Crane Safety Lights (Circuit Design & Positions)
Tall structures like large buildings are not built in a single week or even a month. It takes a long time, lots of effort, and equipment to build tall structures; therefore, there is a need for temporary cranes when these structures are being built.
As with any tall structure, the presence of any number of cranes can become a navigational obstacle for airplanes which has the potential to cause an accident. Therefore, “obstruction lights” or “safety lights” are installed on cranes to increase the visibility of the crane during night time operations. Obstruction lights are displayed at night and are positioned so that the lights are visible from all directions.
According to Federal Aviation Administration (FAA) and International Civil Aviation Organization (ICAO), all structures exceeding 200 feet (or 61 meters) above ground level must be appropriately marked with obstruction lights.
BASIC RULES:
- The number of light levels depends on the height of the structure;
- The number and arrangement of light units at each level should be placed so the obstruction lights are visible from every angle;
- Lights are applied to display the general shape of the structure;
- The width and length of buildings determine the number of lights that need to be installed at each light level.
| Height | Numbers and types of lighting |
| Height < 45m | 1 level of obstruction lights is needed: low-intensity obstruction lights |
| 45m < Height < 105m | 2 levels of obstruction lights are needed: top-level with medium intensity. intermediate with low intensity. |
| 105m < Height < 210m | 4 levels of obstruction lights are needed: top with medium intensity. 1st intermediate with low intensity. 2nd intermediate with medium intensity lower level with low intensity. |
Low Intensity Red Lights:
Short cranes are installed with low intensity red lights. They are positioned as close as possible to the highest point and must be visible from all directions.
Medium Intensity Red Lights:
Tall cranes will also have medium intensity red lights installed that are positioned at the highest point and both ends of the crane jib. The lighting will indicate the crane’s height and the radius of the crane’s jib. Depending on the cranes hight multiple levels of medium intensity lights may be needed.
Review: A crane is a machine that creates a mechanical advantage to move heavy loads. Cranes are mainly used for lifting and lowering construction materials.
There are many different types of cranes but the most recognizable are the “tower crane” and the “truck mounted crane”.
Practice Problems
- Describe how the “5V Regulator Project” works in regards to:
- What does a diode do? Would this circuit work without it? What do you think the main purpose of the diode is for?
- What does a capacitor do? Why do you think this circuit uses capacitors? What is the specific function of the capacitors in this circuit design?
- Describe what the L7805CV does and how it works.
- Describe how the “Adjustable Astable Timer Circuit” works in regards to:
- What is a potentiometer? What does it do and how does it work? What is the function of the potentiometer in this circuit? What does it do?
- What is a 555 timer. What does a 555 timer do?
- Describe how the 555 timer works when it is configured in “astable mode”.
- What does the capacitor do in this circuit? Why is the capacitor significant?
Course Navigation
Go to the previous lesson
Go to the next lesson