Boiler Types and Construction
Not publishedof exam
Combustion, Fuels and Burners
Not publishedof exam
Fittings, Valves and Controls
Not publishedof exam
Water, Steam and Treatment
Not publishedof exam
Operation, Inspection and Licensing
Not publishedof exam
Quick Facts
- Exam
- ASOPE Third Class
- Format
- 50 multiple-choice questions
- Time
- 3 hours
- First Class time
- 4 hours
- Pass
- 70 percent minimum
- Fee
- $45 per attempt
- Renewal
- $38 each year
- Rules
- Closed book, formula sheet
- Calculator
- Non-programmable only
- Retest waits
- 30, 90, 120 days
- Third Class scope
- 500 BHP LP, 500 tons
- Weights
- Not published
Boiler Horsepower
1 BHP = 34.5 lb/hr = 33,475 Btu/hr
From and at 212FAbout 9.8 kWNot shaft horsepower
Firetube vs Watertube
Firetube
- Gas inside tubes
- Large water volume
- Slower load response
Watertube
- Water inside tubes
- Small water volume
- Higher pressure, faster steaming
Gas inside vs water inside
Boiler Type Picker
- Steam above 15 psig→Section I power boiler
- Steam at 15 psig→Section IV heating boiler
- Water 160 psig, 250F→Section IV hot water
- High pressure, fast steaming→Watertube design
- Steady load, more water→Firetube design
- High temperature, low pressure→Thermal fluid heater
- Full of water, circulated→Hydronic boiler
- Compact packaged unit→Scotch marine firetube
Boiler Types
- Firetube
- Gas inside, water outside
- Watertube
- Water inside, gas outside
- Scotch marine
- Packaged firetube, 2-4 passes
- Steam boiler
- Waterline with steam space
- Hydronic boiler
- Runs completely full
- Thermal fluid heater
- Hot oil, low pressure
- Electric boiler
- Elements or electrodes
- Cast iron sectional
- Bolted low-pressure heating sections
Power vs Heating Boiler
Power boiler
- Above 15 psig steam
- ASME Section I
- S stamp
Heating boiler
- 15 psig steam maximum
- ASME Section IV
- H stamp
15 psig draws the line
Code Pressure Limits
- Section IV steam
- 15 psig maximumHeating
- Section IV water
- 160 psig, 250F maximum
- Section I steam
- Above 15 psigPower
- MAWP
- Maximum allowable working pressure
- S stamp
- Section I power boiler
- H stamp
- Section IV heating boiler
- M and E stamps
- Miniature and electric boilers
- V and HV stamps
- Section I, Section IV valves
- Heating surface
- Fire-side area, square feet
- Over 500 sq ft
- Two valves, two feeds
Drums + Heat Recovery
- Steam drum
- Holds waterline, separates steam
- Mud drum
- Collects sludge, bottom blowdown
- Downcomer
- Cooler water descends
- Riser
- Steam and water ascend
- Economizer
- Flue gas preheats feedwater
- Superheater
- Adds heat above saturation
- Air preheater
- Warms incoming combustion air
- Furnace
- Where the fuel burns
BHP Conversions
- 1 BHP heat
- 33,475 Btu per hour
- 1 BHP steam
- 34.5 lb per hour
- 1 BHP power
- About 9.8 kW
- 1 ton cooling
- 12,000 Btu per hour
- 1 kW
- 3,412 Btu per hour
- 1 horsepower
- 746 watts
- 1 gallon water
- 8.33 pounds
- 1 cubic foot water
- 62.4 pounds, 7.48 gallons
- 1 psi head
- 2.31 feet of water
- Atmospheric pressure
- 14.7 psi, 29.92 inHg
Refractory + Insulation
- Refractory
- Heat-resistant furnace lining
- Castable
- Poured cement-like refractory
- Plastic refractory
- Rammed into place
- Insulating firebrick
- Light, low conductivity
- Spalling
- Cracking from thermal shock
- Dry-out
- Slow controlled first heat-up
- Hot spot
- Failed lining, hot casing
- Lagging
- Outer insulation jacket
Three T's
Time, Temperature, Turbulence make complete combustion
Time: residenceTemperature: ignitionTurbulence: mixingMiss one: carbon monoxide
Combustion Air + Excess Air
- Three T's
- Time, temperature, turbulence
- Stoichiometric air
- Exact theoretical air
- Excess air
- Air beyond theoretical
- Gas excess air
- About 10-15 percent
- Too little air
- Carbon monoxide, smoke, soot
- Too much air
- Heat lost up stack
- Complete combustion
- Carbon dioxide, water vapor
- Incomplete combustion
- CO, soot, unburned hydrocarbons
Flue Gas Trim
Lowest oxygen that still shows zero CO
Oxygen up: air upCO present: air shortNever trim into CO
Flue Gas Readings
- Oxygen rising
- Excess air climbing
- Carbon dioxide falling
- Excess air climbing
- Any carbon monoxide
- Air starved, dangerous
- Trim target
- Lowest oxygen, zero CO
- High stack temperature
- Fouling or excess air
- Smoke spot
- Poor oil atomization
- Draft gauge
- Inches of water column
- Oxygen trim
- Automatic excess air control
Fuel Heating Values
- Natural gas
- About 1,000 Btu cubic foot
- Propane
- About 2,500 Btu cubic foot
- No. 2 oil
- About 140,000 Btu gallon
- No. 6 oil
- About 150,000 Btu gallon
- Bituminous coal
- About 12,000 Btu pound
- Flash point
- Vapors ignite momentarily
- Pour point
- Lowest temperature oil flows
- Viscosity
- Resistance to flow
- Heavy oil preheat
- Needed for proper atomization
Burners + Draft
- Atomizing burner
- Steam or air shears
- Pressure-atomizing burner
- Pump pressure, narrow turndown
- Turndown ratio
- Maximum to minimum firing
- Air register
- Directs and swirls air
- Natural draft
- Stack effect only
- Forced draft
- Fan pushes air in
- Induced draft
- Fan pulls gas out
- Balanced draft
- Both fans, slight vacuum
Low Water Response
Secure fuel, never feed, cool, then inspect
Fuel off firstNo cold waterCool slowlyInspect before restart
Safety Valve vs Relief Valve
Safety valve
- Steam service
- Pops fully open
- Steam heating boilers
Relief valve
- Liquid service
- Opens gradually
- Hot water boilers
Steam pops, liquid creeps
Dangerous Condition Response
- No water in glass→Secure fuel now(Never feed water)
- Level unproven or doubtful→Blow down the glass(Try cocks confirm)
- Pressure above high limit→Secure fuel, check controls
- Safety valve lifting→Cut firing, find cause
- Flame failure lockout→Purge before relight(Never bypass)
- Repeated lockouts→Stop, call service(Never jumper interlocks)
- Tube leak suspected→Controlled shutdown, cool slowly
- Water hammer in line→Close valve, drain condensate
- Priming into steam line→Lower level, blow down
- Smoke or furnace puff→Secure fuel, purge fully
- Fuel gas odor→Secure fuel, ventilate, evacuate
Safety Valve Rules
- Safety valve
- Steam, pops full open
- Relief valve
- Liquid, opens gradually
- Safety relief valve
- Built for either service
- Lowest set pressure
- At or below MAWP
- Accumulation limit
- 6 percent over MAWP
- Shutoff valve ban
- None before or after
- Discharge piping
- Safe point, drained low
- Try lever test
- Proves valve still free
- Valve blowdown
- Pop minus reseat pressure
Cold Startup Order
Water, vent open, low fire, vent closed
Check level firstVent until steady steamFire at low rateHeat metal slowly
Operating vs High-Limit Control
Operating control
- Cycles the burner
- Automatic reset
- Normal setpoint
High-limit control
- Backup trip only
- Manual reset
- Set above operating
Auto reset vs manual
Low-Water Cutoff Tests
- Low-water fuel cutoff
- Stops burner on low
- Float type
- Float switch in chamber
- Probe type
- Conductivity through the water
- Blowdown test
- Flush float chamber routinely
- Slow drain test
- Lower level, watch trip
- Annual service
- Dismantle and inspect internals
- Auxiliary cutoff
- Second, manual reset device
- Top accident cause
- Low water, poor maintenance
Feed Line Order
Pump, check valve, stop valve, boiler
Check stops backflowStop nearest boilerService check under pressure
Gauge Glass + Water Column
- Gauge glass
- Shows actual water level
- Blow down glass
- At least once per shift
- Fast return
- Connections clear, level true
- Slow or no return
- Plugged line, false level
- False high level
- Classic dry-fire setup
- Two glasses
- Above 400 psi MAWP
- Remote indicators
- May replace one glass
- Try cocks
- Independent check on level
- Water column
- Chamber holding level devices
Valves + Fittings
- Gate valve
- Fully open or closed
- Globe valve
- Throttles, flow under seat
- Check valve
- Prevents reverse flow
- Feed line order
- Pump, check, stop, boiler
- Two stop valves
- Shared header requirement
- Free-blow drain
- Proves outboard valve holding
- Steam trap
- Drains condensate, holds steam
- Nonreturn valve
- Automatic stop-check on header
Burner Management Timings
- Flame failure response
- 4 seconds maximum
- NFPA 85 valve closure
- Within 1 second
- CSD-1 valve closure
- Within 5 seconds
- CSD-1 purge
- At least 4 air changes
- NFPA 85 purge
- 8 watertube, 4 firetube
- Purge airflow
- 70 percent full-load minimum
- Post-purge
- Clears fuel after shutdown
- Interlock string
- Wired in series
- Operating control
- Automatic reset, cycles burner
- High-limit control
- Manual reset backup trip
Priming vs Carryover
Priming
- Sudden water slugs
- High level or surge
- Mechanical cause
Carryover
- Any water leaving
- Includes foaming
- Umbrella term
Priming is one carryover
Water Problem Picker
- Hard white deposits→Scale, soften feedwater
- Pits and tubercles→Oxygen corrosion, deaerate
- Rusty water in glass→Acid corrosion, raise pH
- Grooved condensate pipe bottom→Carbonic acid, dealkalize
- Stable foam on surface→High solids, blow down
- Water slugs into header→Priming, lower level
- TDS climbing steadily→Increase surface blowdown
- Sludge in mud drum→Bottom blowdown
Feedwater Chemistry Limits
- Boiler water pH
- Maintain about 11NB-410
- Condensate pH
- 7.5 to 8.5NB-410
- Carbonic acid pH
- 6.9 down to 4.4
- TDS rule of thumb
- About 1,000 ppm maximum
- Hardness
- Dissolved calcium and magnesium
- Oxygen at 70F
- About 8.6 ppm
- Oxygen at 150F
- About 4.3 ppm
- Oxygen at 212F
- About zero ppm
- Deaerator outlet
- About 0.005 cc per liter
- Oxygen scavenger
- Sodium sulfite catches traces
Scale vs Corrosion
Scale
- Hardness deposits
- Insulates and overheats
- Fix by softening
Corrosion
- Oxygen and acid
- Pits and tubercles
- Fix by deaerating
Deposit adds, corrosion removes
Blowdown + Cycles
- Bottom blowdown
- Short dump, clears sludge
- Surface blowdown
- Continuous, controls dissolved solids
- Cycles of concentration
- Boiler TDS over feedwater
- 200 ppm feedwater
- Five cycles reaches 1,000
- 25 ppm feedwater
- Forty cycles reaches 1,000
- Blowdown percent
- 100 divided by cycles
- Excess blowdown
- Wastes heat and chemicals
- Blowdown tank
- Cools and vents discharge
Bottom vs Continuous Blowdown
Bottom blowdown
- Short intermittent dump
- Lowest point or drum
- Removes settled sludge
Continuous blowdown
- Steady surface draw
- Just below waterline
- Controls dissolved solids
Sludge below, solids surface
Steam Table Basics
- Sensible heat
- Changes temperature only
- Latent heat
- Changes state only
- 32F to 212F
- 180 Btu per pound
- Latent at 212F
- About 970 Btu pound
- Total heat 0 psig
- About 1,150 Btu pound
- Saturation 15 psig
- About 250F
- Saturation 100 psig
- About 338F
- Saturation 150 psig
- About 366F
- Steam expansion
- About 1,600 times volume
- Superheat
- Heat above saturation temperature
Water Treatment Equipment
- Zeolite softener
- Swaps hardness for sodium
- Brine regeneration
- Restores resin exchange capacity
- Dealkalizer
- Cuts alkalinity, carbon dioxide
- Reverse osmosis
- Membrane strips dissolved solids
- Deaerator
- Heats and vents gases
- Feedwater tank
- Stores condensate and makeup
- Chemical feed pump
- Doses treatment continuously
- Condensate return
- Cuts makeup and fuel
CSD-1 vs NFPA 85
CSD-1
- Below 12.5 MMBtu input
- Automatically fired boilers
- 4 air changes purge
NFPA 85
- 12.5 MMBtu and above
- Larger fired units
- 8 air changes, watertube
Fuel input picks code
Which Code Applies
- Power boiler construction→ASME Section I
- Heating boiler construction→ASME Section IV
- Auto-fired below 12.5 MMBtu→ASME CSD-1
- 12.5 MMBtu and above→NFPA 85
- Inservice repair or alteration→NBIC
- Worker safety in plant→OSHA general industry
- License to operate→ASOPE or local board
Codes + Standards
- ASME Section I
- Power boiler construction
- ASME Section IV
- Heating boiler construction
- ASME CSD-1
- Auto-fired below 12.5 MMBtu
- NFPA 85
- 12.5 MMBtu input and above
- NBIC
- Inservice inspection and repair
- NBIC parts
- Installation, inspection, repairs, valves
- OSHA
- General industry safety
- Jurisdiction
- State or city board
ASOPE License Facts
- Third Class scope
- 500 BHP low pressure, 500 tons
- Exam length
- 50 multiple-choice questions
- Third Class time
- 3 hours
- First Class time
- 4 hours
- Pass mark
- 70 percent minimum
- Exam fee
- $45 per attempt
- Annual renewal
- $38 per year
- Age and school
- 18, diploma or GED
- Training required
- 6 months or 3 credits
- Retest waits
- 30, 90, 120 days
- Result reported
- Pass or fail only
- Curriculum list
- 19 minimum topics published
Electrical Basics
- Ohm's law
- Volts equal amps times ohms
- Current
- Volts divided by ohms
- Power
- Watts equal volts times amps
- Series circuit
- One path, all close
- Parallel circuit
- Many paths, same voltage
- Interlock string
- Any open contact trips
- Motor starter
- Contactor plus overload relay
- Fuse or breaker
- Protects conductors from overload
Plant Safety + LOTO
- Lockout/tagout
- Isolate, lock, tag, verify
- Energy sources
- Fuel, electric, steam, feedwater
- Personal lock
- Only the owner removes
- Confined space
- Permit required for drums
- Blanking
- Blind off connected lines
- Atmosphere test
- Oxygen, flammables, toxics
- Attendant
- Outside with rescue means
- PPE
- Gloves, glasses, hearing protection
Common Traps
Safety valve vs relief valve
Safety pops on steam ≠ Relief creeps on liquid
Section I vs Section IV
Section I above 15 psig ≠ Section IV 15 psig maximum
Bottom vs surface blowdown
Bottom clears settled sludge ≠ Surface controls dissolved solids
Priming vs foaming
Priming is level surge ≠ Foaming is dissolved solids
Never feed a dry boiler
Cold water cracks metal ≠ Secure fuel and cool
CSD-1 vs NFPA 85
CSD-1 below 12.5 MMBtu ≠ NFPA 85 at 12.5 up
Boiler horsepower is not shaft
BHP is 33,475 Btu ≠ Shaft hp is 2,545 Btu
Scale is not corrosion
Scale insulates and overheats ≠ Corrosion pits and thins
Gate valve never throttles
Gate: open or closed ≠ Globe: throttles the flow
Last Minute
- 1.Section IV steam: 15 psig
- 2.Section IV water: 160 psig, 250F
- 3.Section I: above 15 psig
- 4.Over 500 sq ft: two valves
- 5.Accumulation: never over 6 percent
- 6.Two gauge glasses above 400 psi
- 7.Flame failure 4 seconds, close 1
- 8.Purge: 70 percent airflow minimum
- 9.1 BHP = 34.5 lb, 33,475 Btu
- 10.Low water: secure fuel, never feed
- 11.Boiler water pH 11; condensate 7.5-8.5
- 12.TDS rule of thumb: 1,000 ppm
- 13.CSD-1 below 12.5 MMBtu; NFPA above
- 14.ASOPE: 50 questions, 70 percent
- 15.Third Class: 500 BHP, 500 tons
- 16.Retest: 30, 90, 120 days
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