Whether by car or on foot, chances are you’ve traversed a Neenah Foundry manhole cover. Millions of our flagship products can be found in cities all across the country. We manufacture cast iron manhole frames and covers in various sizes, shapes, and designs, including logo customization for large projects.
Overview of Manhole Covers & Frames
Manhole covers and frames provide maintenance crews with safe, secure access to underground utilities, stormwater, and sewer systems. These covers must also support heavy traffic loads.
A complete manhole assembly consists of a cast-iron frame set into the structure and a precision-fit cover. Manhole covers and frames protect utilities from debris, distribute loads, and maintain alignment.
Neenah Foundry’s manhole covers are made from durable cast iron and are trusted globally. They are backed by our decades of expertise in high-performance infrastructure castings.
What Are Manhole Covers & Frames?
Manhole covers and frames are cast-iron components used by utility, public works, and civil engineering professionals. They provide safe entry to underground infrastructure. The frame is set into the structure and helps support the roadway. The cover seats inside the frame to form a complete assembly.
There are several different variations of manhole covers and frames, including:
- Vented
- Non-vented
- Locking
- Bolted
- Watertight designs
When selecting manhole covers and frames, it’s important to consider load ratings and safety requirements.
What Are Manhole Covers and Frames Used For?
Manhole covers and frames are used in:
- Municipal sewer systems
- Stormwater
- Electrical & Communications Utility access
Cast iron covers and frames are the preferred option in the United States due to their durability and natural corrosion resistance.
Composite covers have gained some traction, but they are not backed by any testing standard in the U.S. Therefore, you should turn to cast iron as a proven solution for protecting underground infrastructure and allowing maintenance access.
Key Features and Options
When exploring options for manhole covers and frames, consider certain features.
Performance & Safety Features
Neenah Foundry offers manhole covers and frames that provide the following:
- Compliance with AASHTO standards
- Multiple load ratings, including H-20, H-25, and airport rated.
- Coated options for added corrosion prevention
- Anti-skid surfaces
- Noise reduction features
- Safety add-ons
- Security mechanisms
Additionally, you can select from watertight, bolt-down, or tamper-resistant options.
Customization Options
Neenah Foundry goes above and beyond for our partners, offering several customization options, such as:
- Badging or Lettering Classification
- Various sizes, shapes, and frame styles
- Various cover designs, logos or city seals
- Coating options
If you opt for logos or branding, we will cast the design directly into the cover.
Why Choose Neenah Foundry for Manhole Covers & Frames?
Clients trust Neenah Foundry for their manhole covers and frames because we provide:
- 150+ years of foundry experience and engineering expertise
- Products made in the USA
- Compliance with Build America, Buy America requirements
- A huge in-stock inventory
- Short lead times on custom orders
- Consistency, durability, and quality control
- A broad catalog of standard and custom assemblies
- Support from in-house engineering experts
- Long service life
When you need a solution that will last, Neenah Foundry is the team for the job.
Product Highlights
Neenah Foundry provides manhole safety and security solutions designed to meet the performance, load, and safety requirements of today’s municipal and industrial systems. From standard frames and covers to advanced pressure‑relief and assisted‑opening technologies, our products help simplify maintenance while improving long‑term infrastructure resilience. Learn more about Neenah Foundry’s manhole safety and security solutions.
Non-Vented Manhole Covers
Non-vented manhole covers are a simple, rugged solution used for roadways and utilities access. They can hold up against the daily beating from vehicles driving over them.
Vented or Slotted Covers
These covers can provide airflow, which is important for preventing pressure buildup in certain sewer and stormwater applications.
Safety Covers – Controlled Pressure Release (CPR II)
Our Controlled Pressure Release safety covers mitigate potential damage or injury from rapid changes in pressure and explosions within vaults by allowing pressure to vent from below the lid, while keeping the lid engaged with the frame. Our covers will release pressure when there’s a rapid change in pressure or an explosion event happening underground. We supply these to the largest electrical distribution companies in the U.S.
Security Covers – InfraLock
Prevent unauthorized access with InfraLock manhole covers. These are valuable options when used in high-risk or mission critical zones. They feature locking mechanisms to prevent unauthorized access or intentional break-ins, providing access control to communications and electrical vaults as well as reducing potential for tampering with water supply and sewage systems. Lock options include: mechanical, electro-mechanical, and Bluetooth.
InfraLOCK while also allow pressure to vent in the case of an explosion or other pressure buildup within the vault.
Our Capabilities
Neenah Foundry is a full-service manufacturer that supports our clients with:
- Engineering
- R&D
- Manufacturing
- Quality control
- Sustainable practices
- Nationwide distribution
When you need a partner you can count on, go with Neenah Foundry.
Frequently Asked Questions About Manhole Frames and Covers
What Materials Are Manhole Covers Made From?
Our manhole covers are made from cast iron, which is available in gray iron and ductile iron, the latter of which can offer higher load ratings. We do not use composite, as there is no U.S. testing standard for composite manhole covers.
How Do I Choose the Right Load Rating?
Talk to our team for questions about load rating. We will help you choose the appropriate option based on your intended use case.
Can Manhole Covers Be Customized?
Yes, Neenah Foundry can add lettering, logos, and coatings. We offer manhole covers in several different shapes and sizes.
Why Aren’t Neenah Foundry Manhole Frames and Covers Painted?
Neenah Foundry supplies unpainted manhole covers and frames to support environmental compliance and long‑term performance. Asphaltic paints contain volatile organic compounds (VOCs), which are regulated at the federal and state level. To reduce VOC emissions and support cleaner, compliant installation practices, these products are manufactured and delivered without paint.
Cast iron offers natural corrosion resistance, making coatings unnecessary for long-term durability. The carbon and silicon in gray iron form a protective graphite layer and a durable black oxide‑silicate scale over time, helping the metal withstand exposure in roadway and utility environments.
Leaving the castings unpainted also ensures a strong bond with surrounding concrete, since paint can act as a barrier during installation. Unpainted surfaces allow clear visual inspection of the casting surface, ensuring that municipalities, engineers, and contractors can easily verify the surface condition before installation. Industry guidance for standardized highway drainage products further reinforces this approach by noting that painting cast iron castings is not permitted.
Are Manhole Covers Standardized for All Municipalities?
Most DOTs and municipal agencies have their own standards, but some smaller cities do not have their own standard. In this instance, they often defer to the county or state’s standards.
How Long Do Neenah Manhole Covers Last?
We have seen many of our covers last over 100 years. There are covers in use that say “Ayward & Sons,” which was changed to Neenah Foundry in 1921.
Do Manhole Assemblies Require Ongoing Maintenance?
No, cast iron has natural protective properties and requires no maintenance.