introduction 5A Manhole – A 5A manhole refers to a standard manhole (name may vary according to region). In Alberta, and most other North American jurisdictions, the standard diameter of a manhole is 1200 mm (48 inches). Inlet and Outlet Connections – An inlet (or inlets) refers to the pipe connections entering the manhole. The invert elevation of the inlet pipes refers to the elevation at which the bottom of the inside diameter of the pipe sits within the manhole, which will always be higher than the outlet. An outlet refers to the pipe connection exiting the manhole. For all manholes, municipal specifications may have limitations for maximum allowable openings. 1-S Manhole – A 1-S manhole is square in shape and is used for pipe connections too large to be accommodated by smaller, round manholes (i.e. 5A Manholes). A 1-S structure consists of top and bottom monolithic halves. An intermediate section may sometimes be placed between the halves for added height. Skimming Manhole – A skimming manhole refers to a 1-S manhole with extended top and bottom halves. Within the manhole, there are slots running down the center of two opposing sides of the structure where a weir wall may be installed. Large Diameter Manholes – Large diameter manholes refer to round manholes larger in diameter than the standard 1200 mm. At Lafarge, large diameter material is available up to 3000 mm in diameter. Box Manholes – A box manhole is square or rectangular in shape and is comprised of vertically oriented concrete box sections. See page 48 for more information. Haunch – A haunch is located in the corner of a square manhole (1-S or box manhole), and joins the adjoining walls with a 45 degree stop-gap that prevents a 90 degree right angle corner. Weir Wall – A weir wall is literally a wall located within a manhole structure that separates the storage into two or more chambers whereby the stormwater must raise to a certain level within the structure to pass over the wall. Weir walls are often used to collect sediment or control stormwater flow. Baffle Wall – Similar to a weir wall, a baffle wall is a concrete wall situated within a concrete structure that can reduce flow by forcing the stormwater or effluent through a specified path. T-Riser Manhole – a t-riser manhole refers to a vertical manhole barrel connected to a horizontal pipe in line with the stormwater or sanitary sewer system. Oil/Grit Separator – An oil and grit separator is a structure similar to a manhole or catch basin, except that it is equipped with a number of components (which vary according to technology) that are designed to separate oil and sediment from the stormwater passing through the device. Inlet Control Device (ICD) – an ICD is a solid metal plate that is placed directly over an opening in a manhole and contains a smaller opening to limit the flows entering or exiting the manhole. box sections concrete pipe 1-S Manholes are only specified for use and accepted in the City of Calgary. Refer to page 26 for more information. stormwater treatment technologies See page 46 for more information. See the Stormceptor section of this eManual for more information on oil grit separator and stormwater quality. manhole and catch basin material LAFARGE PIPE eMANUAL PAGE 3