Hi, If a Castel key interlocking device is fitted to a piece of equipment will this remove the requirement for LOTO for mechanical hazard during maintenance and cleaning operations?

The castel is to isolate electrical power power to machine so that the rotating auger can not function when key is removed from position. Operators have to remove a nose cone that is the physical guard for the auger during cleaning operations of the equipment. The key is removed from electrical panel isolating power to the rotating auger and used to open the guard section to access the auger for cleaning. The guard is then replaced and key removed and placed back into the electrical panel to reenergize the equipment to jog the auger further forward for cleaning. This is repeated until internals are cleaned. Without the key in the power panel the auger cannot be energized and the guard cannot be removed without the electrical panel being first isolated. I see this as meaning isolation has been achieved but i'm a little wary of not having LOTO in place in addition to the Castel Key system.

Had a very bad experience in a previous life with castell locks. Due to the fact that they are made of softish metal, and they must fit snugly, they are easily damaged and will not fit if out of shape if dropped etc. Then I found out the electrical department held spare master keys!! So we went to LOTO. But as Tabs has already said - even LOTO will not prvent the release of stored energy. If the auger is jammed or being held back, it could release and injure someone. Look at what else could go wrong. David

Castel key systems are usually used to prevent two incompatible actions being performed at the same time. Typical example is on vessel protected from over pressure by relief valves. There may one duty and one standby. The Castel key makes sure at least one is always online. That being the case, I don't think a Castel can be used in place of LOTO. In fact I would question whether removing the key really isolates the power supply, or whether it simply prevents the switch from being activated. It may be that a risk assessment will show the risk is relatively low. In that case the Castel key may provide sufficient protection. However, it would not be acting as LOTO, which would provide a higher form of control.

Safetyman2010, The requirement for LOTO is never removed. It is sometimes replaced with alternative protective measures that are more appropriate in the circumstances. Before using an interlocking system s series of questions should be answered. Can the work be performed with the equipment locked out or are other control methods appropriate for the task under consideration? To make this decision there is another series of questions. Is the task integral to the production process? (From CSA Z460 - Control of Hazardous Energy) To be considered integral to production, designed tasks shall exhibit most of the following characteristics: (a) of short duration; (b) relatively minor in nature; (c) occurring frequently during the shift or production day; (d) usually performed by operators or others functioning as operators; (e) represent predetermined cyclical activities; (f) minimally interrupt the operation of the production process; (g) exist even when optimal operating levels are achieved; and (h) require task-specific personnel training. If you have now come to the conclusion that "other control methods" are the appropriate response to risk, failure modes associated with the "other control methods" need to be taken into account as mentioned by the other members. Contact me off-line if you would like some basic guidance on how to go through that process. Cheers. Tom Doyle Industrial Safety Integration