Engineering Services Division
Technical Memorandum No. 97-26-DS-05
August 21, 1997
| TO: | Distribution 57, 612, 618 and 650 |
| FROM: | David S. Ekern Director/Assistant Chief Engineer Engineering Services |
| SUBJECT: | Adjusting Rings |
This technical memorandum supersedes Technical Memorandum 90-26-ES-06 and
96-22-DS-01 and will expire on August 20, 2002 unless superseded.
Concrete adjusting rings are used in the construction of manholes and catch basins to obtain the proper height of these structures. When used in catch basins, a four-inch concrete encasement must be placed around the outside of the adjusting rings and the frame casting to prevent infiltration of water. The encasement is to be placed at the time of final casting placement as shown in the attached drawing.
High density polyethylene (HDPE) adjusting rings can be used as an alternate to concrete adjusting rings. However, only formulations and designs for which test data have been submitted to and approved by Mn/DOT will be permitted.
HDPE adjusting rings must be property sealed as recommended by the manufacturer and approved by the Engineer.
Any questions can be addressed to the Design Standards Unit at 651-296-4859.
Products containing hazardous chemicals can pose health risks to employees and the public, as well as threaten the environment. In addition, hazardous products often require special and costly waste disposal methods. Buy products that are labeled with none of the following signal words or those with the lowest level of hazard possible (but that still get the job done).
- Caution: mild to moderate hazard
- Warning: moderate hazard
- Danger: corrosive, extremely flammable, or highly toxic
- Poison: highly toxic
If less-hazardous alternatives are not readily available, use the least amount of a hazardous product needed to accomplish a task. Use up all of the product before throwing the container or packaging away.
Reducing energy use is important because most energy production contributes to problems such as carbon dioxide emissions (tied to global warming), mercury releases, acid rain, volatile organic compounds, and nuclear waste. The U.S. Environmental Protection Agency and U.S. Department of Energy developed the Energy Star label to help purchasers identify energy-efficient products. These products reduce utility bills and help the environment.
Recycled-content products save energy and resources, while also keeping waste out of landfills and incinerators. Recycled-content products can be made with post-consumer content, pre-consumer content, or a mix of both. Products made with post-consumer recycled content support our recycling programs at home and at work. If people do not buy products with post-consumer recycled content, manufacturers will no longer want the paper, cans, glass, or plastic we separate from trash. Pre-consumer content comes primarily from manufacturer scrap, and as such does not directly support such recycling efforts.
Minnesota generates over 5 million tons of municipal solid waste annually, and this amount is increasing every year. Much of this waste comes from disposable and over-packaged products. Preventing waste can conserve natural resources and avoid the need to build new, expensive waste disposal facilities. You prevent waste when:
- Reducing the amount of material you buy to accomplish any task;
- Reusing a product in its original form; or
- Using repairable, refillable, or durable products.
VOCs evaporate ("volatilize") easily at room temperature and often have a sharp smell. They are contained in many products, such as office equipment, adhesives, carpeting, upholstery, manufactured wood products, paints, solvents, pesticides, and cleaning products. Some VOCs can cause cancer in certain situations, especially when they are concentrated indoors. When VOCs hit sunlight, they create ozone, an air pollutant harmful to both people and plants. Many low-VOC versions of products reduce risks to human health and the environment.
Less than 1% of the Earth's water is available for human consumption. There is no "new" water on Earth. Dry spells have reminded us that our water supply can be threatened - even in the Land of 10,000 Lakes - resulting in watering bans in some municipalities. Choosing products and services that conserve water, such as automatic flushers and low-flow faucets and toilets, can conserve this vital resource while reducing water and sewer bills.
What happens to a product after we use it? Some materials cannot go in the trash because they are hazardous in some way and therefore need separate - and sometimes expensive - special management. Some products are more easily recycled than others that do the same job. Making wiser buying choices can prevent a disposal concern at the end of a product's useful life, keep hazardous materials out of the environment, and expand options for recycling and reuse.
Rollover to learn more or view the complete symbols list.
Environmentally Preferable Purchasing Guide published by the Solid Waste Management Coordinating Board, 4/00. The SWMCB includes members from the Minnesota metropolitan counties of Anoka, Carver, Dakota, Hennepin, Ramsey, and Washington, with ex-officio members from the Minnesota Pollution Control Agency.
Last Revised April 12, 2008 - 9:20pm