When a sprinkler (1) opens, the water discharging lifts the valve clapper (2) and flows through the alarm port (3) to the retard chamber (4) if equipped. When the retard chamber is filled water flows to the water motor alarm bell (5) and the waterflow alarm switch activating the alarm bell and the fire alarm panel initiating circuit.
Disadvantages to using a wet pipe fire sprinkler system include:
Wet pipe systems are the most common fire sprinkler system. A wet pipe system is one in which water is constantly maintained within the sprinkler piping. When a sprinkler activates this water is immediately discharged onto the fire.
Advantages to using a wet pipe fire sprinkler system include:
System simplicity and reliability - Wet pipe sprinkler systems have the least number of components and therefore, the lowest number of items to malfunction. This produces unexcelled reliability which is important since sprinklers may be asked to sit in waiting for many years before they are needed. This simplicity aspect also becomes important in facilities where system maintenance may not be performed with the desired frequency.
Relative low installation and maintenance expense - Due to their overall simplicity, wet pipe sprinklers require the least amount of installation time and capital. Maintenance cost savings are also realized since less service time is generally required compared to other system types. These savings become important when maintenance budgets are shrinking.
Ease of modification - Wet pipe fire sprinkler systems are advantageous since modifications involve shutting down the water supply, draining pipes and making alterations. Following the work, the system is pressure tested and restored. Additional work for detection and special control equipment is avoided which again saves time and expense.
Short term down time following a fire - Wet pipe sprinkler systems require the least amount of effort to restore. In most instances, sprinkler protection is reinstated by replacing the fused sprinklers and turning the water supply back on. Pre-action and dry-pipe systems may require additional effort to reset control equipment.
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