Composite Fiberglass Filter Paper: What’s Actually Changing on the Factory Floor

If you’re speccing an air, oil-mist, or liquid coalescing line right now, you’ve probably bumped into composite fiberglass filter paper. To be honest, it has moved from niche to default in many projects—mostly because engineers are chasing higher capture at lower ΔP without paying a penalty in service life.

Industry trend check

Three things I keep hearing: tighter micron control (um1–um30), migration to multi-layer microglass + PET scrims, and cert-ready documentation for ISO 16890/ASHRAE 52.2. Surprisingly, even oil-gas separators are borrowing HEPA-style test language to compare apples to apples.

What it is (and why it works)

Composite fiberglass filter paper blends micro-glass fiber layers with PET nonwoven reinforcement and a resin system—usually acrylic or epoxy—calendered for pore-size control. The result: high efficiency on submicron aerosols, decent dust holding, and mechanical stability in cartridges and pleats.

Typical specs (project-level)

Grade	Nominal Cut	Basis Weight	Initial ΔP	Efficiency	Max Temp
UM1	≈1 µm	85–110 g/m²	80–110 Pa @ 5.3 cm/s	≥99.95% @ 0.3 µm	120–150°C
UM5	≈5 µm	120–160 g/m²	60–90 Pa	95–99% @ MPPS	120–150°C
UM30	≈30 µm	160–220 g/m²	40–70 Pa	70–90% (coarse)	120–150°C

Real-world use may vary by pleat height, resin %, and face velocity. Many customers say UM5 hits a sweet spot for oil-mist coalescers.

Process flow and QA

Composite fiberglass filter paper production (Handan, Hebei, China, Second Building and Studying No21 Shiji Street):

• Raw materials: micro-glass fibers, PET nonwoven scrim, acrylic/epoxy binder.
• Wet-laid forming → multilayer lamination → resin impregnation → calendering → curing → slitting.
• Testing: ISO 16890 or ASHRAE 52.2 (air), ISO 29463 for HEPA tiers, ISO 12500 for oil aerosol, ASTM D2986 for particle penetration/ΔP.
• Service life: HVAC 6–18 months; oil-mist coalescers 2–6 months; liquid polishing 1–3 months (depending on load).

Applications and advantages

Use it in oil-gas separation, liquid polishing, cleanroom pre-HEPA stages, compressor intake filters, lab fume capture. Advantages: high capture of submicron aerosols, stable pleatability, lower initial ΔP, and predictable loading curve. Actually, it also holds up nicely at elevated temps up to ~150°C.

Vendor snapshot (quick comparison)

Vendor	Media Type	Certs	Lead Time	Notes
FiltersMaterial (Hebei)	Micro-glass/PET composite	ISO 9001; RoHS/REACH	2–4 weeks	Custom um1–um30, roll or cut.
Global OEM A	Glass + synthetic blends	ISO 16890 reports	4–6 weeks	Strong HEPA/ULPA lineup.
EU Supplier B	Coalescing media	CE, ISO 12500 data	3–5 weeks	Premium pricing, low MOQ.

Customization, testing, and a quick data point

You can dial fiber diameter, binder %, and PET scrim weight to balance stiffness vs. permeability. For one customer, a UM5 variant with 6% acrylic binder cut initial ΔP by ~12% while maintaining 99.5% @ 0.3 µm (ISO 29463 MPPS); dust-holding improved ~9% on an ASHRAE 52.2 loading curve. It seems that minor calendering tweaks matter more than most expect.

• Certs: ISO 9001; material RoHS/REACH compliant.
• Formats: 500–1000 mm roll widths, cut sheets, pleatable packs.
• Traceability: lot-based test reports attached to each shipment.

Mini case notes

– Electronics plant (SEA): swapped in composite fiberglass filter paper pre-HEPA; ΔP dropped ~18 Pa, HEPA life extended ~5 months.

– CNC shop (EU): oil-mist coalescing stage using composite fiberglass filter paper UM5; 30% fewer changeouts over 10 months.

– Food packaging (NA): liquid polishing with composite fiberglass filter paper UM10; clearer effluent, ISO 4406 improved from 18/16/13 to 16/14/11.

Where to start

If you’re unsure, spec UM5 or UM10, face velocity 5.3–8.5 cm/s, and request ISO 16890 or ISO 12500 test sheets. And, yes, ask for calendering parameters—small changes, big results.

Authoritative references

1. ISO 16890: Air filters for general ventilation.
2. ASHRAE 52.2: Method of Testing General Ventilation Air-Cleaning Devices.
3. ISO 29463: High-efficiency filters and filter media for removing particles from air.
4. ISO 12500: Filters for compressed air—Test methods for oil aerosols and vapors.
5. ASTM D2986: Standard Test Method for Airflow and Particle Penetration of Filter Media.