Environmental Engineering Reference
In-Depth Information
behind the hatch. Like all doors, a hatch consists of a frame anchored to
the horizontal structure, a door or doors, hinges connecting the door to the
frame, and a latching or locking mechanism that keeps the hatch door closed.
It should be noted that improving hatch security is straightforward and
that hatches with upgraded security features can be installed new or they
can be retrofit for existing applications. Many municipalities already have
specifications for hatch security at their water and wastewater utility assets.
Depending on the application, the primary security-related attributes of a
hatch are the strength of the door and frame, its resistance to the elements
and corrosion, it ability to be sealed against water or gas, and its locking
features. Hatches must be both strong and lightweight so that they can with-
stand typical static loads (such as people or vehicles walking or driving over
them) while still being easy to open. In addition, because hatches are typi-
cally installed at outdoor locations, they are usually fabricated out of corro-
sion-resistant metal that can withstand the elements such as high-gauge steel
or lightweight aluminum.
The hatch locking mechanism is perhaps the most important component of
hatch security. A number of locks can be implemented for hatches, including
• Slam locks (internal locks located within the hatch frame)
• Recessed cylinder locks
• Bolt locks
• Padlocks
Ladder Access Control
Water and wastewater utilities have a number of assets that are raised above
ground level, including raised water tanks, raised chemical tanks, raised
piping systems, and roof access points into buildings. In addition, communi-
cations equipment, antennae, or other electronic devices may be located on
the top of these raised assets. Typically, these assets are reached by ladders
that are permanently anchored to the asset; for example, raised water tanks
typically are accessed by ladders that are bolted to one of the legs of the tank.
Controlling access to these raised assets by controlling access to the ladder
can increase security at a water or wastewater utility.
A typical ladder access control system consists of some type of cover that is
locked or secured over the ladder. The cover can be a casing that surrounds
most of the ladder or a door or shield that covers only part of the ladder. In
either case, several rungs of the ladder (the number of rungs depends on the
size of the cover) are made inaccessible by the cover, and these rungs can
only be accessed by opening or removing the cover. The cover is locked so
only authorized personnel can open or remove it and use the ladder. Ladder
access controls are usually installed at several feet above ground level, and
they usually extend several feet up the ladder so they cannot be circum-
vented by someone accessing the ladder above the control system.
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