Exam 2 WE-1-DP Drawing Interpretation 120102a
What are the elements of a working drawings?
- graphic/pictorial portion of contract documents - conveys design intent of A to C - shows design, dimensions, quantity, and location of work - plans, elevations, sections, details, schedules. They also allow changes before the final draft.
How are metric dimensions show on a drawing?
-All dimensions are shown using one unit to avoid confusion and costly errors. -Working drawings used for fabrication and construction of a project show all dimensions in millimeters because this dimension allows for reasonable accuracy. The suffix mm for millimeter is not required unless other dimension units are on the drawing. -Decimal fractions are preferred instead of common fractions. For example, 11/4 is written 1.25. -A decimal quantity is normally shown by a dot on the line. (Some parts of the world use a raised dot or a comma to show a decimal quantity). -If the quantity is less than one unit, a zero precedes the decimal point as in 0.375. -Large numbers use a space to group numbers into threes on both sides of the decimal point. (For example, 321 454.567 2). This rule is ignored if the number is four digits as with 1454 or 0.1257.
How are imperial dimensions show on a drawing?
-Drawings using imperial measurements for larger projects use both feet (') and inches (") for all dimensions. -A dimension of exactly seven feet is written 7' - 0". -A dimension of seven inches is written 0' - 7". -A dimension of seven feet and seven inches is written 7' - 7". -Portions of an inch are usually expressed as a common fraction although a decimal fraction is used in some cases, especially where precision measurements are required. Precision measurements are usually made to the nearest one thousandth of an inch (written 0.001"). -In some instances, a dimension is expressed in feet and decimal fractions of a foot. Be very careful in this circumstance. For example, a dimension of 3.5' measures 3' - 6", not 3' - 5". -Drawings of smaller projects may use inches only. These drawings are usually used where the project is less than six feet for any dimension. On these drawings, the foot symbol ( ' ) is not used. -Drawings should not mix both styles because this can lead to confusion and costly errors. If you encounter such a situation, verify the dimensions before continuing with the project.
What are the type of sections?
-Full Section -Half Section -Off Sections -Revolved Section -Aligned Section
What are the advantages of using CADD?
-Hard copies can be printed on paper at high speeds -Drawing revisions are fast, easy and accurate. -Inactive drawings requires little storage.
Which are the basic Lines that are standard to drawings?
-Object lines -Hidden lines -Section lines -Centrelines -Extension and dimension lines -Terminals -Leader lines -Cutting plane lines and viewing plane lines -Short break lines -Long break lines -Phantom lines
What are called the reference points on a blue print for a Pressure Vessel?
-Seam Lines -Tangent Line -Datum line
Which are the three ways of placing dimensions?
-Unidirectional: Places the number inside the arrow with the numbers placed in the horizontal position. -Aligned: Also places the number inside the arrows except that the numbers are placed in the direction the arrow running. -Architectural places the number the same way as aligned, using a solid arrow with the numbers beside the arrow instead of inside the arrow.
Revision Cloud
A cloud like circle around a change made to a print after the drawing has been released for construction.
What is the purpose of a Drawing?
A drawing is a mean of communication, that conveys information to the fabricator supplying permanent record of the fabrication by providing a freehand sketch or detail drawing plans. It is usually impractical for the engineer to be present while weldment is being fabricated so the information must be supplied by some method other than verbal communication.
What are Sectional Views?
A drawing that shows the interior of an object as it would appear if cut in half or quartered. Shows an object as if part of it were cut away to expose its insides.
What is an aligned Section View?
A section view wherein the cutting plane is offset, with the result showing odd numbered features; usually used on a cylindrical part.
What is a revolved section view?
A section view wherein the cutting plane is presumed to be cutting parallel with the line of sight for a view, at the sectional shape is revolved 90 degrees about an axis of revolution and superimposing the section view on the orthographic view.
What are Dimensions Lines?
Are fine lines with arrow heads, unbroken except where the dimensions is placed. Those lines touch the extensions lines showing the distance given by the dimension.
What are terminal lines?
Beside using arrowheads as terminals on a dimension line, slashes and dots can also be used. They are called like this when found together as dimension and extension lines.
What is CADD?
Computer Aided Design and Drafting.
What are structural Drawings?
Consist of all the drawings that describe:-Framing plans, major structural sections, wall section, beam details, foundation, .plans detail sections and connection detail.
What is offset section view?
Cuts into different parts of an object to see detail
What are Alternate Lines (Cutting or Viewing Plane Lines) (Preferred Cutting Plane Lines)?
Cutting plane line is a heavy broken line made up of a series of one long and two short dashes alternately spaced. Arrowheads placed at right angles to the cutting plane lines are solid heavy line or a series of long dashes. A viewing plane line is similar to a cutting view line and is used outside the object. Indicates where an imaginary cut is made through the object. Arrows show the direction in which the section is viewed. Letters next to the arrowhead identify the section in cases where more than one section is shown on the drawing. A view plane line shows the direction of viewing.
What is a blueprint?
Detailed building original copies of a plan used to evaluate design, determine feasibility, and guide construction of a structure. The plans are usually drawn by a draftsman.
Developed view
Dimensions on the developed view include any allowance necessary for bending and rolling. In general, each industry establishes its own method of determining bend allowances and sets up formulas to compute allowances based on the angle of the bend and the thickness of the material.
What is an architectural drawings
Drawings that contain information about the size, shape, and locations of all parts of a house or structure.
Full section view
IS A VIEW OF AN OBJECT THAT IS IMAGINED TO BE CUT THROUGH TOP TO BOTTOM, BUT NOT NECESSARILY THROUGH THE CENTER. THE PART NEAREST THE OBSERVER IS REMOVED SO THAT THE CUT SURFACE CA BE VIEWED FOR DETAIL. THIS PART THAT IS IMAGINED AS REMOVED IS NOT MISSING IN THE OTHER VIEW
Considerable view of a L shape and the small pipe joining the large pipe.
In this position, the true shape of the object ca be determinate to give a more complete description of the object and to make the drawing easier to read. Although this is a violation of true projection, it is preferred.
What are Leader Line?
Is a fine, straight line with an arrowhead or round solid dot or a squiggle at one end. It is usually drew at an angle, never horizontal or vertical. Points directly to the surface for purpose of dimensioning or adding a note. A dot may be used at the end of a straight line where reference is made to a surface area.
What is a Datum line?
Is a line that runs around the circumference of the shell of the vessel near one end of the shell. Reference marks are punched at regular intervals around the circumference. This line is the best reference to use since nozzle holes are often cut out of the shell before the shell is completely welded to the head.
What are Object Lines / Visible line?
Is a thick, solid line that shows the visible shape part, which is the outside edge of the surface of the part.
What are long Break Line?
Is a thin, straight light line with freehand zigzag. It is used to shorten an object on a drawing. Like short break lines they conserve space on a drawing. There is not industrial standard for when to use those lines, May end a partial section.
What is Developed view?
Is also called a development, is a view of a part as it appears when stretched or laid out on a flat surface. This view shows the part before it is shaped by bending, rolled or any other fabrication method.
Auxiliary View means what?
Is other views to show depth or projected incline or oblique plane. To draw the auxiliary view, look directly at the slanted surface. In Auxiliary views, only the slanted surface shown. The balanced of the object is omitted from the view, using short break lines. This because the balance of the object would not be in its true shape size.
What are seam line?
Is the line between the shell of the vessel and the end of the vessel. This line is not good reference point for thick-walled vessels because the centre of the weld is difficult to determinate.
What are tangent lines?
Is the line that touches the curved head at the highest point of curvature. This point may difficult to locate on a head and is not used as a reference point for critical measurements.
What are Construction Line (thin)
Light lines used in initial stages of drawing that are removed later. To aid in the construction of final drawing.
What are Phantom Lines?
Light, broken line made up of a series of one long and two short dashes. To show alternate positions of a part. To show relationship of existing part to a new part. To show machined surfaces.
Full section view illustration
Location of the cutting plane line in the top view, the location of the cut, the full section view and the front view of thew full section.
What a blueprint consist of?
May consist of white lines on a blue or black background, blue lines on a white background or other color combination. They use a sign language that is precise and exact, which is universally understood equally well by everyone involved in a project.
What are hidden lines?
Medium weight and composed of short dashes. They define edges, outlines and surfaces that are not visible in a particular view. More than one view is required to identify what hidden lines represent.
What is half section view?
One quarter of the part is cut away. The cutting plane line goes half-way through the object.
What are specification and notes?
Primarily written in content in a note, produced by the architect and engineer to give details of construction and of what. This includes: -The kind of materials to be used, -The welding processes and =The type of filler metal. To conserve space on blueprints, notes are sometimes shown as abbreviation or symbols. Specifications are usually found adjacent to a view or in space provided on the print for this purpose. However a general NOTE is placed away from the views so that it can be readily seen. If a note specifies the materials required, the welding process to be used and the type and size of filler material, it is called a specification
What is an as-built drawings?
Record drawings completed by the contractor and turned over to the owner at the end of the project identifying any changes or adjustments made to the conditions and dimensions of the work relative to the original plans and specifications.
What are Section Lines are?
Series of fine lines, solid or solid and broken arranged in specific patterns. They may be shown either straight or curved. When shown straight, they are usually drawn at 45 degrees angle. However, this angle will vary when applied to adjacent surfaces. To indicate the imaginary cut surface referred to by the cutting plane line and to represent various kinds of materials.
Disadvantages of using CAD?
The proper use of the program requires a through knowledge of blueprints reading and welding symbols.
What are blueprint views?
The views are used to convey information depending on the object being depicted: -Auxiliary view -Developed view -Revolved view -Untrue projection
How many divisions of drawing are associated with building construction?
There are five types of drawing: -Structural -Electrical -Plumbing -Finishing You may not work with all of them, but you must learn how to find information on a blueprint.
What are drawing elements found on a blue print?
There are three basic elements: -Lines which convey shapes and aid in dimensions that are used in the formation of symbols. -Dimensions gives the sizes and locations -Notes give details of construction not shown by lines. They may be symbols or abbreviations.
How to re-design changes on a blueprint?
These changes are often made on the original tracing from which the blue print was made. In some cases, the original size and dimensions are removed and the new ones are substituted. When such a procedure is followed, a listing of of the original sizes is usually made on the drawing. All changes must be initialed by authorized personnel and include the date of change.
What are centre lines?
They are fine (thin) and broken lines made of series of short and long dashes alternatively spaced. They are used to show the centre of a circle, arcs and symmetrical shapes objects and to aid in the dimensions of these parts.
What are extension Lines?
They are fine lines (thin) used to show size and location dimensions. They extend from the object with a slight break between. Extension lines help show the extend of a dimensions.
What is the function of symbols?
They are used to draw your attention to correction or revisions and details drawings.
What are Landscaping drawings?
They show the elevations of the ground that surround the building and the location of the trees and plants.
What are Short Break Line?
Thick (heavy), irregular line drawn freehand. To show greater detail behind the object of an object. Is also used to conserve space on a drawing. Ends a partial section.
What are mechanical drawing?
This are drawing that indicates the elements of the building's mechanical systems, such as plumbing, air conditioning, sprinklers, waste disposal, heating,and disposal sources, etc.
What are Electrical Drawings?
This drawing locates the power, lighting, the routing of circuits and telecommunication plans; signal and security systems; one-line diagrams and transformer, size of the panel boards, equipment, and fixture schedules in a building.
What are the Alphabet of Lines?
Those establish a common standard used on drawings. The lines convey information between designers and fabricators
What are symbols, views and sections?
WELDING SYMBOLS, OTHER SYMBOLS, DIFFERENT VIEWS AND A NUMBER OF SECTIONS ARE QUITE OFTEN USED ON BLUEPRINTS. When reading blueprints, you should be familiar with and understand these different symbols, views and sections.
What is a revision Cloud?
When an entire section of the drawing has to be changed, the section may be enclosed in a revision cloud. This is also referenced by a number or a letter in a circle or triangle. This corresponds to the revision list, which identifies specific changes made in that area of the drawing.
How corrections or revision are dealt with on a drawing?
When an error is discovered on a drawing, it is often marked with red or yellow pencil. Any such error is usually reported to the supervisor so that corrections can be made on future drawing. Corrections are shown on a blue print by use of letters or numbers that have circle or triangles drawn around them.
What is revolved view?
When an object is shown in true projection, it is drawn in all views as it actually appears. However, for better clarity in some cases, one view of the object may be shown as it does not actually apper. A portion of the object is rotated to obtain a straight axis for better detail and dimensioning.
What to do if there is conflict between specifications and the drawing?
You must check the information in the specification because is usually assumed correct. However, it is best to confirmed by checking with the engineer or architect.
