What to Specify When Ordering Filters for Multiple Sites Across Queensland

When you are managing multiple properties or plants across Queensland, air filters can become surprisingly difficult to standardise. One site may use a slightly different frame depth, another may have a different media grade, and a third may have inherited a legacy part number that no one quite trusts anymore.

The simplest way to keep ordering under control is to define exactly what needs to be consistent across the portfolio and what can vary by site. At Total Air Filtration, a family-owned air filter manufacturer and supplier in Hillcrest, Brisbane QLD, we often help teams turn a messy mix of site-specific orders into a clearer filter specification.

Start with a master filter register

Before you place a group order, build a master register of every filter type in use across the portfolio. This does not need to be complex, but it should capture enough detail that someone else can order the same item without guessing.

Include the following for each site and system:

• •Site name and building or plant area
• •Equipment type and unit identifier
• •Filter dimensions in millimetres
• •Filter frame type and depth
• •Part number or internal code
• •Filter stage, if there is more than one stage
• •Media type and rating
• •Final resistance or pressure drop information where available
• •Any special notes, such as moisture exposure, access constraints or unusual installation direction

If you do not already have a reliable record, it is worth starting with a physical survey. Our how to measure an air filter guide is a useful reference when dimensions are unclear or the existing label has worn off.

Standardise dimensions first

Dimensions are the easiest place for variation to creep in. A filter that is only a few millimetres different may look close enough on paper, but it can leak around the frame, bow during installation or fail to seat properly.

For portfolio work, standardise the following wherever the equipment allows:

Face size and depth

Record the exact nominal size and the actual measured size. In many sites, the part number may describe a nominal dimension, while the real outside dimensions differ slightly by manufacturer. Both matter.

If you have several identical units, check that all frames are the same before assuming the same filter will fit every location.

Frame material and construction

A metal frame, cardboard frame or synthetic frame can change how a filter handles handling, moisture and installation conditions. Where possible, keep one construction type per equipment family so maintenance teams are not dealing with mixed formats.

Seal method and installation direction

If the filter relies on a gasket, bead, knife edge or other sealing arrangement, record that clearly. The same applies to airflow direction, especially where filters have a labelled upstream and downstream face.

If you need a custom size, see our custom air filters page for options that can match non-standard openings or legacy equipment.

Make part numbers work across the portfolio

Part numbers are only useful if everyone uses the same naming logic. A common source of ordering errors is when one site uses a supplier code, another uses an old internal asset code, and a third orders from a description typed into an email.

To simplify procurement, create a single portfolio naming convention that includes:

• •Site or asset group code
• •Filter stage number
• •Size identifier
• •Media or rating class
• •Frame type
• •Special feature, if required

For example, keep the structure consistent even if the underlying filter differs. A label that clearly separates size, rating and construction is easier to audit than a long free-text description.

If you manage multiple sites, it can also help to add a cross-reference field in your maintenance system. That way, site staff can search by local asset code while procurement orders against one standard part number.

Specify the performance requirements clearly

Once the physical size is sorted, define the filter performance in terms that suit the application. This is where portfolio managers often benefit from aligning specifications across like-for-like sites, rather than writing a fresh description for every purchase.

Useful details to include are:

• •Intended application, such as general HVAC, pre-filtration, finer particle filtration or special process use
• •Required dust holding or filtration stage within the system
• •Media type, if a particular construction is needed
• •Pressure drop target or allowable resistance where the equipment documentation gives one
• •Any need for low odour materials, moisture resistance or a specific frame type

If you are working to a building ventilation design, confirm site requirements with the mechanical services engineer or building owner. If AS 1668.2:2024 is relevant to the system, make sure the specification is checked against the actual installation rather than assumed from a previous purchase.

Be careful with rating systems

Do not mix rating systems without checking the product data. MERV, EN 779 and ISO 16890 do not convert directly, so avoid asking suppliers to “match” a different standard unless you are comparing the actual product performance data.

If your sites still use EN 779 language, you may see G3/G4/F5-F9 used in existing documents. These are still widely referenced in Australia, even though ISO 16890 is now the newer standard in many contexts. Keep the wording consistent within your portfolio records so the wrong class is not ordered by mistake.

For HEPA applications, specify the exact class needed. H13 is at least 99.95% efficient at the most penetrating particle size under EN 1822, and H14 is at least 99.995% efficient at the most penetrating particle size under EN 1822. Only use these designations where they are genuinely required by the application.

Plan for site conditions, not just the drawing

Two sites with the same plant can still need different filter considerations if their operating conditions are different. Coastal exposure, dust load, access issues and cleaning practices can all affect what should be ordered.

When documenting each site, note:

• •Whether the location is exposed to outdoor dust, salt air or construction activity
• •Whether the equipment runs continuously or intermittently
• •Whether access is difficult and requires specific packaging or handling
• •Whether the filter is in a cleanroom, commercial HVAC system, workshop or process area
• •Whether the equipment manufacturer specifies a particular filter construction

Some filters are designed to be washable - check the product instructions before assuming that a reusable option is suitable. If a site has a wash-down area or higher moisture exposure, that detail should be recorded with the specification.

Inspection frequency should always depend on the system, site conditions and dust load. Follow the filter or equipment manufacturer instructions, and monitor pressure drop where gauges are fitted so replacement can be planned around actual condition rather than guesswork.

Use the same process for every site order

Once the portfolio standard is set, the ordering process should be the same every time. That consistency is what prevents errors when multiple people are involved.

A good process is to require each site order to include:

• •Site name and contact
• •Asset or unit identifier
• •Standard part number
• •Filter dimensions
• •Rating or media specification
• •Quantity
• •Delivery instructions
• •Any photo or reference label from the existing filter

You may also want one approved contact to sign off changes to any specification. That is especially useful when a site wants to substitute a size or rating because the old item is unavailable. Small substitutions can create bigger problems later if they are not documented centrally.

If you also arrange ongoing maintenance, our filter servicing and commercial filter servicing pages may be useful when you are coordinating supply with inspection or replacement work.

Keep the specification simple enough to repeat

The best portfolio filter specification is detailed enough to avoid mistakes, but simple enough for site teams, maintenance contractors and procurement staff to use without interpretation.

A practical standard document should let anyone answer these questions quickly:

• •What filter fits this unit?
• •What is the approved part number?
• •What performance class is required?
• •What frame and seal type is needed?
• •Are there any site-specific conditions to note?

If the answer is not clear from the document, it is worth tightening the specification before the next order. That saves time across the portfolio and reduces the risk of receiving the wrong item.

Total Air Filtration can help you standardise the order

If you are rationalising filters across multiple Queensland sites, Total Air Filtration can supply or make the right filters once the dimensions and specification are set. We work from clear measurements, site notes and part numbers so your ordering stays consistent across the portfolio.

Call 07 3800 3448 to discuss your filter requirements, or request a quote. You can also contact us if you need help checking a specification before the next group order.