Composite manhole covers or FRP manhole covers are becoming very popular alternatives to cast iron manhole covers in watewater collection systems, sewer systems, stormwater systems, utilities, septic systems, grease traps, and industrial applications. But what are the advantages to using fiberglass manhole covers, composite covers, polymer manhole covers or plastic manhole covers to replace heavy cast iron manhole lids and frames?
Our top 10 Reasons for Using Composite Manhole Covers
1.) Composite Manhole Covers Have ZERO Scrap Value and Eliminate Manhole Lid Theft
Cast iron manholes and metal manhole lids are being stolen every day. 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.
Composite Manhole Covers offer a quick, easy and affordable way to prevent manhole cover theft. FRP or composite manhole covers have no scrap value. When would be thieves discover they are not dealing with cast iron, they simply move on to the next city or source of scrap.
2.) Composite Manhole Covers Reduced Weight = Reduced Worker Injuries
Composite Manhole Covers are much lighter and are easier for utility works to handle and place.
Cast iron manhole covers normally weigh between 100 to 200+ pounds. Composite manhole covers and plastic manhole covers reduce weight by 63% to 85%!
Which manhole cover would you rather lift? Iron or composite?
What about kicking that cast iron manhole cover into place?
Which one manhole lid would you rather have drop on you?
- 22 3/4″ composite manhole covers are only 42.5 lbs (Cast iron lids are 114 lbs!)
- 23 3/4″ composite manole covers are only 44.8 lbs (Cast iron lids are 137 lbs!)
- 24″ FRP manhole covers are only 28 lbs
- 24″ Manhole Covers with Frames are only 66.1 lbs.
- 25 1/2″ Composite manhole covers are only 54.2 lbs (Cast iron lids are 180 lbs!)
- 26″ FRP manhole covers are only 30 lbs
- 26″ Hinged FRP manhole covers are only 65 lbs
- 30″ Hinged FRP manhole covers are only 83 lbs
- 32″ FRP manhole covers are only 55 lbs
- 38″ FRP manhole covers are only 75 lbs
3.) Composite Manhole Covers Stay Where They Should Be – Locked Into Place
Manhole lids that have popped off are a big problem and liability for utilities. Sewer backups, storms, flooding, vandals and even truck tires can cause the lids to be knocked out of place or even missing manhole covers. The callout costs due to this have become much higher and losses due to liabilities are mounting.
[info_box type=”success_box”]Cast iron manhole covers or lids are typically held in place by the weight of the lid. Composite manhole covers or FRP manhole lids are normally secured with a locking mechanism or worm gear.[/info_box]
While cast iron lids have long been fitted with locks, even the best locks can be defeated with tools, torches or brute force. The crooks can still swipe your cast iron manhole lid in just a few seconds. Once a manhole lid is off or missing, the sewer or storm sewer is open to children, bikes, cars, animals, debris or even worse. In contrast, plastic manhole covers are locked down and secured with a unique worm gear that ensures the lid stays where it should be. Do you need a more secure manhole? Ask about our high security and individually keyed high security FRP manhole covers.
4.) Composite Manhole Covers Are Fully Traffic Rated
Composite Manhole Covers are available in fully traffic rated versions that offer 30% more weight loading than the current US DOT / highway legal weight limits. Our FRP / composite manhole covers comply to the following standards:
- AASHTO M-306
- H-20 “Fully Traffic Rated” or “Full H20” – Learn about load rating
- H-25 50,000 lb load rating
5.) Composite Manhole Covers Can Reduce Inflow & Infiltration in Sewers
Manholes are a major source of I&I (Inflow and Infiltration) in wastewater collection systems or sewer systems. Old school cast iron manhole lids are designed to be loose-fitting. This inherent design flaw allows more surface water into our collection systems and sewers. All of this excess water still has to be treated at the sewer plant. Tight fitting composite manhole lids and covers are manufactured to tighter tolerances and can greatly reduce inflow and infiltration (I&I). Add manhole ring seals to your installation and these plastic manhole covers become very effective in eliminating a source surface water infiltration.
Composite or FRP manhole covers with frames and O-ring seals help:
- Reduce energy used for pumping excess water from liftstations and pump stations to the treatment plant
- Reduce wastewater treatment costs – less power, fewer chemicals and smaller facilities required
- Keep excess water, spills and runoff out of our sewers and stormwater systems
- Keep more oil and contaminants out of sewers, stormwater systems, creeks, rivers, lakes and oceans
6.) Composite Manhole Covers Are Ideal for Corrosive Environments
Sewer and wastewater systems can be highly corrosive. Hydrogen sulfide gas is commonly found in these systems. It is corrosive, very poisonous, heavier than air, flammable and even explosive. When dissolved in water, it becomes a weak acid called hydrosulfuric acid or sulfhydric acid.
Composite manhole lids and frames are perfect for the most corrosive settings found in municipal collection systems, sewers and industrial pretreatment applications. Effluents rich in sulfides are common in these humid and warm environments. When the heat and humidity is combined with long retention times, ideal conditions are created for microbiologically induced corrosion (MIC). This MIC can eventually destroy most sewer infrastructure but not composite manhole covers or FRP manholes. This inherent corrosion resistance makes composite (FRP) manhole covers ideal for effluent manholes, outfalls, industrial pretreatment, industrial process, equalization tanks, holding tanks and basins.
Check out these corrosion resistant manhole covers with frames.
7.) Composite Manhole Lids Can Reduce Odors
Collection systems and sewers are widely known to have problems with Hydrogen Sulfide (H2S) and other sewer gas odors. The typical foul rotten egg smell is an indicator of Hydrogen sulfide (H2S), a colorless gas is found in sewer systems.
Composite covers and (FRP – fiber-reinforced polymer) manhole covers and frames are designed with odor control in mind. These composite manhole lids are manufactured with better sealing in mind which helps contain the odor. Plastic or composite manhole covers are also ideal for residential areas and urban environments sensitive to sewer odors. These composite manhole covers solve manhole issues for resorts, hotels, entertainment districts. Many engineers and facility managers have been using composite covers in parks and recreation areas, malls, outlet malls, high density developments, water parks, beaches, trailer parks, campgrounds and even all inclusive island resorts.
8.) Composite Manhole Covers Are Ideal for Non Conductive Applications
Many Telco and electrical utility manhole applications require manhole lids and rings to be non conductive. Composite manhole lids are well suited for these non-conductive manhole requirements. Manholes can also be fabricated and fitted with non conductive fiberglass ladders, platforms and railings.
9.) Composite Manhole Covers Allow AMR and Radio Signals to Pass Through
Traditional cast iron manholes can block or interfere with radio signal transmission. Different antennas, antenna extensions, special lids, adapters or cover drilling are sometimes required when using cast iron lids. Composite manhole covers allow radio frequency signals from Automatic Meter Reading (AMR) systems and telemetry systems to pass through with little to no interference. This makes fiberglass reinforced plastic manhole covers and composite manhole covers an ideal fit for monitoring systems, AMR systems, sewer flow meters, telemetry, SCADA, sewer and manhole level transmitters, water quality monitoring, water samplers, wastewater samplers and other devices.
10.) Composite Manhole Covers Reduce Operation Costs and Save Energy
Utilities are facing ever increasing operating costs. Higher fuel costs combined with higher vehicle acquisition and maintenance costs have managers looking for more creative ways to save the budget.
Reduced manhole and cover maintenance helps:
- Reduces staff callouts while increasing time for family and the enjoying the benefits of recreation.
- Reduces fuel consumption and trips required to maintain the system.
- Saves on vehicle weight and fuel by not hauling around the heavier cast iron manhole lids. Three plastic manhole lids weigh less than one cast iron cover.
Quality composite manholes and covers typically last 30+ years or more. Cast iron manhole systems usually require significant maintenance or replacement costs during that same 3o year period of time.
- Composite manhole covers offer a one time cost as low as $199.
- Composite manhole covers cost less to ship and use less fuel per unit to deliver to the jobsite.
- Composite manhole covers and lids require less labor, time and equipment to install and maintain.