A fence is a freestanding structure designed to restrict or prevent movement across a boundary. It is generally distinguished from a wall by the lightness of its construction: a wall is usually restricted to such barriers made from solid brick or concrete, blocking vision as well as passage (though the definitions overlap somewhat).
Fences are constructed for several purposes, including:
* Agricultural fencing, to keep livestock in or predators out
* Privacy fencing, to provide privacy
* Temporary fencing, to provide safety and security, and to direct movement, wherever temporary access control is required, especially on building and construction sites
* Perimeter fencing, to prevent trespassing or theft and/or to keep children and pets from wandering away.
* Decorative fencing, to enhance the appearance of a property, garden or other landscaping
* Boundary fencing, to demarcate a piece of real property
Underground sprinklers (generally used for high-end home lawns and gardens) function through means of basic electronic and hydrolic technology. A 110 volt supplied controller, or sprinkler box sends a pre-determind 24 volt signal to an awaiting solenoid valve buried in the yard. This valve and all of the sprinklers that will be activated by this valve are known as a zone. Upon activation, the solenoid, which sits on top of the valve is magnetized lifting a small stainless steel plunger in its center. By doing this, the activated (or raised) plunger allows air to escape from the top of a rubber diaphragm located in the center of the valve. Water that has been charged and waiting on the bottom of this same diaphragm now has the higher pressure and lifts the diaphragm. This pressurized water is then allowed to escape down stream of the valve through a series of PVC pipes. Along these pipes and flush to grade level are pre measured and spaced out sprinklers. These sprinklers can be fixed spray heads that have a set pattern and generally spray between 7 and 15 feet, full rotating sprinklers that can spray a broken stream of water from 20 to 40 feet, or small drip emitters that release a slow, steady drip of water on more delicate plants such as flowers and shrubs..