// EVALUATION FRAMEWORK · 5-STEP DECISION TREE

Filter Evaluation Framework

Shift from "which product?" to "what contamination target?" This 5-step framework prioritizes contamination control metrics (ISO 16889 Beta ratio, ISO 4406 cleanliness codes, bypass pressure) over brand or price.

Define Contamination Target (ISO 4406)

•What contamination mode threatens your equipment?
•What cleanliness code does equipment design require?
•What bypass pressure is safe?

Example: Heavy-duty truck engine: particle wear threat → target 16/14/11 cleanliness → 4.0 bar bypass

Select Filter Specification (ISO 16889)

•Beta ratio (particle capture efficiency): Beta₂₀ ≥200 minimum
•Absolute rating (largest particle passed): 18-micron (MACROCORE), 10-micron (NANOFORCE)
•Dirt capacity: 15g/L (standard), 25g/L (premium), 40g/L (extended)

Example: For 16/14/11 target, select Beta₂₀ ≥200 filter at 18-micron absolute with 25g/L capacity

Verify Bypass Valve Setting

•Does filter bypass valve match application pressure?
•Is bypass pressure ≥filter collapse rating?
•Does bypass threshold prevent uncontrolled contamination ingestion?

Example: Fuel filter SYNTAPORE: 3.0 bar bypass protects injectors from starvation during cold engine start

Establish Replacement Trigger (Condition-Based)

•Monitor differential pressure across filter
•Analyze oil/fuel samples at intervals
•Replace when cleanliness drifts from target

Example: Hydraulic system: replace proportional valve filter when ISO code exceeds 17/15/12 or pressure drops 3+ psi

Document System & Measure Impact

•Record baseline equipment condition
•Track maintenance intervals and downtime events
•Measure bearing life extension in operating hours

Example: After 24 months: engine bearing life extended from 3,000 to 18,000 hours; downtime reduced 75%

Quick Selection Matrix

Application	Threat	ISO Target	Beta₂₀ Min	Bypass (bar)
Lube Oil (HD Truck)	Particle wear	16/14/11	≥200	4.0
Hydraulic (Proportional)	Spool wear	16/14/11	≥200	3.5
Fuel (HPCR Injector)	Water stiction	17/15/12	≥200	3.0
Air Intake (Turbine)	Blade erosion	ISO 5011 Class 4	≥1000	N/A
Cabin Air (Health)	PM10 exposure	HEPA grade	≥1000	N/A