Air systems
AHUs, VAVs, extract, pressure regimes and terminal delivery.
SYS-01PW / Cx-096 / fictionalWitnessed performance
Installed is not commissioned.
Plenum verifies that building services operate as a system: measured air and water, credible sensors, working sequences, useful alarms and a handover the facilities team can actually run.
±5%
airflow witness tolerance
72 h
typical trend review
100%
defects assigned an owner
01
signed closeout register
SUPPLY
2.84 m³/s
STATIC
412 Pa
MODE
OCC
About / independent verification
A green light on the BMS means very little until the physical system agrees.
We work from design intent, approved sequences and measurable acceptance criteria so witness testing is more than watching equipment switch on.
Field readings are compared with controls points and trend data. A sensor that looks plausible but reads the wrong condition is still a defect.
Closeout is operational: outstanding items, retests, seasonal checks, setpoints and operator actions are visible in one handover record.
Offerings / systems under test
Hydronic systems
Chilled and heating water flow, pumps, coils, differential pressure and valve authority.
SYS-02Controls
Sequences, sensors, alarms, trend logs, mode changes and operator interfaces.
SYS-03Indoor conditions
Temperature, humidity, CO₂, pressure relationships and representative occupied-zone checks.
SYS-04Process / verify
Measure the chain, not the component.
01 / DESK
Review
Design criteria, sequences, schedules, controls points and previous test evidence become the commissioning matrix.
02 / FIELD
Witness
Representative air, water and environmental measurements are taken with instrument IDs and test conditions recorded.
03 / CONTROLS
Exercise
Modes, safeties, overrides, alarms and failure states are triggered deliberately instead of assumed from static screens.
04 / TREND
Verify
Time-series data checks stability, reset logic, simultaneous heating/cooling, sensor drift and behaviour outside the witness hour.
05 / CLOSE
Retest
Defects are assigned, corrected and re-witnessed before they leave the open-item register.
Projects / witnessed handover
Tower 8 cooled perfectly at noon and failed every morning.
At a fictional 22-storey office, daytime witness tests passed. Trend review showed chilled-water differential pressure collapsing during the 05:30 start sequence, leaving upper floors without valve authority. The pump reset logic was corrected and retested across three mornings before practical completion.
22
floors
72 h
trend window
14
open items found
14
closed by retest
612
fictional functional tests witnessed
97%
closeout before occupation
4.2%
median airflow correction after first witness
0
items closed without evidence
People / commissioning team
Field judgement backed by instruments.
CX-01
Ravi Pillay
Commissioning authority
Air/water systems, acceptance criteria, witnessed closeout.
CX-02
Imogen Reed
Controls specialist
Sequences, BMS points, trend analysis and failure-state testing.
CX-03
Tawanda Moyo
Field engineer
Airflow, pressure, temperatures, instrumentation and retests.
Insights / test notes
A sensor can be precise and still be wrong
A stable reading from the wrong location, wrong scale or wrong point mapping can drive a control loop confidently in the wrong direction.
Seasonal commissioning is not optional on paper
Heating and cooling systems cannot always be proven in one weather condition. Deferred tests need dates, owners and acceptance criteria before handover.
Operators need reasons, not just setpoints
A number without design intent becomes folklore. We document what the setpoint protects and what changing it is likely to disturb.
Objections / commissioning questions
Proof before closeout.
Are you the mechanical contractor?
No. Plenum is an independent commissioning practice. We verify installed performance, witness tests, reconcile controls and document unresolved defects without replacing the contractor's construction responsibility.
Why commission after balancing?
Balancing proves distribution at a moment in time. Commissioning checks that plant, sensors, sequences, alarms and controls work together across modes and that the result remains understandable to operators.
Can you fix problems you find?
We can diagnose, propose corrective tests and support retesting, but ownership of physical rectification stays with the responsible trade unless separately appointed.
Contact / conversion
Appoint commissioning before defects become handover history.
Send the design stage, system scope, completion dates and current commissioning plan. We will identify required witnesses, trend periods and evidence gaps.
cx@plenumworks.example