Best Practices Report: Bale Storage
Proper bale storage can help maintain the quality of prepared post-consumer PET plastics while improving safety in the workplace. NAPCOR reports these "best practices" for the PET intermediate processing industry. These best practices were developed by the Association of Postconsumer Plastic Recyclers, the Clean Washington Center for the Environmental Protection Agency, and NAPCOR.
Protecting Bale Quality
PET bale quality can be compromised by dirt, moisture, and exposure to sunlight, which causes ultraviolet degradation of PET plastic. Bales should be stored indoors, if possible, but if outdoor storage is necessary, the bales should be completely covered to limit exposure to the elements. Bales should be stored on pallets or clean, dry surfaces to avoid contamination.
Pushing bales directly across the floor can cause unwanted contaminants to become embedded in the bale. For this reason, bales should always be elevated off the floor surface while being transported.
Poorly stacked bales can fall on workers or plant equipment,causing serious damage or injury. Before stacking bales, an individual should familiarize himself or herself with local fire codes and building codes that apply to bale storage. For example, fire codes may require proper clearances from sprinkler heads, clear aisles, and unblocked points of exit. Building codes may limit the amount of floorspace that can be occupied with stored materials and the load impacts for storage floors that are not on grade. These regulations are strictly enforced by the federal Occupational Safety and Health Administration.
Safe stacking procedures start with the first bale. The bottom of a stack must establish a sturdy foundation for all additional bales. If the stack will be placed against a wall, placing the bottom bale roughly six inches away from the wall will allow upper bales to lean into the wall and not toward workers and equipment. If the bales are not stacked against a stationary wall, building a group of stacks sequentially rather than finishing one stack to its maximum height will allow nearby stacks to brace and reinforce each other.
Beyond these local regulations and stacking procedures, safe stacking height in a facility is a function of bale integrity, bale dimensions, and ceiling heights. The safety of everyone in the facility relies on a firm understanding of these factors and an adherence to the resulting stacking limitations.
Selling and Receiving Bales
Facilities that produce baled material for sale to other reprocessors should weigh and "tag" bales prior to storage. This procedure can help in weight determination during storage and solve any potential weight disputes that might arise later. It will also assist in ensuring compliance with legal shipping weights for road transport.
Facilities that receive bales should store them in distinct"lots" organized according to the material's supplier. If inferior quality material is discovered during processing and if punitive price adjustments are necessary because of such quality problems, it will be easier to identify the source of the material.
Best Practices Guidelines:
To protect the quality of PET bales and ensure safe storage,follow these guidelines:
- Protect bales from particles, dirt, moisture, and sunlight
- Elevate bales off floor surface during handling
- Know fire codes and building regulations for stacking bales
- Stack the bottom bale at least six inches from nearest wall
- "Build" stacks sequentially in small groups
- Weigh and "tag" bales prior to storage
- Store received bales in "lots" grouped according to supplier