Although we generally tend to think of energy being constantly supplied via outlets and in turn think that energy can be switched off using a switch or similar device, there are many instances when stored energy is also used to power a piece of machinery, particularly in the event of the regular continuous power source ceasing operation.
As a result of this, during lockout procedures it is important to determine not only the main source of power from a continuous energy source but is also of extreme importance to determine any stored energy sources and take steps to lock them out and drain any excess residue energy before maintenance teams can go ahead with repairs.
If this wasn’t done, it is perfectly possible for the stored energy source to activate while maintenance is being carried out on dangerous machinery, thus reactivating the machinery and potentially gravely injuring someone who might be inside the machine at that point in time.
An example of stored energy being used would be a battery backup being in place to activate when electrical power is cut off, primarily used in the presence of a blackout.
Stored energy can be present in many different forms, and here’s a brief guide to ensure you know exactly what types to look for and some of the steps you can take to prevent stored energy from being used.
Gas Release
Sometimes hazardous gasses used in many processes can be left behind in areas where teams are about to work. Since some gasses are completely invisible but can be extremely dangerous, the process of siphoning away these gasses is of the utmost importance.
To do so, the most common method is to locate the ball, gate, butterfly or other type of valve that is used for siphoning the gas away. By using this valve, the residual pressure inside a line or accumulator is released and dissipated.
Gravity Control
In machinery that has vertical moving parts, the force of gravity can suddenly move parts of the machinery even when it is powered down.
In order to prevent this, maintenance teams must use pins, blocks or similar devices that rigidly hold vertical machinery in place and ensure that it cannot be moved at all by gravity or other forces.
Motion Control
If any machinery can suddenly be moved by any means without a continuous energy supply, the maintenance team must ensure that this cannot happen.
Not doing so could result in a moving machinery part being moved when a worker was near it, leading to a potential injury scenario.
To perform this control, the team uses pins and restraints to stop the movement of machinery, particularly cylinder operated slides.
Dissipate Rotation
Flywheels and other forms of spinning equipment should be fully stopped and not be able to move.
The maintenance team should check this rigorously before proceeding with maintenance.
Release Hydraulic
Hydraulic pressure inside oil actuators can be siphoned away by the use of a ball valve.
Release Water
The presence of water inside multiple areas, particularly those that might be enclosed, runs many risks.
It is important when locking down water-based energy sources that a ball valve is used to release residual water pressure, and that any water is also drained away to ensure it can’t flow when maintenance personnel may be working in an enclosed space.
Release Pneumatic
The air pressure held within machinery can also be a catalyst for injury – make sure any residue energy is completely siphoned away by use of a ball or gate valve which will remove any compressed air pressure.
Release Chemical or Coolant.
The pressure that drives dangerous chemicals and coolants must also be handled by use of a ball/gate valve.
Not doing so could cause damage via dangerous chemicals or result in flammable chemicals being ignited by unforeseen circumstances.
Release Electrical
Any capacitors that supply electrical energy must be left to discharge for 2-5 minutes and must be checked thoroughly to ensure all excess energy is no longer present.
Release Steam
Steam can have extremely high temperatures, and it is important to syphon away excess steam to prevent extreme burns from happening to maintenance personnel.
To siphon away steam, the person carrying out the lockout uses a ball, gate or butterfly valve to gradually release steam pressure from an area.
Thermal Energy Dissipation
Devices with extreme temperatures must be allowed to warm up or cool down before maintenance work proceeds. The threshold for extreme temperature is 105 degrees Fahrenheit for hot and below 28 degrees Fahrenheit for cold.
