Description
Standard Inlet Frame and Grate – 5″ High
Heavy-Duty Cast Iron Stormwater Collection Assembly for Municipal, Commercial, and Transportation Infrastructure
The Amercast Standard Inlet Frame and Grate – 5″ High is a municipal-grade cast iron drainage casting engineered for efficient stormwater interception, structural durability, and long-term performance in demanding infrastructure environments. Designed for installation in catch basins, storm drain structures, roadway drainage systems, parking facilities, industrial developments, and municipal stormwater networks, this inlet assembly provides reliable runoff collection while supporting repetitive vehicular loading.
Unlike curb-opening drainage structures that capture flow primarily through a curb throat, the Standard Inlet Frame and Grate utilizes a surface collection design that intercepts runoff vertically through the grate opening. This configuration makes it particularly effective in parking lots, roadway low points, commercial developments, loading facilities, utility corridors, and stormwater conveyance systems where sheet flow and concentrated runoff must be rapidly transferred into underground drainage infrastructure.
Manufactured from premium gray cast iron and designed for heavy-duty service conditions, the Amercast 5″ High Inlet Frame and Grate provides municipalities, engineers, contractors, and infrastructure owners with a dependable drainage solution capable of delivering decades of field performance.
Why a 5″ High Frame Matters
While frame depth is often overlooked during design, it plays a significant role in the overall performance of a drainage casting.
The 5-inch frame profile provides:
- Increased structural engagement with surrounding concrete
- Improved load distribution into the drainage structure
- Enhanced casting stability
- Greater resistance to frame movement
- Improved bearing surface performance
- Longer service life in high-traffic environments
Compared to shallow-profile inlet castings, a deeper frame section helps create a more robust interface between the drainage structure and the cast iron assembly.
Typical Applications
The Standard Inlet Frame and Grate – 5″ High is commonly specified for:
Municipal Infrastructure
- City Streets
- Residential Roadways
- County Highways
- Public Works Projects
- Streetscape Improvements
Commercial Developments
- Shopping Centers
- Office Complexes
- Mixed-Use Developments
- Retail Facilities
- Distribution Centers
Industrial Applications
- Manufacturing Facilities
- Logistics Centers
- Utility Installations
- Equipment Yards
- Transportation Terminals
Stormwater Systems
- Catch Basins
- Storm Drain Structures
- Collection Networks
- Surface Drainage Systems
- Site Drainage Improvements
Engineering Design Features
Reinforced Cast Iron Construction
Manufactured from gray cast iron meeting ASTM A48 Class 30B requirements or equivalent municipal casting specifications, the inlet assembly provides exceptional compressive strength, abrasion resistance, and dimensional stability.
Gray cast iron remains the preferred material for municipal drainage castings due to its proven ability to withstand heavy traffic loading, environmental exposure, and decades of service life.
Optimized Hydraulic Collection
The grate opening pattern is engineered to balance:
- Stormwater intake capacity
- Structural strength
- Debris management
- Maintenance accessibility
Properly designed grate openings maximize runoff capture while maintaining casting integrity under traffic loads.
Maintenance-Friendly Access
The removable grate design allows:
- Routine cleaning
- Sediment removal
- Catch basin inspections
- Stormwater maintenance
- Utility access
This simplifies long-term maintenance and helps preserve hydraulic efficiency throughout the life of the drainage system.
Actual Product Dimensions
Based on the Amercast engineering drawing provided.
| Reference | Dimension |
|---|---|
| C | 20″ |
| CC | 40″ |
| D | 5″ |
| F | 22″ |
| FF | 33″ |
| G | 28″ |
| H | 1.5″ |
Dimensional Interpretation
| Measurement | Description |
|---|---|
| 20″ | Grate Opening Width |
| 40″ | Overall Frame Length |
| 5″ | Frame Depth |
| 22″ | Internal Clear Opening |
| 33″ | Bearing Length |
| 28″ | Overall Grate Seat Width |
| 1.5″ | Grate Thickness |
These dimensions provide a robust drainage casting capable of supporting municipal roadway and commercial drainage applications while maintaining efficient stormwater collection characteristics.
Industry Standard Inlet Sizes
Based on commonly published municipal drainage catalogs, DOT standards, and North American drainage casting specifications, the following inlet frame and grate sizes represent the most frequently utilized configurations throughout the industry.
| Nominal Opening | Typical Frame Size | Common Application |
|---|---|---|
| 20″ × 20″ | 28″ Frame | Parking Areas & Site Drainage |
| 24″ × 24″ | 32″–34″ Frame | Municipal Catch Basins |
| 24″ × 36″ | 40″–48″ Frame | Commercial Drainage Systems |
| 24″ × 48″ | 48″–54″ Frame | Roadway Drainage Applications |
| 30″ × 48″ | 54″–60″ Frame | High Capacity Collection Systems |
These dimensions are consistent with common drainage casting families used throughout North America for stormwater collection infrastructure.
Available Industry Standard Configurations
Amercast can manufacture and supply a wide variety of inlet frame and grate assemblies to meet municipal, commercial, and project-specific requirements.
| Size Category | Typical Opening | Typical Use |
|---|---|---|
| Small Area Inlet | 20″ × 20″ | Sidewalks, Utility Areas |
| Standard Catch Basin | 24″ × 24″ | Municipal Streets |
| Intermediate Inlet | 24″ × 36″ | Commercial Developments |
| Extended Drainage Inlet | 24″ × 48″ | Parking Lots & Roadways |
| Large Capacity Inlet | 30″ × 48″ | Transportation Infrastructure |
| Custom Configurations | Project Specific | DOT & Municipal Standards |
Custom dimensions, grate styles, frame depths, municipal logos, and project-specific casting requirements are available upon request.
Hydraulic Performance Considerations
According to FHWA stormwater design guidance, inlet performance is influenced by several factors beyond the casting itself.
Key variables include:
- Rainfall intensity
- Drainage area size
- Gutter spread
- Longitudinal slope
- Cross slope
- Surface roughness
- Grate opening geometry
- Debris accumulation
- Inlet spacing
A properly sized inlet frame and grate helps reduce:
- Roadway ponding
- Surface flooding
- Hydroplaning risks
- Pavement deterioration
- Erosion around drainage structures
For high-flow applications, engineers frequently increase inlet length and grate opening area to improve interception efficiency and reduce bypass flow.
Material Performance Characteristics
| Property | Performance Rating |
|---|---|
| Compressive Strength | Excellent |
| Abrasion Resistance | Excellent |
| Traffic Durability | Excellent |
| Impact Resistance | High |
| Freeze-Thaw Resistance | Excellent |
| Corrosion Resistance | Excellent |
| Dimensional Stability | Excellent |
| Service Life | Multiple Decades |
Advantages of Cast Iron Drainage Castings
Proven Municipal Performance
Cast iron drainage products have been utilized throughout North America for more than a century because of their reliability and structural capacity.
Exceptional Load Transfer
Cast iron effectively distributes wheel loads into the supporting concrete structure.
Long-Term Durability
Properly installed castings routinely remain in service for decades with minimal maintenance requirements.
Sustainable Infrastructure Material
Cast iron products are frequently manufactured using recycled materials and are fully recyclable at the end of their service life.
Related Amercast Products
- Standard Inlet Frame and Grate – 4″ High
- Inlet Frame and Grate with Type N Curb Piece
- 48″ Inlet Frame and Grate with Curb
- Double Inlet Frame and Grate
- Inlet Frames and Grates
- Catch Basin Frames & Grates
- Manhole Frames and Covers
- Drainage Systems
- Municipal Castings
Engineering Resources
FHWA Urban Drainage Design Manual (HEC-22)
https://www.fhwa.dot.gov/engineering/hydraulics/library_arc.cfm?id=189&pub_number=22
AASHTO Transportation Drainage Publications
https://store.transportation.org
EPA Stormwater Infrastructure Resources
https://www.epa.gov/npdes/stormwater-discharges-municipal-sources
These resources provide guidance regarding stormwater collection systems, inlet design methodology, roadway drainage calculations, hydraulic capacity evaluation, and municipal drainage infrastructure planning.
Why Choose Amercast?
Amercast manufactures cast iron drainage products for municipalities, transportation agencies, consulting engineers, contractors, developers, utility authorities, and infrastructure owners throughout North America.
Our inlet frames, grates, catch basin components, and custom drainage castings are engineered to provide:
- Long-term structural performance
- Reliable stormwater collection
- Municipal-grade durability
- Industry-standard compatibility
- Custom manufacturing capabilities
- American-made quality
Whether your project requires a standard inlet frame and grate, replacement drainage components, or custom-engineered municipal castings, Amercast can provide a solution tailored to your project requirements.
Request a Quote
Need pricing, CAD drawings, submittal packages, replacement grates, municipal specifications, or custom drainage castings?
Contact Amercast today to request a quote for the Standard Inlet Frame and Grate – 5″ High. Our team can assist with municipal drainage systems, roadway improvements, commercial developments, stormwater infrastructure projects, and custom cast iron solutions manufactured to meet your project specifications.
