Most waste generated in oral healthcare settings is office waste.9 Office waste (i.e., common refuse and recyclable trash) is considered municipal waste. The standard methods of collecting, storing, transporting, and disposing of such wastes are regulated by state and/or local jurisdictions. Note that these rules may include mandatory requirements for recycling certain materials (e.g., newspapers, cardboards, plastics, glass containers, and aluminum cans).
There are no special requirements for the containment of office waste. The waste receptacle, lined with a plastic liner bag, should be of sufficient size and strength to accommodate the type and quantity of waste generated. Liner bags used for the containment of office waste may be clear, black, white, or gray. Liner bags may be made of low density (LD), linear low density (LLD), and high density (Hi-D) polyethylene resins.14-16
LD polyethylene resins are used to manufacture lower-end utility liners. LLD liners are more puncture, stretch, and tear resistant than Hi-D liners, but have lower load capacity. LLD liners are used for the containment of rough or sharp trash. Hi-D liners, while less puncture, stretch and tear resistant than LLD liners, are more temperature resistant and have a higher load capacity. Hi-D liners are appropriate for the containment office waste without rough or sharp edges.
Gauge is the term used to describe the thickness of a liner. LLD liners are measured in mils, while Hi-D liners are measured in microns. One mil is one thousandth of an inch (0.001 inches). One micron is one thousandth of a millimeter (0.001 mm). One mil is 25.4 microns. Common LLD liners range from 0.30 to 4.00 mils in thickness. Common Hi-D liners range from 6 to 24 microns in thickness.
Liner bags must be (1) of sufficient thickness and durability, (2) puncture resistant, and (3) have sufficient burst strength to prevent rupture and leaks. However, film thickness alone is not enough to determine bag strength. Advanced polymer formulations have allowed manufacturers to produce thinner, lighter bags that are stronger than the traditional thicker bags. Appropriate bag strength for the type and quantity of waste is best determined by “lifting strength” (Table 3).
Table 3. Lifting Strength of Liner Bags.
|LLD polyethylene liners||Hi-D polyethylene liners|
|Lifting strength||Approximate gauge in mils||Approximate container size||Lifting strength||Approximate gauge in mics||Approximate container size|
X Super H
XX Super H
|< 10 gallons (small)||20-30 gallons (midsize)||> 30 gallons (large)|
The bottoms of liner bags may be sealed by star, flat, or gusseted seal methods. The “star seal” is the most common design; it eliminates gaps along the seal and is virtually leak-proof (Figure 3). The star seal also allows the bag to more easily conform to the shape of the container, distributing the weight of the refuse more evenly and, therefore, maximizes the bag’s carrying capacity. Star seal liners are sized in two dimensions, e.g., 40 x 46 inches.
Figure 3. The “Star Seal” Design.
The “flat seal” design is a straight seal along the bottom of the liner bag, which results in a 2-dimentional bag with a bottom seal, much like a pillow case (Figure 4). Although flat seals are strong, they have a tendency to leak wet trash from the corners. They are also clumsy to handle and they do not conform well to the shape of most trash receptacles. Flat seal liner bags are also sized in two dimensions, e.g., 40 x 46 inches.
Figure 4. The “Flat Seal” Design.
The least common method to seal the bottom of liner bags is the “gusset seal.” It is obtained by tucking in both sides of the bag to form gussets (Figure 5). Where indented, it has to be sealed through four layers of film while the middle of the bottom has only two sealed layers. This leads to an inherently weak bottom seal and the bags have the tendency to leak wet trash from the center at gusset points. Gusset seal liners are sized in three dimensions, e.g., 23 x 17 x 46.
Figure 5. The “Gusset Seal” Design.
Finally, the receptacle must be matched with a liner bag of appropriate size to ensure (1) a snug fit, (2) correct length, and (3) proper overhang (Figure 6). To determine the width of the liner, measure the outer circumference of the receptacle and divide it by two. To determine the length of the liner, measure the height of the receptacle, add ½ of the diameter or ½ of the diagonal of the container, plus 3 inches for overhang.
The shape and dimensions of the receptacle determine the width and height of the container liner.