Select an ULPA filter when the process or approved design requires its lower permitted particle penetration, and match the selected element to its housing and operating airflow. A higher filter class alone does not establish a cleaner room. For an existing installation, the useful comparison is between complete, compatible selections: filter performance, seal arrangement, fan duty and the evidence needed at handover.
This distinction matters when replacing a ceiling filter, ordering a fan filter unit or buying a modular enclosure. A panel can fit the opening and still be unsuitable for the installation. Conversely, buying the highest available class can add cost without addressing the reason that particles reach the work.
Filter class and room class answer different questions
EN 1822 classifies high-efficiency filter elements using integral and local performance criteria. H13 and H14 are HEPA classes; U15 is an ULPA class. The integral efficiency criteria at the most penetrating particle size, or MPPS, are:
| Class | Minimum integral efficiency at MPPS | Maximum integral penetration at MPPS |
|---|---|---|
| H13 | 99.95% | 0.05% |
| H14 | 99.995% | 0.005% |
| U15 | 99.9995% | 0.0005% |
These are classification thresholds, not measured results for every filter offered by shengtongJH. Local leakage criteria also apply; an overall efficiency number is not the complete test specification. See MANN+HUMMEL's EN 1822 classification explanation.
The extra decimal places describe a substantial difference in penetration: the U15 limit above is one tenth of the H14 limit. That arithmetic does not mean that changing H14 to U15 will reduce the room's particle concentration by the same factor. Room classification concerns measured airborne particle concentrations at defined sampling locations, as described in ISO 14644-1. Filter class and room class are different acceptance criteria.
Where is the installation failing?
Before specifying an upgrade, separate three situations. A documented filter-class requirement calls for a compatible element with the required evidence. An unexplained deterioration calls for investigation of the installed system. A new workstation calls for a decision about the area that actually needs controlled air. Treating all three as an order for a higher-grade panel can leave the original problem unresolved.
- The existing room performs as intended, but filters need replacement
- Use the approved filter schedule as the starting point. Preserve the relevant interfaces and acceptance requirements. A different class is a design change to assess, rather than an automatic improvement.
- Particles increased after a replacement
- Review the replacement identity, installation and test records before ordering another grade. The timing makes the changed assembly a useful investigation point, but does not by itself prove a defective filter.
- A new exposed process needs protection
- Define where the product is exposed and how operators and equipment use that space. A local clean-air arrangement and a whole-room installation have different supply boundaries. Specify the required result before selecting the equipment format.
Compare the assembly, not just the label
A practical quotation comparison should keep these items on the same line of the purchasing schedule:
- Filter and housing interface: element dimensions, frame depth, gasket or gel arrangement, seal location and retention method. A drawing of the existing housing is more useful than a nominal panel size alone.
- Operating airflow: compare pressure-drop information at the intended flow, together with the available fan duty. An isolated resistance number without a flow condition cannot describe the installed operating point.
- Replacement access: identify the removal side and the space needed to withdraw the element. Include the route for the packaged replacement, not only the ceiling opening.
- Acceptance evidence: distinguish the individual element's factory report from the agreed tests after installation. State who supplies each record and who performs the site work.
Factory testing evaluates the filter element under stated conditions. Camfil explains why individual testing and MPPS performance matter. It should not be presented as a site acceptance report for a completed room.
For controlled rooms and zones, ISO 14644-3 describes performance test methods and distinguishes as-built, at-rest and operational states. The purchase specification should identify the relevant state and agreed tests. An empty-room result should not silently become a promise about production with people and equipment operating.
Turn the requirement into a useful enquiry
For a replacement, send the existing filter label, housing drawing, quantity, operating flow and acceptance requirements. For a new installation, add the process layout and the part of the work that needs particle control. This lets the supply discussion identify whether the requirement is for an element, a housing, a fan-powered unit or a wider equipment package.
Compare mini-pleat HEPA filters with ULPA filter options when the element class is the decision. For a fan-powered assembly, review the fan filter unit and its connection requirements. shengtongJH is an equipment and materials sourcing business; configuration and documentation need to match the selected supply scope. Send the application and interface requirements to discuss a configuration for your operating conditions.