The Pros and Cons of Pre-detailing

Posted on November 3, 2014 by Ewen Dobbie

The last decade of industry pioneer, Hugh Dobbie Sr’s active business career saw him work tenaciously to facilitate what has now become an increasing trend; Steel detailing services providers working directly with, and/or, for the engineer rather than following the more traditional historical contractor relationship, the steel fabricator.

With detailers and engineers using modern virtual construction technologies and processes, a more collaborative and integrated model centric workflow, the detailer engineer contractual relationship makes sense. The steel fabricator need not be involved in the process until the engineer/detailer team has a complete and accurate Manufacturing Model that the fabricator can utilize for pricing, procurement, manufacturing, and construction. This workflow minimizes additional costs associated with re-design during the fabrication and construction phases, ensures initial project schedules are met, and potentially eliminates budget over-runs.

In the 1950s, most steel fabricators had detailing resources in house. In the 1960’s fabricators found it increasingly difficult to maintain the right balance of detailing staff during the peaks and valleys associated with steel construction. The 1960’s in British Columbia, Canada saw the emergence of independent detailing companies. Dowco’s founder Hugh Dobbie Sr, started his first company in 1966, before incorporating Dowco Consultants Ltd in 1970. The changes in the steel industry since then have been staggering; pencil to 2D Cad, to 3D modeling and today, BPM (digital Building Product Modeling), also referred to as BIM (Building Information Modeling). Despite such advancements, steel detailers still encounter problems with incomplete design drawings. In fact, as the budget for projects have shrunk, the quality and completeness of design drawings has diminished.

The design team (Engineer and Architect) are constantly under pressure to complete their design. Today’s typical fast-track projects, combined with thin margins only serve to magnify the issue of incomplete design submittals. While steel detailers require definitive information to prepare shop detail drawings, engineers work with concepts. In most cases, the engineer may receive the preliminary design from an architect on a commercial project or receive direction from an owner on an industrial project. The design process is often an evolving one, and architects and owners have a propensity to change their minds, creating further challenges for the design team.

All too often, in the 2D flat world of drawings, engineers on commercial projects prefer to leave dimensions off their design drawings because of the difficulty in implementing architectural changes in a timely manner. This procedure forces the steel detailer into a review of the architectural drawings, a process that is alien to what is spelled out in the CISC Code of Standard Practice. Working with and collaborating with the engineers, sharing models on a daily, and or weekly basis, will not only alleviate the need for dimensional clarification, it saves the project time and money.

Surprisingly, some contract specifications still state in part “Detail Drawings must be prepared under the supervision, and bear the seal of, a professional engineer.” This is wording that should be vigorously opposed by both the steel detailer and the fabricator. The detailer’s responsibility is not one of design, but rather to interpret the drawings from the engineer of record in order to prepare the shop drawings for fabrication. According to many engineers of record, they believe the seal ensures a responsible professional has looked at the drawings. A problem arises when the engineer of record and his team receive poorly prepared steel detail drawings for review. The additional time spent reviewing shop drawings could better be used to keep the engineering drawings up to standard and within the engineer’s budget. Better yet….and this day is damn near; the engineer and detailer can share their 3D Design model and drawings with each other on a regular basis.

Detailers can clean up their act by paying more attention to accuracy and timeliness of steel detail drawings. It is important detailers understand the engineer’s problems and work with them to produce good working drawings. An ideal scenario would be for the detailer to work with the engineer to produce an accurate 3D structural fabrication model that can be used for fabrication tender.

As Hugh Dobbie correctly postulated more than a decade ago, the steel detailer would be much more effective as part of the design engineer’s team. The steel fabrication industry would be better served if engineers collaborated with detailers to generate accurate 3D models earlier in the process. Doing so, would not only result in engineering drawings being more complete, a 3D fabrication model and shop detail drawings would be available at the bid stage. Thanks to the proliferation of 3D modeling tools, an increasingly more open, model centric and collaborative way of working, detailers working with the engineer of record, while the design is evolving, is an increasing trend.

There are, of course, both pros and cons to the steel detailer working for the engineer (or owner) rather than the fabricator.

Pros:

  1. Detailer has direct contact with the engineer addressing problems as they arise.
  2. Faster response to Requests For Information (RFIs).
  3. Changes only handled by detailer and not the fabricator, resulting in lower costs.
  4. Design assist by detailer. Detailer can offer constructive comments on connection design and potential erection problems.
  5. Expedite preparation of shop detail drawings.
  6. Material take-off for estimating and job costing.
  7. Advance order bills available at time of award.
  8. 3D Model to examine clash check and clearances for equipment.
  9. Detailing continues through bid evaluation.
  10. First issue of detail drawings and hardware sheets available with fabrication award.
  11. Engineer/GC can use a number of fabricators to expedite project.
  12. Engineer of Record has more control over the project.
  13. Fabricator off the hook for detailing errors. (Detailer can carry Errors & Omissions Insurance.)

Cons:

  1. Fabricator may want different type connections. (This can be accommodated if recognized early enough in the process.) i.e. CISC Code of Standard Practice “The client shall prepare these shop details, insofar as practicable, in accordance with the detailing standards of the fabricator.”

    Fabricator does not have full control of the detailing….this should not be a problem if the fabricator receives shop drawings issued on schedule. i.e. CISC Code of Standard Practice; “When the shop details are furnished by the client, he shall deliver them in time to permit fabrication to proceed in an orderly manner according to the time schedule agreed upon”

  2. Fabricator may want to ship large components (Not a problem, as e.g., with Tekla Structures assembly drawings can be quickly prepared to suit.)

The following article is an adaptation of a Hugh Dobbie’s article on Pre-Detailing written more than a decade ago.


Dowco Group - Ewen Dobbie

Business Strategist, Owner, President, CEO, Director, for technology companies serving the design & construction industry.


Dowco Group of Companies