During my career, piping design developed from hand draughting to 2D computer aided design to 3D computer modelling but always seemed to take longer than planned
It repeatedly was late and therefore impacted the management and cost of the construction works. Mitigating measures such as obtaining vendor data early, float in programmes and ensuring sufficient checking resources rarely seemed to work.
I came to the conclusion that piping design (and to an extent piping fabrication and construction) is such a specialised and shrinking discipline, in the overall UK engineering market, that these constraints should be expected and must always have a place on the project risk register.
A key issue seems to be the lack of Designers stepping up to become leaders to check and verify the design
If you’ve ever delivered a capital project, you already know: piping design is one of the first disciplines to slip and one of the hardest to recover. Schedules look clean during front end engineering and estimating, but once detailed design starts, reality shows up quickly.
Here’s why piping design routinely overruns—and what you can do about it.
1. Late Inputs Create Early Delays
Piping depends on everyone: civil, structural, equipment vendors, process, electrical, and even procurement.
If any of these deliverables come in late—or change—piping loses hours immediately. Re-routing adds even more.
Tip: Lock in long-lead equipment data early and protect interface points with “freeze dates” that mean something.
2. The 3D Model Is Never as ‘Ready’ as the Schedule Claims
Schedules often assume the model is available on Day 1. It rarely is.
Missing nozzles, incomplete steel layouts, placeholder equipment, or inaccurate tie-points all force redesign.
Tip: Build explicit model-maturity milestones into the schedule, not just discipline start dates.
3. Congestion Isn’t Obvious Until You’re Deep in the Work
Piping designers don’t know where the real battles are—rack congestion, valve access, interferences—until they’re inside the model. That’s when hours spike.
Tip: Run early clash reviews—even with a “dirty” model—to identify congestion zones before detailed routing begins.
4. “Small Changes” Aren’t Small in Piping
A nozzle shift of 150 mm might sound minor, but it can invalidate multiple lines, supports, stress calcs, and MTOs.
Each revision cascades across disciplines.
Tip: Track changes visually and quantify hours. Make the impact visible so stakeholders respect the downstream cost.
5. Stress and Supports Are the Hidden Schedule Killers
Routing is just the beginning. Stress and supports often reveal that a “finished” line is not actually finished.
A single stress issue can unravel hours of routing.
Tip: Integrate stress and supports early, not at the end. Treat them as part of routing—not a follow-on activity.
Bottom Line
Piping design takes longer because it sits at the intersection of almost every discipline and absorbs every upstream imperfection.
You can’t eliminate the complexity—but you can manage it by protecting inputs, validating model maturity, and treating “small changes” like the schedule risks they truly are.