EngiMetric Arena — Explore the Engineering World

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Open any challenge to begin. Once you solve one, this panel points at the next challenge on the ladder that fits your record.

Progression

The five stages

STAGE 01 · Error recognition
Explorer

Find the mistake in a calculation, an assumption or an arrangement.
8 challenges
STAGE 02 · Fault diagnosis
Investigator

Read the symptoms and identify the plausible cause from the evidence.
8 challenges
STAGE 03 · Technical interpretation
Analyst

Read a result, a method or a test record for what it does and does not establish.
8 challenges
STAGE 04 · Engineering design
Designer

Produce a defensible design value under stated constraints.
8 challenges
STAGE 05 · Trade-off judgement
Master Engineer

Balance competing criteria where more than one answer can be defensible.
8 challenges

2 challenges

Civil & Structural Engineering

Structural capacity, serviceability, load paths, geometry and the materials that carry them.

Civil & Structural Diagnose the Failure advanced

Diagnose the corrosion staining on a marine facade

Rust staining appears on a coastal concrete facade. Use the cover and chloride exposure to decide which mechanism fits.

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Civil & Structural Interpret & Validate intermediate

Is a 1.2 m embedment enough for a Class B lap?

A detail uses 1.2 m for a 20 mm top bar. Compare it with the development length and the Class B lap the detail actually needs.

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5 challenges

Construction Engineering & Quantity Surveying

Estimating, quantities, temporary works, site method and the commercial reality of building it.

Construction & QS Spot the Error foundation

Did the block order count the openings and the waste?

A 12 m by 3 m wall has a 6 m2 opening and a 5 % waste allowance. Find the block quantity the takeoff supports.

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Construction & QS Spot the Error foundation

Review this cement order: the bags were rounded down

A one-cubic-metre mix needs 6.34 bags of cement. The site ordered six. Decide whether that is acceptable.

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Construction & QS Spot the Error foundation

Review this concrete order: wastage counted twice

A slab take-off adds five percent wastage, then adds five percent again. Decide what the order should actually be.

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Construction & QS Interpret & Validate intermediate

Does a lower A1-A3 carbon total prove a lower whole-life carbon?

Two options are compared using cradle-to-gate factors only. Decide what the comparison actually establishes.

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Construction & QS Interpret & Validate intermediate

Is a 2.8 % rebar delivery difference a problem?

A theoretical bar weight and a delivery ticket differ slightly. Decide whether that difference proves an error.

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7 challenges

Electrical Engineering

Load, conductor sizing, voltage behaviour, protection and the distribution that carries power.

Electrical Spot the Error intermediate

Did the transformer review forget future growth?

A 520 kVA connected load is reviewed at 75 % demand and 10 % growth. Find the rating the calculation actually supports.

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Electrical Spot the Error intermediate

Is 500 mm2 a conduit size or just the arithmetic minimum?

A reviewer divides conductor area by the fill limit and orders the result. Check whether that number is a standard conduit.

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Electrical Spot the Error intermediate

Review this voltage-drop check: the phase factor is wrong

A balanced three-phase feeder is rejected for voltage drop. Check the factor used before accepting the rejection.

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Electrical Engineering Trade-off advanced

Choose a cable size that satisfies drop and ampacity

Several standard conductor sizes meet both voltage drop and ampacity. Pick one inside the terminal limit.

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Electrical Engineering Trade-off advanced

Choose a conduit that is neither too full nor oversized

Four 95 mm2 conductors must fit between 25 % and 40 % fill. Pick a standard conduit internal area.

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Electrical Engineering Trade-off advanced

Choose a target power factor the capacitor bank can deliver

A plant needs correction, but the bank is capped. Find a target power factor inside the limit.

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Electrical Engineering Trade-off advanced

Choose a transformer rating inside the loading band

A 620 kVA load at 70 % demand plus 10 % growth needs a standard transformer. Pick a rating that is neither overloaded nor oversized.

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6 challenges

Mechanical & Fluid Engineering

Pumps, piping, pressure drop, heat transfer and the fluid behaviour that decides equipment duty.

Mechanical & Fluids Spot the Error intermediate

A 15 kW motor for a 120 m3/h pump: hydraulic or input power?

A reviewer sizes the motor from hydraulic power and ignores pump and motor efficiency. Find the motor input the engine requires.

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Mechanical & Fluids Diagnose the Failure intermediate

Diagnose the gravelly noise at the pump suction

A transfer pump becomes noisy and unsteady at high flow. Read the suction conditions before blaming the impeller.

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Mechanical & Fluids Diagnose the Failure advanced

Why does the pipe bang when the valve closes slowly?

A 1.2 s valve closure is slower than the 0.3 s wave round trip, yet the line still bangs. Identify the surge mechanism.

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Mechanical & Fluids Diagnose the Failure intermediate

Why is the compressor cycling every 25 seconds?

A 500 L receiver serves 30 L/s between 8 and 6.5 bar, but the network needs two minutes. Diagnose the short cycling.

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Mechanical & Fluids Design Challenge intermediate

Specify a pump efficiency that keeps the duty inside its budget

Static lift, friction and minor losses are known, and the duty is capped. Choose a pump efficiency that satisfies both constraints.

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Mechanical & Fluids Design Challenge foundation

What total dynamic head must the pump produce?

Add static lift, friction, minor losses and residual pressure head to find the pump duty.

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10 challenges

Water Treatment & Desalination

Treatment processes, membrane systems, mass balance and the plant that produces usable water.

Water & Desalination Spot the Error intermediate

Review this RO energy calculation: the credit is missing

A designer has issued an energy figure for a seawater RO plant with an energy recovery device fitted. Identify the mistake in the review.

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Water & Desalination Diagnose the Failure intermediate

Diagnose a calcium-carbonate risk signal on RO feed

Feed chemistry returns a positive saturation index. Decide what that signal does and does not establish before you act on it.

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Water & Desalination Diagnose the Failure advanced

Diagnose the RO train that lost output despite more pressure

Normalized flow is down and pressure drop is up. Decide what the operating record actually points to.

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Water & Desalination Diagnose the Failure advanced

Permeate TDS rose while pressure drop stayed flat. Why?

An RO train loses rejection with stable flow, pressure and differential pressure. Diagnose the likely cause.

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Water & Desalination Interpret & Validate intermediate

Can a filter submittal claim 0.45 m of calculated head loss?

A vendor quotes a clean-water head loss the sizing engine explicitly refuses to compute. Decide what the number actually establishes.

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Water & Desalination Interpret & Validate intermediate

Does a 6.5 % charge-balance gap matter?

A water analysis is outside the typical cation-anion balance guideline. Decide whether it can be used for design.

Open challenge

Water & Desalination Interpret & Validate foundation

How long must the water stay in contact?

A chlorine residual and a required CT are given. Compute the contact time — and read carefully what that number does and does not prove.

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Water & Desalination Design Challenge foundation

How many RO elements can you actually buy?

The membrane area you need is not the number of elements you can procure. Work out how many elements a real vessel array must contain.

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Water & Desalination Design Challenge intermediate

What circular clarifier diameter does the SOR require?

Size a clarifier from flow, surface overflow rate and a safety factor, then convert the area to a diameter.

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Water & Desalination Engineering Trade-off advanced

Choose a recovery rate that the plant can actually run

Two site limits constrain system recovery. Any recovery inside the feasible band is a defensible engineering choice — find one, and see the trade-off.

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5 challenges