Boilers and Pressure Vessels MCQs 2026

Retention time in steam drum allows

1. Aonly fuel combustion✓
2. Bonly ash fusion✓
3. Conly compressed air storage✓
4. Dwater droplets to separate from steam by gravity and internals✓

Boiler cold startup requires

1. Ainstant full firing always✓
2. Bzero ventilation✓
3. Ccontrolled heating rates to avoid thermal shock and uneven expansion✓
4. Dimmediate full load on turbine✓

Dissimilar metal welds in boilers need attention to

1. Aonly aesthetic bead profile✓
2. Bthermal expansion mismatch and galvanic corrosion✓
3. Conly shortest weld length always weakest✓
4. Donly lowest cost filler always without spec✓

Creep in boiler tubes at high temperature requires

1. Amaterial selection and wall thickness for long-term rupture strength✓
2. Bonly room temperature tensile test data alone✓
3. Conly paint coating✓
4. Donly shorter diameter only without stress✓

Accumulation test of safety valves verifies

1. Avalves lift and relieve at set pressure without undue delay✓
2. Bonly colour of valve paint✓
3. Conly weight of valve cap✓
4. Donly serial number font✓

Inspection of boiler in Pakistan typically involves

1. Aonly self-certification without records always✓
2. Bregulatory authority and certified inspector per safety rules✓
3. Conly painting colour check✓
4. Donly operator verbal report✓

Pakistan industrial boilers commonly use fuels such as

1. Aonly liquid nitrogen✓
2. Bonly helium✓
3. Cnatural gas, furnace oil, coal and bagasse✓
4. Donly distilled water as fuel✓

Shrink and swell phenomenon in drum level during load change is due to

1. Aonly gauge glass leak✓
2. Bonly chemical dosing colour✓
3. Conly soot deposit✓
4. Dbubble volume change in risers under pressure change✓

Three-element drum level control uses

1. Aonly colour of flame✓
2. Bonly ambient humidity office✓
3. Conly coal pile height visual✓
4. Dsteam flow, feedwater flow and drum level✓

Combustion control maintains

1. Aonly maximum air always wasteful✓
2. Bzero oxygen in flue always✓
3. Cfuel-air ratio for safe efficient firing✓
4. Donly manual coal shovel rate without feedback✓

Stack temperature indicates

1. Aonly wind speed✓
2. Bheat lost with flue gases; lower improves efficiency if not condensing limit✓
3. Conly coal particle size only✓
4. Donly feed pump power only✓

Boiler efficiency on HHV basis accounts for

1. Alatent heat in water vapour from combustion in flue gas✓
2. Bonly sensible heat ignoring vapour✓
3. Conly radiation to sky at night only✓
4. Donly ash mass✓

Dissolved oxygen in feedwater causes

1. Apitting corrosion of steel boiler components✓
2. Bprotective oxide always beneficial unlimited✓
3. Chigher steam purity always✓
4. Dautomatic descaling✓

Phosphate treatment in boiler water maintains

1. Aacidic corrosion promotion deliberately✓
2. Balkaline pH and sequesters hardness✓
3. Conly oil emulsion✓
4. Donly chlorine gas injection always✓

Carryover of solids with steam can cause

1. Aimproved turbine efficiency always✓
2. Bzero maintenance need✓
3. Cturbine blade deposits and erosion✓
4. Dbetter lubrication of bearings✓

Differential pressure across boiler circulation loop drives

1. Aonly electromagnetic radiation✓
2. Bonly acoustic resonance✓
3. Conly colour change✓
4. Dnatural or assisted water circulation✓

Package boiler is

1. Aonly field-erected utility boiler always✓
2. Bonly domestic kitchen kettle✓
3. Conly hydraulic power pack✓
4. Dfactory-assembled unit shipped ready for site connection✓

Waste heat boiler recovers heat from

1. Aonly solar PV panels✓
2. Bonly wind kinetic energy directly✓
3. Cexhaust gases of process or engines without separate furnace✓
4. Donly hydro penstock✓

Fluidized bed combustion boiler burns fuel in

1. Aonly stagnant pile without air✓
2. Bbed of hot particles suspended by upward air flow✓
3. Conly pure oxygen without fuel✓
4. Donly water mist✓

Soot blower in boiler cleans

1. Aheat transfer surfaces of ash deposits in flue gas path✓
2. Bonly feedwater resin bed✓
3. Conly turbine blades in condenser✓
4. Donly lubricating oil filter✓

Manhole on boiler drum allows

1. Ainternal inspection and maintenance access✓
2. Bonly steam outlet to turbine✓
3. Conly fuel injection✓
4. Donly continuous blowdown line only✓

Heat exchanger classified as pressure vessel when

1. Aonly if painted blue✓
2. Bonly if vertical orientation✓
3. Cshell or tubes exceed pressure limits per code✓
4. Dnever in any service✓

Vacuum breaker on vessel prevents

1. Aonly overpressure burst✓
2. Bonly excess temperature✓
3. Conly noise✓
4. Dcollapse due to internal vacuum during cooling or pump-out✓

Rupture disc provides

1. Aonly slow adjustable control✓
2. Bonly flow regulation throttling always✓
3. Conly vacuum support only without burst✓
4. Dnon-reclosing overpressure relief for rapid excursion✓

Relief valve on pressure vessel protects against

1. Aonly underpressure vacuum collapse always without valve✓
2. Bonly mechanical vibration✓
3. Coverpressure from process upset or thermal expansion✓
4. Donly misalignment of flanges cosmetic✓

Corrosion allowance in vessel thickness adds

1. Aonly decorative coating thickness marketing✓
2. Bextra material for expected metal loss over life✓
3. Czero always by code mandate✓
4. Donly insulation thickness as metal✓

Non-destructive testing of pressure welds commonly uses

1. Aradiography and ultrasonic examination✓
2. Bonly colour vision test of operator✓
3. Conly hammer sound on wood✓
4. Donly weighing vessel empty✓

Weld joint efficiency in pressure vessel accounts for

1. Areduced strength due to welding compared to seamless✓
2. Bonly paint colour✓
3. Conly surface roughness aesthetic✓
4. Donly shipping weight✓

Factor of safety on pressure vessel design uses

1. Aonly aesthetic margin✓
2. Ballowable stress below material yield or ultimate per code✓
3. Conly paint thickness✓
4. Donly bolt count decorative✓

Thin cylinder hoop stress formula is

1. Aσ = p t / r inverted✓
2. Bσ = p r² only without t✓
3. Cσ = zero always✓
4. Dσ = p r / t✓

Pressure vessel is

1. Aonly open water tank without lid✓
2. Bonly conveyor belt✓
3. Conly gear coupling✓
4. Dcontainer designed to hold gas or liquid at pressure substantially different from ambient✓

Hydrostatic test of boiler is performed at

1. Azero pressure vacuum only✓
2. Batmospheric only without water✓
3. Cpressure above design per code (e.g. 1.5 times design)✓
4. Donly during full power generation✓

Indian Boiler Regulations (IBR) and ASME codes govern

1. Aonly textile weaving patterns✓
2. Bdesign, fabrication and inspection of boilers in respective jurisdictions✓
3. Conly road traffic signals✓
4. Donly computer software licensing only✓

Excess air in combustion should be

1. Aenough for complete combustion but minimized for efficiency✓
2. Binfinite always✓
3. Czero always without stoichiometric balance✓
4. Donly measured by boiler colour alone✓

Boiler turndown ratio is

1. Aratio of maximum to minimum stable firing rate✓
2. Bonly stack height to width✓
3. Conly tube count to drum diameter only✓
4. Donly ash fusion temperature✓

Natural circulation boiler relies on

1. Aonly forced pump without density head ever✓
2. Bonly compressed air lift✓
3. Conly electromagnetic pump✓
4. Ddensity difference between downcomer and riser✓

Forced circulation boiler uses

1. Aonly gravity without any pump always✓
2. Bonly steam jet ejector for combustion✓
3. Cpumps to ensure adequate water flow through tubes✓
4. Donly manual bucket feed✓

Blowdown in boiler removes

1. Aonly flue ash from stack✓
2. Bconcentrated dissolved solids from drum water✓
3. Conly lubricating oil from bearings✓
4. Donly compressed air moisture trap water only✓

Boiler feedwater treatment aims to prevent

1. Ascale, corrosion and carryover✓
2. Bonly increasing dissolved oxygen always✓
3. Conly colour of flame green always✓
4. Donly noise in turbine✓

Foaming in boiler water leads to

1. Ahigher purity steam always✓
2. Bzero dissolved solids✓
3. Cwet steam and possible damage to superheater and turbine✓
4. Dautomatic efficiency gain✓

Safety valve on boiler is set to relieve at

1. Azero pressure always✓
2. Bvacuum only✓
3. Conly after catastrophic rupture without opening✓
4. Dmaximum allowable working pressure (plus margin per code)✓

Two or more safety valves on boiler provide

1. Aonly decorative appearance✓
2. Bonly flow measurement✓
3. Conly feedwater heating✓
4. Dredundancy and capacity per code requirements✓

Maximum continuous rating (MCR) of boiler is

1. Aminimum turndown only✓
2. Bmaximum sustained steam output under design conditions✓
3. Ccold startup rate only✓
4. Dblowdown volume only✓

Boiler drum (steam drum) serves to

1. Aonly store fuel oil✓
2. Bonly filter feedwater chemically without separation✓
3. Conly measure stack opacity✓
4. Dseparate steam from water and provide circulation head✓

Reheater in power boiler

1. Acondenses steam to water only✓
2. Bonly heats feedwater✓
3. Creheats steam between turbine stages✓
4. Donly cools flue gas✓

Superheater adds

1. Alatent heat at constant pressure saturation only✓
2. Bsensible heat to steam above saturation temperature✓
3. Cwater subcooling only✓
4. Donly compressed air✓

Economiser in boiler heats

1. Afeedwater using flue gas waste heat before entering drum✓
2. Bonly combustion air leaving stack directly✓
3. Conly steam after turbine✓
4. Donly cooling tower water✓

Locomotive boiler is

1. Aonly nuclear pressurizer✓
2. Bhorizontal fire tube boiler with smokebox and firebox✓
3. Conly refrigeration evaporator✓
4. Donly hydraulic intensifier✓

Babcock and Wilcox boiler is

1. Avertical fire tube domestic only✓
2. Bonly once-through supercritical without drums always✓
3. Conly hydraulic pump✓
4. Dwater tube boiler with inclined tubes and chain grate or pulverized firing✓

Water tube boiler has

1. Aonly fire through large diameter tubes in water pool exclusively always✓
2. Bno steam generation✓
3. Cwater and steam flowing inside tubes heated externally by gases✓
4. Donly condenser function✓

A boiler is a closed vessel in which

1. Awater or other fluid is heated under pressure to generate steam✓
2. Bonly air is compressed for tyres only✓
3. Conly fuel is burned without heat transfer purpose✓
4. Donly water is stored at atmospheric pressure only✓