WHAT IS MAGNAPLAST™
MagnaPlast™ is a monolithic, extrusion‑wound HDPE sanitary sewer manhole system engineered to eliminate the corrosion, cracking, infiltration, and maintenance cycles associated with concrete and polymer‑concrete structures.
Manufactured in the United States and built on more than 50 years of proven European HDPE performance, MagnaPlast delivers a fully integrated, corrosion‑resistant solution with a modeled 100‑year design horizon.
THE MAGNAPLAST™ SYSTEM
MagnaPlast is a factory‑assembled, monolithic HDPE manhole system engineered for long‑term performance in corrosive wastewater environments.
Each unit is built as a seamless structure; base, cylinder, anti‑flotation system, riser, and access components, all integrated in a controlled manufacturing environment.
This eliminates joints, field welding, coatings, and multi‑stage assembly, delivering a watertight, corrosion‑resistant system ready for rapid installation.
A one‑piece, factory‑assembled HDPE structure built using spiral extrusion‑wound technology and a rotomolded base.
No joints or weak points
Factory pressure and vacuum leak‑tested
Modeled for 100‑year design life (ASTM/DVS methodology)
Uniform wall thickness (0.75–2 in.) for consistent structural performance
Exceptional hoop strength to resist soil, groundwater, and traffic loads
This core forms the backbone of the MagnaPlast platform, delivering long‑term reliability in demanding wastewater environments.
Engineered for high groundwater, saturated soils, coastal regions, and flood‑prone environments.
HDPE cement‑fill tub (7 ft)
Buoyancy‑resistant base assembly
Structural stability in poor soils
Eliminates uplift risk common in concrete manholes
Threaded Adjustable Riser, Direct Frame & Cover Mount, or Grade Adjustment Ring.
Precision grade control for any installation environment
24, 27, and 30‑inch riser options
Up to 9 inches of vertical adjustment
Proprietary gasketed sealant for watertight riser interface
Supports cast iron or composite covers
Compatible with direct‑mount or grade‑ring installations, including Cretex PRO‑RING
Engineered for municipal compatibility and long‑term reliability.
Direct‑mount frames
Grade‑ring configurations
Composite or cast‑iron covers
Traffic‑rated options for H‑20 / HS‑25 loading
- Precision‑formed rotomolded HDPE base designed for watertight performance.
Smooth internal flow surfaces (Manning’s n = 0.010)
Leak‑free inlet and outlet interfaces
Minimal maintenance over decades
Compatible with standard pipe materials and deflection angles
- Factory‑formed connections engineered for watertight performance.
Smooth, precision‑formed surfaces
Eliminates infiltration and exfiltration
Supports long‑term minimal maintenance
Compatible with PVC, HDPE, DIP, and other pipe materials
High-Density Polyethylene Manhole
The complete MagnaPlast™ manhole system
Anti-Flotation Concrete Fill
The integrated 7‑ft cement‑fill tub provides engineered ballast, ensuring reliable anti‑flotation stability even in coastal, saturated, or high‑groundwater installations.
MagnaPlast™ Base
Looking down into the MagnaPlast base
Outlet Detail
A close-up of outlet connection detail Illustrating the smooth, precision-formed surface that supports leak-free performance and long-term minimal maintenance.
America's Wastewater Infrastructure is Failing
Concrete and polymer‑concrete manholes continue to experience premature deterioration driven by:
- H₂S and MIC corrosion
- Cracking and structural degradation
- Infiltration and exfiltration at joints
- Groundwater uplift
- Escalating rehabilitation and maintenance cycles
HDPE provides a corrosion‑resistant alternative engineered to eliminate these failure modes.
WHY ENGINEERS, UTILITIES & MUNICIPALITIES SPECIFY MAGNAPLAST™
Corrosion‑Resistant Material System
HDPE is immune to H₂S, MIC, sulfuric acid, and industrial wastewater.
Lower Lifecycle Cost
No coatings, liners, patching, or rehab cycles.
No Infiltration or Exfiltration
Monolithic construction eliminates joint failures, the primary source of I&I.
Faster, Safer Installation
Installs in one‑third the time of concrete; lightweight construction reduces equipment needs.
Proven Structural Performance
Spiral extrusion‑wound HDPE has 50+ years of successful use in corrosive wastewater environments.
Engineered for Municipal Approval
Meets ASTM F1759, D3350, D2321, F477 and AASHTO traffic‑loading criteria.
APPLICATIONS
MagnaPlast™ is engineered for the environments where concrete and polymeric concrete consistently fail. Its monolithic HDPE construction, corrosion‑proof performance, and factory‑assembled reliability make it ideal for municipal, industrial, and high‑risk wastewater applications.
Municipal Wastewater Systems
Sanitary sewer collection systems
Interceptor and trunk lines
Lift station transitions
Gravity sewer networks
High‑H₂S environments
Areas with chronic I&I problems
High-Corrosion Environments (H₂S, MIC)
Force main discharge points
Downstream of pump stations
Industrial wastewater zones
Warm‑climate sewer systems with high biological activity
High Water Table & Poor Soil Conditions
Coastal regions
Flood‑prone areas
Saturated soils
Soft or unstable sub-grades
Urban & Roadway Installations
Streets and intersections
High‑traffic corridors
Urban reconstruction projects
Tight construction windows
Industrial & Process Wastewater
- Food processing
- Chemical manufacturing
- Petroleum and refining
- Mining wastewater
- Steel and metals industries
Greenfield and Replacement Projects
- New sanitary sewer construction
Replacement of failing concrete manholes
Rehabilitation avoidance (no coatings or liners needed)
Standardized municipal specifications
Sanitary sewer collection systems
TECHNICAL SPECIFICATIONS
Structural & Long‑Term Performance
Modeled for 100‑year design life using ASTM F1759 and DVS long‑term creep methodology
Monolithic, spiral‑extrusion‑wound HDPE structural cylinder
Factory‑assembled base, riser, and anti‑flotation system
Factory leak‑tested prior to shipment
Smooth internal flow surfaces (Manning’s n = 0.010) for optimized hydraulic performance
Watertight Interfaces
Fully sealed inlet and outlet penetrations
Watertight riser connections
No joints, seams, coatings, or liners required
Load & Traffic Rating
Designed for H‑20 / HS‑25 traffic loading
Compatible with municipal and DOT roadway reconstruction requirements
Groundwater & Soil Conditions
Engineered for high groundwater, buoyancy, and saturated soil environments
Integrated anti‑flotation system with cement‑fill ballast tube
Suitable for coastal regions, flood‑prone areas, and unstable sub‑grades
Standards & Compliance
Compliant with ASTM, AASHTO, and CSI MasterFormat requirements
Meets municipal and industrial wastewater design criteria
Compatible with existing concrete and polymer‑concrete systems
Installation & Integration
Lightweight, crane‑ready HDPE structure
Rapid installation with reduced construction window requirements
Ideal for greenfield construction, replacements, and rehabilitation avoidance
MagnaPlast manholes in assorted heights
(click to enlarge image)
ENGINEERING SUPPORT
Foundation and backfill guidance
Traffic‑bearing structural details
Anti‑flotation analysis
Custom submittal drawings
Pipe compatibility and deflection angles
CSI‑formatted performance specifications
Engineered in collaboration with strategic partner Dan Early, P.E., of Infrastructure Dynamics, a specialist in thermoplastic solutions for municipal water and wastewater infrastructure.
