An air handling unit is only as good as the ductwork behind it. Gemini AMPM designs, supplies and installs AHU and ductwork systems to DW/144, the BESA specification that governs how commercial ductwork is made and fitted. From data centres to hospital wards, we build ventilation that delivers the air the design promised.
We supply and install air handling units — bespoke or modular — and integrate them with existing HVAC plant and BMS controls. Ductwork is designed and installed to DW/144, the BESA specification that governs how commercial sheet metal ductwork is constructed, supported and sealed. Low pressure or high, fire-rated where the strategy demands it, insulated for heat and sound where the building does.
We work with the manufacturers specifiers already trust — Swegon, Systemair, Nuaire, Daikin and FlaktGroup among them — across data centres, hospitals, hotels, schools and manufacturing sites. And not every project starts from scratch. We retrofit and upgrade too: replacing tired AHU components, re-routing ductwork around refurbishments and lifting efficiency without condemning plant that still has life in it. Every install gets a design for the building in front of us, not a catalogue answer.
Most installers hand over and disappear. We service, clean and test ventilation for a living, so we install with the next ten years in mind — access doors where TR19® cleaning crews will need them, test points where commissioning requires them, dampers a human can actually reach. Our wider ventilation services then keep the system honest: hygiene, testing, service and repair under one roof.
Gemini AMPM has been in building services since 1997 and is now an employee-owned trust, which means the engineers on your roof have a stake in the outcome. If something fails after handover, a named engineer responds within 24 hours. No call centres, no mystery subcontractors — the firm that designed and installed the system stands behind it. That is rarer than it should be.
DW/144 is the BESA specification for sheet metal ductwork — the industry rulebook covering materials, construction, joints, supports and airtightness for low, medium and high pressure systems. Ductwork built to DW/144 behaves predictably: it can be leakage tested against known classes, cleaned to TR19® and commissioned without surprises. Ductwork built to nothing in particular usually reveals itself later, at your expense. Every duct run we install is designed and fabricated to DW/144.
Yes, and we usually do. Most replacements happen in live buildings, so we plan around occupancy: phased strip-out, out-of-hours lifts, temporary ventilation where the space cannot lose air handling, and clean reinstatement. We survey access routes and plant space first, so there are no surprises on the day. The aim is that occupants notice the better air, not the works that delivered it.
Both. We can take a consultant’s design and install it faithfully, or take a performance brief — air change rates, heat loads, noise limits — and produce the design ourselves. Either way the drawings coordinate with structure, fire compartmentation and BMS controls before anything is fabricated. Design and build suits clients who want one firm accountable for the numbers the system eventually has to deliver.
A named engineer, not a call centre, comes back within 24 hours. Tell us the building and what you’re dealing with, and we’ll scope it properly.