Appendix D: Legionella testing protocols
From: Public Services and Procurement Canada
Definitions
- NLPL:
- Non-Legionella Pneumophila Legionella
- TBC:
- Total bacteria count
- CFU:
- Colony Forming Units
- LPTOT:
- Legionella Pneumophila (total all serogroups)
- LPSG1:
- Legionella Pneumophila Serogroup 1
- Culture test:
- Legionella bacterial culture test in accordance with ISO 11731
- CFU/ml:
- Colony Forming Units per millilitre
Figure 1: Cooling tower bacterial test protocol normal mode
Image description
Figure 1 describes the minimum bacterial testing and frequency requirements for cooling towers during normal operation and the required actions based on the testing results. For more information, please consult clauses 3.5.5, 3.5.6 and 3.5.7.
Notes
- Clean and disinfect system within 7 days.
- Option 1: Shutdown within 48 hours to perform the cleaning and disinfection procedure.
- Option 2: Perform a running disinfection within 48 hours. Shutdown within 7 days to perform cleaning and disinfection procedure.
- Perform additional culture testing if condenser water temperature is above 18 °C. If condenser water temperature is less than or equal to 18 °C then no additional culture testing is required.
- With adjusted O&M and water treatment program.
- Refer to MD 15161 clause 3.5.14 when there is interfering flora in the test result.
Figure 2: Open water system bacterial test protocol normal mode
Image description
Figure 2 describes the minimum bacterial testing requirements for open water systems during normal operation and the required actions based on the testing results. For more information, please consult clauses 4.4.5, 4.4.6 and 4.4.
Notes
- Clean and disinfect system within 7 days.
- Option 1: Shutdown within 48 hours to perform the cleaning and disinfection procedure.
- Option 2: Perform a running disinfection within 48 hours. Shutdown within 7 days to perform cleaning and disinfection procedure.
- With adjusted O&M and water treatment program.
- Refer to MD 15161 clause 4.4.14 when there is interfering flora in the test result.
Figure 3: Humidifier bacterial test protocol normal mode
Image description
Figure 3 describes the minimum bacterial testing requirements for humidifiers during normal operation and the required actions based on the testing results. For more information, please consult clauses 5.3.8 and 5.3.9.
Notes
- Clean and disinfect system within 48 hours.
- With adjusted O&M.
- Refer to MD 15161 clause 5.3.16 when there is interfering flora in the test result.
Figure 4: Hot water systems bacterial test protocol normal mode
Image description
Figure 4 describes the minimum bacterial testing requirements for domestic hot water systems during normal operation and the required actions based on the testing results. For more information, please consult clauses 6.4.19 and 6.4.20.
Notes
- Disinfect the system and flush the tank within 48 hours. Maintain tank temperature at a minimum of 50 °C until tank flushing and system disinfection.
- If the storage tank temperature is less than 60 °C then the storage tank temperature is to be adjusted to 60 °C where the system is equipped with measures to prevent scalding at the point of use.
- With adjusted O&M and storage tank temperature.
- Most remote fixture for systems with a storage temperature below 50 °C that serve multiple areas in a building and are not connected to showers.
- Refer to MD 15161 clause 6.4.27 when there is interfering flora in the test result.
- Clean the storage tank in accordance with manufacturer’s recommendations and disinfect the system.