The American Institute of Architects (AIA), Construction Specifications Institute (CSI), and National Institute of Building Sciences (NIBS) unveiled the United States National CAD Standard (NCS) Version 4.0, the first update to the Standard since 2005.

The latest edition, designed for owners, architects, engineers, contractors, facility managers, code officials, manufacturers, and suppliers, adds the following improvements to Version 3.1:

  • Expanded and reorganized CAD Layer Guidelines make it easier to locate layer names, including new telecommunications and electrical discipline layer names.
  • Updated Uniform Drawing System adds new and revised symbols for geotech, security, fire suppression, masonry, plaster, and updates, as well as clarifies common drawing practices.
  • Completely re-written Plotting Guidelines reflect that line widths are no longer required to be mapped to color numbers.
  • Version 4.0 now includes documents in PDF, Excel, and .dwg file formats, making it easier to search and integrate the standard into CAD, BIM, costing, and other software.

"CSI and our colleagues at AIA and NIBS are proud to introduce the latest version of the National CAD Standard," said Walter Marlowe, CSI’s executive director. "NCS Version 4.0 will further streamline design, construction, and facility operations communication among all participants in the facility lifecycle. Better communication means fewer errors and lower costs for all disciplines."

"A current, widely used National CAD Standard is an essential part of NIBS’ cooperative effort with AIA, CSI, and the buildingSMART Alliance to ensure an open, interoperable information format and communication environment—including integration into the new National Building Information Model Standard (NBIMS)—that will serve both the building community and the general public," said NIBS President David A. Harris, FAIA.

NCS Version 4.0 will benefit a wide range of industry stakeholders:

  • Owners and facility managers will benefit from a consistent appearance of drawing sets for all projects, reducing errors and change orders.
  • Designers will spend less time creating and maintaining in-house office standards.
  • Contractors will benefit from a consistent detail reference system.
  • Code officials will benefit from the consistent location of regulatory information in the drawing set and on specific individual sheets.
  • Manufacturers and suppliers will save time on price quotes and submittal review and approval.

The NCS incorporates three important components from the partnering organizations: AIA’s CAD Layer Guidelines; Modules 1-8 of CSI’s Uniform Drawing System; and NIBS’ Introduction, Appendices, and Plotting Guidelines (all maintained and balloted by the NIBS NCS project committee). Combining these resources, the NCS prescribes CAD layer names, drawing set organization, drafting, notation, and plotting conventions. It adds an extensive symbols library and thousands of terms and abbreviations.

More than 5,000 workplaces have voluntarily adopted the NCS since its debut in 1999. Many federal agencies require NCS use and many private-sector users have adopted it. The NCS helps building designers, constructors, and operators coordinate their efforts by classifying electronic design data consistently, easing information retrieval. It improves communication among owners and project teams, cuts or eliminates costs of developing and maintaining company-specific standards, and reduces the expense of transferring building data from design applications to facility management applications.

To order NCS Version 4.0, visit