Prevent Crushed Fingers

Each year, workers suffer approximately 125,000 injuries that occur when body parts get caught between two objects or entangled with machinery. These hazards are referred to as “pinch points”. If you have ever slammed your finger in a door, you can appreciate the pain associated with this common type of caught/crush injury. The physical forces applied to a body part caught in a pinch point can vary and cause injuries ranging from bruises and cuts to amputated body parts and even death.

To prevent these injuries, look for possible pinch points before you start a task. Take the time to plan out your actions and decide on the necessary steps to work safely. Give your work your full attention. Don’t joke around, daydream, or try to multi-task on the job – most accidents occur when workers are distracted. Read and follow warning signs posted on equipment. If you value all that your hands can do, THINK before you put them in a hazardous spot.

Also, dress appropriately for work with pants and sleeves that are not too long or too loose. Shirts should be fitted or tucked in. Do not wear any kind of jewelry. Tie back long hair and tuck braids and ponytails behind you or into your clothing. Wear the appropriate, well-fitting gloves for your job.

Machinery can pose a hazard with moving parts, conveyors, rollers, and rotating shafts; these are only a few of the vast number of hazards. Never reach into a moving machine. Properly maintain and always use the machine and tool guards provided with your equipment. Don’t reach around, under, or through a guard and always report missing or broken barriers to your supervisor. These guards act as a barrier between the moving parts and your body. Turn equipment off and use lockout/tagout procedures before adjusting, clearing a jam, repairing, or servicing a machine.

Vehicles, powered doors, and forklifts can pose a crush hazard unless they have been blocked or tagged out. Never place your body under or between powered equipment unless it is de-energized. Doors, file drawers, and heavy crates can pinch fingers and toes. Take care where you place your fingers. Test the weight before lifting, carrying, and placing boxes; an awkward or heavy load can slip and pinch your hands or feet. Get help or use tools to move large and/or heavy items.

Take the time to learn about the caught/crush hazards in your workplace so you don’t learn about the consequences first hand (no pun intended).

When a Backup Isn’t a Backup

The International Association of Engineering Insurers found that the highest frequency of steam turbine failures worldwide is due to loss of oil pressure. Most of these failures are caused by an unreliable backup system to maintain oil pressure to the bearings should the primary AC-driven lube oil pumps fail. These AC motors are powered by either the turbine’s output or the grid, and will fail if the turbine or generator trips, or if there is an external outage.

Modern turbines have backup powered DC oil pumps mounted on the oil tank which are triggered by a pressure switch in the event of a loss in oil pressure. It is very important to conduct tests with the AC and DC oil pumps during scheduled maintenance inspections to ensure that the DC pump engages as required. Such tests can be referred to as cascade pump pressure inspections. These tests will confirm the pressures when the DC oil pump will engage after the AC oil pump is actually turned off. Backup batteries should also be verified. These tests should be performed on a regular basis when the unit is down and mandatory tests should be performed before the unit is placed in operation after an overhaul.

Older turbines can use steam-driven pumps as backup. On these designs, a pressure regulator will sense the drop in bearing oil pressure and turn on the steam supply to the blade wheel of the pump. While these pumps are usually very reliable, they still must be manually tested on a regular basis and after an overhaul. Care must be taken to not overspeed the pump or it will cause internal component damage and may even completely destroy the pump.

Some older turbines use gravity lube oil tanks.  These tanks are mounted above the unit on stands and are controlled by a check valve type of arrangement.  There are no pumps involved; gravity provides the bearings with sufficient lubrication in an emergency situation. While less complicated than DC or steam powered backups, their operation must still be routinely checked.

Bottom line, a backup is not a backup unless it is reliable. And it can only be reliable if it is tested.