HEPA and ULPA Filters: Differences and Selection Guide

In cleanrooms and clean environments, HEPA (High Efficiency Particulate Air) and ULPA (Ultra Low Penetration Air) filters are core components for maintaining air cleanliness. According to EN 1822 and ISO 29463 standards, HEPA filters encompass H13 (≥99.95%@MPPS) and H14 (≥99.995%@MPPS) grades; ULPA includes U15 (≥99.9995%), U16 (≥99.99995%), and U17 (≥99.999995%) grades. MPPS here refers to "Most Penetrating Particle Size," typically ranging between 0.1-0.3μm.

The core difference between the two lies in trade-off between filtration efficiency and pressure drop. Using Baisheng Technology's products as examples, 610×610×292mm H14 HEPA at rated airflow 1000 CMH has initial pressure drop of approximately 220 Pa, while same-size U15 ULPA reaches 280 Pa, approximately 27% higher. Higher pressure drop means fans require greater power to push air through the filter, directly increasing energy consumption costs.

Choosing HEPA or ULPA should depend on required cleanroom grade. ISO 14644-1 defined ISO Class 5 (equivalent to US Class 100) environments can satisfy requirements with H14 HEPA; ISO Class 3 and below super-clean environments (such as advanced semiconductor lithography areas) must use U15 or U16 ULPA. ISO Class 6-7 general cleanrooms can even be satisfied with H13 HEPA alone.

Practical selection recommendations: First, do not blindly pursue highest grade—over-specification increases initial procurement costs and long-term maintenance expenses. Second, pay attention to filter leakage test results—meeting overall efficiency does not mean no local leakage; request suppliers provide per-unit scan test reports (Scan Test per EN 1822-4). Third, consider system fan curve and filter terminal pressure drop matching; recommend setting terminal pressure drop at 2-2.5 times initial pressure drop as replacement timing. Baisheng Technology provides complete product line from H13 to U16 high-efficiency filters, and can provide customized sizes and frame material options based on customer requirements.