We are often asked about using fiberglass manhole covers or composite manhole covers for sewer, wastewater and utility applications. Fiberglass manhole covers are an excellent replacement for the traditional heavy cast iron manhole lids and frames.
Our top 10 Reasons for Using Fiberglass Manhole Covers and Frames
1.) ZERO Scrap Value
Today’s reality is that traditional cast iron manholes are being stolen left and right to pay for habits, addictions, gas for cars, electric bills and even food. That is the sad state of the economy and society in many areas. Fiberglass manhole covers offer a quick and affordable way to deter further manhole theft. Standard or Hinged Fiberglass Manhole Covers (or composite manhole covers) have no scrap value so thieves just move on to the next source of scrap.
2.) Reduce Manhole Injuries Falls, Vehicle Damage
Every city, town, county or utility has real liabilities when it comes to manholes. Semi-trucks or snowplows often flip up manhole covers – even during regular traffic. Thieves are stealing the cast iron manhole covers for scrap allowing vehicles, people or animals to drop in the hole. Just look at the Google News Results for Manhole Injury.
3.) Reduce Worker Injuries
Fiberglass and Polymer Manhole Covers are lighter and easier for utility workers to move and place.
A typical cast iron manhole cover is between 100 to 200+ lbs. Which would you rather lift? What about kicking that heavy manhole into place? Which would you rather move out-of-the-way to access the manhole? Which would you rather have land on you?
- 22 3/4″ Polymer manhole covers are only 42.5 lbs (Cast iron lids are 114 lbs!)
- 23 3/4″ Polymer manole covers are only 44.8 lbs (Cast iron lids are 137 lbs!)
- 24″ Fiberglass manhole covers are only 28 lbs
- 25 1/2″ Polymer manhole covers are only 54.2 lbs (Cast iron lids are 180 lbs!)
- 26″ Fiberglass manhole covers are only 30 lbs
- 26″ Hinged Fiberglass manhole covers are only 65 lbs
- 30″ Hinged Fiberglass manhole covers are only 83 lbs
- 32″ Fiberglass manhole covers are only 55 lbs
- 38″ Fiberglass manhole covers are only 75 lbs
4.) Keep your manhole lids in place and where they should be
Utilities are often called out to deal with manhole lids that have been popped off by truck tires, sewer backups, storms or vandals. Traditional cast iron manhole covers or lids are typically held in place by the weight of the lid. They can be fitted with locks but even those can be defeated allowing the crooks to swipe your lid. Once a manhole cover is off or missing, the sewer is now open to animals, sticks, debris, children or worse. Tell us what you have found in your sewer by using the comments section below. Fiberglass manhole covers are locked down and secured with 1/4 turn theft resistant stainless steel hardware that ensures the lid stays in place. Fiberglass manhole covers can also be fully traffic rated – supporting 30 percent more weight than the current legal weight limit across much of the US.
Crew time spent maintaining covers are greatly reduced along with callouts, overtime fuel costs for extra trips. The greater benefit is the reduction of unwanted rainwater, snowmelt, sand, dirt, trash and sewer debris into the system. This decreases treatment and maintenance costs while increasing public safety.
5.) Reduce Inflow and Infiltration (I&I) in sewers and collection systems
A major source of inflow and infiltration in sewers or wastewater collection systems are manholes. Traditional cast iron manhole lids are meant to be loose-fitting and consequently allow more surface water in to our sewers and stormwater collection systems. This excess water then has to be treated at a higher cost at the sewer plant or adds volume to an already overflowing storm sewer. Tight fitting manholes lids and fiberglass manhole covers are made to tighter tolerances and can greatly reduce inflow and infiltration (I&I).
- Keeps excess water, spills and runoff out of our sewers and stormwater systems
- Reduces the volume of water sent to liftstations and treatment plants
- Keeps more oil and spills out of our sewers, stormwater systems, creeks, rivers, lakes and oceans
6.) Fiberglass manholes and manhole covers are ideal for corrosive settings
Many sewer and wastewater systems are highly corrosive. Fiberglass manhole covers and frames are perfect for the most corrosive settings found throughout municipal and industrial settings. Sulfide rich effluents along with a warm, humid atmosphere and long retention times create ideal conditions for microbiologically induced corrosion (MIC). MIC destroys typical sewer infrastructure but not fiberglass manholes. Fiberglass manhole covers are also ideal for industrial pretreatment applications, equalization tanks, holding tank and effluent manholes.
7.) Fiberglass manhole covers are better for non conductive applications
Some electrical and telco applications require manhole lids and rings to be non conductive. Fiberglass manholes are well suited for this and can also be fitted with non conductive fiberglass ladders.
8.) Fiberglass manholes covers can help control odor
Sewer and collection systems can have significant problems with Hydrogen Sulfide (H2S) and other odors. Fiberglass manhole covers and frames are engineered and fabricated to seal better resulting in better odor control. Fiberglass manhole covers are ideal for areas sensitive to sewer odors: high density neighborhoods, parks, recreation areas, trailer parks, campgrounds, islands, beaches and resorts.
9.) Fiberglass manhole covers work better for radio signals, AMR and telemetry
Cast iron manholes can interfere or block radio signal transmission. This normally requires different antennas, antenna extensions, special lids, adapters or drilling. Fiberglass manhole covers offer little interference with radio frequency signals. This makes fiberglass retrofit and replacement manhole lids an ideal fit for AMR systems, SCADA, telemetry, level monitoring, samplers, flow meters and other data acquisition devices.
10.) Reduce ongoing operation costs
Utilities are looking for ways to do more with less. High diesel and gasoline costs demand that every manager look for ways to save on fuel and vehicles. If you can reduce manhole cover maintenance, you can reduce callouts, reduce fuel consumption and trips required to maintain the system. One utility even found significant saving in both weight and fuel by not hauling around the extra weight of the cast iron manhole lids. You could keep up to three lightweight fiberglass, plastic or polymer manholes covers in the place of one cast iron manhole.
The minimum lifespan of a quality fiberglass manhole is 30+ years. A typical cast iron manhole system may require significant maintenance or replacement costs over that same period of time. Fiberglass manhole covers offer a one time cost as low as $295. One news outlet recently reported the average cost to replace a single manhole as $200+ per cover per occurrence. Add labor costs to that number and you are up to $500. Fiberglass manhole covers help stop the theft cycle while also requiring less time, labor and equipment to install due to the lower weight and construction. Fiberglass manhole covers also cost less to ship and use less fuel per unit to deliver due to the lower weight per unit.
What are your reasons for considering or using fiberglass manholes or fiberglass manhole covers?
Do you prefer them over cast iron manhole covers for certain applications?
What about the good old-fashioned cast iron manholes?
What applications to you prefer to use with them? Leave your comments below.
Also check out our 10 reasons for Composite Manhole Covers