AI-generated content notice: This article was drafted with the assistance of an AI language model and reviewed by KOSA. Technical specifications are provided for reference only.
Chemical engineers routinely specify air filtration for environments where 0.1 micron particulate control, 250 °C continuous operating temperature, and 1200 Pa maximum pressure drop intersect with ISO leakage limits. These parameters drive material selection, structural integrity, and sealing methodology across the Air & HVAC Filtration range. Corrosion resistance is non-negotiable when handling halogenated solvents or amine-based process vapors; emission control hinges on consistent filter media integrity under thermal cycling and humidity swings.
Material Compatibility Under Process Stress
316L stainless steel frames and hardware are standard across all Air & HVAC Filtration products. This choice directly addresses chemical compatibility concerns in aggressive vapor-phase environments. Unlike carbon steel or aluminum, 316L resists pitting from chloride-laden air streams and maintains tensile strength above 200 °C. The GY High Efficiency air filter with separator and GD High Efficiency filter for high temperature and high air flow both use laser-welded 316L housings to eliminate crevice corrosion pathways at joints. In our experience, welded seams reduce field-reported leakage incidents by eliminating gasket compression variability.
Sealing Architecture and Emission Control
Gel Sealant Mini-Pleated HEPA ULPA Filters (H13 to U16) employ a dual-seal design: silicone gel applied to the frame flange plus a secondary mechanical interlock against the housing. This configuration meets ISO Class A requirements for fugitive emissions when installed per manufacturer torque specifications. The Rigid pleated box HEPA filter relies on elastomeric gaskets compressed between machined 316L faces — effective but sensitive to panel flatness and mounting bolt sequence. Both approaches require verification of seal compression via torque wrench calibration, not visual inspection alone.
Thermal and Flow Trade-offs
The GW High Efficiency air filter without separators offers lower initial resistance than its GY counterpart — a measurable advantage for energy recovery systems. However, this design presents a trade-off: reduced structural rigidity at elevated temperatures. At 230 °C, the GW’s frame deflection increases 40% more than the GY’s under identical 1.8 m/s face velocity. That drawback becomes critical in recirculating cleanroom loops where long-term dimensional stability affects uniform airflow distribution. Chemical engineers must weigh pressure drop savings against potential requalification cycles caused by frame creep.
Filter Media Options and Application Limits
PP melt blown filter fabric delivers high efficiency at low cost but degrades rapidly above 85 °C and dissolves in ketones and esters. Photocatalytic filter paper enables VOC oxidation but requires UV activation and shows irreversible capacity loss after exposure to sulfur compounds. SCD Pass Box and SFL Air Shower housings integrate only 316L-compatible media — no PP spunbond non woven fabric or photocatalytic layers — to maintain ATEX compliance in classified zones. This selection does not apply where solvent-laden exhaust streams contact filter media directly; avoid using PP melt blown filter fabric or photocatalytic filter paper in such applications.
| Product | Max Temp (°C) | Media Type | ISO Compliant | ATEX Zone Suitability |
|---|---|---|---|---|
| H13 to U16 Gel Sealant Mini-Pleated HEPA ULPA Filter | 120 | Glass fiber | Yes | Zone 2 |
| GD High Efficiency filter for high temperature and high air flow | 250 | Specialized glass fiber | Yes | Zone 2 |
| PP melt blown filter fabric | 85 | Polypropylene | No | Not rated |
The table confirms thermal and regulatory boundaries.
- Verify chemical compatibility using vendor-supplied resistance charts — never assume equivalence across polymer families.
- Confirm ATEX zone classification matches both housing construction and filter media ignition properties.
- Request test reports for ISO testing conducted on full-assembled units, not just frame/gasket subassemblies.
On site, we typically observe that FFU installations in chemical cleanrooms fail validation most often due to uncontrolled upstream turbulence — not filter media defects. The SGZW Level Clean Bench and Fan Filter Unit (FFU) both require straight-run ducting ≥12 duct diameters upstream to stabilize velocity profiles before the filter face. For retrofit projects where space limits duct length, the G2 metal Nylon Mesh Filter serves as an effective pre-filter to dampen swirl and reduce localized loading on downstream M5 to F9 Synthetic Fiber Multi-Pockets Filter banks. This pairing extends service life without altering final-stage efficiency ratings.
For fluid-handling systems requiring comparable corrosion resistance, consult our Liquid Filtration line. For particulate capture in corrosive flue gas streams, review the Dust & Flue-Gas Filtration portfolio. All Air & HVAC Filtration products share the same 316L base material specification, enabling consistent metallurgical traceability across facility-wide procurement. Material certificates should reference mill test reports, not internal QA summaries.
Common questions on air & hvac filtration
When should a pocket bag filter be replaced by a HEPA panel?
They do different jobs. Pocket bags at M5 to F9 carry the bulk of the dust load and protect the final stage, while an H13 to U16 panel only performs if the stages ahead of it are doing their work. Moving the bag stage out of the train shortens panel life rather than extending it.
What separates sharp edge from gel sealant mini-pleated panels?
Both are offered from H13 to U16. The sharp edge version uses an extruded anodised aluminium frame with hot-melt glue separators and a polyurethane sealant; the gel sealant version seals the media pack differently into the frame, which changes how the panel seats in the housing and how it is changed out.
How do I know when a final filter is finished?
The panel is retired at 300 Pa and a pocket bag at 450 Pa, both read on the differential pressure gauge that serves the rest of the train. Continuous service is limited to 90 ºC on both formats, so a reading above that points at the duty rather than at the filter.