Efficient Design Drawings

Important changes in the National CAD Standard Version 6 improve project delivery.

By Ed Lowe

Version 6 of the United States National CAD Standard (NCS) has been released, and it contains important changes that will help reduce the costs of developing and maintaining individual office standards and of transferring building data from design applications to facility management applications. These changes are designed to help civil engineers, structural engineers, and other members of the building and construction industry improve project delivery.

NCS — which includes the Construction Specifications Institute’s Uniform Drawing System, The American Institute of Architects’ CAD Layer Guidelines, and the National Institute of Building Sciences’ BIM Implementation and Plotting Guidelines — comprises interrelated standards, guidelines, and tools for uniformly organizing and presenting facility drawing information. It’s the only comprehensive standard for facility planning, design, construction, and operation drawings. Simply stated, NCS offers greater efficiency in the design and construction process.

NCS only makes changes, when needed, through a consensus process. This process ensures that users and practitioners from all disciplines are represented and that any proposals made are properly vetted before being submitted to the Project Committee for a vote. The latest of these consensus ballots has been completed and several of the new and revised items are particularly relevant to civil and structural engineers.

A new BIM Implementation Guide is one example. The intent of this new section is to outline the use of the NCS in a building information modeling (BIM) workflow. It outlines the best way to incorporate the 2D printed output of a CAD workflow with the 3D BIM output established by the National Building Information Modeling Standard-U.S. It goes module by module and explains the relationship between the NCS and what is considered the minimum BIM requirement.

We also saw major changes in the symbols library. Specifically, the Project Committee:

replaced and updated all 1,300+ symbols in the NCS;

properly categorized each symbol with an identifier to make them easier to find and store;

converted the symbols, which were originally developed in millimeters, to inches and provided new insertion points, where needed; and

updated the line type and pattern file definitions where appropriate and gave them better identifiers.

The committee approved 72 new symbols in a wide range of categories including Communications, Electronic Safety and Security, Fire Suppression, and General Division 1 symbols. The committee also created and approved new sections on how to create new symbols and how to use color in symbols, and provided a more complete explanation of approved fonts for use in the NCS. These new sections act as a template for understanding the use of the existing symbols library as well as a guide for future symbol creation and adoption into the NCS.

The CAD Layers Guidelines section saw many new major and minor groups added for civil disciplines:

Airport items include airspace-related features, aprons, helipads, and decontamination zones.

The committee also covered grading work, gray water systems, and plan and profile major group designations for civil-related work.

New minor groups were also added to aid in clarifying details when line widths need to be identified in the layer names.

We also added two new discipline designators this time — one for “Survey/Mapping Land” to use with ALTA surveys and one for “Survey/Mapping Boundary” for boundary survey clarification.

Most of the changes in the CAD Layers Guidelines section were civil engineering-related. We have seen an increased interest over the past years in the adoption and use of the NCS in those disciplines, as these updates demonstrated.

How to best adopt NCS in your workflow

Have you adopted the NCS yet to use in your workflow? If not and you’re not sure where to start, we recommend simply buying a copy and familiarizing yourself with the material. It’s now an online resource, so you can gain access and search specifically for what you need. A good place to start is “Appendix I – Implementation Guidelines.”

This appendix outlines the basics for adopting the NCS in phases, allowing you to customize how you rollout the NCS to your company. It gives tips on how to approach management, how long it takes to rollout different sections, and the benefits of using a nationally recognized CAD standard instead of one that is home grown. In easily digestible phases, it takes you through identifying a “first project” and building from there. Before you know it, all parts of the NCS will be adopted by your company.

What does the NCS have under the cover? Quite simply, the sections or modules cover all subjects pertinent to 2D drawing production and delivery:

AIA CAD Layers Guidelines — outlines a layer/level naming process for CAD files.

Drawing Setup Organization — establishes a hierarchy for sub-dividing the plan set into manageable sections via discipline designators.

Sheet Organization — organizes individual sheets into a consistent, understandable structure.

Schedules — establishes an effective way to communicate data via tables and schedules.

Drafting Conventions — the mother lode of all things CAD, including line weights, scaling, hatching, dimensions, placement of details on sheets, title blocks, etc.

Terms and Abbreviations — brings together the terms and abbreviations from a dozen-plus sources. It may not be the end all collection for these items, but rather establishes guidelines for use and brings together a searchable list of the more commonly used abbreviations.

Notations — provides guidelines for creation and use of notes in drawings.

Symbols — includes a full range of symbols covering all disciplines and establishes guidelines for creation of new symbols.

Code Conventions — establishes guidelines for consistency in identifying regulatory information to be shown in construction drawings.

BIM Implementation Guide (new section) — provides an explanation of the relationship between the 2D CAD workflow and the 3D BIM workflow.

Plotting Guidelines — provides tables for both color-dependent and color-independent styles of plotting.

The NCS was established in 1999 and has become the most well-rounded CAD standard for today’s use. By continually updating this important standard, the National Institute of Building Sciences, Construction Specifications Institute, and other organizations help offer greater efficiency and cost savings in the building and design process.

Ed Lowe, CAD coordinator for Burgess & Niple, Inc., is chair of the United States National CAD Standard Project Committee and a member of the National BIM Standard-United States Project Committee.