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Manhole and sewer bricks manufactured from shale and clay should meet requirements of applicable codes such as ASTM C 32 in order to be able to serve its purpose properly. The purpose of sewer structure and related structures are transportation of sewage, industrial wastes, and storm water.
Manhole and sewer bricks can be manufactured from clay, shale, or similar naturally occurring materials and treated by proper firing or elevated temperature to create adequate bond between components, and hence achieve adequate strength and durability.
Types of Bricks
Sewer and manhole bricks are classified into several types based on their grades. The classes of manhole and sewer bricks are presented in table 1.
Table 1 Classes of Sewer and Manhole Bricks Made from Clay and Shale
|Classes of bricks for sewer structure|
|Grade SS||Use in structures that require low absorption and resistance to the action of sewage carrying large quantities of abrasive material at velocities greater than 2.4 m/s.|
|Grade SM||Use in structures that need to withstand the action of sewage carrying abrasive materials at velocities less than 2.4 m/s.|
|Classes of bricks for manhole|
|Grade MS||Employ in manholes and catch basins that require low degrees of abrasive resistance, high and uniform degree of resistance to frost action and disintegration.|
|Grade MM||Use in manholes require high degrees of abrasive resistance, moderate and nonuniform degree of resistance to frost action and disintegration.|
- Bricks should have rectangular cross section and its edges and corners must be straight to a great extent.
- Maximum 5mm depression or kiln marks is permitted on the backside of sewer and manhole bricks.
- Surfaces and sides of sewer bricks must be smooth and plain
- Surface of manhole bricks should be plain and fairly textured.
- physical properties of bricks made from clay and shale are presented in Table 2.
Table 2 Physical Properties of Manhole and Sewer Bricks Made from Clay and Shale
|Brick type||Minimum Compressive Strength, Average Gross Area, (MPa)||Minimum Compressive Strength, Average Gross Area, (MPa)||Maximum Water Absorption by 5-h Boiling, %||Maximum Water Absorption by 5-h Boiling, %|
|Average of 5 Brick||Individual||Average of 5 Brick||Individual|
|Grade SS Sewer brick||55||41||6||9|
|Grade SM Sewer brick||34||26||12||15|
|Grade MS Manhole brick||21||17||17||20|
|Grade MM Manhole brick||17||15||22||25|
- Drainage structures for the transport of sewage, industrial wastes, and storm water.
- Catch basins