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					                                      Scales
•   It is impractical to draw buildings, plots of land, and large parts of buildings such
    as doors and windows to their full size.
•   They simply would not fit on a piece drawing paper. Instead they are normally
    drawn to a smaller reduced size. The size they are reduced will be to a ratio of the
    real item:
     •   Twice as small 2:1
     •   Ten times smaller 10:1 etc
•   When drawings are drawn in this way they are called SCALED DRAWINGS
•   To draw buildings and objects to a scale, recognised ratios called SCALES are
    used to relate real dimensions and measurements to a drawing.




                Building reduced in size to fit on drawing paper
                                                                                     1
                             Scales

The main scales     1:1     Full size used for unusual details or templates
or ratios used in   1:2
construction        1:5     Complicated building details
drawings are-:      1:10
                    1:20
                    1:50
                            Plans, elevations and sections
                    1:100
                    1:200
                    1:200
                    1:500  Site plans
                    1:1250
                    1:1250
                           Block or location plans
                    1:2500


                                                                         2
                          Use of scales

•   The choice of scale will depend on two things:
    1. The size of the object to be drawn
    2. The amount of detail that needs to be shown

•   A scale is used to measure distances on drawings and for taking
    measurements of a drawing.

                                15.35 m
    •   The distance shown above represents 15.35m it will be to a scale.
•   If scaled dimensions and written dimensions disagree, then the
    written dimension should always be used.
•   The scale shows how much smaller the plan or object is to its original
    size.

                                                                            3
                              Use of scales

•   In a house drawing to a scale of 1:20 :
     • 1 mm will represent 20 mm
     • 2 mm will represent 40 mm
     • 10 mm will represent 200 mm
     • 100 mm will represent 2000 mm or 2 m

•   To a scale of   1: 10    100 mm will represent 1,000 mm or 1 m
•   To a scale of   1: 100   100 mm will represent 10,000 mm or 10 m
•   To a scale of   1: 50    100 mm will represent 5,000 mm or 5 m
•   To a scale of   1:5      250 mm will represent 1,250 mm or 1.250 m
•   To a scale of   1:200    150 mm will represent 30,000 mm or 30 m

•   It is simply a matter of multiplying the scale measurement by the scale ratio
      • 1: (10) x 100mm = 1000mm or 1m
      • 1: (50) x 100mm = 5000mm or 5m
      • 1: (200) x 150mm = 30,000mm or 30m

                                                                                    4
                     Student Activity

• The drawing shows a ground
  floor plan of a small bungalow
  drawn to a scale of 1:100.
• Using a scale rule complete
  the table by inserting all the
  required dimensions.




                                        5
                    Student Activity

•   Complete the tables below by taking measurements from ground
    floor plan of bungalow


                                                      Length of
        Room         Length     Width       Area
                                                       skirting
       Lounge
      Bedroom 1
      Bedroom 2
        Hall 1
        Hall 2
       Kitchen

                                                                  6
                   Student Activity

• Insert the width of all the windows of the bungalow


    Windows                             Width
       W1
       W2
       W3
       W4
       W5

                                                        7
                 Student Activity

Scale Rule – Scale 1:100
• Mark on the scale rule the line representing 1.6m to a
  scale of 1:100




                                                           8
                 Student Activity

Scale Rule – Scale 1:20
• Mark on the scale rule the line representing 1.7m to a
  scale of 1:20




                                                           9
                 Student Activity

Scale Rule – Scale 1:50
• Mark on the scale rule the line representing 6m to a
  scale of 1:50




                                                         10
                 Student Activity

Scale Rule – Scale 1:1250
• Mark on the scale rule the line representing 130m to a
  scale of 1:1250




                                                           11
                        Drawing Lines

Lines should be of THREE thicknesses
1. Thick
   0.75 – 1mm thick for borders and
   drawing outlines

2. Medium
   0.35 – 0.5mm thick ½ the thickness of
   the thick lines for hatching

3. Fine




                                                     350mm
   0.2 – 0.25 mm thick ½ the thickness of
   the medium lines for dimension lines.
                                            600mm



                                                    12
                Dimension Lines

• All drawings must be clear and accurate and easily
  understood by everyone who uses them.
• In order to achieve this method of layout, symbols and
  abbreviations have been standardised ( See BS 1192 ).
• Next slide are some examples of the most common
  different lines and what they represent on working
  drawings.


                                                           13
  Dimension Lines

• Thick           Main outlines
• Medium          General details and outlines
• Thin            Construction and dimension Lines
• Breakline       Breaks in the continuity of a drawing
• Thick chain     Pipe lines, drains and services
• Thin chain      Centre lines
• Section line    Showing the position of a section cut,
                  the pointers show the direction of the view
• Broken line     Shows hidden details
• Dimension line Indicates the distance between two points



                                                          14
                             Drawing Notation

North Sign
On site plans this sign shows the
direction of true North.




    1   2   3   4   5   6    7   8   9   Stairs
                                         Arrow shows the direction of
                        UP
                                         the steps and the number of
                                         steps in the stair.

                                                                        15
                 Drawing Notation

Windows
A dotted line in the shape of a pointed arrow indicates the
haging edge of a window sash




                                              Bottom hung
                        Top hung
     Side hung

                                                              16
                       Dimension Lines

• These should be thin lines, the ends can be shown in several ways
                               350mm




• Open arrow head showing outside measurement                    0.5m



• Closed arrow head showing inside measurement

               1000        2500        50       3500

                               Running totals


                                                                        17
                 Dimension Lines

• Written dimension on horizontal lines should always be

  on top, preferably in the centre.

• Written dimensions on vertical lines should be to the left

  and preferably in the centre.

• All dimensions should be read from the bottom right

  hand corner.


                                                           18
                             Symbols

• Symbols are graphical illustrations, which are used to represent
  the different building materials and components in a building
  drawing.
• It was the custom to colour drawings, particularly the drawings
  submitted to the local authority for planning permission.
• Sadly the practice is rarely used as it is slow and time consuming.
• However is still the custom to colour in the position of a building in a
  block plan to show the position of the building and its surrounding
  boundaries.
• Next slide are some of the most common symbols used and what
  they represent.


                                                                         19
Symbols




          20
                       Lettering Drawings

•   The majority of drawings will require lettering and numbering.
•   This may vary from very little or none on a design to a great deal of production
    drawings and schedules.
•   Various techniques can be used, their application depending upon the type of
    drawing and its use.
•   The quickest method is by hand and it is important to develop a neat and
    accurate style from the beginning.
•   Poor lettering can ruin an otherwise good drawing.
•   Any lettering that is used, whether for notes, titles or headings, must be clear
    and easy to read.
•   Good use of lettering will not only give information but can improve the
    presentation of the drawing.
•   Faint guide lines could be drawn to help you practice the letters and numbers.

                                                                                   21
                   Lettering Drawings

 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

                   1 2 3 4 5 6 7 8 9 10 11




• The size of the letters depends on the size of the drawing paper.
• For A1, A2 and A3 sized paper, the letters should be between 7 mm
  and 4 mm.
• For A4 sized paper the letters should be between 5 mm and 3 mm


                                                                      22
                             Title Panels

• The British Standard 1192 sets the following recommendations.
   •   Job Title and number
   •   Name and Address of issuing firm or practice
   •   Description of the drawing
   •   Scale
   •   Date the drawing was completed
   •   Author of drawing
   •   Checker of the drawing
   •   Drawing number

• Many construction firms have their drawing paper pre-printed with a
  title panel.
• The panel should be at the bottom right hand corner of the drawing.

                                                                        23
Title Panels




                     J & M Builders
                     Drawing No 235
                     W R Smith
                     10 Greenways
                     Greenham
                     Scale 1:100 March 2003
      Title Panels   Drawn CPR


                                     24
                       Abbreviations

• Abbreviations are a simple way of conveying information on
  drawings, reducing words to first letters, e.g. rain water pipe
  becomes R.W.P.
• They allow the maximum information to be included on the drawing
  in a concise way.
• Abbreviations have to be used in context e.g. MS stands for Mild
  Steel in the context of construction but it could also be an
  abbreviation for some other word in another situation.
• Avoid making up your own abbreviations as these can lead to
  confusion.

                                                                     25
                Abbreviations

•   Aggregate   agg    •   Copper                cu
•   Air brick   Ab     •   Damp proof course     dpc
•   Aluminium   al     •   Discharge pipe        DP
•   Asbestos    asb    •   Foundation            fdn
•   Asphalt     asph   •   Hardcore              hc
•   Bitumen     bit    •   Hardboard             hdbd
•   Boarding    bdg    •   Hardwood              hwd
•   Brickwork   bwk    •   Inspection chamber    IC
•   BS Beam     BSB    •   Insulation            insul
•   Building    bldg   •   Tongued and grooved   t&g
•   Cast iron   CI     •   Joist                 jst
•   Cement      ct     •   Plasterboard          pbd
•   Column      col    •   Reinforced conc       RC
•   Concrete    conc



                                                   26
             Graphical Symbols


• These are small standard pictures used to reduce
  the amount of drawing detail required on individual
  drawings.

• Abbreviations and graphical symbols are often used
  together to give complete information.




                                                        27
        Representation of components -
                    fittings


 Sink        Bath       Bidet    Toilet      Hot & Cold Cold water Hot water Stop
                                             Water drain Cistern   Cylinder valve
                                                 off




 Drain or      Foul water       Rain water      Surface       Rainwater    Gulley
Sewer Flow                        head           water          outlet


             Radiator    Towel rail          Boiler       Cooker    Pump

                                                                               28

				
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