Engineering Drawings
Types and importance of drawings in construction. El-Eman Office provides survey drawings in DWG and PDF formats.
The full set of documents for any project
Engineering drawings and plans are not just attractive sheets but a connected set. It starts with a cover sheet and a drawing index, then general plans, then the architectural, structural, electrical, plumbing and mechanical drawings, followed by finishing, door and window schedules and the technical specifications. Each sheet refers to the others, and inconsistency between them is behind many errors. For example, a beam opening needed by the plumbing must appear on the structural sheet.
What makes a good drawing
- A clear scale suited to the type of sheet.
- Dimensions written clearly and consistently, never left to guesswork.
- Standard symbols with a legend explaining them.
- Levels written for floors, roofs and openings.
- Numbering, date and revision number on every sheet.
- Enlarged details for complex junctions such as roofs, entrances and bathrooms.
Coordination between disciplines
Most construction problems happen where disciplines cross: a drain pipe running into a beam, an air-conditioning duct that lowers the ceiling, or an electrical panel in an unsuitable place. This is handled by a coordination review before construction in which the sheets are overlaid on one another. Modelling software such as Revit detects clashes automatically, while in AutoCAD the check is done manually by reviewing the drawing layers.
Construction drawings and as-built drawings
- Permit drawings: submitted to the authorities to approve the project.
- Construction drawings: more detailed and used on site.
- Shop drawings: prepared by the contractor or supplier for fabrication, such as aluminium and steel.
- As-built drawings: record what was actually built, including changes.
Keeping as-built drawings matters for maintenance and any future additions, since they show the routes of concealed pipes and cables.
Managing drawing revisions
One of the most common causes of site errors is using an old version of a sheet. Every drawing should therefore carry its revision number and date, and old copies should be withdrawn from site when a new version is issued. Keep a revision log showing what changed in each issue and who approved it.
- Use one central folder for approved files.
- Issue printed copies with an approval stamp or mark.
- Tell the contractor and supervisor about any change in writing.
Frequently asked questions
What is the difference between PDF and DWG?
PDF is for viewing and printing and is not easy to edit. DWG is a drawing file that can be edited in AutoCAD and other software. It is best to get both.
Why do drawings change during construction?
Because of clashes found on site, new wishes from the owner, or different ground conditions. What matters is documenting every change with written approval.
Do I need detailed drawings for a small apartment?
Yes, at least floor plans, services and equipment locations. They reduce errors and allow accurate pricing and comparison of offers.
