Drawing Standards, Protocol and conventions

Question 1

The function of British Standards

Answer 1

Standards are a set of rules for doing things. Drawings contain a lot of information so they can easily become cluttered and not easily understood by all working with them. One way to keep them tidy and consistent is to use standards and conventions.

In Britain, the British Standards Institute sets standards.

Question 2

Third angle projection symbol

Answer 2

Third Angle Projection is the drawing method used in British Standards and is the format that we use in Graphic Communication.

This symbol is used to show:

the way the views are projected/laid out
the projection type used
the orientation of views

Question 3

Orthographic projection

Answer 3

Orthographic projection in Third Angle Projection has all views projected from the elevation. All views must be aligned to the elevation.

Elevation: This should be looking at the front of an object if it was sitting on a table.

End Elevation: This would be looking at the side of the item and should be drawn in line with the elevation.

Plan: This sits above the elevation and is looking down at the item.

Question 4

Outline

Answer 4

Outlines are used to show visible outlines and edges of items. They are shown as a continuous thick line.

Question 5

Projection

Answer 5

Projection lines are used to project sizes to different views. They are also used for dimension and leader lines. They are shown as a thin solid line

Question 6

Centre

Answer 6

Centre lines comprise long lines and dashes. They are used to show the centre of items that have an axis to show centres of symmetry.

Question 7

Hidden detail

Answer 7

Hidden detail lines show hidden outlines and edges. These are shown as a dashed line

Question 8

Cutting plane

Answer 8

Cutting planes are used to show where a section has been created. They comprise a centre line with thick ends and arrows showing the direction of the section.

Question 9

Fold

Answer 9

Fold lines are used to show the folds in an object that has been flattened into a 2D shape. It is shown as a long line double dash.

Question 10

Dimension overview

Answer 10

Dimensions are included on production drawings to show sizes or angles.

Conventions for dimensioning:

All sizes in millimetres.
Dimensions must sit above the dimension line.
Dimensions must be read from looking at the page or rotating the page clockwise (shown on linear dimension).
There must be a gap between the extension line and the item.
Arrow heads must all be long and thin, this must be consistent across the page.

Question 11

Across flats and across corners

Answer 11

AC is used with hexagonal shapes to show the dimension across the corners.

AF is used with hexagonal shapes to show the dimension across the flat faces.

Question 12

Title block

Answer 12

Title blocks need to be included on every drawing. They contain vital information such as:

Scale
Date
Product name
Drawing/page number
Drawn by
Tolerance
Unit of measurement
Materials
Company brand
Drawing type
Third Angle Projection symbol

Question 13

Exploded views

Answer 13

Exploded views are often used to show how parts go together

Question 14

Conventions for sectional views

Answer 14

Sectional views use a cutting plane to show an assembled view cut. These are useful to show interior details, which would be hard to see in the hidden detail on an ordinary orthographic view .Should be at 45 degrees.There are several parts of components that do not have hatching applied in a sectional view. These include:

Webs
Axle/shaft
Screws
Bolts
Nuts
Pins
Holes
Voids
Washers

Question 15

Scale

Answer 15

When creating drawings it is important to consider scale. It would be impossible to fit the floor plan for a house on a single sheet of A3 paper, therefore scale is used to make the drawing smaller. This also works when an item is very small and details would not be captured.

If a drawing is
-Ordnance Survey maps use a scale of 1 : 2500 or 1 : 50000
-Architects use scales of 1 : 1250, 1 : 500, 1 : 200, 1 : 100 etc.
People in the Architecture and Built Environment sector often use scale rules to help them to measure accurately on printed scale drawings.
For reading location and site plans you must know the directions and be able to interpret them from a North Point Symbol.

Question 16

Location plans

Answer 16

Location plans are the first drawing in a project set.
They identify the location of the new building within its surroundings as neighbouring buildings and their boundaries, roads, street names and fields are all shown.
The scale is normally 1:1250.

Question 17

Site plans

Answer 17

Site plans show the site boundary and outline of the new building.
It also shows paths, roads and neighbouring plots are also shown.
Dimensions are shown to allow the builder to mark out the site, lay drainage pipes and build manholes.
The scale depends on the size of the building but is usually 1:200 or 1:250

Question 18

Floor plans

Answer 18

Floor plans are a type of sectional view which represents a plan view of the building with the roof off.
It shows the arrangement of rooms, position of the windows and doors, the types of internal and external walls.
Used by builders, plumbers, electricians and joiners to plan the build.
The scale is normally 1:50 or 1:100.

Question 19

Sectional views

Answer 19

Sections are cross sections showing a slice through the wall.
They gives builders, joiners and roofers information about how the building should be constructed.
It is usually in sectional views that the symbols for building materials such as blockwork, brickwork, timber and insulation board are displayed.
Sections can be shown through any part of the building and are normally at a scale to 1:20.

Question 20

Elevations

Answer 20

Elevations are orthographic projections of a building produced by and architect or designer.
They show the style of the building, the external appearance, style of roof and positions of doors, windows, and chimneys.

Question 21

Symbols on building sites

Answer 21

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