NIULPE Class 3 case studies
NIULPE Class 3 · Put your knowledge to work in context.
The NIULPE Class 3 Engineer certification is a professional credential for operating engineers who supervise or maintain high-pressure boiler plants and associated mechanical systems. It sits above entry-level licensing and is typically pursued by engineers ready to take charge of a shift, direct firemen or lower-grade operators, and make decisions about combustion, water chemistry, and equipment condition. The NIULPE Class 3 case studies are 5 cases and about 3,005 words.
1Safety Valve and Fitting Deficiencies on a 400 hp Firetube Boiler
A 400 hp firetube boiler, built in 1998 and stamped ASME Section I, operates at 150 psig saturated steam. The single safety valve is stamped 150 psig and rated 6,000 lb/hr; the boiler's rated capacity is about 13,800 lb/hr.
611 words, about 3 min2Low-Fire CO and Flame Scanner Instability After Burner Tune
A 30,000 lb/hr packaged watertube boiler fires natural gas with parallel-positioning fuel/air linkage and O2 trim that has been left in manual for six months. After a contractor "tuned" the burner at high fire, operators report rumble and rising CO at low fire.
652 words, about 3 min3Corrosion Repair and R-Stamp Question on a 250 psig Watertube Boiler
A 50,000 lb/hr, 250 psig watertube boiler is opened for its 10-year internal inspection. The lower mud drum shows a 4 in.
593 words, about 3 min4Feedwater Pump Cavitation From Low NPSH Available
A centrifugal boiler feed pump is rated 400 gpm at 450 ft head, 1,800 rpm, driven by a 75 hp motor. It takes suction from a deaerator operating at 5 psig and 228°F; the pump centerline is 8 ft below the deaerator outlet.
574 words, about 3 min5Softener Hardness Slip and Condensate Corrosion
A 150 psig, 20,000 lb/hr steam boiler uses a sodium zeolite softener and returns about 60% condensate. The softener was regenerated two days ago, but the lab reports 2.5 ppm total hardness in the softener effluent, boiler water OH alkalinity 650 ppm, silica 140 ppm, and pH 10.9.
575 words, about 3 min