1.0 INTRODUCTION
Vertical transportation systems are of vital importance in high-rise buildings. Escalators are used on lower floors for moving high volumes of people over short distances. In Nigeria few retail buildings and airports have escalators, and many commercial buildings have elevators, and elevators could be said to be the most common means of vertical transportation in tall buildings in Nigeria. Lifts can be defined as devices used for vertical transportation of passengers or freight to different floors or level in buildings or mines David J.O (2011).
An elevator (or lift in the Commonwealth excluding Canada) is a type of vertical transport equipment that efficiently moves people or goods between floors (levels, decks) of a building, vessel or other structures. Elevators are generally powered by electric motors that either drive traction cables or counterweight systems like a hoist, or pump hydraulic fluid to raise a cylindrical piston like a jack. In agriculture and manufacturing, an elevator is any type of conveyor device used to lift materials in a continuous stream into bins or silos.
Several types exist, such as the chain and bucket bucket elevator, grain auger screw conveyor using the principle of Archimedes’ screw, or the chain and paddles/forks of hay elevators . Simply put an elevator is a hoisting or lowering mechanism which moves in a vertical direction. , while an escalator is a continuous moving stair which operates without attendant at a speed of approximately 98feet per minute on 30o incline.
A low rise building might be described as one where the able bodied do not need a lift to reach their floor, but if one is available they invariably use it. This would imply a building of 3-5 floors. A mid rise building is one where there may be 8-10 floors and the lift becomes essential, in order for occupants to use the building. A high rise building might be one which contains 15-16 floors and maybe equipped with lifts serving two zones. Low, mid and high rise buildings describe the majority of the building stock of Nigeria commercial cities..
Tall buildings might be defined as those buildings over 30/40 stories high. This height can be related to nature, as the tallest tree ever measured was 132. 6 m. The Council on Tall Buildings and Urban Habitat survey of the 100 tallest buildings in 1999 (reported in Elevator World, 1999) indicated 63 were in North America, 30 around the rest of the Pacific Rim, four in Europe (one in London) and three others. The heights of the top 50 ranged from 260-450 m, a 190 m range, whilst the bottom 50 ranged from 230-260 m, a 30 m range.
There must be hundreds of buildings between 130 m (the highest tree) and 230 m. Very tall buildings sometimes described as `monumental’ buildings are few in number compared to the totality of buildings world wide and their traffic design requires expert consideration. The tallest building in Nigeria and fourth in Africa is the 160m (520 feet) NITEL building Lagos, with 32 floors. The world’s tallest man made structure is the 829. 8m (2,722 ft) tall Burj Khalifa in Dubai, United Arab Emirates with 163 floors.
The building gained the official title of “Tallest Building in the World” at its opening on January 4, 2010. It is with the help of vertical transportation, can movement of people be possible in these “One Roof Towns”. The comparison made above between a high-rise building and a small town also applies with tens of thousands of people that stream into a mega building to start work and leave again within a very short space of time at the end of the day. or with regard to the number of people inside the building: in the course of a few hours every morning,
