| 1 | Define the contaminant and its risk | Identify whether the target is dirt, rust, process solids, catalyst fines, microorganisms, or another contaminant. | Specify particle type, concentration, shape, and allowable downstream loading. | Micron size alone does not describe particle hardness, density, compressibility, or the damage it may cause. |
| 2 | Set the nominal or absolute micron basis | Confirm whether the supplier’s micron rating is nominal, absolute, or associated with a defined test method. | Use an ISO 16889 beta rating when a quantified particle-removal target is required. | Different rating conventions can produce substantially different results at the same stated micron size. |
| 3 | Translate efficiency into a beta ratio | Use the ISO 16889 multi-pass particle-counting relationship at the selected particle size. | Efficiency = 1 − 1/β 99.0% = βx 100 99.9% = βx 1,000 | A beta ratio gives a numerical basis for comparing filtration performance rather than relying on a vague “fine filter” description. |
| 4 | Choose the particle-size test point | Check the subscript in βx, where x represents the particle size in micrometres used for the rating. | Example: β10 ≥ 1,000 means at least 99.9% efficiency for particles measured at 10 µm under the stated test conditions. | β10 does not automatically prove β5 or β20 performance. The test size must match the process risk. |
| 5 | Balance protection and pressure drop | Compare clean pressure drop, allowable final pressure drop, fluid viscosity, and operating temperature. | Select a housing and element combination that remains within the equipment’s pressure-drop limit at maximum flow. | A tighter filter may improve particle removal but can increase energy use and shorten service life if undersized. |
| 6 | Size for flow and viscosity | Use maximum, normal, and minimum flow rates together with the fluid’s operating viscosity and density. | Size from the element’s verified flow-versus-pressure-drop data, not from connection size alone. | High-viscosity fluids generally create higher pressure drop and may require more filtration area or a larger housing. |
| 7 | Verify pressure and temperature ratings | Check maximum allowable working pressure, design temperature, differential-pressure rating, and any derating requirements. | The housing rating must exceed the highest credible operating and upset conditions. | Pressure and temperature limits apply to the complete assembly, including seals, clamps, covers, and element supports. |
| 8 | Match materials and seal compatibility | Review fluid chemistry, pH, solvents, oxidizers, temperature, and cleaning or sanitization chemicals. | Confirm wetted-material and seal compatibility using documented chemical-resistance data. | Material incompatibility can cause swelling, embrittlement, corrosion, leakage, or contamination of the process fluid. |
| 9 | Plan installation and maintenance | Check element length, closure type, orientation, drain and vent locations, access clearance, and replacement procedure. | Provide isolation, depressurization, venting, draining, and a differential-pressure monitoring point where appropriate. | Safe access and reliable change-out procedures reduce downtime and prevent exposure to trapped pressure or hazardous fluids. |
| 10 | Request complete performance documentation | Ask for the test method, beta ratio, rated particle size, flow conditions, test fluid, pressure-drop data, and material specifications. | For a 99.9% target, specify βx ≥ 1,000 at the selected x-micrometre test point and verify application suitability. | Documented test conditions make performance claims traceable and prevent direct comparison of incompatible ratings. |