BACKFLOW PREVENTION

Information­Rules and Regulations

Backflow regulations are outlined in the National Plumbing Code of Canada, 1995 edition. Protection from contamination is briefly described in the section 6.2 of the Code. The Code also incorporates the Canadian Standards Association (CSA) B64.10 Standard which is more detailed than the Code. The Code can be obtained through the Queens Printers (780) 427-4952 and the CSA B64.10 Standard through the CSA Office in Edmonton at (780) 450-2111.

Western Canada Water and Waste Water Association also has an excellent reference book on backflow prevention. It can be obtained by writing to Western Canada Water & Wastewater Association at Suite 203, 301 - 14 Street N.W., Calgary, Alberta. T2N 2A1.

Our Industry

Backflow is generally classified into three groups­severe, moderate and minor.

Pressure washers with aspirators are generally classified as severe hazards and require an air gap or a reduced pressure principle backflow preventer (RP) on the water supply for protection.

A minor hazard would only make the water aesthetically objectionable. A pressure washer without an aspirator connected to a hose bibb would qualify for this type of hazard. A simple hose connection vacuum breaker would suffice to protect the water supply.

Thanks to Roland Tomuschat at Aqualta. He may be reached at (780) 412-6806.

Chemical Dispensers

As dispensing systems connect to the potable water supply, a backflow preventer is required.

Subject to the conditions that appear below, a Dual Check Atmospheric Port (DCAP) is the minimum acceptable backflow prevention device that may be with dispensing units.

1. The proportion unit is equipped with a manual button which must be physically held in the open position while the container is being filled. Note: If the button is lockable, the degree of hazard for the total installation will increase, therefore a Reduced Pressure Principal Type Backflow Preventer will be required.

2. The "DCAP" Backflow Preventer will only be subjected to a back-siphonage condition.

3. The chemical or detergents used will not exceed a moderate hazard as per the chemical manufacturer's analysis report.

4. The complete installation would be considered a minor hazard based on the probability of a backflow condition occurring. (A negative pressure on the water supply line, with simultaneous failure of the backflow device while the manual button on the proportion unit is held in the open position.)

5. If the degree of hazard is in excess of that mentioned in Point 3 or 4 above, a Reduced Pressure Principal Type Preventer shall be used.