Because of their aerodynamic design, some modern racing cars create enough vacuum to lift a manhole cover off its recess. During races on city streets, manhole covers must therefore be welded or locked down to prevent injury. In 1990, during the Group C World Sportscar Championship race at Circuit Gilles Villeneuve (located in a public park in Montreal, Quebec), a Brun Motorsport Porsche 962 struck a manhole cover that was lifted by the ground effect of the car he was following, a Courage C24 Porsche. This caused the trailing Porsche to catch fire, and safety issues ended the race shortly afterwards.^{[citation needed]}

The designation DN250 refers to the nominal diameter of the valve, which is 250 millimeters (or approximately 10 inches). This size is commonly used in various industrial applications, including water supply, sewage treatment, and mining operations, where controlling the flow of large volumes of fluids is necessary.

Sustainability and Economic Benefits

The Tale of Two Dustbins