Lockout/Tagout
Tags: Valve Safety Instrumentation
lockout/tagout positions
Lockout
The placement of a lockout device on an energy isolating device in accordance with an established procedure, ensuring that the energy isolating device and the equipment being controlled cannot be operated until the lockout device is removed.
tagout
The placement of a tagout device on an energy isolating device, in accordance with an established procedure, to indicate that the energy isolating device and the equipment being controlled may not be operated until the tagout device is removed.
lock open
Lock open is used on valves that must be open during normal operating conditions. A valve is termed "Lock Open" when it is required by the applicable code, safety protocols or standard operating conditions.
Examples of where would this be used would be on the inlet and outlet valves on a PSV.
lock closed
Lock closed is used on valves that must be closed during normal operating conditions. A valve is termed "Lock Closed" when it is required by the applicable code, safety protocols or standard operating conditions.
Examples of where would this be used would be on a blow down valve or on a bleed valve on a double block and bleed assembly.
lockout device
A device that utilizes a positive means such as a lock, either key or combination type, to hold an energy isolating device in the safe position and prevent the energizing of a machine or equipment. Included are blank flanges and bolted slip blinds.
tagout device
A prominent warning device, such as a tag and a means of attachment, which can be securely fastened to an energy isolating device in accordance with an established procedure, to indicate that the energy isolating device and the equipment being controlled may not be operated until the tagout device is removed. The tagout device must contain the name of the employee and the date the tag was applied to the device.
fail positions
Fail position is the term used to describe how an actuator reacts when there is a loss of power, loss of signal or similar event. There are three different fail scenarios, each has its own consequences and safety effects.
fail open
Fail Open is the term where a valve opens at loss of signal. This scenario might be chosen to prevent overpressure in the event of a blocked line or in case of a catastrophic failure.
When sizing a pneumatic actuator this is indicated as "spring to open" or "air to close."
fail closed
Fail Closed means the valve will closed when the signal is interrupted. An example of this would be block valves closing to isolate a steam injection well on loss of power. Because uncontrolled steam is dangerous and potentially lethal, automatic valve closure might be required.
When sizing a pneumatic actuator this is indicated as "spring to close" or "air to open."
fail in place
Fail in Place might apply to a ball valve or a control valve that does not react on loss of power or signal. This would be used where the process cannot be shut down or where it is undesired to do so.
normal positions
normally open
A normally open, as its name implied, it is to show which valves are open during standard operating conditions.
normally closed
Normally closed, as its name implied, it is to show which valve are open during standard operating conditions.
normal operation
The utilization of a machine or equipment to perform its intended production function.
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