Mechanical

A106, A312, P11 — how to read a piping material grade, why carbon steel is the default, and what forces an upgrade to alloy or stainless.

A516, A240, Monel, Hastelloy and titanium — why a plate specification is not a pipe specification, what each alloy is bought to survive, and why you almost never buy a solid exotic vessel.

NPS, DN and schedule numbers explained. Why the outside diameter is fixed, what changes when the schedule goes up, and how to read a pipe size chart.

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.

Elbows, tees, reducers and caps, and the branch fittings that take a small line off a big one. What each is for, why the dimensions are fixed, and why a branch needs reinforcement.

Gate, globe, ball, butterfly and check valves explained by what each is built to do. Why throttling with a gate valve destroys it, what double block and bleed means, and how check valves slam.

Pneumatic, electric and hydraulic actuators, why a spring is what makes fail-safe possible, how fail open and fail closed are chosen per service, and what a positioner actually does.

What a flange class means, how pressure–temperature ratings work, the common facing types, and why a gasket and bolt set are part of the rating.

How a bolted joint actually seals, reading a spiral wound gasket by its colours, choosing stud and nut materials, and the bolt-up sequence that decides whether any of it works.

SMAW, GTAW, GMAW and the rest, explained by what they are good at. Then the paperwork that makes a weld legal — WPS, PQR and welder qualification — and how welds are inspected.

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.

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.

What MAWP means and why it matters more than design pressure, how heat exchanger types differ, and why the relief device is the one protection that cannot be bypassed.

Why the vapour space is the whole design question, how a tank breathes, why overfill protection must be independent of the gauge, and why a tank is far weaker against vacuum than pressure.

How to read a piping isometric, why spool breaks decide what happens in the shop and what happens at height, and the test and reinstatement sequence that gets a line handed over.

Four different reasons to insulate and why confusing them causes corrosion, how steam and electric tracing differ, why tracing fails silently, and why surface preparation is most of a paint system.

Why welding can ruin the corrosion resistance of stainless steel without touching the weld, what the three conditions for galvanic corrosion are and which one to break, why sour service controls hardness rather than strength, what carbon equivalent predicts, and why zinc and stainless are kept apart.

Why nobody inspects everything equally, how likelihood and consequence combine into an inspection plan, why naming the damage mechanism is the whole job, and the ways an RBI programme quietly goes wrong.

Why every NDE method is blind to something, what magnetic particle cannot do on stainless, why ultrasonics can miss a crack lying the wrong way, the difference between an indication and a defect, and why the examiner's qualification is part of the result.