Locking off

The welders should have known that they should never enter a vessel until they or their foreman has checked that the vessel is isolated. by slip-plates or disconnection, and has accepted (and signed) an entry permit. Power supplies should have been disconnected, or if merely locked off, each person entering should have added his or her personal lock and kept the key. It is hard to believe that this was the first time normal good practice had not been followed. The management system was at fault. 

Vaporizing liquid halogen agents are electrically non-conductive and are effective on a wide range of combustibles, particularly flammable liquids and electrical fires. A lock-off system is required on fixed installations to protect personnel, the normal extinguishing concentration being 5% by volume. 

QQ Start-up routine, calibration routine, data transfer/backup, data integrity, power failure, auto lock off, human-machine interface, security access/audit trail, system stress test in event of power failure, alarm tests, operator data entry tests... 

IQ Proper installation of system Correct software version All parts are present and connected correctly Software virus check Integrity of hard disk Availability of source code, manuals OQ Start -up routine Calibration routine Data transfer/backup Data integrity Power failure Auto lock off Human-machine interface Security access/audit trail System Stress test in event of power failure Alarm tests... 

If an RCS file is private, i.e. if only the owner of the file is expected to deposit revisions into it, the strict locking feature is unnecessary and may be disabled. If strict locking is disabled, the owner of the RCS file need not have a lock for check-in. For safety reasons, all others still do. Turning strict locking off and on is done with the commands ... 

Lock off all power to conveyor and pumps, and disconnect or lock closed solvent lines from storage. 

When the manager was brought to me, he tried to convince me that he was only an accountant. When he hesitated at my command to unlock the door, I said Beatson, shoot the lock off. If he gets in the way, shoot him. ... 

The effects of capillary condensation were included in the network model, by calculating the critical radius below which capillary condensation occurs based on the vapor composition in each pore using the multicomponent Kelvin Equation (23.2). Then the pore radius was compared with the calculated critical radius to determine whether the pore is liquid- or vapor-filled. As a significant fraction of pores become filled with capillary condensate, regions of vapor-filled pores may become locked off from the vapor at the network surface by condensate clusters. A Hoshen and Kopelman [30] algorithm is used to identify vapor-filled pores connected to the network surface, in which diffusion and reaction continue to take place after other parts of the network filled with liquid. It was assumed that, due to the low hydrogen solubility in the liquid, most of the reaction takes place in the gas-filled pores. The diffusion/reaction simulation is repeated, including only vapor-filled pores connected to the network surface by a pathway of other vapor-filled pores. 

Figure 4.25 Always ensure that circuits are locked off before working on them.

Lock off the supply and place warning notices. Only then should work commence on the dead supply. 

All electrical machinery should have isolators with locking-off fadhties. Before starting any maintenance, repair or other work that requires access into the machinery the isolator must be locked-off by padlock and identifying tag attached. 

Where bare pick-up conductors are used to carry the power supply they must be shielded from accidental contact particularly if near cabin access. Suitably worded notices, e.g. WARNING - BARE LIVE WIRES, should be posted on the walls or building structure. The power supply isolating switch should be provided with means for locking-off during maintenance work. 

Because of the injury potential of these conveyors, they should be guarded so that when in use there is no possible means of access to them Figure 27.23). Repairs and maintenance should only be undertaken when the drive motor is locked-off. 

There is now a variety of equipment available for use with conveyor systems, such as pivoting corner units, right angle transfer units, etc. Where these are power driven, particularly on automatic or remote control, they should be fenced to prevent unauthorised access. For maintenance, adjustment or repairs, a safe system of work should be laid down and followed involving the locking-off of the main drive before work commences. 

When work is to be carried out on a part of a circuit or piece of electrical apparatus, certain precautions need to be taken to protect the worker concerned from electrical danger. The electricity supply should first of all be switched out and locked off to ensure that the circuit or apparatus being worked upon is effectively electrically isolated and cannot become live. 

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