"> Enviro Labs Limited | Environmental Testing - Cooling Tower Water Testing
Enviro Labs Limited | Environmental Testing - Cooling Tower Water Testing
Cooling Tower
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              Environmental Testing Services

Cooling Tower Water Testing

Cooling tower is a heat removal devices used to eliminate waste heat of air released to atmosphere. This process allows airborne contaminants, organic matters and particles to become deposited into the cooling water. This, combined with the contaminants in the feed water, creates an environment for microorganism growth, solid deposits and scaling.

Improper treated cooling tower water could be an amplifier of biological hazardous agent. The warm and moist environment of a cooling tower favors the growth of Legionella bacteria which causes the outbreak of the deathly Legionnaires’ disease. Thus, cooling tower water quality must be monitored in a regular basis to prevent spreading of diseases to users.

In Hong Kong, Code of Practice for Water-cooled Air Conditioning Systems, published by the Electrical and Mechanical Services Department (EMSD), HKSAR Government, recommends to monitor the following parameters regularly.

Parameter Cooling Water Quality Criteria

(Fresh Water Typed Tower)

Minimum Monitoring Frequency
Heterotrophic plate count < 100,000 cfu/mL Monthly
Legionella bacteria count < 10 cfu/mL Monthly / Quarterly
Conductivity < 1500 μS/cm Monthly
Total dissolved solids < 1500 mg/L Monthly
Suspended solids < 180 mg/L Monthly
Calcium hardness < 500 mg/L Monthly
pH 8 – 10 Monthly
Total alkalinity 80 – 500 mg/L Quarterly
Chloride as mg/L < 200 mg/L Quarterly
Sulphate as mg/L < 200 mg/L Quarterly
Total iron as mg/L < 1.0 mg/L Quarterly
Total Residual Chlorine < 0.3 mg/L Monthly
Biochemical Oxygen Demand (BOD5) Refer to EPD’s Technical Memorandum on Standards for Effluent Discharged into Drainage and Sewerage Systems, Inland and Costal Waters Monthly
Chemical Oxygen Demand (COD)



Ref: Code of Practice for Water-cooled Air Conditioning Systems Part 2: Operation and Maintenance of Cooling Towers (EMSD, HKSAR, Jan 2007)

To ensure the accuracy of the test results, testing should be carried out by the laboratories accredited by the Hong Kong Laboratory Accreditation Scheme (HOKLAS). Enviro Labs Ltd. (ELL) is registered as a HOKLAS accredited laboratory (HOKLAS 128) in Environmental Testing and our company holds HOKLAS accreditation for ALL the tests listed as above.