Testing and Commissioning Before Handover in Citywest

Testing and commissioning are two separate jobs

Testing proves the installation is sound. Commissioning proves it performs. The two are often lumped together on a programme, but they answer different questions and happen in a set order.

Testing comes first, while pipework and ductwork are still accessible. Heating and chilled water pipework is typically pressure tested at about 1.5 times its working pressure and held for at least an hour, with the result witnessed and signed. Ductwork on medium and high pressure systems is leakage tested in sections. Any failure found here is cheap to fix. The same leak found after ceilings are closed is not.

What happens, in the order it should happen

Much of the commercial stock around Citywest Business Campus, Magna and out towards Saggart and Rathcoole is offices, logistics units and light industrial space, so the systems vary, but the sequence is broadly the same.

• Pressure and leakage testing of pipework and ductwork, with signed test sheets.
• Flushing and chemical cleaning of closed heating and chilled water circuits, followed by water sampling. Laboratory results usually take one to two weeks, so this needs to start early.
• Chlorination of domestic hot and cold water services, again with samples sent for analysis.
• Static checks and first start-up of boilers, heat pumps, chillers, air handling units and pumps, normally with the manufacturer present for larger plant.
• Water balancing, where flow through every coil and radiator circuit is measured and adjusted, usually to within about 10 per cent of the design figure.
• Air balancing, where supply and extract volumes are measured at each grille and diffuser and set to the design rates.
• Controls and building management system checks, proving every sensor, valve, damper and alarm point responds correctly.
• Integrated tests, such as confirming ventilation plant shuts down and smoke dampers close when the fire alarm activates.

How long it takes and what affects the cost

For a single fitted-out unit or small office floor, expect roughly one to two weeks of commissioning once the installation is complete and permanent power is live. A multi-storey office block or a building with process cooling can take four to eight weeks, and more if systems are handed over in phases.

Cost depends on the number of systems, how complex the controls are, how many terminal units need balancing and whether an independent commissioning manager is appointed. As a rough guide, commissioning often falls somewhere between 1 and 3 per cent of the mechanical package value, but a simple warehouse with a small office block sits very differently to a laboratory or data hall.

The most common cause of delay is not the commissioning itself. It is late permanent power, incomplete controls wiring, or a programme that has been squeezed so that the commissioning period absorbs earlier overruns. Ask to see the commissioning period on the programme and check that it has been protected.

The paperwork you should receive

Buildings in Citywest fall under South Dublin County Council as the building control authority. On most commercial projects a Certificate of Compliance on Completion has to be lodged and registered before the building can be opened or occupied, and the Assigned Certifier relies on ancillary certificates from the mechanical contractor to sign it. Commissioning records are part of that evidence.

At handover you should receive an operation and maintenance manual containing the following:

• Pressure test and ductwork leakage certificates.
• Flushing, water treatment and chlorination reports with laboratory results.
• Air and water balancing sheets showing design and measured figures side by side.
• Plant start-up reports and manufacturer warranties.
• Controls point-to-point check sheets and a description of how the system is meant to operate.
• As-installed drawings and a planned maintenance schedule.

What to check before you sign off

Attend the witness tests, or send someone who will be running the building. Seeing a flow rate measured or a damper close on a fire signal tells you more than a signed sheet.

Make sure your facilities staff get proper training on the controls, not a ten minute walk round. Finally, ask about seasonal commissioning. A building handed over in July has not had its heating tested under real load, so a return visit in the first winter, and ideally a review at around 12 months, should be agreed in writing.