TECHNICAL 71 geyser installation . The fact is that it is a backflow prevention device that is installed on an anti-siphon loop on the cold inlet and hot outlet of a properly executed geyser installation .
All a vacuum breaker does is to allow air into the system when a negative pressure ( vacuum — sufficient enough as to create a siphonic action ) is caused on any part of the installation , thus breaking the siphon . Have you ever tried siphoning fuel from a petrol tank using a pipe with holes in it ? It doesn ’ t work . This not only precludes the geyser being drained during shut down of the municipal water supply or when other maintenance is done on any part of the system , but also protects the quality of the water in the system from backflow of polluted water into the potable lines .
Figure 7 shows how without vacuum breakers installed , the bucket containing insecticide could be back siphoned into the potable water lines via the hosepipe and the connection to the municipal main supply or any other part of the system .
Many municipalities insist on vacuum breakers or B / A backflow preventers to be installed at all garden taps for this reason . A vacuum breaker thus in terms of backflow prevention device classification is an antivacuum valve D / A type .
CONCLUSION It is crucial that all of us in the industry take adequate measures to protect our precious water resources and to act responsibly on the understanding that we must be accountable for our actions .
We must also take cognisance of the South African National Regulations and understand the reasons behind them having been written . Rules and laws are written to protect the public and are sometimes written in anticipation of something nasty happening , or after a disaster has occurred . They are based on knowledge and common sense . Without knowledge , common sense cannot prevail .
Already , in our expanding population , there have been a great number of cases where people have been exposed to waterborne diseases and poisoning caused by irresponsible practice . The Romans understood this well and knew that to establish a strong and healthy nation , clean water supplies and proper sanitation were key . Some of these ancient systems are still in use today . They understood the theory of backflow prevention and many of their water supply systems incorporated methods and simple devices to prevent the backflow or ingress of polluted water into their clean water storage systems . PA
About the author Chris Kyle is the general manager at Calafrica Hydronic Solutions .
Figure 7 : Vacuum breakers prevent back siphoning of water .
www . plumbingafrica . co . za April 2018 Volume 24 I Number 2