How Building Managers Should Spec Replacement Filters for Strata Office Towers

Strata office towers can have a mix of plant rooms, risers, tenant fit-outs and rooftop equipment, which makes filter replacement more complicated than it first appears. The best way to avoid ordering the wrong product is to keep a clear specification for every filter in the building, from size and media type through to access details and repeat ordering notes.

A good filter record does not need to be complicated. It just needs to be accurate, easy to update and complete enough that a replacement can be ordered without guesswork.

Start with a building-wide filter register

The first step is to create a simple register for every air handling unit, return air grille, pre-filter and final filter location in the tower. This is especially important in strata buildings where plant may be installed across multiple levels and managed by different contractors over time.

Each entry should identify:

• •The equipment location, such as rooftop plant, basement mechanical room or tenant floor unit
• •The unit or system name used on site drawings or labels
• •The filter type used in that location
• •The direction of airflow, if it is relevant to the filter frame or installation
• •Any access issue that affects replacement

If you inherit an existing building, do not rely on memory or old purchase records alone. A quick physical check of each unit is worth doing before placing repeat orders. If you need help identifying the right product range, start with our products or arrange filter servicing if the system needs attention at the same time.

Record the exact size, not the approximate size

Filter sizes are one of the most common causes of ordering errors. A filter that looks close to the right dimensions may still leave gaps, bypass, or simply fail to fit the frame properly.

When measuring, record the full size in millimetres and note whether the dimensions are nominal or actual. If the filter is already in service, measure the frame opening and the existing filter where appropriate, then confirm the measurement against the equipment itself. For practical measuring tips, use how to measure an air filter.

Make sure the record includes:

• •Length, width and depth in millimetres
• •Whether the filter is panel, pleated, pocket, rigid or another style
• •Any unusual frame depth or flange detail
• •Whether the filter has handles, beads, clips or a special seal
• •Any orientation requirement for installation

If the building uses non-standard sizes, note that clearly. In many strata towers, the original equipment may have been modified over time, so the size on paper may not match the reality in the plant room. Where a standard product will not fit, custom air filters may be the better path.

Specify the media type and filtration stage

Filter media affects how the product fits into the system and how it should be ordered in future. Building managers do not need to become filter designers, but they do need to record the product type accurately enough for a supplier to match it.

Useful details to capture include:

• •The media type, such as synthetic, fibreglass, paper or pocket media
• •Whether the filter is disposable, extended surface or reusable
• •The filtration stage it serves, such as pre-filter or final filter
• •Any visible markings on the filter, frame or label
• •The rating or classification shown on the product, where applicable

If a building uses EN classes, MERV, or ISO 16890-rated products, record the exact rating printed on the filter. These systems do not convert directly, so it is better to document the original product specification than to try to translate it later. If the tower has higher-efficiency filters, record the exact class rather than relying on a shorthand description.

Where HEPA filters are used in specialised areas, record the exact class. Under EN 1822, H13 is at least 99.95% efficient and H14 is at least 99.995% efficient at the most penetrating particle size. Only include this information when it is relevant to the actual equipment installed.

Note access, fixings and site conditions

A replacement filter can be the right size and still be awkward to change if access details are missing. That is a common issue in office towers, especially where plant is behind locked doors, above ceilings, or located in tight risers.

Your register should note:

• •How the filter compartment is accessed
• •Whether access requires a key, ladder, lift, permit or shutdown window
• •Any space restrictions around the unit
• •Whether the filter needs to be inserted from the front, side or top
• •Any fragile components, wiring or controls nearby
• •Whether the area is dusty, humid or exposed to building works

These details help the replacement happen smoothly and reduce the chance of damage during servicing. They also help plan inspections, which should depend on the system, site conditions and dust load rather than a fixed calendar. Follow the filter and equipment manufacturer instructions, and monitor pressure drop where gauges are fitted.

If the building has unusual access arrangements, include photos in the maintenance file. A simple image of the frame, latch, or access path can save time later and reduce the risk of ordering a filter that is difficult to install.

Build repeat ordering notes that actually help

Once you have the right filter in place, the next step is to make future orders easier. The best repeat ordering notes are specific, brief and tied to the actual site.

Include:

• •The preferred product code or internal reference
• •The exact size and media description
• •The quantity used for each system
• •Which building or tenancy area it belongs to
• •Any packaging preference for storage or handling
• •Any notes about installation direction or sealing surfaces

If the site uses multiple similar filters, separate them clearly. For example, two filters may share the same face dimensions but differ in depth, frame type or media grade. A good record prevents those products being grouped together by mistake.

It is also worth noting who is responsible for approvals and ordering in a strata environment. Sometimes the building manager orders directly, while in other cases the owners corporation, strata committee or building owner confirms the purchase. Keeping that chain clear can avoid delays when filters are needed.

Keep the record aligned with the building’s mechanical documentation

The filter register should sit alongside the building’s mechanical services paperwork, not in isolation. That means matching the filter notes to as-built drawings, maintenance logs and any current service instructions.

If the system has changed, make sure the register changes too. A filter spec can become outdated when equipment is replaced, ducts are modified or a tenant fit-out alters the airflow path. Where there is doubt about what the system requires, confirm site requirements with the mechanical services engineer or building owner. For ventilation-related matters, AS 1668.2:2024 may be relevant, but it should be checked against the actual installation and site obligations.

Useful record-keeping habits

• •Keep one master file for the building and one copy in the plant room if practical
• •Update the record after every filter change or equipment modification
• •Save supplier part numbers, not just descriptions
• •Photograph the installed filter and label where possible
• •Note whether some filters are designed to be washable - check the product instructions

If a filter is reused, cleaned or replaced as part of servicing, record the instruction that applies to that product rather than assuming it works the same way as another filter in the building.

When to ask for help

If a filter is hard to identify, if the sizes vary between floors, or if the system has been modified over time, it is worth getting help before ordering. The right supplier can confirm the product type, suggest alternatives for non-standard sizes and help document repeat orders properly.

Total Air Filtration is a family-owned air filter manufacturer and supplier in Hillcrest, Brisbane QLD, established 2009. We work with building managers and facility managers who need practical filter records, accurate replacements and straightforward repeat ordering for commercial buildings.

For support with replacement filters, custom sizes or site-specific ordering notes, call 07 3800 3448 or request a quote. You can also contact us or view filter servicing options if your tower needs a broader maintenance conversation.