MBS/General/TBT-MBS-010

Chiller and Cooling Tower Safety

Mechanical Building Services › General › Chiller and Cooling Tower Safety

Presenter		Project
Location		Date

Chillers and cooling towers are large mechanical systems used for building cooling and process temperature control.
Installation involves heavy lifting, pipework connection, electrical termination, and refrigerant charging.
Refrigerant gases including R-410A and R-32 can displace oxygen in enclosed spaces and cause asphyxiation.
F-Gas Regulations require that only certified personnel handle fluorinated refrigerant gases.
Cooling towers present a legionella risk during commissioning and must be managed under HSG274.
Chiller units are heavy — typically 500 kg to several tonnes — requiring detailed crane or rigging plans.
Electrical connections involve high-current three-phase supplies with significant shock and arc flash hazards.
Pressure testing of refrigerant circuits must follow manufacturer procedures to prevent vessel failure.
Cooling tower fills and drift eliminators are accessed at height and in wet, slippery conditions.
Commissioning involves multiple hazardous energy sources operating simultaneously for the first time.

Refrigerant hazards	Refrigerant leaks in enclosed spaces displace oxygen and can cause rapid asphyxiation without warning.
Legionella risk	Cooling towers create ideal conditions for legionella bacteria growth, which causes potentially fatal Legionnaires' disease.
Heavy lifting	Chiller units weighing several tonnes require proper lift planning to prevent crushing and structural damage.

Don't

Ensure only F-Gas certified personnel handle refrigerant charging and recovery
Prepare a lift plan for positioning chiller units considering weight and access
Isolate and lock off electrical supplies before making any termination connections
Follow HSG274 guidance for legionella control during cooling tower commissioning
Ventilate enclosed plant rooms before and during refrigerant handling operations
Pressure test refrigerant circuits using dry nitrogen before charging with refrigerant
Wear appropriate PPE when working at height on cooling tower structures
Brief the commissioning team on all energy sources and emergency shutdown procedures
Monitor plant room atmosphere for refrigerant leaks using gas detection equipment
Record all commissioning data including pressures, temperatures, and refrigerant charge

DON'T handle refrigerant gases without valid F-Gas certification
DON'T enter an enclosed plant room where a refrigerant leak is suspected
DON'T energise electrical connections before isolation has been formally confirmed
DON'T commission cooling towers without a legionella risk assessment and controls
DON'T lift chiller units without a detailed lift plan approved by an Appointed Person
DON'T pressure test with refrigerant gas — use dry nitrogen for initial testing
DON'T access cooling tower internals without fall protection on wet surfaces
DON'T vent refrigerant to atmosphere — it is illegal under F-Gas Regulations
DON'T bypass safety interlocks during commissioning to speed up the process
DON'T neglect to record the exact refrigerant type and charge weight on completion

See also: Mechanical Building Services Safety | Refrigerant Handling (F-Gas)

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