Vibration is the earliest, cheapest, and loudest warning a rotating machine can give you — but only if someone is actually listening on a schedule. A monthly vibration route turns that warning into a structured data stream: same points, same directions, same person, same CMMS record, every 30 days. Done right, it catches boiler feed pump bearing degradation 60–90 days before failure, flags ID/FD fan imbalance before blade damage, and gives auditors an unbroken trail of rotating-equipment health. This page is the working checklist your route technician carries — built around ISO 10816 thresholds, real BFP/fan/motor measurement points, and the CMMS workflow that captures every reading.
2–3 mo
Lead time monthly route gives on BFP faults
4.5 mm/s
ISO 10816-3 Zone B/C boundary (rigid, large)
12 pts
Readings per typical motor + driven machine
3 axes
Horizontal, vertical, axial — per bearing
What a Monthly Vibration Route Actually Is
A vibration route is a fixed, repeatable walk-down of every critical rotating asset in the plant, where the technician collects the same vibration readings, at the same measurement points, in the same units, every month. The route is built once and locked: BFP bearings 1–4, ID Fan motor DE/NDE, FD Fan inboard/outboard, condensate pump motor, cooling tower gearbox — each in horizontal (H), vertical (V), and axial (A) directions. The point of monthly cadence is trending — a single reading tells you almost nothing; twelve readings in twelve months tell you whether vibration is stable, drifting, or accelerating toward failure.
Why monthly
Monthly BFP monitoring detects most faults two to three months before failure. Critical units are often moved to two-week intervals where consequence of failure is highest.
Why fixed points
Repeatability is everything. Reading 4.2 mm/s last month versus 4.8 mm/s this month means nothing if the sensor was held at a different spot or angle. Same surface, same orientation, every time.
Why three axes
Horizontal exposes imbalance, vertical reveals looseness and structural issues, axial flags misalignment and thrust-bearing wear. Single-axis readings hide half the failure modes.
Why CMMS-tracked
Spreadsheet routes lose the trend the moment the file is misnamed or the technician changes. CMMS records pin every reading to the asset, the date, the technician, and the threshold.
ISO 10816 / ISO 20816 Severity Zones at a Glance
Every reading on the route gets compared against an ISO 10816-3 (now ISO 20816-3) zone for that asset class. The zones are unambiguous: Zone A is acceptance for new machines, Zone B is acceptable for unrestricted long-term operation, Zone C means restricted operation pending corrective action, and Zone D means damage is occurring. The boundaries shift depending on machine size and foundation type — small machine on rigid foundation has a different limit than a large machine on a flexible foundation — but the four-zone logic is the same everywhere.
| Severity Zone |
Small Machine, Rigid (≤15 kW class limits) |
Medium, Rigid (15–300 kW) |
Large, Rigid (≥300 kW) |
Route Action |
| Zone A |
≤ 1.4 mm/s RMS |
≤ 1.8 mm/s RMS |
≤ 2.8 mm/s RMS |
Newly commissioned — accept and baseline |
| Zone B |
1.4 – 2.8 mm/s |
1.8 – 4.5 mm/s |
2.8 – 4.5 mm/s |
Acceptable for unrestricted operation |
| Zone C |
2.8 – 4.5 mm/s |
4.5 – 7.1 mm/s |
4.5 – 7.1 mm/s |
Restricted — plan repair at next outage |
| Zone D |
> 4.5 mm/s |
> 7.1 mm/s |
> 7.1 mm/s |
Damage is occurring — shut down to assess |
Values shown are broadband RMS velocity, measured 10–1000 Hz on bearing housings. Steam turbines >50 MW use ISO 20816-2; gas turbines >3 MW use ISO 20816-4; hydraulic plant uses ISO 20816-5. Always confirm the correct sub-standard for your asset class.
The Monthly Route Walk — Asset by Asset
This is the exact sequence a vibration technician follows on a typical thermal or combined-cycle plant route. Each block lists the measurement points, the directions, and the realistic alarm thresholds for that asset. The order matters — start at the BFP train (highest criticality), work through draft fans, then auxiliary pumps, then cooling tower — because if route time is cut short, the most critical assets are already captured.
Measurement Points
M-DEMotor drive end — H, V, A
M-NDEMotor non-drive end — H, V, A
P-IBPump inboard bearing — H, V, A
P-OBPump outboard / thrust bearing — H, V, A
BPBooster pump bearings if separate — H, V, A
What to Watch
1× shaft frequency rising → unbalance or wear ring damage
2× shaft frequency rising → coupling misalignment
Vane-pass frequency (impeller blades × RPM) → flow recirculation
High-frequency band 1–20 kHz → cavitation when present
Zone B/C boundary typically 4.5 mm/s RMS for large BFP class
Measurement Points
M-DEMotor drive end — H, V, A
M-NDEMotor non-drive end — H, V, A
FC-INFluid coupling input bearing — H, V, A
FC-OUTFluid coupling output bearing — H, V, A
F-IB / F-OBFan inboard and outboard bearings — H, V, A
What to Watch
1× rising → blade fouling, ash buildup, lost balance weight
2× motor RPM with high axial → coupling misalignment
Axial direction high → thrust bearing or duct resonance
FV-3 acceptance: ≤ 4.5 mm/s RMS; investigation above 7.1 mm/s
Above 10 mm/s on main shaft → schedule emergency stop
Measurement Points
M-TOPMotor top thrust bearing — H, V, A
M-BTMMotor lower guide bearing — H, V
P-HEADPump head / discharge flange — H, V, A
P-BASEPump base plate / foundation — H, V
What to Watch
High axial on motor top → thrust bearing distress
High horizontal at base → grout cracking, loose hold-down bolts
Sub-synchronous peaks → submerged bearing wear, oil whirl
Vane-pass spikes → cavitation from low NPSH at suction
Measurement Points
M-DE / NDEDrive motor bearings — H, V, A
GB-INGearbox input shaft bearing — H, V, A
GB-OUTGearbox output shaft bearing — H, V, A
F-HUBFan hub support / fan deck — V, A
What to Watch
Gear mesh frequency (teeth × RPM) → tooth wear or pitting
Sidebands around mesh frequency → eccentricity, broken tooth
Sudden 1× spike → lost blade balance weight or blade damage
Cooling tower fans often auto-trip on vibration — verify trip setting
Measurement Points
M-DEDrive end bearing — H, V, A
M-NDENon-drive end bearing — H, V (axial if accessible)
L-DE / L-NDEDriven equipment bearings — H, V, A
What to Watch
2× line frequency (100 / 120 Hz) → stator electrical issues
Rotor bar pass sidebands → broken rotor bars
High-frequency bearing tones → early raceway damage
Medium-class Zone B/C boundary typically 4.5 mm/s RMS
Stop Running Your Vibration Route Out of a Spreadsheet
OxMaint logs every monthly reading against the asset, the bearing, the direction, the technician, and the ISO zone — and trends them automatically across 12 months so degradation jumps off the screen before the bearing fails.
The Reading Sheet — What Every Entry Must Capture
Every reading on the route needs the same six data points written down — or, better, captured directly in the CMMS on a mobile device at the asset. Missing fields are why monthly routes lose their analytical value. The technician who skips the "load condition" field is the reason next quarter's trend chart cannot be interpreted. This is the minimum capture set for every measurement point on the walk.
01
Asset ID & Point Code
Tag number, bearing code (M-DE, P-IB, etc.), and direction (H, V, A). No free text — pick from CMMS dropdown to keep trending intact.
02
RMS Velocity (mm/s)
Broadband 10–1000 Hz velocity in mm/s RMS. This is the headline number that gets compared to the ISO 10816 zone for the asset class.
03
Peak Acceleration (g)
High-frequency envelope or peak g — the leading indicator for rolling-element bearing damage well before broadband velocity moves.
04
Load & Speed Condition
Plant MW output, pump discharge pressure, fan damper position, motor RPM. Variable-speed assets need the operating point recorded.
05
Date, Time, Technician
Automatically stamped in CMMS. Manual sheets get this wrong — and trend lines built on bad timestamps lead to false alarms.
06
Zone & Action Flag
A / B / C / D zone auto-calculated from the threshold. Any reading at Zone C or D auto-generates a corrective work order in OxMaint.
The Monthly Route Checklist — Pre-Walk, Walk, Post-Walk
A vibration route is not just the readings — it is what happens before the technician leaves the office, what happens at each asset, and what happens to the data afterward. Skipping any leg of this three-part workflow is where monthly programs lose their predictive value and turn into "data we collect because we have always collected it."
A
Pre-Walk Preparation
Done at the desk, the day before the route
Sync data collector to last month's route file from CMMS
Confirm asset list — note any equipment offline or under outage
Check sensor calibration date — accelerometer within 12 months
Review last month's flagged points — bring expected vs actual
Confirm PPE: hearing protection, gloves, hot-work permit if needed
B
At-the-Asset Reading
Done at each measurement point on the route
Verify asset is in steady-state operation, not start-up or coast-down
Place sensor on machined surface — not coverings, lids, fins
Hold same orientation as the marked measurement point
Capture H, V, A for each bearing; A at thrust bearing minimum
Note unusual sound, smell, oil leak, temperature on the spot
C
Post-Walk Review & Sign-Off
Done within 24 hours of completing the route
Upload route file to CMMS — every point synced with timestamp
Review Zone C / D flagged readings against trend
Generate corrective work orders for any confirmed Zone C / D
Update PdM register — assets escalated, recovered, or stable
Reliability engineer countersign — audit trail closed for the month
Common Faults the Monthly Route Catches
The point of the route is not the number — it is the pattern. A trained vibration technician can read a frequency spectrum the way a doctor reads an ECG, and the same handful of fault signatures account for the majority of what monthly routes pick up across power generation assets. These are the five patterns your CMMS-trended data should make obvious.
Imbalance
Signature: dominant 1× shaft frequency, mostly radial (H/V), phase steady
Most common fan fault. Caused by ash buildup, lost balance weights, blade erosion. Field balancing usually returns asset to Zone A within hours.
Misalignment
Signature: high 2× shaft frequency, especially axial direction
Coupling misalignment between motor and driven machine. Often appears after maintenance. Laser alignment at next opportunity normally clears it.
Bearing Damage
Signature: high-frequency peaks at bearing tones (BPFI, BPFO, BSF)
Earliest detection is on peak g / envelope demodulation, well before RMS velocity moves. Plan replacement before Zone D — the failure mode is sudden.
Looseness
Signature: multiple harmonics 1×, 2×, 3×… with raised vertical readings
Foundation bolts loose, grout cracked, soft foot on motor. Look for high vertical at base. Tightening or re-grouting often restores readings quickly.
Cavitation
Signature: random high-frequency noise floor, 1–20 kHz band
BFP and condensate pumps suffering low NPSH. Sounds like gravel. Operational fix — raise suction pressure or correct flow — usually solves it.
Electrical Faults
Signature: 2× line frequency (100/120 Hz) or rotor bar pass sidebands
Stator imbalance, rotor bar damage, or eccentric air gap. Pair vibration data with motor current signature analysis to isolate root cause.
What CMMS Tracking Adds That a Spreadsheet Cannot
Plenty of plants run monthly routes today — the question is what happens to the data afterward. A spreadsheet route lives on one person's laptop, dies the day they leave, and produces no automatic work order when a reading enters Zone C. A CMMS-tracked route in OxMaint binds every reading to the asset, the bearing, the technician, the threshold, and the corrective workflow — and gives auditors and reliability engineers the trend chart instantly. Below is the operational gap between the two approaches.
| Capability |
Spreadsheet Route |
OxMaint CMMS Route |
| Reading tied to specific asset & bearing code |
Free-text — often inconsistent |
Locked dropdown, never drifts |
| 12-month trend chart per measurement point |
Manual — only built when something fails |
Auto-generated on every reading |
| ISO zone auto-flagged on entry |
No — relies on technician memory |
Yes — A/B/C/D coloured in real time |
| Zone C/D auto-creates corrective work order |
Manual escalation, often missed |
Automatic with severity priority |
| Audit trail for compliance and ISO reviews |
File-by-file reconstruction |
Single export with timestamps and sign-off |
| Mobile capture at the asset |
Paper sheet, re-keyed later |
Direct entry on tablet/phone in the field |
| Survives technician turnover |
Often lost with the laptop |
Permanent asset record, accessible to all |
How Plants Build the Route the First Time
If your plant has never had a structured monthly route, building one is a three- to four-week exercise. The output is a locked, repeatable walk-down that any qualified technician can execute the same way every month — and that the CMMS expects on a fixed cadence. This is the build sequence that reliability teams follow when standing up a route for the first time.
Step 1
Criticality Classification
Rank every rotating asset A (critical, no standby), B (important with workaround), C (non-critical, easily replaced). A-class goes monthly or biweekly; B-class monthly to quarterly; C-class spot checks only.
Step 2
Measurement Point Map
Walk every A and B asset. Mark each bearing housing with a permanent location dot, photograph the orientation for H/V/A, and write the point code into the CMMS asset record.
Step 3
Threshold & Zone Setup
Assign each asset its ISO 10816/20816 class and the Zone B/C and C/D boundaries. Confirm with OEM data for any non-standard equipment (steam turbines, gas turbines, hydro).
Step 4
Baseline Survey
Run the full route once. Record baseline readings. Any asset already above Zone B/C boundary at baseline gets a corrective work order before the monthly cadence starts.
Step 5
Cadence Lock & Sign-Off
CMMS PM scheduled monthly with reminder, technician assignment, and auto-generated route file. Reliability engineer signs off the route definition — locked unless formally revised.
Frequently Asked Questions
Is monthly the right cadence for every rotating asset?
No. Monthly is the standard for A-class critical assets like main BFPs, ID/FD fans, and condensate pumps. The most critical, where failure stops generation entirely, often move to two-week intervals. B-class auxiliaries can sit at monthly or quarterly. Cadence is set by criticality, not by convenience — and is tracked automatically in
OxMaint PM scheduling.
Which ISO standard applies — 10816 or 20816?
ISO 20816 is the current standard; it superseded ISO 10816 and unified housing- and shaft-vibration evaluation. Most working plants still refer to the legacy ISO 10816 zones because the thresholds and four-zone logic are identical for most asset classes. Use ISO 20816-3 for general industrial machinery above 15 kW, with the sub-parts for turbines and hydro.
Can the monthly route replace permanent online monitoring on the BFP?
No — they complement each other. Permanent proximity probes on main BFPs provide trip protection and continuous shaft-relative vibration data. The monthly route covers bearing-housing velocity and acceleration, captures fault modes the online system may not flag, and audits the online system's accuracy. Both feed the same asset record in the CMMS.
How does OxMaint handle Zone C and Zone D alerts?
Any reading captured in OxMaint that crosses into Zone C or D against its configured threshold auto-generates a corrective work order at the matching severity, routed to the responsible planner. The asset is flagged on the reliability dashboard, and the trend chart for that point is attached to the work order. To see the workflow,
book a 30-minute walkthrough.
What documentation do auditors actually look for from a vibration route?
Auditors want unbroken monthly evidence per critical asset: the reading sheet, the technician sign-off, the trend chart, the corrective work orders generated against Zone C/D, and the reliability engineer countersignature. A CMMS-tracked route produces this as a single export. Spreadsheet routes typically fail audit because the trail is fragmented across files and people.
Run Your Vibration Route on a CMMS Built for Power Plants
OxMaint comes with pre-built measurement-point templates for BFPs, ID/FD fans, condensate pumps, and cooling tower drives. ISO 10816/20816 zones are pre-loaded. Trend charts auto-generate. Zone C/D readings trigger work orders. Your route becomes a living reliability record, not a stack of spreadsheets.
