AHU Condition Surveys and Asset Registers

Most buildings we take on have some record of their ventilation plant. Very few have one that’s accurate. Units get replaced and the list doesn’t change, filter sizes drift, and the person who knew where everything was has moved on.

A condition survey and a proper asset register fix that, and they’re usually the first thing worth doing on a site nobody has got a grip on.

What a condition survey covers

We go round every unit and record what’s actually there, not what the drawings say. For each unit:

• Location, reference and what it serves. Surprisingly often, nobody is certain which unit feeds which part of the building.
• Make, model, age and duty, where it could be established.
• Physical condition of casing, frame, panels, insulation and drain pans.
• Component condition: fans, coils, dampers, filters, heat recovery, humidifiers.
• Controls, and whether they’re doing anything useful.
• Access, including how components would be removed when they fail.
• Compliance items: fire dampers, filter grades, water hygiene risks.
• Photographs, so the record means something to someone who hasn’t been there.

We’ll also flag anything that needs attention now rather than waiting for the report.

What you get out of it

A budget you could defend. A survey turns “the plant is getting old” into a list with condition grades and likely remaining life. That’s what gets capital approved.

A maintenance schedule that fits the plant. Task schedules only work if the asset list is right. Our guide to SFG20 AHU maintenance explains how the schedules are built.

Evidence for compliance. Nearly every ventilation duty relies on showing the plant is maintained. Our guide to who is responsible for HVAC compliance sets out the duties and the records behind them.

A replacement plan in sequence. Rather than replacing whichever unit fails next, you could sequence the work around budgets and building use.

The asset register

The survey produces the register, and the register is what keeps the value. It should hold, for each unit, the identification and duty details, filter sizes and grades, belt sizes where fitted, component details, service history and the commissioning data.

The filter sizes alone justify it. Chasing a filter size on the day of a service is one of the most common causes of a wasted visit.

What we find most often

In our experience, surveys turn up the same things:

• Units running loads that have nothing to do with the building’s current layout
• Heat recovery that stopped working years ago and nobody noticed, which we cover in thermal wheel heat recovery
• Fire dampers that have never been tested or can’t be accessed
• Controls in hand, overridden years ago to solve a complaint
• Filters of the wrong grade, or housings that let air bypass them. See our AHU filter maintenance guide
• Drain traps missing or wrongly configured, which is the root of most hygiene problems. See AHU hygiene

None of these show up on a drawing. They show up when someone opens the unit.

Surveys on buildings that can’t stop

A condition survey doesn’t need the building to shut down. We work around operating hours, and we’ve surveyed and worked on plant in live airport facilities, hospitals and retail buildings. Our guide to ventilation in live operational facilities covers the approach, and the fan upgrades at Colmore Row in Birmingham were carried out with the building working around us.

From survey to plan

A survey is only useful if it leads somewhere. Ours end with recommendations split into what needs doing now, what to plan for, and what to keep an eye on. From there the options are maintenance, refurbishment or replacement, and our guides to AHU refurbishment vs replacement and AHU lifecycle costs cover that decision.

How we could help

We survey air handling plant across the UK, from single units to estates. See our AHU maintenance page, or get in touch to arrange a survey.

Frequently asked questions