Explain the difference between a wet pipe sprinkler system and a dry pipe sprinkler system, including their advantages and disadvantages.

A wet pipe sprinkler system is a fire suppression system where the pipes are constantly filled with water under pressure. When a fire occurs and a sprinkler head is activated by heat, the pressurized water is immediately discharged onto the fire. The main advantage of a wet pipe system is its rapid response time. Because the pipes are already filled with water, there is no delay in water discharge. Wet pipe systems are also relatively simple and inexpensive to install and maintain. However, the disadvantage of a wet pipe system is that it cannot be used in locations where the temperature may drop below freezing, as the water in the pipes could freeze and damage the system. A dry pipe sprinkler system, on the other hand, is a fire suppression system where the pipes are filled with pressurized air or nitrogen, rather than water. When a fire occurs and a sprinkler head is activated, the pressurized air is released, which opens a dry pipe valve and allows water to flow into the pipes and onto the fire. The advantage of a dry pipe system is that it can be used in locations where the temperature may drop below freezing, as there is no water in the pipes to freeze. However, the disadvantage of a dry pipe system is its slower response time. It takes time for the air to be released and for the water to fill the pipes, which can delay the discharge of water onto the fire. Dry pipe systems are also more complex and expensive to install and maintain than wet pipe systems.