A pipe wall that's thinned past its retirement thickness doesn't announce itself. It sits behind lagging, running hot steam or condensate day after day, and the first sign of trouble is often a leak, a wet spot, or a section of insulation that's suspiciously warm. Sign up to run your B31.1 power piping inspection program — thickness surveys, hangers, supports, and expansion joints — from one CMMS that keeps every reading and every record audit-ready.
Why It Matters
Power piping runs at temperatures and pressures that don't forgive gradual wall loss. B31.1 exists because a schedule of thickness readings, support checks, and expansion joint inspections is the only thing standing between "the line was probably fine last time" and proof that it still is today.
The Three Areas Every B31.1 Program Has To Cover
Thickness Measurement
Ultrasonic readings at fixed points along high-energy piping, tracked against nominal and retirement thickness so wall loss trends are caught before they become a leak.
Hangers & Supports
Spring hangers, rigid supports, and guides checked for load setting, travel, and physical condition, since a piping system that can't move as designed puts stress somewhere it shouldn't.
Expansion Joints
Bellows and slip joints inspected for corrosion, misalignment, and fatigue cracking, because a joint that's lost its flexibility transfers thermal stress straight into the pipe wall.
Each of these carries its own inspection basis. Thickness surveys run on a corrosion-rate schedule that tightens as a line approaches retirement thickness. Hangers and supports get checked on a fixed interval tied to plant operating hours. Expansion joints follow a visual and functional check that shortens if a joint shows early signs of wear — but only if someone is tracking which joints are trending that way.
Where Piping Inspection Programs Break Down
Missed CML Points
A condition monitoring location that gets skipped this round breaks the trend line the next corrosion rate calculation depends on
Stale Hanger Settings
A spring hanger left at its cold-set load long after commissioning is silently pushing stress onto the pipe run around it
Overlooked Expansion Joints
Joints buried behind insulation or in tight pipe racks get skipped more often than they get inspected
No Retirement Thickness on File
A reading means nothing without the calculated minimum it's being compared against
Inconsistent UT Locations
Readings taken from a slightly different spot each round make a corrosion trend look noisier than it actually is
Scattered Records
Thickness logs, hanger reports, and joint inspections split across spreadsheets nobody can produce as a single history
Never Lose Track Of A Thinning Pipe Wall Again
Oxmaint tracks every CML, hanger, and expansion joint against its own inspection basis, flags anything trending toward retirement thickness, and keeps the reading history attached and searchable. Sign up for a free trial to run it on your own piping systems, or book a demo to see it set up for your plant.
Fixed Interval vs Condition-Based Inspection
Some elements of a B31.1 program run on a fixed calendar or operating-hours interval no matter what the last reading showed. Others shift based on measured condition — a line with a fast corrosion rate gets checked sooner than one that's barely moved in years. Running both at once means tracking two different clocks per component, which is exactly the kind of detail a spreadsheet loses track of and a system built around component type and interval keeps straight.
Typical Inspection Basis By Component
| Component |
Inspection Basis |
What Gets Verified |
| High-energy piping walls |
Condition-based, corrosion rate driven |
Wall thickness against calculated retirement value |
| Hangers & supports |
Fixed interval, operating-hours based |
Load setting, travel range, physical condition |
| Expansion joints |
Visual and functional verification interval |
Corrosion, alignment, fatigue cracking |
Frequently Asked Questions
Q
What piping actually falls under a B31.1 inspection program?
High-energy steam, feedwater, and condensate lines within a power plant, along with their hangers, supports, and expansion joints — anything carrying pressure and temperature that would create a safety or reliability event if the wall thinned past its limit.
Q
How is retirement thickness calculated for a pipe run?
It's derived from the design pressure, temperature, and material properties of the specific line, which is why a single blanket minimum thickness across an entire piping system is rarely accurate and needs to be tracked per line, not per plant.
Q
Why do hanger settings drift if nothing looks physically wrong?
Thermal cycling, minor sag, and gradual spring relaxation shift a hanger's load setting away from its cold-set value over time, and none of that shows up on a visual walk-down — it only shows up when the setting is actually measured and compared to the record.
Walk Into Your Next Audit With A Clean Piping Record
Oxmaint keeps thickness readings, hanger checks, and expansion joint inspections tied to their component, their interval, and their evidence, all in one auditable log. Sign up for a free trial to run it on your own piping systems, or book a demo to see it configured for your plant.
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