Safety with press hydraulic systems
Preparing for and handling hydraulic fluid spills
What happens when a hydraulic system—pumps, hoses, and fittings—fails—Knowing how to avoid, cope with and clean up the mess to ensure personnel safety and minimize downtime could come in very handy one day.
In a large sheet metal plant, a typical order was being processed on a 200-ton hydraulic press. The setup workers were finished setting the 6-ft. dies in the press and adjusting the backstop. The light curtain operation had been verified, and the operator began forming an order for 800 U-shaped channels from 12-ga. material.
Everything seemed normal. There was nothing particularly out of the ordinary about the day, the plant, or the work. The plant was fairly clean. Some oil around the base of the press was being soaked up by a clay absorbent. The press hadn't been a problem for the operations or maintenance departments. In fact, it was one of the more reliable machines in the plant.
The Trouble Starts
However, that changed within a few seconds. An operator picked up a blank, put it into the die, and adjusted it to the backstop. Then he depressed the foot switch. The ram came down on the blank. Then, halfway through the bend cycle the machine made a noise — a pop — and stopped.
The sheet metal department foreman, who was standing a few feet away reviewing orders, looked up when he heard the sound, but before he could say anything, he was drenched from head to toe in hydraulic fluid. The 80-gal. hydraulic fluid reservoir on the press was almost half empty.
The foreman began spitting out hydraulic fluid and called for a rag to wipe his eyes and face before trudging over the slippery, oil-soaked floor to the locker room to change. Several other workers in the area, who also were sprayed when the hose broke, followed. It all happened very quickly, and seemingly without warning.
The maintenance crew arrived to find nearly 40 gal. of superslick hydraulic fluid spreading all over the shop floor. While some of the crew started tackling this mess, others began inspecting the machine, finding a broken hydraulic hose between the pump and the ram. They also noticed that the other hoses were deteriorated and would need to be replaced. It would not be especially difficult or expensive to replace the hoses, but it would require some downtime.
When the job was complete, the work order showed 10 labor-hours against the machine: two people for one hour each to fabricate and install four new hydraulic hoses, and four people for two hours each to clean up the area, dispose of the waste oil, clean the machine, and replace hydraulic fluid.
The total downtime was another story. In addition to the 10 labor-hours already recorded, time was lost when the doused workers from neighboring presses had to change their clothes and wait for the floors in their area to be safe before returning to their duties. The safety team also took time to investigate the incident, and all of the machine settings on the press had to be rechecked before work could resume.
There were no records of inspection for any of the hoses in the facility. Routine inspections could have helped prevent this incident. Repairs to the press also would have been easier if the hydraulic hoses had been more accessible, but they were 8 ft. above the floor, requiring the area to be relatively clean before ladders or lift equipment could be placed anywhere in the area to do the repair work.
When the hose blew, the entire work area became hazardous. The floor was covered with hydraulic fluid, which is a first-class slipping hazard. The few bags of clay that were available were insufficient to contain and absorb the mess. The spilled hydraulic fluid also posed a major fire hazard because of the open motors on neighboring machines.
Also, the foreman's safety was compromised when he was soaked with the fluid. Even though he was wearing safety glasses, they were designed for impact resistance, not for this unexpected drenching. He got hydraulic fluid in his mouth and eyes, which easily could have been ingested or could have caused eye damage.
Although the material safety data sheets were somewhere in the plant, copies were not readily available. Additionally, there were no eyewash stations or drench showers in the area to aid the foreman in fast removal of the skin-irritating oil.
The maintenance crew spent eight labor-hours sweeping and shoveling oil-soaked clay and soaking up the fluid with whatever rags they could find. In this case, a practical alternative would have been a spill-response kit containing absorbents, such as socks and mats, that soak up spilled liquids quickly and can be disposed of easily.
Simple Steps Can Help
Although there were no serious injuries, the broken hydraulic hose caused a number of problems. The safety and cleanup issues were the most pressing and required immediate attention.
An oil-soaked floor is a dangerous condition in any plant, because it puts everyone in the area at serious risk of slipping and falling. The hard concrete floors can cause serious injury, as can the metal and machinery throughout the plant, in the event of a fall. Additionally, the fire hazards from hydraulic oil spills are equally as dangerous. If a fire starts, a company can be out of business in a matter of hours.
Had there been a formal practice of cleaning and inspecting the hydraulic system, the deteriorating hoses would have been discovered and replaced long before this job started, and the incident could have been avoided. Had there been proper and adequate spill cleanup materials, the cleanup time and costs would have been minimized.
Simple steps, such as routine inspections of all machines, hoses, and material storage areas and adherence to safety regulations, can help reduce downtime and go a long way toward ensuring worker safety.
STAMPING Journal is the only industrial publication dedicated solely to serving the needs of the metal stamping market. In 1987 the American Metal Stamping Association broadened its horizons and renamed itself and its publication, known then as Metal Stamping.