The manhole security system from SewerLock thwarts terrorists, vandals and illegal dumping and increases safety for municipal crews, contractors and pedestrians.

The product consists of a heavy-gauge, stainless steel sub-ring that fits below the existing manhole frame and cover, independent of existing lips or edges; and a padlocked stainless steel pan that rests atop the sub-ring. The pan is slightly concave and can be flipped over to create a small dome, depending on the application. It’s easily removed for maintenance, says Dave Ross, company co-owner.

The pan weighs eight pounds. Tiny holes prevent standing nuisance water and allow gas diffusion, but the pans also can be fabricated without holes if needed. The device prevents accidents that occur when manhole covers are stolen or accidentally left off by workers. “Workers step backward and fall into an open manhole,” Ross says. “When the SewerLock pan is in, no one can fall into the manhole.”

To install the unit in an existing manhole, a stainless steel sub-ring is affixed to the manhole barrel with fiberglass. Next, the sub-ring is secured to the barrel with anchor bolts. Then the entire assembly is sealed with more fiberglass.

For new manhole construction, the sub-ring barrier is placed between grade rings during manhole assembly, immediately securing the manhole.

The pan fits onto the sub-ring over 1/2-inch eyebolts attached to the sub-ring, opposite each other. The pan is secured to the sub-ring with tamper-proof padlocks that fit through the eyebolts. The eyebolts can be tightened to prevent lid blowoffs or set to allow the pan to rise in case of overflow.

“Each sub-ring and pan is custom-made,” Ross says. “We measure the inside diameter of the manholes to manufacture a custom-fit product.”

The system decreases liability by preventing injuries to pedestrians who could fall into manholes left open by cover theft. It also prevents unauthorized access to manholes by terrorists and vandals, and prevents illegal dumping of grease, construction debris, and other materials that can clog sewers and create backups. Agencies avoid fines and penalties from SSOs and comply with recent mandates to lock manholes, Ross notes.

Optional stainless steel cables secure manhole covers to the SewerLock assembly. For information: www.sewerlock.com; 408/761-5882.