Final answer:
Pressure-reducing valves can be bypassed for fire department use by installing a bypass valve parallel to the PRV, controlled by a valve accessible to firefighters. Systems can also have automatic bypasses that activate based on predefined conditions. It's essential for these bypass mechanisms to be regularly tested and to comply with local building codes.
Step-by-step explanation:
Pressure-reducing valves (PRVs) are devices installed in water distribution systems to control and reduce the pressure from a higher input pressure to a lower, more manageable output pressure. While these valves are essential for the protection of plumbing systems and to ensure consistent water pressure for consumers, they need to be bypassed during a fire emergency to provide the high pressure required by fire department equipment. To enable firefighters to access the full water supply, a system should be equipped with a bypass that can be activated manually during emergencies.
To bypass a PRV in preparation for fire department use, a bypass valve is typically installed parallel to the PRV. This allows for an alternative path for the water to travel at higher pressure. The bypass can be operated via a control valve that is accessible to fire department personnel, usually near the PRV setup or in a location that is known to them. It is crucial that these valves are clearly marked and that fire department personnel are trained on their location and operation.
In some instances, automatic bypass systems can be installed which activate based on demand. This would allow for increased pressure without manual intervention, based on predetermined setpoints, such as a signal from a fire alarm or a drop in system pressure. Regardless of the method, it is critical that these bypass options are tested regularly to ensure they function correctly during an emergency.
Moreover, building codes often stipulate the installation of bypass systems and their compliance with safety standards. It is therefore necessary to consult local regulations and to work with certified professionals to ensure that the bypass systems are installed and maintained in accordance with legal and safety requirements.