> Pre-Action System
A Pre-action system is used primarily in freezers or computer rooms and is a fail safe method of using a wet system to protect an area. The pre-action system has a special valve which holds the water from entering the system mechanically. All other aspects of the system are like a wet system, it is calculated as one, and performs as a wet system. The piping in a pre-action system extends to sprinklers which are closed and ready to fuse. The system piping can be under air pressure which it called supervisory air or it may not be. since the valve must be tripped by sensors in the area of protection, it is normally done with a separate set of electrical detectors.

These detectors send and signal back to the pre-action valve which trips the valve. This case would be a single action pre-action valve. Upon one signal the valve would release water into the system. In the case where a greater measure of assurance against water inadvertently entering the system, a double action system is used. In this case the valve must have both a signal from the detectors in the area, and the release of air in the system piping to release water into the system.

Main Points to Establish

Main Control Valve
* Is the main control valve open and all valves down stream of the connection to the water supply open?
* Is this and all other valves controlling water to the system locked in the open position or supervised and functioning?

Pressure Gauges
* Supply water pressure beneath the valve should be shown.
* Pressure in the auxiliary chamber on the side of the valve.
* If there is supervisory air, there should be air pressure indicated in the system piping. This usually is a very low pressure.

Alarm Mechanism
* The alarms for a pre-action system are the same as for a wet accept all pre-action valves use a panel which monitors the detection sensors and supervisory air. Panel receives the signals and actually trips the valve.

Drain
* This valve allows the system to be drained and is used to test to see if the city water valve is open. This is done by opening the valve wide open while reviewing the pressure drop on the pressure gauge. The loss should not be significant. If it is the city water supply should be investigated.

Fire Department Connection
* This is used to allow the fire department to pump into, using their pumper truck to supplement the city water pressure. Threads should be checked to see if they meet standard threads used by local fire department.

Alarm Testing Apparatus
* Since the testing of a pre-action valve involves flowing water into an area of high concern, this testing must be done by a qualified contractor and special testing apparatus.

Sprinklers
* There should be a supply of extra sprinklers in the facility as per NFPA #13 and a sprinkler wrench.
* As you walk through a facility there should be no gaps in coverage in those areas requiring sprinklers.
* The question should be asked if any area has been changed from one occupancy to another after original system had been installed.
* Are any sprinklers blocked or painted?
* What is the age of the sprinklers?

Certification of Inspection
* The owner, under NFPA #13A, is responsible for certain tests and the collection of certain data to demonstrate the performance capability of the system. The owner should have documentation of periodic testing and inspection.

 

|| home | about us | services | faq | testimonials | employees | industry links | contact us ||

Email Us! Bay Line Fire Protection Website! Iron Motorsports Website! A Head 4 A Cure Website! Home About Us Services Faq Testimonials Employees Industry Links Contact Us