Backflow Prevention and Cross-Connection Control

Backflow prevention and cross-connection control under the Ontario Building Code, CSA B64.10 and municipal water by-laws, followed through an apprentice protecting a Hamilton mixed-use tower: why cross-connections matter; backpressure and backsiphonage; surveying buildings for cross-connections; minor, moderate and severe hazards; air gaps and atmospheric vacuum breakers; pressure and spill-resistant vacuum breakers; double check valve assemblies; reduced pressure principle assemblies; premise, zone and fixture isolation; installation requirements; field testing with a differential gauge; and cross-connection control programs, tester certification and records.

PLB-320 12 lessons · 4 h 9 min ▶ Video lessons coming soon

Offered by HSM University · Plumbing

This is the Canadian version of this course. See the American version.

What you'll learn

Explain why cross-connections endanger public health, using documented waterborne disease and contamination incidents, and describe the shared responsibility of plumbers, owners and water suppliers.
Distinguish backsiphonage from backpressure, calculate the pressures involved, and identify the building conditions that create each.
Survey a building for cross-connections, recognize common direct and indirect connections, and record findings in a form a utility can use.
Classify cross-connections as minor, moderate or severe hazards following the Ontario Building Code and CSA B64.10, and explain how the class sets the level of protection.
Size air gaps and install atmospheric and hose connection vacuum breakers correctly, including height, downstream valve and continuous pressure limits.
Describe how pressure and spill-resistant vacuum breakers work, where they may be used, and how high they must be installed above the downstream piping.
Explain the operation and limits of double check valve assemblies, double check detector assemblies and dual check valves, and account for their pressure loss and thermal expansion effects.
Explain how a reduced pressure principle assembly protects against both backsiphonage and backpressure, and size the drain for its relief valve discharge.
Select the correct device for premise, zone and fixture isolation from the hazard, the type of backflow and whether the condition is continuous pressure.
Install backflow preventers with correct height, clearance, drainage, orientation, strainers and thermal expansion control, and commission them before use.
Describe field test procedures for reduced pressure assemblies, double checks and vacuum breakers, interpret differential gauge readings, and decide whether a device passes.
Explain how a cross-connection control program works, including surveys, tester certification, test reports, scheduling and enforcement.

Course content

12 lessons · 4 h 9 min total · final exam

1 Why cross-connections matter 20 min · quiz
2 The hydraulics of backflow: backpressure and backsiphonage 24 min · quiz
3 Cross-connections in buildings 21 min · quiz
4 Degrees of hazard: minor, moderate and severe 20 min · quiz
5 Air gaps and atmospheric vacuum breakers 21 min · quiz
6 Pressure vacuum breakers and spill-resistant vacuum breakers 22 min · quiz
7 Double check valve assemblies 21 min · quiz
8 Reduced pressure principle assemblies 20 min · quiz
9 Selecting the right device: premise, zone and fixture isolation 20 min · quiz
10 Installation requirements for backflow preventers 20 min · quiz
11 Field testing backflow prevention assemblies 20 min · quiz
12 Cross-connection control programs, tester certification and records 20 min · quiz
E Final exam 20 questions

Requirements

PLB-210 National Plumbing Code I

Recommended background. You can start any course at any time.