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.”
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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. |
