How do the ULPA ratings of EN 1822 and ISO 29463 correspond?

This problem occurs intensively when importing equipment, cross-border projects, or switching suppliers.

The contract on one side may be labeled 'U15', and the report on the other side may be labeled 'ISO 55 U'. Are these two talking about the same thing? They generally correspond, but they cannot be directly interchanged based only on letters and numbers. The corresponding prerequisites are: confirm the standard version, confirm the efficiency index caliber, and confirm the overall and partial judgment methods.

Ignoring these items and directly translating U15 into ISO 55 U may cause problems in the acceptance process.

The relationship between two sets of standards

Let’s first explain where they come from.

EN 1822 is a European standard, released in 1998, which established for the first time a high-efficiency filter classification system based on MPPS (most penetrating particle size). The set of markings U15, U16, and U17 come from EN 1822-1.

ISO 29463 is an international standard, first released in 2011. Its core content and classification method are derived from EN 1822 . ISO 29463 retains the three classification groups of EPA, HEPA, and ULPA, but replaces the original E10-E12, H13-H14, and U15-U17 with 13 levels from ISO 15 E to ISO 75 U.

ISO 29463 does not replace EN 1822. EN 1822-1 is still under revision and effective use. The relationship between the two is: EN 1822-1 retains its own classification table, but the test methods (Part 2 to Part 5) have been aligned with the ISO 29463 series.

Correspondence between ULPA grades

According to the public standard comparison table, the correspondence between U15, U16, U17 and ISO 29463 levels is roughly as follows:

This correspondence is consistent across multiple standards sources and industry literature.

But 'correspondence' does not mean 'interchangeable annotation'. U15 and ISO 55 U point to the same level in terms of efficiency indicators, but their standard versions, reference terms and local judgment requirements may not be exactly the same. The contract is written as U15, and the report is written as ISO 55 U. During acceptance, you should first confirm whether the indicators on both sides are comparable under the same caliber.

What to look for when checking

If the project involves the mixing of two standards, it is recommended to check these items:

Standard version. EN 1822-1 has a 2019 version and a 2026 version that is being revised. ISO 29463-1 has 2011, 2017 and 2024 versions. Different versions may have different details.

Caliber for judging overall efficiency. Both sets of standards are based on MPPS efficiency, but which MPPS range and test air volume are marked on the report need to be confirmed. MPPS is not a fixed value, and the glass fiber filter material is usually between 0.12 and 0.25 microns.

local efficiency requirements. HEPA and ULPA grades (Group H and U) need to meet both global and local efficiency requirements. Local judgment cannot be omitted. In ISO 29463, the local efficiency limit of ULPA is also linked to the overall efficiency.

detection method. ISO 29463-1 lists five leak detection methods, EN 1822-1 specifies only three, and specifically excludes the aerosol photometer method. If the procurement document refers to EN 1822, the selection of test methods is narrower than ISO 29463.

What to do when files are inconsistent

When contracts, drawings, labels and reports reference different standards, the approach is not to 'find a conversion table and change the annotation'.

The supplier is required to explain the corresponding basis. Ask them to point out which of the contract requirements the indicators in the report correspond to, and which clause of which standard is used.

Supplementary testing if necessary. If the original data is insufficient to prove the corresponding relationship, retest or supplement the test according to the method agreed in the contract.

Do not 'translate' one level into another qualified conclusion without checking the indicators. This approach is untenable during acceptance, and the responsibility for subsequent problems cannot be clarified.

Project judgment example

A certain project contract purchases U16 filters in accordance with EN 1822, and the arrival report is marked with ISO 65 U.

During the acceptance inspection, you cannot release the product just because the efficiency figures are close. It needs to be confirmed: whether the reported test method meets the requirements of the standards quoted in the contract, whether the overall efficiency and local efficiency are recorded, whether the test air volume and MPPS conditions are comparable to the design conditions.

If the report lacks local leak detection records or the test methods are inconsistent, supplements or clarifications should be requested. involving For products of different grades of HEPA/ULPA air filters , the requirements for standard verification are the same—confirm the diameter first, and then look at the numbers.

Selection and Acceptance Checklist

About Aili Industrial’s standard labeling cooperation

Inconsistent standard labeling is a common problem when transnational projects or supplier switching occur. If the information is clearly written, communication costs will be reduced a lot during acceptance.

Aili Industrial's manufacturing system covers filters, motors, fans, control systems and complete machine assembly, and can provide ULPA ultra-high efficiency filter and supporting air supply equipment. The product information will indicate the standards and test conditions based on it to facilitate verification by the project party. filter with When the FFU fan filter unit and EFU are delivered together, the standard labeling and testing data can be confirmed uniformly.

Clarifying the standard version, grade requirements and testing scope when making an inquiry will help with subsequent acceptance correspondence. Specific information shall be subject to the project agreement and contract documents.