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Spring 2000 Issue


DoubleCheck Keeps Change Orders in Check

Errors and omissions in building design typically account for half of a project’s change orders, according to William Nigro, a registered architect retired from the U.S. Navy Civil Engineer Corps. The rest are normally due to a variety of unforeseen and/or inconsistent site conditions, and changes in the project owner’s needs.

With a variety of disciplines producing drawings for most building projects, keeping the drawings coordinated is essential to avoiding errors and omissions. If a project’s structural engineering firm revises its drawings to solve a problem, for example, the mechanical contractor’s drawings could be out of sync. Based on a system Nigro developed to discover these kinds of discrepancies, Beyer Construction has devised our own system. 

We call it DoubleCheck.

Typical Coordination Errors

Examples of the types of coordination errors that commonly occur and DoubleCheck is designed to flag are:

• Structural drawings with column locations and grid lines that do not agree with architectural drawings;

• Floor plans that do not match the plans of other disciplines;

• Architectural reflected ceiling plans that do not match the light fixtures on electrical drawings, or ceiling/register grilles on mechanical drawings;

• Electrical drawings that indicate equipment with different horsepower ratings, voltages and phases than mechanical drawings and/or specifications;

• Mechanical drawings that indicate “See structural drawings for additional roof supports” while the structural drawings do not indicate such supports.

An Interdisciplinary System

DoubleCheck is a structured, interdisciplinary design and construction review system consisting of two key components: procedural instructions and a checklist. Both components address the source of most errors and omissions – the point where one discipline or trade bumps up against another.

At Beyer Construction, we provide DoubleCheck as a value-added service for improved coordination of construction projects. Don Harder, Vice President/Director of Preconstruction Services said, “It’s important as a preconstruction service for us to be sure that the drawings are coordinated so we can minimize change orders once construction begins.”

First Things First

Our DoubleCheck checklist is based on the normal sequence of construction and the review of the various disciplines’ drawings:

• Civil engineering drawings

• Structural drawings

• Underground utilities drawings

• Electrical and mechanical drawings

• Architectural drawings

Note that the architectural drawings are at the end of the review process. Although the architect is normally responsible for coordination, unless the architectural and other disciplines’ drawings correspond with each other, high-cost redesigns and change orders are sure to ensue.

Harder said, “The system works nicely for us because, although we’re not designing the building, we want to point out inconsistencies and have them corrected so the project is bid properly.”

The DoubleCheck review encompasses a preliminary overview of all the various disciplines’ documents, a specifications check, and checks of individual discipline plans: civil, structural, mechanical and plumbing, electrical, kitchen/ dietary, and architectural.

The system strongly encourages all disciplines to use a consistent scale and orientation in its drawings. As Harder explained, “When plans are consistent, we can overlay the drawings on a light table and see problems right away.” Laying the mechanical plan over the structural plan, for example, may reveal that an HVAC duct is planned where a beam is to be placed.

“If we get involved in a project early on, we suggest using a consistent scale and orientation to facilitate the coordination of drawings,” Harder said. “For design/build work, we insist on it.”

The Devil’s in the Details

A sampling of civil plan verifications includes checks that any new utilities, including water, sewer, gas, storm drainage, telephone, fuel lines, grease traps, and fuel tanks, have been checked for interferences. Others include verifying fire hydrant and light pole locations with electrical and architectural plans.

Structural plan checks are aimed at validating that expansion joint locations are in sync with architectural plans, that all foundation beams and piers are identified, and that drawing notes do not conflict with specifications. A host of other issues are similarly addressed, from the building’s foundation to its roof.

Mechanical systems are thoroughly reviewed to assure, among other things, that ceiling heights are adequate at worst-case ductwork intersections. Storm drain systems are verified against architectural drawings, along with pipe connections and sizes.

Combined with our preconstruction services, our use of the DoubleCheck system, gives project owners an additional line of defense against costly errors and omissions, change orders and schedule delays.



 

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