BD First Class Boiler Attendant cheat sheet

A first class boiler attendant certificate authorises attendance on any boiler size, while lower classes are restricted by heating surface or capacity limits set by the jurisdiction.

Statutory duties of an attendant typically include maintaining water level, supervising firing, recording readings, and reporting unsafe conditions to the owner without delay.

Boiler registration and periodic inspection intervals are set by regulation; a boiler may not be operated after its certificate of inspection expires.

Owners must keep records of inspections, repairs, and alterations; altering a boiler or its fittings without approval voids the inspection certificate.

Accident reporting is mandatory: explosions, ruptures, and serious injuries must be reported to the authority within a short statutory period.

A qualified attendant must be on duty whenever a boiler is under pressure, except where rules permit unattended operation for specific low-risk classes.

Regulations define maximum allowable working pressure by the weakest component; operating above the stamped pressure is an offence.

Safety valves must be set and sealed by an authorised person, and the seal must not be broken except under approved supervision.

Fire-tube boilers pass hot gases through tubes surrounded by water; water-tube boilers pass water through tubes surrounded by hot gas.

Water-tube boilers suit high pressure and rapid steaming because small-diameter tubes withstand pressure and allow high heat-transfer rates.

A locomotive boiler combines a firebox, large fire tubes, and a smokebox, with the crown sheet covered by water as the critical safety condition.

Cochran and vertical fire-tube boilers use a vertical cylindrical shell with a submerged combustion chamber and cross tubes.

Package boilers are factory-assembled, generally three-pass, and use a wet-back or dry-back reversal chamber to direct gas flow.

Heating surface is the area exposed to hot gas on one side and water on the other; it determines rated capacity and evaporation.

Stay bolts and stay tubes tie flat surfaces to resist pressure loads; broken stays are a serious structural defect requiring shutdown.

Boiler shells are constructed from rolled and welded or riveted plate; welded seams require stress relief and non-destructive examination per code.

A safety valve protects against overpressure; its set pressure must not exceed the maximum allowable working pressure and it must have adequate relieving capacity.

Two independent low-water fuel cutoffs are commonly required, mounted at the correct level so the burner stops before the crown sheet or tubes uncover.

A water gauge glass shows the true level; its lowest visible reading must be above the lowest permissible water level.

The try cocks provide a secondary means of verifying water level when the gauge glass is unreliable or blocked.

A pressure gauge with a siphon and shutoff cock displays steam pressure; a missing siphon allows live steam to damage the Bourne tube.

Blowdown valves at the lowest point remove sludge; a slow-opening valve protects piping from water hammer during blowdown.

A feed check valve prevents backflow from the boiler toward the feed pump, and the feed stop valve isolates the feed line for maintenance.

A fusible plug melts when the crown sheet is uncovered, releasing steam into the firebox as an audible warning and reducing pressure.

Theoretical air is the minimum air needed for complete combustion; excess air is supplied to ensure all fuel burns, typically 10 to 20 percent for oil and gas.

Stoichiometric combustion of carbon yields carbon dioxide; incomplete combustion yields carbon monoxide and soot, wasting heat.

The three T's of combustion are temperature, turbulence, and time; inadequate mixing or short residence time produces smoke and CO.

Atomising oil burners use pressure or steam/air atomisation; poor atomisation causes smoky flame and carbon deposits on the burner tip.

Natural gas is lighter than air and burns with a hot, short flame; gas leaks accumulate at high points and require leak testing before light-off.

Fuel oil viscosity must be reduced by heating to the correct atomising range, typically around 90 to 150 seconds Redwood No. 1.

Flame failure devices must shut off fuel within a short safety time, and the furnace must be purged before every light-off attempt.

Furnace draught is produced by forced draft fans, induced draft fans, or a chimney; balanced draught keeps the furnace slightly negative.

Before light-off, confirm water level in the gauge glass, open air vents, verify all valves in correct position, purge the furnace, and check the flame detector.

Warm a cold boiler slowly: raise pressure gradually to avoid thermal stress and differential expansion between shell and fittings.

Raise steam pressure to the working range before opening the main stop valve, then open it slowly to warm and drain the steam line.

The correct water level is near the centre of the gauge glass; a rising level with constant firing suggests priming or foaming.

During normal operation, monitor water level, steam pressure, flame condition, feedwater flow, and stack temperature at regular intervals.

Blowdown is performed at low fire or low load with the water level high, using short, controlled openings to avoid loss of water level.

Shutdown procedure: reduce firing, allow the boiler to cool, isolate fuel, close the main steam stop valve, and maintain water level while cooling.

Never restart a boiler after a low-water trip until the water level is restored and the cause is found; do not add water to an overheated boiler.

Scale forms from calcium and magnesium hardness; it insulates the heating surface and can cause overheating and tube failure.

External treatment removes hardness by softening, demineralisation, or reverse osmosis before the water enters the boiler.

Internal treatment uses chemicals such as phosphates, chelants, and oxygen scavengers to condition residual impurities.

Sodium sulphite or hydrazine scavenges dissolved oxygen; sulphite is not used where carryover of solids is critical or at very high pressure.

Caustic alkalinity is maintained within a controlled range; excessive alkalinity causes caustic embrittlement and foaming.

Total dissolved solids control is achieved by blowdown; dissolved solids carryover causes priming, foaming, and superheater deposits.

pH is maintained in the alkaline range, typically 10.5 to 11.5 for boiler water, to limit corrosion of steel.

Regular testing of hardness, alkalinity, dissolved oxygen, conductivity, and pH confirms the treatment programme is working.

Saturated steam is in equilibrium with water at the boiling temperature; superheated steam has been heated above saturation temperature.

Enthalpy of saturated steam rises with pressure, but latent heat falls as pressure increases toward the critical point.

Superheating raises steam temperature without raising pressure, improving cycle efficiency and reducing condensation in the turbine.

Feedwater pumps include reciprocating, centrifugal, and injector types; the injector uses steam to lift and force water into the boiler.

A feedwater regulator maintains the water level by adjusting the feed valve in response to level changes.

An economiser recovers heat from flue gas to preheat feedwater; an air preheater recovers heat to warm combustion air.

A deaerator removes dissolved oxygen by heating water to saturation and venting released gases, protecting the feed system from corrosion.

Steam traps remove condensate while retaining steam; a failed-open trap wastes steam and a failed-closed trap causes water hammer.

Internal inspection requires the boiler to be cooled, drained, isolated, and purged of gas; a valid confined-space entry permit is mandatory.

Hydraulic test pressure is typically 1.25 to 1.5 times the maximum allowable working pressure, depending on the code and test purpose.

A hydrostatic test must be held at the test pressure for the specified time and inspected for leakage, distortion, and permanent set.

Safety valve setting and popping tests are performed with calibrated gauges and recorded; the seal is applied after acceptance.

Ultrasonic thickness testing measures remaining wall thickness; corrosion allowance and retirement thickness determine fitness for service.

Non-destructive examination methods include radiography, ultrasonic, magnetic particle, dye penetrant, and visual inspection.

Maintenance records must document repairs, replacement parts, and the welder or inspector qualifications used for pressure parts.

Gauge glasses, try cocks, and low-water cutoffs are checked during routine maintenance and after any repair or replacement.

Low water is the most dangerous condition: shut off fuel immediately, do not add water, and allow the boiler to cool before inspection.

A bulged or overheated crown sheet from low water may rupture if cold feedwater is injected; secure the burner first.

Water hammer results from steam meeting condensate; drain lines before admitting steam and open valves slowly.

A safety valve that fails to lift requires immediate reduction of firing and pressure; never wedge or gag a safety valve.

Boiler explosion energy comes from sudden release of pressurised water flashing to steam; the water volume, not the steam space, holds most of the energy.

Before entering a furnace or drum, isolate, lock out, and tag all energy sources, vent pressure, and test the atmosphere for oxygen and combustibles.

Foaming and priming cause carryover of water into steam lines, leading to water hammer and damage; reduce firing and control dissolved solids.

Emergency shutdown sequence: stop fuel, stop air supply, isolate steam, and notify the supervisor while keeping clear of the firing aisle.

A pressure gauge should be calibrated and fitted with a siphon and a shutoff cock; the gauge glass and gauge should agree within tolerance.

A low-water cutoff uses a float or electrode probe to interrupt the burner circuit when the water level falls below a safe limit.

A flame scanner uses ultraviolet or infrared detection; loss of signal must close the fuel valve within the safety time.

A three-element feedwater control uses drum level, steam flow, and feedwater flow to respond to load changes without level swell effects.

Boiler efficiency is calculated from stack loss, radiation loss, and blowdown loss; stack temperature and excess oxygen are the main indicators.

Flue gas analysis with an oxygen or carbon dioxide meter indicates excess air; high oxygen means excess air and wasted heat up the stack.

Combustion efficiency improves with lower stack temperature, but the dew point of the flue gas limits how far it can be reduced without corrosion.

A heat balance compares heat input with useful steam output and losses; unaccounted losses usually indicate unburned fuel or air inleakage.