Tip #08 · Layout
Drain points belong at the lowest accessible point — not just the lowest point.
After completing any routing, trace every line mentally. At each high point: verify a vent. At each low point: verify a drain. Check accessibility. This takes minutes and saves days.
A drain that cannot be reached by a technician with a wrench will never get used. A vent that cannot be opened from a safe position is a hazard. Factor in platform levels and obstruction clearances when placing drain and vent valves — they are not afterthoughts.
The 3 AM call
A missing drip leg on a 16-inch steam line caused catastrophic water hammer during commissioning. Three supports ripped off the rack. A weld cracked. Root cause: the routing was changed late and the drain was not relocated. That check takes five minutes.
The takeaway: Vents and drains are not details. They are safety-critical elements. Make the mental walkthrough of high points and low points a mandatory personal checklist before every isometric is issued.
