Tag
#design
16 topics across all disciplines.
Reading a PFD and the material balance — where every number starts
What a process flow diagram carries that a P&ID does not, how to read a stream table, why mass in equals mass out is the most useful check on a plant, and how design cases become equipment sizes.
Relief and flare systems — what happens when pressure wins
How relief scenarios are worked out, why the governing case is rarely the obvious one, and why nearly every part of a flare exists to stop it becoming the hazard it was built to remove.
Heat integration — why the plant reuses its own heat, and what that costs
Feed-effluent exchangers, the temperature approach trade-off, why steam comes at several pressures, and why a well-integrated plant is cheap to run and hard to start.
Line sizing — why pipe diameter is an economic decision
The two criteria that size every line, why a bigger pipe costs once and a smaller one costs forever, and the lines where neither rule applies.
Reading a line class — the document that has already decided
How a piping material specification works, how to decode a line number, what a spec break is, and why almost every piping decision on a project was made before you arrived.
Pipe supports and thermal expansion — why you cannot just bolt it down
Hot pipe grows, and it grows with enormous force. How expansion is calculated, why loops exist, what anchors, guides and spring hangers actually do, and how supports protect equipment nozzles.
Expansion loops and offsets — sizing the detour that absorbs the growth
How a loop actually absorbs movement, the guided cantilever hand calculation that gives you a first size, why the answer never fits the rack, and the honest ranking of what to do when it does not.
Anchors, guides and restraint schemes — deciding where the pipe may move
A restraint scheme is one decision for a whole run, not a scatter of supports. Where an anchor belongs, what it actually carries once friction is counted, line stops against full anchors, the gap that is the design, and the accidental anchors that site creates.
Pipe support standards and details — reading SP-58, SP-69 and a project detail sheet
What the support standards actually fix, why a project standard detail is a specification rather than a catalogue, the welded attachment problem on alloy and sour service, shoes and trunnions and shields, and what goes wrong when a support is left to the field.
Nozzle loads and allowables — the constraint that really governs hot piping
Why machine nozzle allowables are so small, where they come from for pumps, compressors, turbines and vessels, what exceeding them actually does, why the symptom surfaces in somebody else's report, and the design and field rules that prevent it.
Pump piping layout — the suction side is where the decisions are made
NPSH available as a consequence of layout rather than a number handed to you. Eccentric reducers and the pocket they prevent, straight run before the impeller, the elbow that must not be in the shaft plane, parallel pump symmetry, strainers, minimum flow, and the discharge order.
Plot plan and equipment spacing — the drawing everything else inherits
What actually sets the distance between equipment, the four drivers that pull against each other, the pipe rack as the spine and how its tiers are allocated, prevailing wind and fired equipment, roads and containment, and why a plot plan mistake cannot be recovered downstream.
Access, operability and maintenance space — what the plant is judged on afterwards
Valve reach and stem orientation, why a chain operator is a confession, platforms and the dead-end with one ladder, headroom, bundle pull and rotor withdrawal, drop-out areas and davits, and the model review that is the last chance to find any of it.
Relief valve and flare piping — the 3 per cent rule, backpressure and reaction force
The piping engineer's half of overpressure protection. Why a relief valve inlet must be short and generous, what chatter actually is, built-up and superimposed backpressure and the 10 per cent limit, reaction force on an open discharge, flare header slope, and the car-sealed valve that must never be closed.
Cables — construction, selection and why sizing is never just about current
What the layers of a cable do, how power, control and instrument cables differ, the four things that decide a cable size, and why the published rating is never the rating you get.
Reading a P&ID — the drawing every discipline works from
How a P&ID differs from a PFD, decoding instrument tags and bubbles, following a control loop across the sheet, and the details that decide what gets built.