| 1 | Drinking-water safety compliance | China’s GB/T 17219-1998 Standard for Safety Evaluation of Equipment and Protective Materials in Drinking Water Systems is a commonly referenced safety-evaluation standard. | Applicable to materials and equipment that may contact drinking water; compliance evidence should be checked for the complete filter assembly. | Request test reports covering the housing, sealing materials, filter media, and any wetted components rather than only the filter cartridge. |
| 2 | Finished-water quality benchmark | China’s GB 5749-2022 Standard for Drinking Water replaced the 2006 edition and took effect on April 1, 2023. | The standard covers microbiological, toxicological, sensory, chemical, and radioactive indicators for drinking water. | Filter performance should be assessed against the intended incoming-water contaminants and the required finished-water quality, not only against turbidity reduction. |
| 3 | International certification route | NSF/ANSI 42 addresses aesthetic effects such as chlorine, taste, and odor; NSF/ANSI 53 addresses specific health-effect claims. | Certification is claim-specific. A product certified for one contaminant or function is not automatically certified for every contaminant. | For export projects, verify the exact model, cartridge configuration, contaminant claim, flow rate, and certificate scope. |
| 4 | Sediment-removal capability | Sediment filters are generally used as prefiltration for suspended particles such as sand, rust, and silt. | Common commercial specifications include nominal or absolute particle ratings expressed in micrometres; the rating must be defined by the supplier’s test method. | Compare particle-rating definitions, pressure drop, dirt-holding capacity, and replacement cost instead of comparing the micron number alone. |
| 5 | Activated-carbon treatment | Granular activated carbon and carbon block media are widely used for reducing chlorine, taste, and odor under suitable operating conditions. | Performance depends on carbon type, contact time, water chemistry, flow rate, and contaminant concentration; there is no universal removal percentage. | Require contaminant-specific test data and a stated service-life basis rather than relying on the phrase “activated carbon filter.” |
| 6 | Membrane filtration option | Ultrafiltration, nanofiltration, and reverse osmosis are different membrane processes with different separation characteristics and operating requirements. | Membrane selection should consider nominal pore or molecular-weight characteristics, recovery, feed pressure, pretreatment, and concentrate handling. | Do not treat all membrane products as interchangeable; the correct process depends on the target contaminants and water pressure. |
| 7 | Hydraulic capacity | Flow capacity is determined by filter area, media depth, cartridge size, pressure differential, water temperature, and the specific filtration target. | Flow should be stated in a defined unit such as L/min or m³/h and tied to an inlet pressure, outlet pressure, and acceptable pressure drop. | Compare tested flow at the same pressure and water conditions; an unqualified maximum-flow figure is not suitable for system sizing. |
| 8 | Storage-tank compatibility | Tank-filter systems may be installed at the inlet, outlet, circulation loop, or point of use, depending on the water-use objective. | Key design variables include tank volume, turnover rate, connection size, available pressure, cleaning access, and whether continuous circulation is required. | A filter sized only by tank volume may be unsuitable; peak demand and required turnover time must also be calculated. |
| 9 | Maintenance and replacement basis | Replacement intervals vary with feed-water quality, daily consumption, filter capacity, disinfectant level, and pressure-drop limits. | A defensible service interval should be expressed by operating hours, treated volume, pressure differential, or verified contaminant breakthrough—not by a universal calendar period. | Include differential-pressure monitoring, sanitation procedures, spare-cartridge availability, and disposal requirements in the purchase specification. |
| 10 | Testing and documentation quality | Product comparisons should distinguish laboratory test results, third-party certification, factory quality-control records, and marketing claims. | Core documents include material declarations, test conditions, flow-versus-pressure data, contaminant-removal results, installation instructions, and traceability information. | Documentation completeness is a more reliable supplier-screening metric than catalogue claims or unverified “top manufacturer” labels. |