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The ISO-standard ISO 15398 regulates the minimum requirements, proofs of suitability and auditing standards for manhole covers made of thermoplastics. The complete title of the norm is Specification for thermoplastics covers and frames for manholes and inspection chambers used in non-traffic areas. Issue date: 1. December 2012. The norm is in ...
The theft of manhole covers often increases when scrap metal prices are high. [18] [19] Manhole cover theft can be a serious problem in China, where missing manhole covers caused at least eight deaths in 2004. [20] According to China's Xinhua News Agency, about "240,000 manhole and street-drain covers were stolen in Beijing in 2004." [21]
This page was last edited on 4 February 2025, at 12:43 (UTC).; Text is available under the Creative Commons Attribution-ShareAlike 4.0 License; additional terms may apply.
The earliest reference to a similar formula appears to be Armstrong (1985, p. 348), where it is called "adjusted MAPE" and is defined without the absolute values in the denominator. It was later discussed, modified, and re-proposed by Flores (1986).
Grade adjustment rings can also be used on top of a cone section instead of the chimney section to adjust the frame to the required level. [20] The cover section is the top most section of sanitary manholes. It consists of a frame and a manhole cover. [16] The covers are designed to withstand the loads of the traffic on top of the manholes.
Manhole covers in Helsinki, Finland. Manhole closings are protected by a grating or manhole cover, a flat plug designed to prevent accidental or unauthorized access to the manhole. These covers are traditionally made of metal, [2] but may be constructed from precast concrete, glass reinforced plastic or other composite materials (especially ...
Nonsampling error, which occurs in surveys and censuses alike, is the sum of all other errors, including errors in frame construction, sample selection, data collection, data processing and estimation methods.
Standard error; References This page was last edited on 17 October 2024, at 06:02 (UTC). Text is available ...