Quick Reference

Fast lookup for FMEA ratings, Action Priority, and common tasks.

Severity Ratings (S)

Rating	Effect	Examples
10	Hazardous without warning	Fire, explosion, injury, regulatory violation
9	Hazardous with warning	Safety issue with detectable warning
8	Very high	Loss of primary function, vehicle inoperable
7	High	Reduced performance, customer dissatisfaction
6	Moderate	Partial loss of function, reduced comfort
5	Low	Minor performance reduction
4	Very low	Fit/finish issue, minor annoyance
3	Minor	Noticeable but no functional impact
2	Very minor	Most customers won't notice
1	None	No effect

Occurrence Ratings (O)

Rating	Probability	Failure Rate
10	Almost certain	≥1 in 2
9	Very high	1 in 3
8	High	1 in 8
7	Moderately high	1 in 20
6	Moderate	1 in 80
5	Low	1 in 400
4	Very low	1 in 2,000
3	Remote	1 in 15,000
2	Very remote	1 in 150,000
1	Nearly impossible	<1 in 1,500,000

Detection Ratings (D)

Rating	Detection Capability	Controls
10	Cannot detect	No controls exist
9	Very remote	Controls unreliable
8	Remote	Manual inspection, random sampling
7	Very low	Manual inspection, 100%
6	Low	Manual with gauges/fixtures
5	Moderate	SPC (Statistical Process Control)
4	Moderately high	SPC with immediate feedback
3	High	Automated detection, operator alerted
2	Very high	Automated detection, prevents defect
1	Almost certain	Defect cannot reach customer (error-proofing)

Action Priority Rules

High Priority (Red 🔴)

Immediate action required

• S ≥ 9 (any O/D)
• S ≥ 7 AND (O ≥ 4 OR D ≥ 4)

Medium Priority (Orange 🟠)

Action needed

• S ≥ 4 (not High)
• S = 3 AND (O ≥ 6 OR D ≥ 6)

Low Priority (Green 🟢)

Monitor

• All other combinations

RPN Calculation

Formula: RPN = S × O × D

Range: 1 to 1,000

Thresholds (traditional):

• ≥200: Unacceptable, immediate action
• 100-199: High risk, action required
• 50-99: Medium risk, action recommended
• <50: Low risk, monitor

Modern Standard

AIAG/VDA now uses Action Priority instead of RPN thresholds. NirmIQ shows both.

Common Tasks

Create New DFMEA

1. FMEA Workspace → Advanced Mode
2. New Analysis → DFMEA
3. Fill component name, design intent
4. Add failure modes with S/O/D

Add Failure Mode

1. Open analysis
2. "Add Failure Mode" button
3. Describe failure, effects, causes
4. Rate S (1-10), O (1-10), D (1-10)
5. AP calculates automatically

Create Action Item

1. Click failure mode card
2. "Add Action" button
3. Describe action, assign owner
4. Set due date and priority
5. Track status: Pending → In Progress → Completed

View Risk Heatmap

1. Open analysis
2. "Heatmap" tab
3. Click cells to see failures
4. Export as image for reports

Track RPN Trending

1. Open analysis
2. "Trending" tab
3. View improvement over time
4. Filter by failure mode

Build Structure Tree

1. Open analysis
2. "Structure Tree" tab
3. Add System level element
4. Add child Subsystems/Components
5. Define functions for each
6. Link to requirements

Link to Requirement

1. Create/edit analysis
2. Click "Link Requirement"
3. Select from dropdown
4. Or: Add requirement_id to Structure Element

Export for Audit

1. Open analysis
2. "Export" button (top right)
3. Choose format:
   • Excel (AIAG template)
   • PDF (summary report)

Keyboard Shortcuts

Action	Shortcut
Create new analysis	Ctrl + N
Add failure mode	Ctrl + F
Add action item	Ctrl + A
Save changes	Ctrl + S
Export	Ctrl + E
Search failure modes	Ctrl + K

Status Workflows

Analysis Status

Draft → In Review → Approved → Active → Archived

Failure Mode Status

Open → In Progress → Completed → Closed

Action Item Status

Pending → In Progress → Completed (or Cancelled)

AIAG-VDA 7-Step FMEA Terminology

The 7 Steps at a Glance

Step	Name	Purpose	Key Output
1	Planning & Preparation	Define scope, team, timeline	5T's completed
2	Structure Analysis	Build system hierarchy	Structure Tree (P-Diagram)
3	Function Analysis	Define what each element does	Function descriptions
4	Failure Analysis	Identify how functions can fail	Failure Net (cause-effect chains)
5	Risk Analysis	Rate S, O, D for each failure	Action Priority (H/M/L)
6	Optimization	Define and track mitigations	Action items assigned
7	Results Documentation	Export and share findings	FMEA reports

Step 1: The 5T's (Planning)

Term	Meaning	Example
InTent	Purpose & Scope	"Analyze battery thermal management for safety"
Timing	Schedule & Milestones	"Complete before design freeze (Q2)"
Team	Cross-functional members	"Design, Quality, Manufacturing, Safety"
Task	Objectives & Deliverables	"Identify all high-priority failure modes"
Tool	Software & Standards	"NirmIQ + AIAG-VDA Handbook"

Step 2: Structure Analysis Terms

Term	Definition
System	Top-level item being analyzed (e.g., "Battery Pack")
Subsystem	Functional group within system (e.g., "Thermal Management")
Component	Individual part or assembly (e.g., "Temperature Sensor")
Characteristic	Measurable property (e.g., "Response time < 100ms")
Structure Tree	Visual hierarchy showing system breakdown
P-Diagram	Parameter diagram showing inputs, outputs, noise factors
Interface	Connection point between elements
Focus Element	The component currently being analyzed
Next Higher Level	Parent element in the structure
Next Lower Level	Child elements in the structure

Step 3: Function Analysis Terms

Term	Definition
Function	What an element is intended to DO (verb + noun)
Primary Function	Main purpose of the element
Secondary Function	Supporting purposes
Interface Function	How elements interact with each other
Requirement Link	Traceability to formal requirement
Function Net	Diagram showing function relationships

Function Writing

Always write functions as verb + noun: "Monitor temperature", "Detect obstacle", "Execute shutdown"

Step 4: Failure Analysis Terms

Term	Definition	Example
Failure Mode	How a function can fail	"Sensor fails to detect temperature"
Failure Effect	Impact/consequence of failure	"Battery overheats, potential fire"
Failure Cause	Root cause of the failure	"Sensor contamination"
Failure Chain	Effect ← Mode ← Cause relationship	Links failures across hierarchy
Failure Net	Visual diagram of failure relationships	Shows cause-effect propagation
Local Effect	Impact at the component level	"Incorrect reading"
Next Higher Effect	Impact at subsystem level	"Thermal control malfunction"
End Effect	Impact at system/customer level	"Vehicle shutdown, stranded customer"

Step 5: Risk Analysis Terms

Term	Definition
Severity (S)	How serious is the effect? (1-10)
Occurrence (O)	How often might the cause happen? (1-10)
Detection (D)	How well can we detect the cause/mode? (1-10)
RPN	Risk Priority Number = S × O × D (1-1000)
Action Priority (AP)	Modern priority rating (High/Medium/Low)
Prevention Control (PC)	Control that prevents the cause from occurring
Detection Control (DC)	Control that detects the cause or failure mode
Current Controls	Existing prevention/detection measures
Filter Code	Indicates if failure is addressed by another FMEA

Step 6: Optimization Terms

Term	Definition
Preventive Action	Action to reduce Occurrence (O)
Detection Action	Action to improve Detection (D)
Design Change	Modification to product design
Process Change	Modification to manufacturing process
Control Added	New prevention or detection control
Responsible Person	Owner of the action item
Target Completion Date	When action should be complete
Status	Pending → In Progress → Completed
Effectiveness	Did the action reduce risk as expected?
Revised Ratings	New S/O/D after action implementation

Step 7: Documentation Terms

Term	Definition
FMEA Header	Project info, team, dates, scope
FMEA Worksheet	Standard form with all failure analysis
FMEA Form Sheet	Official AIAG-VDA format document
Action Status Report	Progress on optimization actions
FMEA-ID	Unique identifier for the analysis
Revision Level	Version number of the FMEA
Baseline	Snapshot of FMEA at a point in time
Sign-off	Formal approval of the FMEA

FMEA Types

Type	Full Name	Focus Area	When to Use
DFMEA	Design FMEA	Product/design failures	During product design
PFMEA	Process FMEA	Manufacturing/process failures	During process design
FMEA-MSR	Monitoring & System Response	Diagnostic/monitoring failures	For safety monitoring systems
SFMEA	System FMEA	Top-level system failures	Early concept phase

Compliance Standards Reference

Standard	Industry	Focus	Safety Levels
AIAG-VDA	Automotive	FMEA methodology	Action Priority (H/M/L)
ISO 26262	Automotive	Functional safety	ASIL (QM, A, B, C, D)
DO-178C	Aerospace	Software	DAL (A, B, C, D, E)
IEC 62304	Medical	Software lifecycle	Class (A, B, C)
IEC 61508	Industrial	Functional safety	SIL (1, 2, 3, 4)

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Quick Decision Tree

"What FMEA type should I use?"

Is it a design or manufacturing issue?
├─ Design → DFMEA
│   Example: "Component may fail under stress"
│
├─ Manufacturing → PFMEA
│   Example: "Weld may be incomplete"
│
└─ System monitoring → FMEA-MSR
    Example: "Sensor may not detect failure"

"Is this High Priority?"

Is Severity ≥ 9?
├─ YES → HIGH PRIORITY (regardless of O/D)
│
└─ NO → Is Severity ≥ 7?
    ├─ YES → Is Occurrence ≥ 4 OR Detection ≥ 4?
    │   ├─ YES → HIGH PRIORITY
    │   └─ NO → Check Medium Priority rules
    │
    └─ NO → Probably Medium or Low Priority

Integration Points

Links to Requirements: Trace failures to requirements Links to Tests: Verify detection methods Links to Jira: Create action tickets Links to Slack: Notify team of high-priority failures Links to Git: Reference design change commits

Support

Documentation: FMEA Overview Tutorials: Creating Advanced FMEA Help: Contact support or use in-app chat