Updated: Dec 15, 2020
Cooling Towers, Drainage, Chemical Treatment, Water Cooled Refrigeration Systems.
In an ongoing effort to make sure our service partners are aware of the incoming changes by the City of Vancouver to the operation of cooling towers and water-cooled refrigeration equipment, we are posting this information to help in the planning on how to become compliant.
Please note - it is the posted intention of other jurisdictions within the Province of BC to follow the lead of the City of Vancouver. What systems are affected:
Steam generation and HVAC water systems are all aspects of the same general process. The objectives are to transfer heat from one place to another, using water as the transfer medium, to conserve heat energy, and to discharge waste heat and water to the environment in an acceptable manner.
Thus, the general objectives of water treatment must be:
Keep the heat transfer surfaces as clean as possible in order to maximize water flow and heat transfer efficiency.
Protect the heat transfer equipment and associated piping from corrosion and fouling damage.
Manage the risks associated with Legionella bacteria proliferation, as well as other types of bacteria.
Conserve water and heat, and meet or surpass all applicable air and water quality regulations.
Accomplish all of this in the most technically appropriate, environmentally sound, safe and cost effective way possible.
Water Treatment Specialists
Water treatment requirements are specific to each system being considered. The needs of a system in one facility will not necessarily be the same as the needs of another. It is important to have each facility evaluated by a water treatment specialist to ensure the requirements are met for each system.
Your water treatment specialist will evaluate:
Type of system
Current system status
An effective chemical treatment program
What is Legionnaires’ Disease?
As per CTI, following the 1976 American Legion Convention at the Bellevue Stratford Hotel in Philadelphia, 34 attendees died and 221 people became ill from pneumonia caused by the bacterium Legionella pneumophila. This disease, now commonly known as ‘Legionnaires’ Disease’, is a respiratory infection that strikes susceptible individuals exposed to Legionella pneumophila. Infection results from inhaling airborne water droplets or mist containing viable Legionella pneumophila, which are small enough to pass deep into the lungs and be deposited in the alveoli, the small pockets in the lungs. The dose of Legionella pneumophila required to infect humans is not definitively known.
Legionella pneumophila is a ubiquitous organism. It appears in almost every ground and surface water. The organism survives typical chlorine disinfection for potable water and consequently can appear in finished water distributed to homes and industry.
Why are we talking about it?
Legionella awareness in Canada has been on the rise since the 2012 outbreak in Quebec.
July 2012 – Outbreak in Quebec
During the Quebec incident, 13 people died and 180 cases were reported. Source was the cooling tower on a 5-storey building
August 2015 – New York City Legionnaires Disease Outbreak
In the Legionnaire’s disease outbreak that occurred in New York City, 10 people died,and at least 100 people contracted the disease since the outbreak began in mid-July. It was reported that the disease was spread by bacteria discovered in the cooling towers of several buildings in the South Bronx neighborhood.
September 2018 – Legionnaires’ disease cluster in Guildford area
Legionnaires’ disease cluster was discovered by Fraser Health Authority in the Guildford area and reported on by several local news agencies. It is believed there are less than 10 cases in total.
Typical Water Treatment Program for Cooling Towers
Minimum Bacterial Testing Requirements and Frequency (Normal Operation), and Action Plans
It is imperative for all facilities with a cooling tower to have an action plan in place as part of any Legionella risk management plan. The plan must be communicated to all parties involved in managing the risk associated with Legionella bacteria. They must be aware of, and understand their roles and responsibilities when intervention is required.
Should a Legionella test yield a positive result, a facility with an action plan can simply implement the associated procedures. The action plan will help avoid any costly over-or-under reactions.
Operation and Maintenance
It is recommended operators of cooling towers follow Section 3.4 of the Public Works Canada document MD 15161-2013 for O&M and Cleaning.
Note: consult the O&M documentation for procedures specific to your equipment for additional details
Routine Chemical Cleaning
Cooling towers must be maintained in a clean operating condition whenever in use in order to extend the life of the equipment, and support bacteria control and disease prevention.
According to Public Works Canada document MD 15161-2013 Section 3.4 – Cleaning:
Cooling towers shall be maintained in a clean working condition whenever the equipment is in use.
Start-up and annual cleaning of cooling towers shall include as a minimum:
Use additives to aid in cleaning, including detergents and anti-foaming agents.
Circulate the water for at least one hour throughout the system to provide coarse cleaning of the wetted surfaces.
Switch off equipment and drain to waste in a manner approved by the local water authority.
Thoroughly clean the internal shell, fill and sump of the cooling tower, moving or flushing away all debris.
Refill with clean water.
Dose with free chlorine or other biocide at recommended levels and circulate for one hour.
Clean all filters, strainers, water nozzles, and fittings.
Refill with clean water and treat again as required.
Once Through Cooling Systems (Water Cooled Refrigeration)
Where will you see these types of systems:
Spot Cooling Applications
Coolers and Freezers
Businesses with these types of systems may include:
Pubs / Night Clubs