BOILER STRENGTH CALCULATOR

Next Scheduled Boiler Inspection:

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Annual Boiler Inspection - September 13, 2025, at 8:30 a.m.
Enter Boiler Data (only Steel boilers are supported):
r = outside shell radius (inches): (ex: 3.3 or 4.5 )
t = shell wall thickness (inches) (ex: .250 or .280 )
C = constant: (1 for seamless tube or 0.8 for welded tube)
p = stay bolt pitch (inches): (larger dimension if not square spacing - ex: 1.5 or 2.0 )
c = constant: (2.1 for welded/silver soldered stay bolts w/o heads or 2.8 w/ heads)
a = stay bolt diameter (inches): (ex: .5 or .375 )
h = stay bolt spacing (horizontal) (inches): (ex: 1.5 or 2.0 )
v = stay bolt spacing (vertical) (inches): (ex: 1.5 or 2.0 )
fl = firebox length (inches): (ex: 13 or 14.5 )
fw = firebox width (inches): (ex: 4.5 or 8 )
fh = firebox height (inches): (ex: 5 or 6.3 )
mop = max. operating pressure (psi): (normally the highest safety valve setting ex: 125 or 115 )
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MAWP and Steaming Capacity
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MAWP Boiler Shell:
MAWP Stayed Surfaces:
MAWP Stay Bolts:
BSC Boiler Steaming Capacity (lbs/hour)
CFS Calculated Factor of Safety