CAD Drafting Standards

Transcription

1 Marine Institute of Memorial University of Newfoundland CAD Drafting Standards Marine Engineering Systems Design Department Revision 1

2 List of Revisions Revision Description Date 0 INITIAL ISSUE Sep/16/2009 Section 3: EXPANDED PAPER SIZE DATA TO INCLUDE BOTH METRIC AND IMPERIAL DIMENSIONS AND ISO AND ANSI PAPER SIZES. Section 4: CHANGED Part nos. for machinery should be shown as a circle, as such: TO Part nos. for machinery and pipe components should be shown as a circle, as such: 1 Section 6: CHANGED All diagrammatic drawings should include the following notes: TO All diagrammatic drawings should include notes that are similar to the following, as applicable: Section 6: CHANGED The below notes would be modified to suit the specifics of the system design and requirements: TO The below notes should be modified to suit the specifics of the system design and requirements: Section 6: ADDED Care should be taken not to repeat information that is provided in tabular form. March 2, 2010 Section 7: ADDED B.O.M. TABLE. Page 1 of 12

3 1.0 Introduction The standards described in this document are primarily intended for Marine Engineering Systems Design students enrolled in the three year Diploma of Technology program. Introducing drawing or drafting standards to the classroom at the Marine Institute serves two purposes. First, it makes students aware such standards exist and familiarises them with the format and use of drafting standards as found in the shipbuilding industry. Secondly, drafting standards will allow a class of students to work to the same standard and therefore produce similar standard drawings as would be expected by industry drawing offices. This Drafting Standard can be used as a constant source of reference by all students. Instructors may deviate from this standard depending on the type of lab/drawing work being done. 2.0 Drawing Layout The layout of technical drawings will be as described by the course instructor, as this largely depends on the type of drawing being produced. For example, System Diagrammatic, Pipe Spools, and Machinery Arrangement drawings require different layouts and information to be included on them. Instruction on these aspects of the drawings will be included in the lecture portion of the lab sessions. Drawing layouts will vary depending upon the drawing purpose and type Page 2 of 12

4 3.0 Drawing Format 3.1 Standard Formats (Border and title block) Drawings to be submitted for evaluation are to be on a standard Marine Institute format as supplied or approved by the course instructor. The following standard sheets may be used (course instructor to advise preferred size for final submission); ISO Paper Sizes Inches Millimeters A x A x Technical Drawings A x A x "x17" A4 8.3 x Letter The allowed tolerances are ±1.5 mm for dimensions up to 150 mm, ±2 mm for dimensions above 150 mm up to 600 mm, and ±3 mm for dimensions above 600 mm. ANSI Paper Sizes Inches Millimeters ANSI A 8.5 x x 279 Letter ANSI B 11 x x "x17" ANSI C 17 x x 559 A2 ANSI D 22 x x 864 A1 ANSI E 34 x x 1118 A0 General notes and reference drawings to be shown on the drawing (if any) are positioned in the area above the title block. This area should be left clear for this purpose and no portion of the drawing on the sheet (or details) should extend into it. Typical boarder / title block - Layout and requirements will differ amongst companies. Page 3 of 12

5 3.2 Text and Leader Lines All text is to be upper case, ROMANS font, 2.5 mm high for general text and 5.0 mm high for view titles (Plan View, Section, Elevation, etc.). A width factor of 1.0 (default) is generally to be used throughout the drawing except where slight compression of the text is required to fit the text on the drawing. Arrow heads on leader lines are to be solid fill, 2.5 mm long. Leader lines shall have a short horizontal line next to the text label and the arrow head should touch the object being labelled (but not extend into it). Multiple line text will be aligned on the left hand side, regardless of which side of the text the leader line is on. See example below. When producing production or working drawings, view titles and details are to be labelled using the sheet number-grid location on the drawing format. Grid Reference: This refers to the horizontal numbers and vertical letters in the margin of the drawing border. It allows the designer to give each view and detail its own unique designation, which makes referencing (AKA calling-out ) simpler and much less prone to error. Each grid reference can only be used once per drawing sheet. Page 4 of 12

6 3.3 Scales All drawings done using AutoCAD are to be drawn full size (i.e. 1:1 scale), and the drawing format (border and title block) selected scaled up to suit the size of the object(s) drawn. The course instructor may advise an appropriate scale for the lab drawing being done. Production/working drawings requiring enlarged detail views will also be drawn full size and each detail scaled up to an appropriate standard scale (i.e. 1:10, 1:5, 1:2, etc.) as required to make the detail clear to the drawing reader. NOTE: ALL DRAWINGS submitted for evaluation MUST BE PLOTTED TO SCALE as advised by the course instructor (i.e. they must be able to be scaled using the appropriate scale rule). Imperial Scales: Scale Factor Final Scale 192 1/16" = 1'-0" 128 3/32" = 1'-0" 96 1/8" = 1'-0" 64 3/6" = 1'-0" 48 1/4" = 1'-0" 32 3/8" = 1'-0" 24 1/2" = 1'-0" 16 3/4" = 1'-0" 12 1" = 1'-0" 8 1 1/2" = 1'-0" 4 3" = 1'-0" 2 6" - 1'-0" Page 5 of 12

7 3.4 Dimensions Duplication of dimensions shall be avoided. If a dimension is not to scale, it must be emphasised by a broken dimension line and the suffix NTS (Not To Scale) added after the dimension text. Dimension text is to be ROMANS font, 2.5 mm high, and centred ABOVE the dimension line, or to the outside as space dictates. Arrow heads are to be 2.5 mm long and solid filled. Extension lines are not to touch the object being dimensioned. There should be a gap clearly visible between the extension line and the drawn object. Example: Refer to the handout Do s and Don ts of Dimensioning for additional information. 3.5 Pen Assignments (Pen Widths) The following are standard pen widths to be used on all drawings; Colour Width (MM) 1) Red ) Yellow ) Green ) Cyan ) Blue ) Magenta ) White ) Grey ) All Others Note: Set plot style to monochrome for black & white plotting (ie: no colour or gray-scale plots) Page 6 of 12

8 3.6 Linetypes and Linetype Scale The following standard line types shall be used as required on drawings. Some examples of the use of each line type and the colour of each line type are given. Linetype Use Colour Example Continuous Outlines of plan views elevations, sections White Continuous General drawing use Cyan Hidden Hidden Centerline Phantom Hidden objects, nonwatertight floors, bulkheads Hidden W.T./O.T. bulkheads and decks Centerline of vessel, plan view and sections Definition of withdraw space or relocation of items Red/Yellow Green Red Yellow Text View title White General drawing text Green Break Lines Short Break Bylayer Long Break Bylayer The Linetype scale for the drawing should be selected so that each linetype is clearly defined on the drawing when the drawing is plotted to scale. Individual linetype scales may be adjusted if required to suit details, keyplans, etc. which have been scaled up or down as needed. Linetypes that are used to differentiate various piping systems, for example, on a piping composite drawing, should use layer names that indicate the piping system (ex: BILGE for the bilge system). Page 7 of 12

9 3.7 Layers The following layers will be used on ALL drawings: Layer Use 0 AutoCAD s default layer do not use. CL Centrelines (linetype set to centerline ) Dim Dimensions Text All other text, including leader lines Title Block Title Block, drawing border, and associated text. Additional layers will be used as required at the draftspersons discretion. However, some thought should be given to the development of layers on a drawing to take full advantage of the layer options. These layers will vary depending on the type of drawing being produced and possible uses of the drawing file by other departments within the drawing office (such as piping, electrical departments etc). Example: Structural Drawing Layer Structure Structure_Primary Structure_Secondary Pillars Use Structural Elements Primary Structural Elements (webs, girders) Secondary Structural Elements (stiffeners) Pillars (structural) Example: Marine Engineering Drawing Layer Use Equipment Equipment items Piping Pipe systems Piping_Bilge Bilge piping system Piping_Ballast Ballast piping system Piping Each system can be specified as needed. 4.0 Part Numbers Drawings to be used for fabrication purposes on the shop floor (i.e. Production or Working Drawings) must include piece part numbers for part identification. All parts cut from plates or shapes must have individual part numbers unless the parts are identical and are interchangeable on either side of the vessel, where one common number will be sufficient. Should the parts be the same but handed to one side of the vessel, different part numbers will be assigned with the suffix P or S as applicable to indicate on which side the part is installed. Part nos. for parts cut from plate to be shown in a box as such; Part nos. for parts cut from shapes to be shown in a diamond as such; Part nos. for machinery and pipe components should be shown as a circle, as such: Part nos. for pipe spools should be shown as a circular rectangle, as such: Page 8 of 12

10 5.0 Standard Abbreviations Abbreviations are often used on design and construction drawings due to space limitations and to speed up the labelling of drawings. The following is a list of standard abbreviations used on drawings in the shipbuilding industry. Care should be taken to use the abbreviations correctly and consistently throughout the entire drawing package. A/BL BF BKT BL CL DK ELEV FB FF FLG FR GDR IOA L LONG OA P&S PL PROF R (or RAD) S SECT SRB (or RB) STBD TB THK TYP W WHU Above Baseline Bulb Flat Bracket Baseline Centerline Deck Elevation Flat Bar Face Flat Flange Frame Girder Inverted Ordinary Angle Angle Bar Longitudinal Ordinary Angle Port and Starboard Plate Profile Radius Snipe Section Solid Round Bar Starboard Tripping Bracket Thick Typical Web Weld Hard Up Abbreviations developed exclusively for a particular drawing should be defined on the drawing itself. Page 9 of 12

11 6.0 General Notes All diagrammatic drawings should include notes that are similar to the following, as applicable: 1. THIS DRAWING IS DIAGRAMMATIC ONLY. ACTUAL PIPE LOCATIONS TO BE VERIFIED. 2. ALL DIMENSIONS ARE IN MM. 3. WHERE PIPING PENETRATES A WATERTIGHT BHD, A DECK OR A TANK TOP AN ADEQUATE PENETRATION FITTING TO BE PROVIDED TO INSURE WATER TIGHTNESS OF THE STRUCTURE. 4. ALL PIPING SHALL BE ARRANGED SO THAT IT WILL NOT NORMALLY BE SUBJECT TO MECHANICAL INJURY AND TO PRECLUDE IT'S USE FOR OTHER PURPOSES SUCH AS GRAB RODS, STEPPING POINTS & HANDRAILS. 5. UNIONS AND/OR FLANGES ARE TO BE INSTALLED BY THE FIELD AS NECESSARY TO PERMIT DISMANTLING OF THE LINES AND EQUIPMENT. 6. PIPING TO BE THOROUGHLY CLEANED AFTER FABRICATION. 7. ALL PIPING TO HAVE SUFFICIENT FLEXIBILITY TO PREVENT OVERSTRESSING OF PIPING MATERIALS, LEAKAGE OF JOINTS OR DISTORTION OF CONNECTED EQUIPMENT. 8. ALL PIPING SHALL BE AS DIRECT AS POSSIBLE WITH A MINIMUM NUMBER OF BENDS. The below notes should be modified to suit the specifics of the system design and requirements: 9. PIPING TO BE SCH 40, BLK STL. ASTM A53 GR B, ANSI B ALL PIPE FITTINGS TO BE SCH 40, BLK STL, BUTT WELD, ASTM A234, ANSI B16.9. Care should be taken not to repeat information that is provided in tabular form. Page 10 of 12

12 7.0 Tables Marine Engineering drawings are required to present detailed information in tabular format. The below table are generic and additional information may be requested, depending upon the application and regulations used. SYMBOL DESCRIPTION OF SYMBOLS DESCRIPTION BILGE PIPELINE BALLAST PIPELINE GATE VALVE, 150#, FLGD, CAST STL, ASTM A216, GR WCB, ANSI B16.34 etc. LIST OF MACHINERY ITEM DESCRIPTION QTY CHARACTERISTIC 1 BILGE & BALLAST PUMP 2 Q = 100 m 3 /hr, H = 25 m WG 2 FIRE PUMP 1 Q = 66 m 3 /hr, H = 35 m WG etc. HYDRAULIC TEST PRESSURES (BAR) AT WORKSHOP AFTER PIPELINE VALVES PIPES ASSEMBLY LUBE OIL SUCTION LUBE OIL DISCHARGE etc Note: Values shown as examples only. Verify actual test pressures for application as per applicable requirements. Page 11 of 12

13 MATERIAL SPECIFICATION PIPELINES PIPE CONNECTION GASKETS ALL MILD STEEL, SCHD 40 FLANGED RUBBER VALVES BODY INTERNAL PARTS SEAT SEALS CAST IRON or BRONZE or STAINLESS BRONZE or STAINLESS ALL STEEL STEEL STEEL BILL OF MATERIALS Item Nominal No. Dia Schedule Description ASTM ANSI Length Qty 1 3" 40 BLK STL A53 GR B B FT 3 2 3" 40 Elbow, 90-Deg, BLK STL A234 B Page 12 of 12