of this standard (for the work procedure of each edition see Figure 2.0.1 "Work procedure diagram of the engineering design stages of the piping layout discipline" in "Technical Management Regulations of the Piping Layout Discipline for Chemical Plants" (HG/T 20549.3), hereinafter the same).

4 Piping isometric drawings and their index

1) A piping isometric drawing is a three-dimensional detail drawing showing the routing, connections, piping components and related data and materials of a single pipeline; it consists of two parts, the drawing and the material list.

2) The piping isometric drawing index is compiled to facilitate consulting the isometric drawings. Its content generally includes: line number, isometric drawing number, edition, area number, etc.

5 Pipe segment lists and their index

1) The pipe segment list is a material list of a single pipeline compiled for pipelines for which, according to the regulations, isometric drawings need not be drawn.

2) The function and content of the pipe segment list index are similar to those of the isometric drawing index, except that there is no isometric drawing number item.

1.2 Regulations on the content and depth of the piping routing drawing

1.2.1 Purpose

The piping routing drawing is an important document of the basic engineering design stage and the basis for the preliminary estimation of piping investment. Through this work, the equipment layout is verified and modified; the width and number of tiers of the pipe racks are considered; the main platforms are provided; compliance with fire and explosion prevention codes is checked; the feasibility of the installation and maintenance schemes is checked; and preparations are made for the piping study of the next stage. This drawing shall not be sent to the owner.

1.2.2 Basic data

1 Piping and instrument diagrams (PID) editions "A", "B", "C", "D";

2 Equipment data sheets;

3 Equipment layout drawings editions "A", "B", "C", "D";

4 Piping data sheets and special piping item data sheets;

5 Relevant codes.

1.2.3 Scale and drawing division

1 Depending on the size of the plant, 1:100 or another suitable scale may be selected.

2 According to the layout of the plant and the scale selected, the drawing is divided into several plan views. The division of pipe rack drawings shall comply with item 5 of 1.2.7 of this section.

1.2.4 Range of pipe sizes included in the piping routing drawing

1 All process piping shall be drawn; low-pressure piping with nominal diameter (DN) less than 25mm or 1 inch and branch pipes such as vents and drains need not be drawn; but control valve assemblies shall all be shown, in the manner specified in item 4 of 1.2.7 of this section.

2 Utility piping with nominal diameter (DN) greater than or equal to 50mm or 2 inches and all control valve assemblies shall be shown.

3 All piping on the pipe racks shall be shown [with space reserved according to the degree of completeness of the piping and instrument diagram (PID)].

1.2.5 The piping routing drawing shall show the following:

1 Outlines of vessels and heat exchangers;

2 Foundation outlines of rotating equipment;

3 Space occupied by installation and maintenance, reserved space;

4 Outlines of buildings and structures (including columns, walls, doors, platforms, ladders, installation openings and lifting facilities, etc.);

5 Instrument and electrical cable trays on the pipe racks;

6 Column axes of the pipe racks and sections of the main pipe racks, which shall comply with item 5 of 1.2.7 of this section;

7 Pipelines and line numbers, flow directions;

8 Equipment item numbers;

9 Main valves;

10 North arrow.

1.2.6 Dimensioning

The dimensions to be marked are column spacing dimensions, elevations or coordinates, and pipe rack elevations and pipe spacing dimensions; the location dimensions of equipment and piping need not be marked.

1.2.7 Method of representation

1 Pipes are shown by single lines;

2 Weld points need not be drawn for butt-welded fittings;

3 Elbows are shown with right angles; arcs need not be drawn;

4 Control valve assemblies may be replaced by a rectangular box, as shown in Figure 1.2.7 Schematic of control valve assembly;

Figure 1.2.7 Schematic of control valve assembly

5 On plan views, the width of the pipe racks may at first be enlarged not to scale, without drawing tiers separately, with the pipes listed in parallel. Finally, according to the results of the routing study, all pipes arranged on the pipe racks are drawn to scale in plan views by tiers, and the main sections of the pipe racks are drawn, as the basis for deciding the number of tiers and the width of the pipe racks.

1.3 Regulations on the content and depth of the piping layout drawing (study edition)

1.3.1 Purpose

The piping layout drawing (study edition) is a semi-finished product internal to the design organization. Through this work, the equipment layout is determined and the piping layout is also basically determined, so that conditions can be issued progressively to the relevant disciplines. This drawing shall not be sent to the owner.

1.3.2 Basic data

1 Piping and instrument diagram (PID) edition "E";

2 Equipment list and outline drawings;

3 Equipment layout drawing edition "E";

4 Piping data sheets and special piping item data sheets;

5 Piping class sheets;

6 Piping routing drawing;

7 Layout condition drawings of beams and columns of buildings and structures;

8 Battery limit piping conditions;

9 Cable tray conditions of electrical and instrument disciplines;

10 Preliminary instrument condition drawings (or data sheets);

11 Relevant conditions of other disciplines.

1.3.3 Scale and drawing division

1 The scale of the piping layout drawing (study edition) should be consistent with that of the piping layout drawing of the next stage; where the same scale cannot be adopted because of certain restrictive conditions, an intermediate scale may be used.

2 When the same scale is selected in accordance with item 1 of this clause, the area division shall comply with Chapter 4 of "Regulations on the Content and Depth of Equipment Layout Design for Chemical Plants" (HG 20546.1).

1.3.4 Range of pipe sizes included in the piping layout drawing (study edition)

1 All process piping, except high-point vents and low-point drains.

2 Utility piping with nominal diameter (DN) greater than or equal to 50mm or 2 inches, and all underground piping. If piping with nominal diameter (DN) smaller than 50mm or 2 inches accounts for a large proportion in the plant, the range may be extended to piping smaller than DN50mm or 2 inches; but piping requiring stress calculation and control valve assemblies shall be shown irrespective of pipe size.

3 All piping on the pipe racks, irrespective of size, shall be included in the study scope.

1.3.5 Content of the piping layout drawing (study edition)

Except for dimensioning, which is given in 1.3.6 of this section, the following shall be shown:

1 Outlines of vessels, heat exchangers, etc.; for horizontal equipment, the supports shall be drawn and the sliding end or fixed end marked;

2 Foundation outline frames of rotating equipment;

3 Space occupied by installation and maintenance, reserved space (by double-dot chain lines);

4 Outlines of buildings and structures (including columns, walls, windows, doors, platforms, ladders and safety cages, installation openings, railings, trenches, etc.);

5 Beams and columns of the pipe racks;

6 Pipes, valves (including handwheels and handles), fittings and special piping items, etc.;

7 Electrical and instrument cable trays, racks and cable trenches;

8 Local electrical and instrument control valves and instrument control headers;

9 Crane beams, davits, hooks and crane operator cabins;

10 Outline extents of hose stations and eye washers;

11 North arrow.

1.3.6 Dimensioning

Dimensioning shall meet the following requirements:

1 Location dimensions or coordinates of all equipment, and elevations of foundation surfaces. For horizontal equipment, the location dimensions of the equipment supports shall also be marked; for pumps, the elevation of the bottom of the base plate shall be marked, above or below the center line bearing the pump number. For compressors, the center elevations of the crankshaft and of the cylinders shall be marked;

2 The column grid axis numbers and the column spacing dimensions or coordinates of buildings and structures, and the elevations of floors or platforms, shall be marked;

3 For pipe racks, the column spacing dimensions (or coordinates) and the top elevations of each tier shall be marked;

4 The location dimensions of crane beams, beam bottom elevations, loads or lifting capacities shall be marked;

5 Location dimensions shall be marked for local electrical and instrument control panels;

6 The orientations of equipment nozzles, the nozzle numbers and their elevations shall be marked; for the specific marking method see 2.6.2 and 2.7 in Chapter 2 of this regulation;

7 Line numbers, piping classes, flow directions, bottom-of-pipe elevations or work point elevations and their location dimensions or coordinates shall be marked;

8 Where special requirements make it necessary to indicate the location dimensions, coordinates and elevations of piping, such as liquid seal heights or piping in which pockets are not permitted, the corresponding dimensions or text symbols shall be marked;

9 Relevant reference drawing numbers shall be marked.

1.3.7 Method of representation

1 The drawing methods for pipes, fittings, valves, control valve assemblies, etc. are the same as the drawing regulations for the piping layout drawing (design edition);

2 Elbows are shown with arcs; when an intermediate scale is selected as described in item 1 of 1.3.3 of this standard, single-line pipes are allowed to be shown with right angles;

3 Other legends are given in the following regulations:

1) For the legends of pipes, fittings, valves and special piping items on the piping layout drawing (study edition), see Chapter 2 of "Engineering Regulations for Piping Layout Design of Chemical Plants" (HG/T 20549.2).

2) Content relating to equipment layout in piping layout drawings shall comply with Chapter 6 of "Regulations on the Content and Depth of Equipment Layout Design for Chemical Plants" (HG 20546.1).

4 The line widths and lettering of drawings such as equipment and piping layout drawings, piping isometric drawings and fitting drawings shall comply with Chapter 13 of this standard.