Environmental Engineering Reference
In-Depth Information
In addition to the practical considerations for installation of these types
of covers, a number of operations and maintenance (O&M) concerns can
affect the utility of a cover for specific applications, including how the vari-
ous cover materials available will withstand local climatic conditions, what
types of cleaning and maintenance will be required for each particular type
of cover, and how these factors will affect the covers lifespan and its ability
to be repaired when it is damage.
The primary feature affecting the security of a reservoir cover is its ability
to maintain its integrity. Any type of cover, no matter what its construction
material, will provide good protection from contamination by rainwater or
atmospheric deposition, as well as from intruders attempting to access the
stored water with the intent of causing intentional contamination. The cov-
ers are large and heavy, and it is difficult to circumvent them to get into the
reservoir. At the very least, it would take a determined intruder, as opposed
to a vandal, to defeat the cover.
Active and Passive Security Barriers
One of the most basic threats facing any facility is from intruders accessing
the facility with the intention of causing damage to its assets. These threats
may include intruders actually entering the facility, as well as intruders
attacking the facility from outside without actually entering it (e.g., deto-
nating an explosive near enough to the facility to cause damage within its
boundaries). Security barriers are one of the most effective ways to counter
the threat of intruders accessing a facility or the facility perimeter. Security
barriers are large, heavy structures used to control access through a perim-
eter by either vehicles or personnel. They can be used in many different ways
depending on how they are installed or where they are located at the facility;
for example, security barriers can be used on or along driveways or roads to
direct traffic to a checkpoint (e.g., placement of jersey barriers to direct traffic
in particular direction). Other types of security barriers (e.g., crash beams,
gates) can be installed at the checkpoint so guards can regulate which vehi-
cles can access the facility. Finally, security barriers (e.g., bollards or security
planters) can be used along the facility perimeter to establish a protective
buffer area between the facility and approaching vehicles. Establishing such
a protective buffer can help in mitigating the effects of an explosive by poten-
tially absorbing some of the blast and by increasing the stand-off distance
between the blast and the facility. The force of an explosion is reduced as
the shock wave travels away from the source; thus, the greater the distance
between the target and an explosion, the less damage will be incurred.
Security barriers can be either active or passive.
Active security barriers
,
which include gates, retractable bollards, wedge barriers, and crash barri-
ers, are readily movable and are typically used in areas where they must
be moved often to allow vehicles to pass—such as in roadways at entrances
and exits to a facility. In contrast to active security barriers,
passive security
