Valve lockout devices

Different security products are available to protect aboveground versus belowground valves. For example, valve lockout devices can be purchased to protect valves and valve controls located aboveground. Vaults containing underground valves can be locked to prevent access to these valves. 

As described above, a lockout device can be used as a security measure to prevent unauthorized access to aboveground valves located within chemical processing systems. Valve lockout devices are locks that are specially designed to fit over valves and valve handles to control their ability to be turned or seated. These devices can be used to lock the valve into the desired position. Once the valve is locked, it cannot be turned unless the locking device is unlocked or removed by an authorized individual. 

The valve was operated by compressed air, and the two air hoses, one to open the valve and one to close it, were connected up the wrong way around. The two connectors should have been different in size or design so that this could not occur. In addition, they were not disconnected, and a lockout device on the valve—a mechanical stop—had been removed. It is also bad practice to carry out work on equipment isolated from hot flammable gas under pressure by a single isolation valve. The take-off branch should have been slip-plated, and double block and bleed valves should have been provided so the slip-plate could be inserted safely (Figure 1-1), [16, 17]. 

The accident investigation evidence showed that this safe procedure was not followed specifically, the product takeoff valve was removed, the DEMCO valve was in the open position, and the lockout device was removed. This scenario was a serious violation of well-established and well-understood procedures and created the conditions that permitted the release and subsequent explosion. 

Many of these lockout devices are not specifically designed for use in the chemical industry (e.g., chains, padlocks) and are available from a local hardware store or manufacturer specializing in safety equipment. Other lockout devices (for example, valve-specific lockouts or valve box-locks) are more specialized and must be purchased from safety or valve-related equipment vendors. 

The three most common types of valves for which lockout devices are available are gate, ball, and butterfly valves. Each is described in more detail below. 

Butterfly valve lockouts. The butterfly valve lockout functions in a similar manner to the ball valve lockout. The polypropylene lockout device is placed over the valve handle and secured with a padlock. This type of lockout has been commonly used in the bottling industry. 

A major difference between valve-specific lockout devices and the padlocked chain or cable lockouts discussed earlier is that valve-specific lockouts do not need to be secured to an anchoring device in the floor or the piping system. In addition, valve-specific lockouts eliminate potential tripping or access hazards that maybe caused by chains or cable lockouts applied to valves located near walkways or frequently maintained equipment. 

The DEMCO valve did not have its lockout device in place. 

Lockout is accomplished by installing a lockout device at the power source so that equipment powered by that source cannot be operated. A lockout device is a lock, block, or chain that keeps a switch, valve, or lever in the off position. 

The supervisor turns the valve to the off position and places a plastic, circular lockout device over the valve. He then adds a lock and tag. 

Tags should be used to identify locations where equipment has been altered for lockout, including valves, flanges, skillets, spectacle blinds, switches, and blocking devices. The tag should identify the person who applied it, the reason the tag was applied, and the date the tag was applied. 

The Lockout Planner is tasked with, proper isolation boundary points as The procedure addresses the lockout distribution panels, use of pulled air-operated valves. It also provi preparation of lockouts, including and check valves as lockout points, be used in locking out a component, sources, control power sources, all devices or control switches. 

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