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How to Choose HEPA Filter for FFU？ A Complete Buying Guide

2026-04-24

Introduction

A Fan Filter Unit (FFU) is only as good as the HEPA filter inside it. The filter determines the cleanroom class, energy consumption, and replacement frequency. Choosing the wrong HEPA filter can lead to:

Failed certification (ISO 14644)

Higher energy bills

Frequent filter changes

Contamination risks

This guide walks you through exactly how to select the right HEPA filter for your FFU – whether you are a cleanroom contractor, lab manager, or overseas distributor.

dernière affaire concernant How to Choose HEPA Filter for FFU？ A Complete Buying Guide 0

Step 1: Understand HEPA Filter Efficiency Grades

HEPA filters are rated by their efficiency at capturing 0.3 micron particles. For FFUs, two grades are common:

Grade	Efficiency (0.3μm)	Typical Cleanroom Class	Application
H13	99.95%	ISO 5 – ISO 8	General manufacturing, labs
H14	99.995%	ISO 5 (critical)	Pharma, hospitals, microelectronics
U15	99.9995%	ISO 4 or cleaner	Semiconductor (rare for standard FFU)

Recommendation:

For most FFU applications → H13 (best balance of cost and performance)

For strict GMP or sterile areas → H14

Avoid U15 – unnecessary for standard cleanrooms, increases fan load

�� Related: HEPA vs ULPA – Key Differences

dernière affaire concernant How to Choose HEPA Filter for FFU？ A Complete Buying Guide 1

Step 2: Match Filter Dimensions to Your FFU Housing

FFUs come in standard sizes, but not all HEPA filters are interchangeable.

Common FFU filter sizes (nominal):

Width x Height	Depth	Typical Use
610 x 610 mm (2‘ x 2’)	70 / 90 mm	Standard ceiling grid
1220 x 610 mm (4‘ x 2’)	70 / 90 mm	Larger FFU modules
1170 x 570 mm	70 mm	European standard

Check these before buying:

Actual dimensions (some brands use metric vs imperial)

Gasket type and location

Frame material compatibility

Always request a filter drawing from your FFU supplier before ordering replacements.

dernière affaire concernant How to Choose HEPA Filter for FFU？ A Complete Buying Guide 2

Step 3: Choose the Right Frame Material

The filter frame must fit the FFU housing and withstand the operating environment.

Frame Material	Pros	Cons	Best For
Galvanized steel	Low cost, rigid	Can rust in humid areas	Dry manufacturing, labs
Stainless steel 304	Corrosion resistant	Higher cost	Pharma, food, wet areas
Aluminum	Lightweight	Less rigid	Portable FFUs
Plastic / ABS	Cheap, disposable	Short life	Low-cost, single-use

For most FFUs → Galvanized steel is fine.
For pharmaceutical or coastal environments → Stainless steel 304.

Step 4: Select the Correct Sealing Method

The seal between the HEPA filter and FFU housing prevents bypass leakage. Three common types:

Seal Type	How It Works	Leak Risk	Typical Use
Gel seal (liquid)	Filter sits into gel-filled channel	Very low	Pharma, ISO 5 cleanrooms
Knife edge	Metal blade compresses gasket	Low	Standard cleanrooms
Gasket (compression)	Foam/rubber compressed	Medium	Non-critical FFUs

Recommendation:

Gel seal – for critical areas where zero leak is required

Knife edge – best balance for most FFU applications

Gasket – acceptable for low-cost FFUs (ISO 7/8)

Step 5: Pay Attention to Pressure Drop (Initial Resistance)

Pressure drop affects fan energy consumption and filter lifespan.

Filter Type	Initial Pressure Drop (Pa) at rated airflow
Mini-pleat H13 (70mm)	120 – 180 Pa
Mini-pleat H14 (70mm)	180 – 250 Pa
Deep-pleat H13 (150mm)	80 – 120 Pa

Rule of thumb:

Lower pressure drop = lower energy cost and quieter operation

But mini-pleat filters are more compact (better for shallow FFUs)

Most FFUs are designed for 70mm or 90mm deep HEPA filters. Check your FFU housing depth first.

Step 6: Check Certifications and Test Reports

For serious projects (especially export), your HEPA filter must come with documentation.

Required documents:

Individual efficiency test report (scan test or MPPS)

Leak test report (PAO / DOP)

Pressure drop measurement

Frame material certificate (if stainless steel)

Standards to look for:

EN 1822 (European)

IEST RP-CC001 (US)

ISO 29463

�� Never buy HEPA filters without individual test reports – your cleanroom may fail certification.

Step 7: Consider Application-Specific Requirements

Different industries need different filter features.

Industry	Key Requirement	Recommended Filter
Electronics / Semiconductor	Low outgassing, ESD safe	H13 with aluminum separator
Pharmaceutical / GMP	Stainless steel frame, gel seal	H14 stainless + gel
Hospital (OR / ICU)	Low noise, high reliability	H13 deep-pleat
Food processing	Washable frame option	Stainless steel 316
General manufacturing	Cost-effective	H13 galvanized + gasket seal

Quick Selection Checklist (Printable)

Before ordering HEPA filters for FFUs, answer these 5 questions:

What cleanroom class do you need? → ISO 5 (H14) or ISO 6-8 (H13)What is your FFU model / filter dimension? → Check existing filter label

What is your budget? → H13 is 20-30% cheaper than H14

Do you need gel seal or knife edge? → Pharma = gel； General = knife edge

Do you require individual test reports? → Always yes for export projects

Why Choose Prefab Cleanroom for FFU HEPA Filters?

At prefabcleanroom.com, we supply replacement HEPA filters for all major FFU brands:

✅ H13 and H14 grades (EN1822 certified)

✅ Standard sizes: 610x610, 1220x610, 1170x570 mm

✅ Gel seal, knife edge, or gasket options

✅ Galvanized steel or stainless steel 304 frames

✅ Individual test report with every filter

✅ Fast shipping worldwide

We work with cleanroom contractors, facility managers, and overseas distributors.

Ready to Order Your FFU HEPA Filters?

Send us the following information for a quick quote:

Filter size (L x W x H)

Efficiency grade (H13 or H14)

Frame material

Seal type

Quantity

�� Email: sales01@gzkunling.com
�� WhatsApp: +86 13316272504

Volume discounts available for contractors and distributors.

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