Environmental Engineering Reference
In-Depth Information
• “No Trespassing” signs posted along a fence can be a valuable tool
in prosecuting any intruders who claim that the fence was broken
and that they did not enter through the fence illegally. Adding signs
that highlight the local ordinances against trespassing can further
dissuade simple troublemakers from illegally climbing the fence.
Films for Glass Shatter Protection
Most water utilities have numerous windows on the outside of buildings, in
doors, and in interior offices. In addition, many facilities have glass doors or
other glass structures, such as glass walls or display cases. These glass objects
are potentially vulnerable to shattering when heavy objects are thrown or
launched at them, when explosions occur near them, or when there are high
winds. If the glass is shattered, intruders may potentially enter an area. In
addition, shattered glass projected into a room from an explosion or from an
object being thrown through a door or window can injure and potentially
incapacitate personnel in the room. Materials that prevent glass from shat-
tering can help to maintain the integrity of the door, window, or other glass
object and can delay an intruder from gaining access. These materials can
also prevent flying glass and thus reduce potential injuries.
Materials designed to prevent glass from shattering include specialized
films and coatings. These materials can be applied to existing glass objects
to improve their strength and their ability to resist shattering. The films
have been tested against many scenarios that could result in glass breakage,
including penetration by blunt objects, bullets, high winds, and simulated
explosions. They are tested against simulated weather scenarios (including
high winds and the force of objects blown into the glass), as well as criminal
or terrorist scenarios where the glass could be subject to explosives or bul-
lets. Many vendors provide information on the results of these types of tests
so potential users can compare different product lines to determine which
products best suit their needs. The primary considerations with regard to
films for shatter protection are
• The materials from which the ilm is made
• The adhesive that bonds the ilm to the glass surface
• The thickness of the ilm
Fire Hydrant Locks
Fire hydrants are installed at strategic locations throughout a community's
water distribution system to supply water for fire fighting. Because the
many hydrants in a system are often located in residential neighborhoods,
industrial districts, and other areas where they cannot be easily observed
or guarded, they are potentially vulnerable to unauthorized access. Many
municipalities, states, and USEPA regions have recognized this potential
