Plastics In Natural Disasters
The world is an ever changing and frequently hostile environment. Damage can be caused by a range of factors: from storms, floods, tornado to fires, hurricanes and earthquakes – all natural disasters.
This is certainly evident in the recent earthquakes and tsunami that ravaged Japan and Haiti. In addition, we have man made disasters. The nuclear concerns in Japan have captivated people’s attention throughout the globe. The Gulf Oil Spill is an example of another environmental disaster. Plastic materials are the perfect choice in prevention, preparedness and clean up from natural disasters.
Plastics in disaster preparedness.
Many plastic materials are used in the prevention, control and repair management – whenever and wherever a natural disaster may occur.
One of the most visible plastics is the Polycarbonate used in hurricane window covers / shutters. Polycarbonate is a clear rigid plastic that has extremely high impact strength, and is the material most commonly known as ‘Bullet Resistant Glazing’. It is used in safety glasses, riot shields and bank theft prevention glazing. The Polycarbonate protects windows and inhabitants from flying debris and breaking glass caused by the high winds, hurricanes or tornado. Use of the Polycarbonate window coverings saves homes from damage, and helps reduce insurance premiums.
Hillsides are affected by storms and heavy rains, causing mud slides. The standard and most popular solution is to cover hillsides with Polyethylene film. This helps to prevent the rains from saturating the ground and causing the ground to move or shift. The Poly film is normally .004” – .010” thick in widths up to 20 feet and lengths of 100 feet (the same material used as painters tarps from home improvement centers). This film is then attached to the hill with spikes, stakes or sand bags; and this material sheds the water rather than letting it soak in. It can be applied with folds and used like rain gutters to direct water flow away from specific areas. Also, the current sand bags used are not the old cotton fabric bags used years ago; they are now a high strength and tear resistant woven polypropylene ‘fabric’ bag.
The recent critical issues with nuclear leaks bring up an interesting use of a plastic material. As you may recall, after the earthquake and tsunami, the Japanese energy experts were pumping water and boron into the reactors to help control the amount of nuclear energy released.
The nuclear industry uses a plastic material, High Density Polyethylene (HDPE) that has been filled with the natural mineral boron. This boron filled (typically a 5% boron fill) is used to shield neutrons and nuclear energy in many applications; nuclear submarines, nuclear power plants, hospital radiation, dental x-ray shielding and industrial radiation applications. It is normally produced in sheet, and can then be mounted in and around the radiation source as shielding. The benefit to using this boron filled HDPE is this sheet weighs significantly less than traditional lead shielding, and is therefore much easier to install.
Plastic used in clean up from disasters
It is much more difficult to clean up after natural disasters occur. Many of the methods used in the preparation limit the amount of clean up caused by natural disasters.
Depending on the severity of the natural disaster, the uses of plastics in the aftermath are almost limitless. In the cleanup and rebuild after major Earthquakes, shelter is a key component. One of the quick shelters brought in are simple wooden frames with twin-wall plastic sheets made from either Polypropylene or Polycarbonate stapled or nailed to the framework. This provides an inexpensive, easily movable and effective shelter for short term housing. The twin-wall design provides excellent insulation and energy savings. This style shelter is foldable, easy to transport and very easy to set up. Several versions can be made from small huts to larger family areas, to separate sanitary latrine units. These extruded twin-wall materials work well to protect against rain and excessive exposure to the elements. These can be used as assembled, or with a sand bag reinforced perimeter. In Haiti, there were reports of residents filling used one gallon water bottles with mud, and building shelters with these mud building blocks.
The gulf oil spill brought plastics to the front line in disaster cleanup again. Materials used to collect and dispose of excess oil from the waters were rushed to the area. Polyethylene bags are used to collect the oil covered and saturated cleaning rags and clothes, preventing additional dispersion. Many varieties of machinery were brought in to clean the waters. One style machine uses 8” UHMW rod as a squeegee roller that grabs the oil from the water surface and then collects it for later use. Oil booms and rotary wheels are common systems for collecting oil from spills. Because plastics have great surface tension, the oil ‘sticks’ to the plastic surface during the cleaning process. Then the plastic surfaces are wiped clean for reuse and capturing the oil. Plastic tubes and hoses are used to move the oil after collection.
A significant use of plastics would be in the aftermath of natural disasters, specifically in the sanitation and clean water areas. First is sanitation; plastics are used in keeping items clean and dry. Polyethylene film covers items such as medical supplies, shelters, clothing and food cartons. This film keeps the items protected during shipment and ready for use.
Water is the second area of concern. Clean water is critical during the clean up and resettling after a natural disaster. Individual use water bottles are the quick and easy way to deliver water. Larger rotationally molded tanks are brought in with the ability to store large amounts of water in the areas affected. Reverse osmosis equipment (many components are made from plastic) is brought in to convert contaminated water in the clean potable water on site.
In all of these examples, plastic is lighter in weight than the alternatives, normally less expensive that the alternatives, it lasts longer and the plastics are recyclable.