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ULPA vs. HEPA Filters: Which One is Right for Your Cleanroom?

  Encompass  ·  4 minute read
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When it comes to contamination control, no component is more critical than your cleanroom air filtration system. Cleanroom filters are designed to remove microscopic airborne contaminants that could compromise sensitive processes or products. Among the most trusted filtration options are Ultra-Low Penetration Air (ULPA) and High-Efficiency Particulate Air (HEPA) filters. 

Both are engineered to meet high-performance standards and are commonly used in cleanrooms, but each has distinct characteristics that may make it more suitable depending on your specific process, application, and compliance requirements.

ULPA and HEPA filters most notably differ in filtration efficiency, airflow capacity, lifespan, and cost. Understanding their unique benefits is essential during the cleanroom design and construction process, as choosing the right filter can impact everything from operational efficiency to regulatory compliance.

An Overview of Cleanroom Air Filtration Options

What Are Cleanroom HEPA Filters?

HEPA filters are constructed using a dense mat of microporous fibers that physically trap airborne particles. These filters must meet stringent EPA performance criteria—removing at least 99.97% of airborne particles measuring 0.3 micron or larger.

Known for reliability, longevity, and affordability, HEPA filters are a standard choice across a wide range of cleanroom environments. Their higher airflow capabilities make them particularly well-suited for applications that prioritize energy efficiency and lower operational resistance.

Here’s an overview of typical cleanroom HEPA filters:

  • Compliance: Often sufficient for cleanrooms that fall under ISO 5-8 standards.
  • Filtration: 99.97% at 0.3 microns, though many HEPA filters perform up to 99.999%.
  • Airflow: Less restrictive filter translates to 20-50% higher capacity than ULPA filters.
  • Lifespan: Approximately 7-10 years, depending on maintenance practices and environmental conditions.
  • Cost: Lower filtration threshold makes them more economical than ULPA filters.

What Are Cleanroom ULPA Filters?

ULPA filters offer even finer filtration capabilities than HEPA filters. Designed to trap extremely small particles, ULPA filters can remove 99.999% of particles as small as 0.12 microns, making them ideal for ultra-critical cleanroom applications that demand the highest levels of cleanliness.

The tradeoff for this superior filtration is reduced airflow and higher system resistance. As a result, ULPA filters are typically used in applications where maximum air purity is critical and airflow requirements can be adjusted accordingly.

Here’s an overview of typical cleanroom ULPA filters:

  • Compliance: Commonly specified for ISO 3-4 cleanrooms with stringent requirements.
  • Filtration: 99.999% at 0.12 microns or larger.
  • Airflow: Denser filtering material means 20-50% lower capacity than HEPA filters.
  • Lifespan: Approximately 5-8 years, depending on maintenance practices and environmental conditions.
  • Cost: Usually a larger investment than HEPA filters due to enhanced performance.

Comparing ULPA vs. HEPA Filters for Your Application

Selecting between ULPA vs. HEPA filters requires a careful assessment of your cleanroom classification, the nature of your manufacturing or research process, and your energy efficiency goals. To help you compare the two options, the following chart summarizes the key performance differences we discussed:

Criteria

HEPA Filters

ULPA Filters

Filtration Efficiency

99.97% at 0.3 µm

99.999% at 0.12 µm

Airflow Capacity

Higher, due to less dense media

Lower, due to denser filtration

Energy Efficiency

More efficient—requires less fan power

Less efficient—more fan energy required

Lifespan

7-10 years (with proper maintenance)

5-8 years (subject to airflow and particulate load)

Cost

More budget-friendly

More expensive to install and operate

Cleanroom Compatibility

ISO Classes 5-8

ISO Classes 3-4

Typical Applications

Pharmaceutical manufacturing, medical device assembly, general electronics

Semiconductor fabrication, nanotechnology, aerospace microassembly

Best Use Case

Broad, everyday use with solid contamination control

Localized ultraclean zones or recirculated environments with ultra-fine particle control

In short, HEPA filters remain the go-to for most cleanroom operations balancing compliance, cost-efficiency, and longevity. ULPA filters may be necessary in laminar flow hoods, containment systems, or isolation rooms where ultrapure air within a limited volume is critical.

How to Select a Cleanroom Air Filtration System

Choosing between ULPA vs. HEPA filters isn’t just about filtration specs—it’s about understanding your larger cleanroom ecosystem. When evaluating your specific needs, consider these factors:

  • Cleanroom Classification: Use HEPA filters for ISO Class 5-8 cleanrooms. For ISO Class 3-4, ULPA may be required.
  • Industry Standards & Regulations: Industries like microelectronics and semiconductor manufacturing may necessitate ULPA filtration due to contamination sensitivity.
  • Process Requirements: Consider the criticality of your process and the size of particles that must be captured. High-precision or aseptic environments may need ULPA filters.
  • Budget & Operating Costs: ULPA filters offer greater efficiency but often at higher upfront and ongoing costs.

If you’re still unsure whether to choose ULPA vs. HEPA filters, it may be time to consult cleanroom experts for guidance. The technical team at Encompass Cleanrooms is well-versed in customizing cleanroom air filtration​ systems for your specific process requirements. Our recommendations are rooted in industry best practices, compliance standards, cost-efficiency, and long-term performance.

How to Properly Maintain Your Cleanroom Filters

Whether you choose ULPA or HEPA filters, you should conduct regular maintenance to ensure ongoing cleanroom performance. Over time, filters experience increased backpressure as particles accumulate, which reduces airflow and can put a strain on your HVAC system.

Keep in mind these best practices for filter maintenance:

  • Pre-Filtration: Consider installing coarse prefilters upstream to capture larger particles. This extends the lifespan of ULPA or HEPA filters and reduces pressure-related energy costs.
  • Routine Monitoring: Track airflow rates and pressure differentials to detect filter degradation early.
  • Scheduled Inspections: Replace filters based on usage data and environmental conditions rather than waiting for visible contamination.
  • Environmental Controls: Keep surrounding areas clean to minimize the introduction of particulates that could prematurely clog filters.

ULPA filters, in particular, require close attention, as their shorter lifespan and higher pressure drops can make them more expensive to maintain if not managed properly. 

Considering ULPA vs. HEPA Filters for Your Cleanroom?

At Encompass Cleanrooms, we understand how vital air filtration is to your cleanroom’s performance and compliance. Whether you’re designing a new contamination-free environment or upgrading your current space, our experienced engineers can help you compare ULPA vs. HEPA filters and implement the right cleanroom air filtration system.

Reach out to Encompass Cleanrooms today to speak with our technical specialists and get the tailored support you need to ensure cleanroom air quality that meets or exceeds industry standards. We’re here to guide you every step of the way.