Fluid power is harnessed through either hydraulics or pneumatics technologies, which use a liquid or gas, respectively, to transmit power from one location to another. These have their basis in Pascal’s Law, which states that when there is an increase in pressure at any point in a confined fluid, there is an equal increase at every other point in the container. Hydraulics and pneumatics make use of this concept to multiply forces and move power throughout the system. Even though it is not as popular as electromechanical energy, fluid power has many distinct advantages that make it ideal for different services. Additionally, there are many unique qualities to fluid power based machines, so it is essential to maintain the proper guidelines while creating them.
Electricity, despite being one of the main ways that we transmit energy throughout the world, can be incredibly hazardous. According to OSHA, 8.4 percent of all construction fatalities in the United States in 2014 were the result of electrocution, and it is considered one of construction’s “Fatal Four”. Certain environments, such as working during a light rainstorm, can contribute even more to these hazards, and sometimes just a spark is needed to set off a disastrous event. While there are many techniques to mitigate electric shock and related hazards such as burn, machines that use fluid as the source of power avoid this life-threatening issue almost entirely.
Another major advantage of fluid power is that pressure can remain constant without having to apply significant amounts of additional energy to the system. Hydraulic or pneumatic pumps are easier and more cost effective for tasks that require both pressure and position control. Compare this to an electric motor, which requires constant torque to drive and can lead to overheating if it is not limited by the control system. The high levels of power that can be achieved through relatively simple means in hydraulics makes the technology ideal for certain types of heavy equipment, such as cranes, lifts, bulldozers, and diggers.
Hydraulic and pneumatic systems contain many unique components that together coordinate the movement of the fluid throughout the circuit to transfer power. ISO 5598:2008: Fluid power systems and components – Vocabulary establishes the terminology associated with all aspects of fluid power, spanning from construction of machines to their use, which is very helpful for those not well versed in the subject.
Properly marking the different components in fluid power circuits is essential for the functioning of these machines in an efficient and safe manner. ISO 1219-1:2012: Fluid power systems and components – Graphical symbols and circuit diagrams – Part 1: Graphical symbols for conventional use and data-processing applications provides specifications for graphic markings meant to label the fluid power system components at their de-energized, or at rest, position.
While fluid power lacks some of the hazards that are common with electrical machinery, it still maintains many of the same machinery-related opportunities for workers to come under harm and has some unique associated hazards. For example, it is necessary to maintain proper pressure in fluid power machinery to prevent it from behaving erratically and bringing harm to the machine’s operator. The Hydraulic and Pneumatic Fluid Power Safety Package accommodates many of these issues by including different standards that together provide guidelines for hydraulics, pneumatics, and machines in general, dealing with their design, construction, and modification.
The National Fluid Power Association (NFPA) is an ANSI-accredited standards developing organization that publishes standards relating to both hydraulics and pneumatics technologies.