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JR COMPANY’S TOP TEN THINGS
THAT CAN GO WRONG
ON A CONSTRUCTION PROJECT
By Michael DiMercurio
NUMBER 5: GOING INTO THE FIELD TOO EARLY WITH INCOMPLETE DESIGN
This sounds like it is redundant to one or both of these Top Ten List things:
1. Defective and/or late design
2. Improper schedule – i.e., fast track vs. slow track
After all, “incomplete design” of number 5 sounds like number 1’s “late design,” and “too early” sounds like number 2’s “improper schedule.”
But number 5, “going into the field too early with incomplete design,” while admittedly borrowing from the defective design and defective schedule issues, is itself its own JR Company's Thing That Can Go Wrong on a Construction Project, because it is so often done. This mistake was once described as the mistake that happens on EVERY project ever built since Og built the cave for Oog as designed by Ug.
So what’s the countermeasure to this error? Simply wait for design to mature? How do you know when design is mature enough to enter the field? Sometimes the only way to test a design for construction readiness is to attempt to build it. Sometimes the designers, as smart as they are, have no idea that their design is flawed. The ultimate quality assurance of a design is giving the drawings to the craft and asking them to build it.
The immature design – the one not fully thought out, the one with omissions or mistakes such as interferences – will immediately generate a flood of “RFIs” or requests for information. RFIs are dreaded by designers because they, in effect, form a report card of the quality of the design. I’ve watched design leads get RFIs with their morning coffee and their faces more often than not turn beet red. How could the field foreman NOT understand how to install this piping or that circuit? Why are the contractor’s personnel so dense, they ask? But when you look at the RFI, it generally asks fair questions. Many answers to RFIs come from “design disintegration” (lack of integration of the design documents) with the needed information being scattered between multiple drawings and specifications. In the totality of the design, the information might be present, but the field hands are looking at drawings in the field drawing shed, not a book of single space typed specifications filled with engineering jargon or legalese. Nor are they reading the fine print of the drawing marked “NOTES,” the designer’s favorite place to put badly needed information. No, the field hands are opening the drawing for that specific area for that specific day’s work. Frequently something needed for the mechanical contractor is located on an architectural drawing or a structural drawing, so “disintegrating” the design information from the needed discipline to an off-discipline design can be catastrophic in the field. If the information is not RIGHT THERE ON THAT DRAWING, the design is faulty, even if it is correct with no mistakes. Disintegrated design may as well be defective, mistake-ridden design.
So WHY DO DESIGNERS ISSUE DISINTEGRATED DESIGNS?
The answer lies in the alternative. Let’s do a thought experiment, shall we? Take a job where a project manager from the field is put into the role of being a design manager. This PM absolutely hates design disintegration. He vows that the information to build the project will be represented on the applicable drawing. But there’s no way to get around the use of specifications. Nor can the design avoid standard “NOTES” drawings. And information for one discipline will inevitably be needed in another discipline. But if the information is replicated so that it exists in more than one place to facilitate design integration, it is almost certain that there will be conflicts between the information. The design conflicts arise from the iterative nature of design. The first pass of design can be an educated guess or design left over from the last project (a “go-by”), and then more certain information comes in from vendors or the other design departments and the design has to be revised. As authors say, there is no writing, only rewriting. And what happens is the design gets revised one place but not in another, creating the conflicts.
But all the above is part of a well-designed project. What happens in a poorly-designed project? What if vendor details are late or missing? What happens if designers are too busy or too stressed to keep all the changes straight? The result is that design mistakes accumulate at an enormous rate. Design mistakes include conflicts, interferences, and things that are wrong in the absolute sense.
A conflict is where different pieces of paper tell different stories. An example is that a piping and instrumentation drawing (P&ID) or schematic shows a 3” oil pipe on the third floor going to the top nozzle of a tank, but the physical drawing shows the pipe as a 4” pipe and it terminates at the middle nozzle of the tank. Design conflicts sometimes can be resolved by the hierarchy of documents. If the piping physical drawing (isometric drawing) “outranks” the piping schematic drawing (P&ID), then the conflict can be resolved without an RFI. In that case, a field memo is useful to notify the architect/engineer of what the contractor is doing.
An interference is when multiple objects are shown on the design documents occupying the same physical space and in reality that would be impossible. Conduit passing through ductwork is one example, or piping passing through a pressure vessel when it is not supposed to connect to the pressure vessel. An extreme example is a window and a door being in the same space. A famous framed photograph on the wall of a piping design manager shows instrument air piping tied into the kind of stair handrail that is made of pipe. Sometimes this happens from faulty design “coordination” in which someone – not always the architect/engineer – is required to do spatial air traffic control of multiple disciplines of components. As an example, an HVAC contractor might take design responsibility to coordinate the mechanical, electrical and piping designs in a set of coordination drawings so that duct, piping and conduit or electrical raceways do not occupy the same physical space. Sometimes coordination becomes impossible when the architect/engineer failed to provide enough physical space between the bottom of structural steel beams and the finished ceiling, so the duct, piping and raceways cannot physically fit.
The third design mistake is when represented items are incorrect in an absolute sense. An example is circuit wiring that is shown on the drawings as being routed to the wrong circuit breaker. The breaker would try to turn on a fan but instead activates a pump.
While mistakes can slow down a construction crew and add labor and inefficiencies – therefore breaking the budget and extending the schedule – even more vexing are design omissions, when the designer fails to provide ANY information. A design omission can be catastrophic, because that portion of the project goes completely on hold while the design is performed. No discipline can get any work done where there is an area on hold. Omissions fall into several categories as well. Known omissions are costly, but can be planned around. Emergent omissions are design holes that are discovered in the course of construction and can be much worse than known omissions, because emergency communications and planning while idled crews await can eat schedule and budget money as crews become inefficient. In addition, the omission may be the subject of a contract extra, meaning it must be estimated, presented to the owner or construction manager, and then negotiated. All that can be a hassle that your job can’t withstand. Then the time element enters. A known or emergent omission that occurs early in the job can be managed with much lower costs than an omission at the peak of construction, or as punchlists are being cleared to allow a startup. At the peak of field construction, when the job is at its maximum number of personnel, an omission can prove extremely costly.
Sometimes the “fix” for a design flaw is worse than the flaw itself. The famous cartoon of the swing added late to the tree comes to mind, where the swing goes through the trunk of the tree, so the trunk is sawed off in two places to make a hole to swing through and the tree is jacked up by the branches. A design fix in the form of and RFIA (request for information answer) may include sketches and the fix to a dimensional problem or “design bust” but that answer may affect other elements of the design. The other fix is to issue “conformed drawings” that “catch up” the design to the latest information from the architect/engineer’s office. These can be awful as well, because designers hate to “bubble” the prints.
If a designer fails to show on a drawing change exactly what is different, it can send the field construction crews into a tailspin, adding needless study of drawings and comparison to older versions. For that reason, designers are required to “cloud” or “bubble” the change, that is, drawing a circle around what changed and making a notation of what changed. Imagine a circle around a valve and the note, 1” valve changed to 2” valve. Easy day. But the lazy designers bubble the entire drawing when they make three dozen changes and the change note says, “general revision.” Such lazy designers should be beaten with a stick of drawings, because the very conformed design they are issuing to make construction easier actually complicates matters!
As to rushing into the field too early, for some reason, when the initial project schedules are made, the day of breaking ground for civil work is etched in stone – yet the day that civil DESIGN is done isn’t! So our brave construction forces enter the field expecting to dig a hole, insert rebar and formwork on May 1, only to find that design has no idea what the heck we’re building. If design slips, the only alternative is to make up the time in the field, but be cautious – if the design schedule slips and you keep the original construction schedule, you have just accelerated yourself, and that means that every manhour of construction will cost you more, maybe twice as much as the estimate.
In that case, understand what one day of schedule is worth, either by the production of a completed plant earning X dollars per day, or knowing that the penalty to be late is Y dollars per day in liquidated damages. Only when you know what a day is worth should you put your hands under the hood of a construction schedule.
But if every project rushes to the field with incomplete design, is this really something that can go “wrong” on a construction project? Certainly! It is a matter of degree. The better project managers do all they can to get design to mature fast, including working the design shop overtime. After all, putting lines on a piece of paper (or in the CAD system) is cheap compared to running schedule 40 pipe twenty feet in the air (which is what that line represents). Put on more designers, do more checking of design, work designers 60 hours a week, push on vendors for earlier vendor data (structure their purchase orders to pay them a handsome sum for furnishing certified vendor prints). Do anything and everything you can in the design shop to get the design as close to being “full term” before it’s done and given to the field forces.
Then and only then man up and build it. And if you find that you committed to construction too soon, don’t be afraid to enact a jobsite suspension or stop work order. Sometimes that communicates quite well to design that they need to get their design right or else the field refuses to waste time, manhours and money tolerating immature, error-filled, omission-laden design.
Just like a batter at the plate, you have to wait for the ball before you swing. So too with design. Never try to build a project when the design isn’t ripe.
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