Using EN 779 Legacy Data in Building Maintenance Records

If your maintenance files still contain EN 779 filter data, that information is not useless just because procurement has moved on. The key is to keep the old records intact, add clear context, and make sure new orders and replacements are written in ISO 16890 terms so the history and the current specification both make sense.

For facility managers and asset managers, this is mainly a records management task. It is about avoiding confusion at the point of reorder, service, or audit, while keeping enough detail on file to track what was installed, where it was used, and what it was intended to do.

Why EN 779 records still matter

EN 779 may be superseded by ISO 16890, but many sites still have legacy documentation, asset registers, commissioning files, and service logs that refer to G3, G4, F5, F7 or similar classes. Those records can still help you understand what is in the system now, even if you would not use the same wording for a new procurement request.

That matters because maintenance records often do more than show what was purchased. They may also record:

• •the filter type fitted to a specific unit
• •the original supplier description
• •the location and duty of the unit
• •notes from previous inspections or change-outs
• •any modifications to filter holding frames or housings

Keeping that history intact can make it easier to assess compatibility when parts are replaced, especially if the system has been modified over time.

Keep the legacy rating, but label it as legacy

The simplest way to preserve EN 779 information is to keep it exactly as it appeared on the original documents, then add a note beside it that it is a legacy rating.

For example, instead of deleting an old entry that says G4, keep the original reference and add a note such as:

• •legacy EN 779 designation: G4
• •current procurement wording: specify according to ISO 16890 requirements for the application
• •location: plantroom AHU 2, return air section
• •notes: confirm dimensions and frame style before reorder

This approach avoids rewriting history in a way that could confuse future staff. It also helps if you are comparing older service records with current product descriptions from our products or arranging filter servicing.

A good maintenance file should show both what the original record said and how the site now handles the replacement process.

Build a bridge from old ratings to current specifications

EN 779 and ISO 16890 do not convert directly, so avoid trying to force a one-to-one mapping in your records. Instead, record the legacy class as historical information and then describe the replacement requirement in practical terms.

A useful record entry might include:

• •original EN 779 class shown on the existing filter or invoice
• •filter dimensions and frame type
• •system name and equipment tag
• •installation location
• •the current specification wording used for reorder
• •any notes from the mechanical services engineer or building owner

If you need to confirm the actual filter size before replacing it, a simple measurement record can save time. Our guide on how to measure an air filter can help with the dimensions that matter most in procurement and servicing.

For building records, the main point is consistency. Use EN 779 wording only where it already exists in the file, and use ISO 16890 wording for new purchases and current maintenance references.

What to record during the transition

During a transition period, the maintenance file should tell the next person enough to make the right decision without needing to search through old purchase orders.

Include these details wherever possible:

• •asset tag or equipment reference
• •filter stage and position in the system
• •original EN 779 designation, if present
• •current ISO 16890 description for replacement
• •exact dimensions and construction details
• •installation date or service event date if known
• •any pressure drop reading taken at inspection, where gauges are fitted
• •comments on visible dust loading, damage or frame condition

If the system is part of a larger ventilation arrangement, site requirements should also be checked against AS 1668.2:2024 and confirmed with the mechanical services engineer or building owner. That is especially important where the filter change may affect airflow, access, or overall system performance.

Practical wording for maintenance files

Clear file notes save time. The aim is not to write a technical essay, but to make sure anyone opening the record can understand the old and new terminology together.

You might use wording such as:

• •existing record retained for reference; EN 779 class shown on original documentation
• •replacement to be ordered using ISO 16890 terminology only
• •confirm dimensions, frame type and seal arrangement before purchase
• •inspect based on system condition, site conditions and dust load
• •follow manufacturer instructions for the filter and the equipment
• •monitor pressure drop where gauges are fitted

If a filter is part of a commercial system that is difficult to access, it can also help to note whether commercial filter servicing is used on site, or whether the work is handled internally.

This kind of language keeps the legacy record useful without suggesting that the old and new standards are interchangeable.

Special cases: HEPA and washable products

Some sites also keep legacy notes for higher-efficiency products or special-purpose filters. If your records mention HEPA filters, use the correct EN 1822 terminology where relevant. H13 is at least 99.95% efficiency at the most penetrating particle size, and H14 is at least 99.995% at the same point. Keep those ratings separate from EN 779 or ISO 16890 records.

If a product is described as washable, treat that as a product-specific feature rather than a general assumption. Some filters are designed to be washable - check the product instructions. Do not rely on an old record alone if the product label or specification sheet is missing.

Where records are unclear, it is better to verify the filter physically than to guess from an old class name.

Making the handover to new procurement easier

When procurement and maintenance teams use different terminology, the handover can become messy. A good file structure makes it easier to move from legacy references to current ordering practice.

A practical approach is to keep three layers of information together:

• •the historical record, including EN 779 wording
• •the current specification, using ISO 16890 language
• •the practical replacement details, such as size, frame and access notes

That way, a future order can be raised without reinterpreting the whole service history. It also helps when you need a custom size or a non-standard frame. In those cases, custom air filters may be the right path if the existing housing or application calls for it.

If you are reviewing multiple sites, grouping the records by equipment type or building zone can also make the file easier to use during a stock check or maintenance review.

Keeping old data useful while moving forward

Legacy EN 779 information still has a place in maintenance records, as long as it is clearly marked as historical and paired with current ISO 16890 procurement wording. That gives you a cleaner handover between older files and present-day ordering, without losing the detail that helps identify the right filter later.

Total Air Filtration is a family-owned air filter manufacturer and supplier in Hillcrest, Brisbane QLD, and we can help supply or make the right filters for your site. Call 07 3800 3448 or request a quote when you are ready to update your records and replacements.