1 HVACR116 – Trade Skills Drawing Scales and Lines

2 Objectives After completing this unit, you will be able to perform the following tasks: o Identify the scale used on a construction drawing o Read an architect’s scale After completing this unit, you will be able to perform the following tasks: o Identify the scale used on a construction drawing o Read an architect’s scale

3 Scale Drawings Construction projects are too large to be drawn full size on a sheet of paper Drawing to scale: o Everything must be drawn proportionately smaller  House floor plans are often drawn 1/48 of actual size  Small scale is used to fit a large object on a drawing  Scale used is noted on the drawing Construction projects are too large to be drawn full size on a sheet of paper Drawing to scale: o Everything must be drawn proportionately smaller  House floor plans are often drawn 1/48 of actual size  Small scale is used to fit a large object on a drawing  Scale used is noted on the drawing

4 Scale Drawings (cont’d.) Figure 3–1. Portion of a plan view with a firewall.

5 Scale Drawings (cont’d.) Figure 3–2. Detail (plan at firewall).

6 Reading an Architect’s Scale All dimensions should be shown on the drawing Architect’s scale is used to make drawings to scale o Not used to measure the drawing (poor practice) All dimensions should be shown on the drawing Architect’s scale is used to make drawings to scale o Not used to measure the drawing (poor practice)

7 Reading an Architect’s Scale (cont’d.) Figure 3–3. Architect’s scale. Courtesy of Alvin & Co., Inc.

8 Reading an Architect’s Scale (cont’d.) Triangular architect’s scale includes 11 scales frequently used on drawings:

9 Reading an Architect’s Scale (cont’d.) Two scales are combined on each face o Except for full-size scale  Fully divided into sixteenths Combined scales work together o One is twice as large as the other o Zero points and extra divided units are on opposite ends Two scales are combined on each face o Except for full-size scale  Fully divided into sixteenths Combined scales work together o One is twice as large as the other o Zero points and extra divided units are on opposite ends

10 Reading an Architect’s Scale (cont’d.) Figure 3–4. Architect’s triangular scales.

11 Reading an Architect’s Scale (cont’d.) Fraction, or number, near zero at each scale end indicates unit length in inches o Used to represent one foot of actual building Extra unit near zero end of scale is subdivided into twelfths of a foot (inches) o Fractions of inches on larger scales Fraction, or number, near zero at each scale end indicates unit length in inches o Used to represent one foot of actual building Extra unit near zero end of scale is subdivided into twelfths of a foot (inches) o Fractions of inches on larger scales

12 Reading an Architect’s Scale (cont’d.) To read the scale: o ¼-inch scale  Scale is divided on left from zero toward ¼ mark  Each line represents one inch  Counting marks from zero towards ¼ mark, there are 12 lines marked on the scale  Each line is one inch on the ¼" = 1' - 0" scale To read the scale: o ¼-inch scale  Scale is divided on left from zero toward ¼ mark  Each line represents one inch  Counting marks from zero towards ¼ mark, there are 12 lines marked on the scale  Each line is one inch on the ¼" = 1' - 0" scale

13 Reading an Architect’s Scale (cont’d.) To read the scale (cont’d.): o 1/8-inch scale  1/8 is on opposite end of the same side o Read in opposite direction o Counting from zero, there are six lines  Each represents two inches at the 1/8-inch scale To read the scale (cont’d.): o 1/8-inch scale  1/8 is on opposite end of the same side o Read in opposite direction o Counting from zero, there are six lines  Each represents two inches at the 1/8-inch scale

14 Reading an Architect’s Scale (cont’d.) To read the scale (cont’d.): o 1½ -inch scale  Divided unit is broken into twelfths of a foot (inches) and fractional parts of an inch  Figures 3, 6, and 9 represent these inch measurements at the 1½" = 1' - 0" scale To read the scale (cont’d.): o 1½ -inch scale  Divided unit is broken into twelfths of a foot (inches) and fractional parts of an inch  Figures 3, 6, and 9 represent these inch measurements at the 1½" = 1' - 0" scale

15 Alphabet of Lines

16 Objectives After completing this unit, you will be able to identify and understand the meaning of the listed lines: o Object lines o Dashed lines (hidden and phantom) o Extension lines and dimension lines o Centerlines o Leaders o Cutting-plane lines After completing this unit, you will be able to identify and understand the meaning of the listed lines: o Object lines o Dashed lines (hidden and phantom) o Extension lines and dimension lines o Centerlines o Leaders o Cutting-plane lines

17 Introduction Drawings are the language of the construction industry o Basis of language is its alphabet o Construction drawings use an alphabet of lines Drawings are the language of the construction industry o Basis of language is its alphabet o Construction drawings use an alphabet of lines Figure 4–1. Alphabet of lines.

18 Object Lines Line weight or thickness is varied to show relative importance o Help distinguish basic shape from surface details Object lines are used to show object shape o All visible edges are represented by object lines Line weight or thickness is varied to show relative importance o Help distinguish basic shape from surface details Object lines are used to show object shape o All visible edges are represented by object lines

19 Object Lines (cont’d.) Figure 4–2. Elevation outlined.

20 Dashed Lines Hidden lines show object edges that would not be visible o Drawn as a series of evenly sized short dashes o Only used for most important features Hidden lines show object edges that would not be visible o Drawn as a series of evenly sized short dashes o Only used for most important features Figure 4-3. The dashed lines on this foundation plan indicate the footing.

21 Dashed Lines (cont’d.) Phantom lines show important overhead construction o Not in hidden view, just not in view (e.g., beams on a ceiling) Phantom lines show important overhead construction o Not in hidden view, just not in view (e.g., beams on a ceiling) Figure 4–4. The dashed lines on this floor plan indicate the edge of the roof overhang.

22 Dashed Lines (cont’d.) Phantom lines may also show alternate positions May be different weights and lengths Phantom lines may also show alternate positions May be different weights and lengths Figure 4–5. The dashed lines here are phantom lines to show alternate positions of the double-acting door and the door of the dishwasher.

23 Figure 4–6. Different types of dashed lines are used to show different features.

24 Extension Lines and Dimension Lines Extension lines: o Thin, solid lines that project from an object to show extent or limits of a dimension  Do not quite touch the object they indicate Extension lines: o Thin, solid lines that project from an object to show extent or limits of a dimension  Do not quite touch the object they indicate

25 Extension Lines and Dimension Lines (cont’d.) Dimension lines: o Solid lines of the same weight as extension lines o Drawn from one extension line to the next o Dimension is lettered above the dimension line o Expressed in feet and inches o Chain dimensions are dimensions added together to come up with one overall dimension Dimension lines: o Solid lines of the same weight as extension lines o Drawn from one extension line to the next o Dimension is lettered above the dimension line o Expressed in feet and inches o Chain dimensions are dimensions added together to come up with one overall dimension

26 Extension Lines and Dimension Lines (cont’d.) Figure 4-7. Dimension and extension lines.

27 Figure 4–8. Dimension line ends.

28 Centerlines Made up of long and short dashes o Show centers of round or cylindrical objects o Indicate object is symmetrical Made up of long and short dashes o Show centers of round or cylindrical objects o Indicate object is symmetrical Figure 4–9. This centerline indicates that the column is Symmetrical, or the same on both sides of the centerline.

29 Figure 4–10. When centerlines show the center of a round object, the short dashes of two centerlines cross.

30 Figure 4–11. Method of showing the radius of an arc.

31 Leaders Some construction details are too small for clear dimensioning o Dimension is shown in a clear area of the drawing o Leader is the thin line showing where the dimension belongs Some construction details are too small for clear dimensioning o Dimension is shown in a clear area of the drawing o Leader is the thin line showing where the dimension belongs Figure 4–12. Leaders used for dimensioning.

32 Cutting-Plane Lines Show where imaginary cut was made in section view o Usually a heavy line with long dashes and pairs of short dashes o Typical sections are not shown  They would be the same if drawn from an imaginary cut in most parts of the building Show where imaginary cut was made in section view o Usually a heavy line with long dashes and pairs of short dashes o Typical sections are not shown  They would be the same if drawn from an imaginary cut in most parts of the building

33 Cutting-Plane Lines (cont’d.) Figure 4–14. Building section.