Water sprinkler systems, automatic pipes

Sprinkler and water spray installations-Many process and storage area buildings should be protected by automatic sprinkler systems. The size and arrangement for water supply are dependent upon the nature of the hazard and the degree of protection desired. Water spray installations are particularly adapted for cooling uninsulated steel structures, elevated pipe lines, vessels, spheres, and similar plant installations. 

Automatic sprinkler systems have the great advantage that they are comparatively simple in concept and operate automatically, whether or not there are people present on the premises. Water is supplied from the public mains or tanks and pumps into a network of distribution pipes at ceiling level, which covers the whole premises. Water is discharged through nozzles or heads sited at regular intervals in the pipework, which are normally sealed with a he at-sensitive device. 

Wet-pipe Sprinkler System An automatic sprinkler system in which the pipes are constantly filled with water under pressure. 

Zones 2 and 3 of the HCF are protected by an automatic wet-pipe sprinkler system. The sprinkler system is designed for Ordinary Hazard Group 2 occupancy. Therefore, this system will be able to accommodate any unforeseen increases in ordinary combustible loading. The HCF is below grade and will contain any firefighting water used. It is also equipped with heat... 

A combiuatiou of water discharge devices (sprinklers), distribution piping to supply water to the discharge devices or more sources of water under pressure, water flow controlling devices (valves), and actuating devices (temperature, rate of rise, smoke, or other type device). The system automatically delivers and discharges water in the fire area. 

Wet-Pipe Systems. This type of system contains water under pressure at all times water will be discharged immediately on operation of an automatic sprinkler. Water flowing from the wet-pipe sprinkler system actuates an alarm valve that gives off a signal. Hgnre 4.92 illustrates the total concept of the wet-pipe antomatic sprinkler system. 

There are several types of automatic sprinkler systems. These systems have piping of different sizes with sprinkler heads attached and connected to a large water supply. These heads are heat activated by a fire. They will then discharge water over the fire area. There are basically six types of automatic sprinkler systems. 

The principal difference between a pre-action system and a standard dry pipe system is that in the pre-action system, the water supply valve is actuated independently of the opening of the sprinklers. The water supply valve is opened by the operation of an automatic fire detection system, which immediately allows water to enter the overhead piping. Then, when the fire generates enough heat to fuse the sprinkler head, water is immediately discharged on the fire as with a wet pipe system. This system reduces the inherent time lag of a dry pipe system, but can still be used in unheated areas. An example of a pre-action system is shown in Figure 7-26. 

Don t use sprinklers automatic irrigation systems, such as sub-soil drip pipes that allow water to drip into the soil, make great alternatives to sprinklers, and use far less water. They are especially useful for times when you are out of town. 

Where subject to temperatures below 40°F (5°C), a wet-pipe system cannot be used.There are two recognized methods of maintaining automatic sprinkler protection in such locations (1) through the use of systems where water enters the sprinkler piping only after operation of a control valve... 

Local/external alarm - once the alarm monitoring unit has detected a situation that triggers an alarm it may activate a local and external alarm. The local alarm which indicates that there is a flow in the system is commonly achieved by the use of a Pelton wheel where a small quantity of water that is flowing through the range pipes is diverted and turns a mechanical bell situated near the sprinkler control valve location. The alarm can be raised externally through an automatic link to a commercial, alarm receiving centre (ARC). 

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