What Mechanical Contractors Need Before Quoting Filter Changeovers on a Live Site

If you are quoting a filter changeover on a live site, the quality of the job brief matters as much as the filter itself. A few missing details can turn a straightforward swap into a delay, a rework, or an access issue on the day.

For mechanical contractors and facility managers, the best approach is to gather the site information up front so the quote reflects the real conditions, the actual access, and the shutdown constraints involved.

Start with the site and plant access picture

Before you look at filter sizes or product types, confirm how the plant is accessed and where the work will actually happen. A live site often has constraints that do not show up in drawings.

Ask for:

• •The exact plant location and access route
• •Whether the plant is on a roof, in a ceiling space, in a basement, or inside a restricted area
• •Any induction or sign-in requirements
• •Access hours, after-hours restrictions, and permit requirements
• •Whether ladders, scissor lifts, trolleys, or special lifting gear are needed
• •Any loading limits, security controls, or escort requirements

It also helps to know whether the area is still occupied while work is underway. That affects how much noise, dust control, and movement is acceptable during the changeover.

If the site has multiple air handling units, confirm which unit is being serviced and whether the labels on site match the drawings. A simple mismatch between plant room drawings and the actual unit can waste time before the first filter is even removed.

Gather the housing details before you quote

Filter changeovers are easier to price accurately when you know the housing setup in advance. The type of frame, door clearance, filter track, and access orientation all affect how long the change takes and what can be supplied.

Request clear details on:

• •Filter dimensions, depth, and quantity
• •The filter housing type and arrangement
• •Direction of airflow through the unit
• •Available clearance for removing and inserting filters
• •Whether access is from the side, front, top, or rear
• •Any corrosion, deformation, damaged seals, or missing hardware
• •The condition of the holding frame, gasket surfaces, and retaining clips

If measurements are uncertain, ask for photos with a tape measure in place. If the site team is measuring for replacement filters, point them to how to measure an air filter so the dimensions are taken correctly.

Where the existing filter has no readable label, or the housing has been altered over time, a physical check is usually the safest way to confirm the size and fit. If standard filters will not suit the housing, custom air filters may be the better option.

Confirm the filter specification and performance requirements

Not every filter changeover is a like-for-like swap. On a live site, the contractor needs to know what is already installed, what the system is designed to use, and whether the site has any specific requirements that affect the selection.

Clarify:

• •The current filter type and grade
• •Whether the site uses panel, pleated, bag, rigid cell, or other formats
• •Whether pre-filters and final filters are both involved
• •Any special media requirements for dust, odour, or fine particle capture
• •Whether the site uses EN 779 classes such as G3, G4, or F5-F9, or a newer ISO 16890 classification
• •Whether the filter is part of a higher-efficiency application where H13 or H14 HEPA performance is specified

It is worth noting that MERV, EN 779 and ISO 16890 ratings do not convert directly, so avoid assuming one rating is interchangeable with another. If the site is governed by a ventilation design or compliance requirement, confirm the details with the mechanical services engineer or building owner, and consider the requirements in AS 1668.2:2024 where relevant.

If you are unsure which product suits the application, review our products before you price the job.

Ask about staging, handling, and waste removal

A live-site changeover is not just about the replacement filters. It also involves how the new filters will be received, stored, moved, and disposed of once the old ones come out.

Before quoting, ask:

• •Where the filters can be delivered
• •Whether there is a secure area for storage before installation
• •Whether the filters must be staged in small lots rather than in one delivery
• •If old filters need to be bagged, labelled, or removed through a specific waste route
• •Whether packaging must be retained, removed immediately, or disposed of off site
• •Whether there are contamination controls for dusty, greasy, or industrial environments

If the site has limited space, the delivery plan matters. Large cartons or pallet loads can create problems if the plant room access is narrow or the changeover zone is shared with other trades. Ask for photos of the staging area and any access points that could affect manoeuvring.

For ongoing maintenance planning, some sites prefer scheduled attention through filter servicing or commercial filter servicing, especially where access is difficult or the system runs continuously.

Clarify shutdown limits and live-site constraints

The most important quoting detail on a live site is often how much downtime is available, if any. A quote based on a full shutdown will not suit a site that can only allow short windows or partial isolation.

Find out:

• •Whether the system can be shut down fully or only section by section
• •How long the shutdown window is expected to be
• •Whether the building can remain occupied during the work
• •If there are temperature, pressure, production, or process constraints
• •Whether alarms, BMS points, or differential pressure monitoring need to be isolated or reset
• •Who has authority to authorise shutdown and recommissioning
• •Whether hot works, confined space rules, or other permits apply nearby

If the plant must stay online, ask whether temporary measures are acceptable, such as changing filters in stages or scheduling the work around low-occupancy periods. Some filters are designed to be washable - check the product instructions before assuming that a cleaning method is acceptable.

Where pressure drop gauges are fitted, note the readings before and after the work. That helps track when filters are approaching the condition for replacement, but inspection frequency should always depend on the system, the site conditions, and the dust load, while following the filter and equipment manufacturer instructions.

Get the right photos, records, and contact details

A strong quote usually starts with a strong information pack. If the site is busy, photos and simple records can prevent repeated site visits.

Request:

• •Clear photos of the installed filters and housings
• •The filter label or part number, if visible
• •A photo of the access route from the plant entry point to the unit
• •Notes on any damaged seals, bent frames, or unusual fittings
• •The name and contact details of the onsite decision-maker
• •The preferred time for delivery, inspection, and installation

You should also confirm whether the site manager wants a supply-only quote, installation included, or both. If the job needs a short turnaround, ask the client to confirm that the site details are current before sending the request so the quote is based on live conditions rather than assumptions.

What to include in your final quote brief

A clean brief should answer the practical questions before pricing starts. At minimum, it should tell you:

• •What filters are being changed
• •How many are involved
• •How they are accessed
• •What restrictions apply to the site
• •Whether the work is a simple swap or part of a wider servicing scope
• •Who is responsible for shutdown approval and onsite coordination

The more complete the brief, the easier it is to price labour, access, staging, and waste handling with confidence. It also helps facility managers avoid delays when the work starts.

Need help matching the right filters to the job?

Total Air Filtration is a family-owned air filter manufacturer and supplier based in Hillcrest, Brisbane QLD, and we can help you match the right filters to the site conditions and access constraints. Call 07 3800 3448 or request a quote. You can also contact us if you want to discuss a live-site changeover before you visit.