Fire hose couplings

TURNTABLE LADDERS

A turntable ladder, also known as an aerial ladder is the best-known form of specialized fire apparatus. Turntable ladders are used to rescue people from high-rise buildings or help firefighters to get access to fires occurring at height if they cannot get in through the lower floors and where other ladders can’t reach.

The name is derived from the fact that the large ladder is mounted on a turntable on the back of a truck, allowing it to move around a stable base, which in turn allows to achieve a much greater ladder length. In order to increase its length, the ladder is telescopic. Modern turntable ladders are hydraulic or pneumatic in operation.

In some cases, there may be a monitor at the top of the ladder. It can pump up to 1000 litres of water per minute down, or up, onto a fire that may be otherwise inaccessible to the crew below. Some turntable ladders may have a basket or platform mounted at the top of the ladder, and these are called tower ladders. These can provide a secure place for a firefighter to operate equipment from, and allow multiple people to be carried (including rescued persons).

The key functions of a turntable ladder are:

• Allowing access and escape of firefighters and victims at height;
• Providing a high level water supply for firefighting;
• Providing a working platform from which tasks such as ventilation or overhaul can be executed.

Turntable ladders are constructed of metal and are trussed to provide adequate strength. Their usual weight is 14 tones. The ladders generally range in length from 65 to 100 feet, but longer turntable ladders do exist. The usual width is 2,4 m. The ladder can reach up to 30 m in height. Since firefighting takes places in a very hot and dangerous environment with high risks, firefighters work in pairs. That is why the crew of two people operates the ladder.

Since the early use of leather and canvas hoses to carry water to fires, some means has been necessary to connect sections of the hose together. Even then hose couplings were made of metal. Fire hose couplings of today are made of durable material and so designed that it is possible to couple and uncouple in a short time with little effort. The materials used for fire hose couplings are generally alloys of brass, aluminum, or magnesium in varied percentages. Such materials do not corrode easily. Much of the efficiency of the fire hose operation depends upon the condition and maintenance of its couplings.

When the couplings are connected there is less danger of damage during common usage. Connected couplings seldom receive injury from being dropped or dragged. It is the disconnected separated ends that require the most protection. Connected couplings can be bent or crushed when they are run over by heavy vehicles.

Some simple rules for the care of fire hose couplings are as follows:

- avoid dropping or dragging couplings;

- do not permit vehicles to run over fire hose;

- examine couplings when hose is washed and dried;

- clean of tar, dirt, oil.

Дата добавления: 2014-12-29