How do you calculate a bend radius risk score?

Multiply each input by its weight and sum: severity x 0.40 + occurrence x 0.35 + detection x 0.25. With severity 7, occurrence 4, and detection 5, the weighted score is 5.45 on a 0-10 scale.

Why weight severity higher than occurrence and detection?

A macrobend that snaps a fiber backbone is catastrophic regardless of how often it happens, so severity carries 40%. Occurrence (35%) and detection difficulty (25%) modulate priority but shouldn't let a high-consequence bend hide behind low frequency.

What is a high bend radius risk score?

On this 0-10 scale, anything above ~6 warrants design action — added strain relief, larger bend formers, or rerouting. The example's 5.45 is moderate: worth a watch item and a detection improvement, not an immediate redesign.

What does the detection score represent here?

It's detection weakness — how hard the bend condition is to catch before it ships. A high detection score means current inspection or OTDR checks are unlikely to flag the tight bend, which pushes the overall risk up.

Bend radius risk score vs. classic FMEA RPN?

Classic RPN multiplies all three factors equally, so a 5x5x5 looks identical to a 10x10x1. This weighted sum keeps the score on a 0-10 scale and deliberately prioritizes severity, making cross-item comparison more stable.

How do I lower a bend radius risk score?

Attack the biggest weighted contributor. Reducing severity (redesign so a bend can't reach minimum radius) moves the score most; better OTDR or visual checks lower the detection term; bend-formers and routing guides lower occurrence.

Fiber Optic Cable & Photonic Interconnects calculator

Bend Radius Risk Calculator

Bend radius risk scoring is a weighted FMEA-style number that ranks how dangerous a tight-bend condition is in a fiber optic cable or interconnect design. Cable engineers and reliability teams use it during routing reviews and DFMEA to decide which bend hazards get redesigned first. It matters because bending a fiber below its minimum bend radius drives macrobend loss and, over time, mechanical fatigue and fracture — failures that may pass at install and only show up months later as attenuation drift. Unlike a raw RPN, this version weights severity, occurrence, and detection so that the consequences of a broken backbone link outweigh a nuisance that's easy to catch.

What this calculator does

Score bend-radius risk for fiber cable or optical interconnect routing from severity, occurrence, and detection ratings.
Use it when reviewing routing around trays, boots, strain relief, cable managers, transceiver cages, modules, or dense data-center panels.
It computes a single weighted bend-radius risk score by combining severity at 40%, occurrence at 35%, and detection weakness at 25%.

Formula used

Bend-radius risk score = severity × 0.40 + occurrence × 0.35 + detection × 0.25

Inputs explained

Bend-radius severity score:
Bend-radius occurrence score:
Bend-radius detection difficulty score:

How to use the result

Use it during fiber routing design reviews, strain-relief DFMEA, or when triaging field bend complaints to prioritize fixes.
The weights and 1-10 scoring are judgment calls calibrated to a team's scale; scores are only comparable within a consistently rated set, not across different rating rubrics.

Current U.S. benchmarks

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Common questions

How do you calculate a bend radius risk score? Multiply each input by its weight and sum: severity x 0.40 + occurrence x 0.35 + detection x 0.25. With severity 7, occurrence 4, and detection 5, the weighted score is 5.45 on a 0-10 scale.
Why weight severity higher than occurrence and detection? A macrobend that snaps a fiber backbone is catastrophic regardless of how often it happens, so severity carries 40%. Occurrence (35%) and detection difficulty (25%) modulate priority but shouldn't let a high-consequence bend hide behind low frequency.
What is a high bend radius risk score? On this 0-10 scale, anything above ~6 warrants design action — added strain relief, larger bend formers, or rerouting. The example's 5.45 is moderate: worth a watch item and a detection improvement, not an immediate redesign.
What does the detection score represent here? It's detection weakness — how hard the bend condition is to catch before it ships. A high detection score means current inspection or OTDR checks are unlikely to flag the tight bend, which pushes the overall risk up.
Bend radius risk score vs. classic FMEA RPN? Classic RPN multiplies all three factors equally, so a 5x5x5 looks identical to a 10x10x1. This weighted sum keeps the score on a 0-10 scale and deliberately prioritizes severity, making cross-item comparison more stable.

Last reviewed 2026-05-12.