How many times have you gotten a negative response when notifying the customer that the water will be turned off for the test and/or repair of a containment backflow prevention assembly that is a critical service?
Through the years of enforcing San Antonio Water System's Backflow Prevention Program and today actually being involved in the testing and repairing of assemblies, we have always had to deal with many critical services not having manifold installations (bypass arrangements). The reason for a manifold installation is that one backflow prevention assembly can be left on at a time of testing and/or repair. If the installation does not have a manifold backflow prevention assembly, the water has to be turned off to the facility. The only exception being if there happens to be an additional service connection or water source to the facility.
Containment (premise isolation) backflow protection on a critical service can become a nightmare for the facility, tester and enforcement agency. The tester is usually blamed for problems encountered for the water outage while testing or repairing an assembly. Testers have actually been held liable from the facility's viewpoint for an unexpected complicated repair.
Unfortunately facilities like kidney dialysis centers, shopping centers, hospitals, chemical manufacturing plants, high rise office buildings and hotels sometimes have containment backflow protection with no bypass arrangement. Of course the bypass arrangement when installed must have the same type of backflow protection as the main line. If the bypass assembly is to be smaller in size, the sizing should be determined by the facility.
Is this a tester related problem or an engineering snafu? In most instances we view it as an engineering oversight, not to include a manifold installation on a critical service. Water purveyors will sometimes call it to the attention of the design engineer, only to be told by the engineer, "they do not see the necessity of a bypass arrangement and the water can be turned off at night to test and repair the assembly". This drops the ball in the lap of the facility and tester that now has to contend with the testing and repair of the backflow preventer for many years, sometimes resulting in complete and unexpected water outages due to a malfunctioning backflow preventer.
In San Antonio, testers have gone so far as to require a critical service type facility to sign a statement to the affect that the tester will not be liable or responsible for any problems encountered while testing or repairing an assembly without a bypass arrangement.
Draft -- Example of Possible Notice Below:
Notice: Please read the following and with your concurrence and understanding, Johnny's Backflow Service will proceed with testing the containment backflow prevention assembly.
The following is in regard to the containment backflow prevention assembly (BFPA) installed on our incoming water service. The BFPA is installed on what is considered a critical service, i.e., continuous and uninterrupted water service is imperative in the operation of the facility. The BFPA has no bypass arrangement and therefore the water will have to be turned off to the facility in performing the test. This can take from 15 to 30 minutes or longer. This time allocated is only an estimate and can vary with some installations. If a problem occurs while performing the testing procedure, the BFPA could be off for an extended time for repairs.
Johnny's Backflow Service will not be held liable or responsible for problems that can occur with turning the water off to test the backflow prevention assembly. It is the facility's responsibility to ensure all equipment and processes are placed in the appropriate position to allow for discontinuance of water service. Additionally, Johnny's Backflow Service will not be responsible for liable for any contamination events that occur inside the building due to the loss of water pressure and unprotected, internal cross connections.
It is strongly recommended that a bypass arrangement be installed around the containment backflow prevention assembly. The size of the bypass would be determined by the facility. The bypass arrangement will also need a BFPA of the same type. Reduced pressure principle backflow prevention assemblies are capable of dumping an extreme amount of water and without a bypass arrangement can interrupt water service to the facility.
Questions or comments can be directed to Johnny's Backflow Service @ 888-***-**** or your local water department.
I/We have ready and understand the above and we hold harmless Johnny's Backflow Service from problems encountered in the testing and maintenance of the backflow prevention assembly.
Hopefully such a statement would be a wake-up call to a critical service type facility that:
(1) "A manifold installation is a necessity and any problems encountered will not fall back on the tester". Such a statement might also be used as support for the facility's maintenance engineer to obtain the funds for a manifold installation.
(2) Those in the design and engineering of water services to facilities where continuous water service is a necessity should be thoroughly educated on the testing and maintenance involved with backflow prevention assemblies. Also, reduced pressure principle backflow prevention assemblies (RP) gave a relief valve that can dump a lot of water in a full open position, basically severing the water service to the facility and can potentially cause flooding problems.
We know this is not all inclusive of the various situations we see in the field and that there are many variables that can apply in determining what is and is not considered a critical service.
Design Engineers need to "speak some basic backflow" and understand what's involved in the testing and maintenance of backflow prevention assemblies and what can go wrong! The critical service facility representatives also need to be aware of the basic operation of an RP, i.e., appropriate drainage for relief valve, water being off for an extended period, flooding potential, etc.