« Packaging : Maximum Impact! | Main | Two 'Blogging for Books' Winners »
The Importance of Safely Discharging Bulk Bags |
May 16, 2007 |
|
Posted by Kevin Hood at May 16, 2007 11:34 AM |
|
During on-site plant visits, I am constantly surprised to see how companies are discharging bulk bags. Bulk bags, Super Sacks, FIBCs (Flexible Intermediate Bulk Container)...whatever you call them. For whatever reason, engineers, supervisors and operators still have the mentality that it’s just “dumping a bag.” They seem to forget that this is not your average bag. Bulk bags can range from 1,000 to 5,000 pounds in weight and the importance of safely handling them cannot be stressed enough.
I have seen many companies simply raise the bulk bag with a forklift or hoist and dump them into a downstream hopper, tank or feeder. This forces the operator to reach under a suspended load to untie the outlet spout of the bag. You would never see an operator stand underneath a large suspended piece of equipment, but they think it is common practice to untie an unsupported and heavy bulk bag. Unfortunately, it is a somewhat common practice.
The possibilities of injury to the operator are numerous: the bulk bag straps could break, the hoist or forklift could fail, or operator error could cause the operator to be pinned underneath a 2,000 pound bulk bag. A trip to the hospital doesn’t result in a very fun day at work. This happened to one of our customers in Pennsylvania . They used to suspend the bag over a bin and cut it open. One of the operators was found by co-workers pinned between a 4,200 pound bulk bag and a downstream bin which resulted in extensive injuries and a helicopter ride while unconscious to the local hospital.
Most companies tend to take OSHA very seriously, but again it doesn’t seem to apply when unloading bulk bags. OSHA requirements prohibit putting people under suspended loads. Section 1926.550(a)(19) requires that “all employees be kept clear of loads about to be lifted and of suspended loads.” You must follow the requirements in Appendix B of NSS/GO 1740.9B if working under a suspended load is necessary. But is it ever absolutely necessary to work under a suspended (and unsupported) bulk bag? Of course not, there are many bulk bag discharging systems on the market and numerous methods of conveying the material up and over to the desired downstream equipment.
The use of a properly designed bulk bag discharger is important for both safety and ergonomics. If the bulk bags have outlet spouts, it is important to design the discharger so the operator access door is at shoulder level. We have seen systems where operators have to bend over, reach down, and look up in order to untie the bulk bag. This is obviously not good for the back and neck and is an ergonomic “no-no.”
Many bulk bag unloaders currently on the market require the operator to blindly reach up and through an iris valve to find the outlet spout, pull it down and untie. Not only is the iris valve a wear item, but the design is not operator friendly. It is such a pain for the operators that they end up untying the outlet spout while the bulk bag is still suspended. Once the outlet spout is untied the operator lowers the bulk bag into the bulk bag unloader. This not only causes dust issues, but it completely negates the main purpose of the bulk bag unloader – to keep the operator safe! (Yes, although the flow out of the bag and dust control are important issues, the safety of your operator should be the number one priority.)
These same “paddle” or “massager” type unloaders feature a flat plate or “paddles” for the bulk bag to rest on. The paddles push the bag from side to side to discharge the product, but they do not completely support the weight of the bulk bag. The bag may become unstable if it is raised by hoist or raised by vertical support springs in an attempt to improve flow. The paddles themselves can be a pinch point and safety hazard. A bulk bag unloader with a steep sloped hopper and pulsed vibration completely supports the weight of the bulk bag, and is typically better suited for discharging a wide range of ingredients.
Other designs to be careful of are systems which use a liner tensioner with a cable affair as it can be a hazard if it breaks or otherwise comes loose. Some bulk bag unloader manufacturers still use spring loaded hooks to secure the bag loops to their “rigging frame.” This is another safety hazard as the operator’s fingers can be pinched and injured in the spring while rigging the bulk bag.
We have also seen operators lift a bulk bag with a forklift and drive as fast as they can into an I-Beam or wall. This kind of helps to break the bridge of ingredient and make it easier to unload the bulk bag. It’s obviously not an ideal situation and could lead to other operator injuries or accidents. Bulk bag dischargers provide flow inducement to help get the ingredient out of the bag, without having to ram the bulk bag into a beam or pole numerous times. If the product in the bag is very set-up and feels like concrete when you punch the bag, there are devices such as Bulk Bag Squeezers which can help to break down the bridge of ingredient prior to or during discharge. If the “clumps” of product in your bag are larger than the outlet spout, it will be very difficult for any kind of bulk bag unloader to discharge the product without the use of a device such as a Bulk Bag Squeezer. Regardless, driving a forklift like a mad man into a beam should not be recommended by anyone, even if they are your boss.
There are many other factors to consider when selecting a bulk bag discharger which probably deserve their own blog post. Flow inducement, dust control, ease of use and wear items just to name a few. However, the number one priority should be ergonomics and safety for the people in your plant.
Written by Kevin Hood
Vice President of Sales & Marketing
B & H Industrial Products, Inc.
Trackback Pings
TrackBack URL for this entry:
http://www.powderandbulk.com/cgi-bin/blog/mt-tb.cgi/35.
