Work Quiz Flashcards
Types of Sprinkler Systems
Wet Systems, Dry Systems, Deluge Systems, Pre-action Systems and Foam Systems
Wet Systems
Wet Systems are the most common and reliable types of sprinkler systems. This is because no equipment other than the sprinkler heads are required to operate. They are always filled with water with and under a moderate amount of pressure hence the name “Wet pipes” Not recommended where the pipes could freeze.
How do WET Systems Work?
Wet systems use automatic sprinkler heads to piping containing water and connected to a water supply. Water will be discharged immediately from an open sprinkler.
Dry Systems
Dry pipe sprinkler systems are usually installed in unheated buildings or where there is the possibility of sprinkler pipes freezing. The dry pipe valve and related equipment must be in a heated location. They re not filled with water but with compressed air. When activated, a valve releases the compressed air then allowing the water to fill the system. Has a slower reaction time.
How do DRY Systems work?
Dry systems have pressurized air in the sprinkler piping. This allows for supervision of the piping and keeps the dry pipe valve closed which prevents water from entering the system.
When the pressure drops low enough such as from an open sprinkler, the valve will open. This allows the water supply to fill the piping and be discharged through the open sprinkler. When the valve opens, it also exposes the alarm line to the incoming water supply.
When the pressure in this line reaches 6 psi, the water flow switch will trip.
Types of Sprinkler heads
Upright Sprinkler Heads: Found in open ceiling layouts
Pendant: Where the sprinkler aims down through a ceiling.
Side Wall: installed on walls close to the ceiling.
Sprinkler Components
Alarm Valve Butterfly Valve Dry Valve
FDC- Fire Department Connection Gauges
Inspectors Test Valve O S & Y Valve
Post Indicator Valve Pressure Valve
Retard Chamber Signage
Sprinkler Head Cabinet Sprinkler Heads
Sprinkler Wrench Tamper Switch
Water Flow Switch Water Motor Gong
What is a Deluge Systems
Deluge system is a water spray sprinkler system using open nozzles attached to a piping system that is connected to a water supply through a valve that is opened by means of a detection system installed in the same area as the sprinkler nozzles. Like a pre-action system, water enters the pipes when triggered by a heat or smoke detector. There may be a manual function, where pushing a button or pulling a chord activates the system. The sprinkler heads are open, meaning they don’t have a trigger function and are activated simultaneously.
How do DELUGE Systems work?
When the valve opens, water flows into the piping system and discharges through all nozzles attached to the system.
Pre-Action Systems
Pre-Action System is a sprinkler system employing automatic sprinklers that are attached to a piping system that contains air that might or might not be under pressure, with a supplemental detection system installed in the same areas as the sprinklers.These systems must be triggered TWICE before water is dispensed from the sprinkler head. The first trigger, usually a smoke detector or a heat detector that is separate from the sprinkler head- allows water into the pipes. (Acting now like a wet pipe system) The second trigger, the individual sprinkler heads, releases the water. This type of system provides added protection against false sprinkler activation.
What is a Backflow Preventer?
A backflow preventer is a means or mechanism to prevent backflow. The basic means of preventing backflow is an air gap, which either eliminates a cross-contamination or provides a barrie to backflow. The basic mechanism for preventing backflow is:
-A mechanical backflow preventer, which provides a physical barrier to backflow.
What are the Principal types of mechanical backflow preventers?
- The Reduced-Pressure Principle Assembly
- The Pressure Vacuum Breaker Assembly
- The Double Check Valve Assembly
A secondary type of mechanical backflow preventer is the Residential Dual Check Valve.
What is an RPZ Backflow?
An RPZ (Reduced Pressure Zone) is a mechanical backflow preventer that consists of two independently acting, spring-loaded check valves with a hydraulically operating, mechanically independent, spring-loaded pressure differential relief valve between the check valves and below the first check valve.
It includes shutoff valves at each end of the assembly and is equipped with test cocks. An RP is effective against back-pressure backflow and back-siphonage and may be used to isolate health or non-health hazards.
What is a DC Backflow?
A DC (Double Check) is a mechanical backflow preventer that consists of two independently acting, spring-loaded check valves. It includes shutoff valves at each end of the assembly and is equipped with test cocks.
A DC is effective against back-pressure backflow and back-siphonage but should be used to isolate only non-health hazards.
What is a PVB Backflow Preventer?
A PVB (Pressure Vacuum Breaker) is a mechanical backflow preventer that consists of an independently acting, spring-loaded check valve and an independently acting, spring-loaded air inlet valve on the discharge side of the check valve. It includes shutoff valves at each end of the assembly and is equipped with test cocks.
A PVB may be used to isolate health and non-health hazards but is effective against back-siphonage only.
