The Filament Winding Technique is used to construct the manhole cylinder, which is typically of ND ranging in size from 800MM to 4000MM. FW technique allows for versatility in the materials used to construct the cylinder's inner liner, allowing one to regulate the strength of the interface with the fluid it contains. On the other hand, the cylinder's main structure is constructed layer by layer until it reaches the desired stiffness, which is typically ranging from 2,500 N/m2 to 10,000 N/m2. In general, C-glass surface veil, E-glass Chopper Roving, and Vinyl Ester Resin are utilized as raw materials to make the inner liner, whereas E-glass Direct Roving & Isophthalic Resin are used to make the primary structure of the cylinder. 

The manhole's dome is made using a hand-lay-up open-molding process. Similar to the cylinder of the manhole, the raw materials used for the inner liner and primary structure are of the same type.

By hand lay-up lamination, the dome and main cylinder are joined at a width of 30 cm and a thickness equivalent to the main cylinder.

Following the end of the manufacturing process, the following tests are carried out:

Manhole must have a cover and supporting ring attached in order to be loaded. A 150 by 150 by 12-mm steel plate lying on the manhole opening receives the specified load eccentrically (as illustrated in the illustration to the side). The center of the steel loading plate is placed such that it is only 100 millimeters away from the opening's edge. With careful inspection in between increases, the load is increased in 9000-N increments. The stated load is kept for at least 15 minutes.

Deflection Test: The top of the manhole, when loaded according to the preceding process, must not deflect more than 6.5 mm downward when measured at the site of load application when the required load is 107000 N.

A part of the manhole's cylinder portion is tested for stiffness in line with Test Method D 2412. There are no joints, repeating elements, or repairs in the tested portion.

Soundness: A water pressure test is used to establish soundness. A test pressure of 20.68 kPa is used. The entire manhole is checked for leaks while maintaining the set pressure.

Chemical Resistance: The test method used to determine chemical resistance complies with Practice C581.