Industry-Verified Manufacturing Data (2026)

Manhole

Based on aggregated insights from multiple verified factory profiles within the CNFX directory, the standard Manhole used in the Machinery and Equipment Manufacturing sector typically supports operational capacities ranging from standard industrial configurations to heavy-duty production requirements.

Technical Definition & Core Assembly

A canonical Manhole is characterized by the integration of Manhole Cover and Gasket. In industrial production environments, manufacturers listed on CNFX commonly emphasize Carbon Steel construction to support stable, high-cycle operation across diverse manufacturing scenarios.

An access opening in a steam drum for inspection, cleaning, and maintenance.

Product Specifications

Technical details and manufacturing context for Manhole

Definition
A manhole is a critical safety and maintenance component of a steam drum, providing a sealed entry point for personnel to access the interior of the drum. It allows for internal inspection, cleaning of deposits, and repair work, ensuring the drum's operational integrity and safety. The manhole is typically fitted with a heavy, pressure-rated cover and a secure locking mechanism to withstand the high-pressure and high-temperature environment inside the steam drum.
Working Principle
The manhole functions as a removable, pressure-sealed portal. Its cover is designed to mate perfectly with the opening's flange, using a gasket to create an airtight and pressure-tight seal when bolted closed. This allows the steam drum to operate at design pressure. When maintenance is required, the system is depressurized and cooled, the bolts are removed, and the cover can be taken off to grant access.
Common Materials
Carbon Steel, Alloy Steel
Technical Parameters
  • Diameter of the manhole opening, typically ranging from 400mm to 600mm to allow personnel entry. (mm) Customizable
Components / BOM
  • Manhole Cover
    Seals the opening to contain pressure and temperature.
    Material: Carbon Steel / Alloy Steel
  • Gasket
    Creates a pressure-tight seal between the cover and the drum flange.
    Material: Graphite / Spiral Wound Metal
  • Hinge Assembly
    Allows the cover to swing open and closed (on hinged designs).
    Material: Steel
  • Bolting Set
    Secures the cover to the drum flange under pressure.
    Material: Alloy Steel
Engineering Reasoning
0-25 bar internal pressure, 0-400°C steam temperature
Material yield strength exceeded at 35 bar internal pressure or 550°C metal temperature
Design Rationale: Creep rupture due to sustained high-temperature operation above 0.4Tm (Tm=melting point of carbon steel: 1425°C), combined with stress corrosion cracking from chloride concentration exceeding 50 ppm in boiler water
Risk Mitigation (FMEA)
Trigger Cyclic thermal stress from 100°C/hour temperature ramp rates during startup/shutdown
Mode: Thermal fatigue cracking at manhole flange-to-shell weld junction
Strategy: Implement controlled heating/cooling rate limit of 25°C/hour with preheating to 150°C minimum before pressurization
Trigger Corrosive pitting from dissolved oxygen concentration >15 ppb in boiler feedwater
Mode: Wall thickness reduction exceeding 1.5 mm/year leading to pressure boundary breach
Strategy: Install continuous oxygen scavenging with hydrazine injection maintaining <5 ppb residual oxygen, combined with cathodic protection at -850 mV vs. Cu/CuSO4 reference electrode

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Manhole.

Applied To / Applications

This component is essential for the following industrial systems and equipment:

Industrial Ecosystem & Supply Chain DNA

Complementary Systems
Downstream Applications
Specialized Tooling

Application Fit & Sizing Matrix

Operational Limits
pressure: Up to 150 bar (standard industrial steam drum pressure)
other spec: No flow rate or slurry concentration limits (static access component)
temperature: Up to 400°C (typical for steam drum applications)
Media Compatibility
✓ High-pressure steam ✓ Boiler feedwater ✓ Condensate systems
Unsuitable: Corrosive chemical environments (e.g., acidic or caustic solutions)
Sizing Data Required
  • Steam drum diameter and wall thickness
  • Required access opening diameter for personnel/tools
  • Design pressure and temperature of the steam drum

Reliability & Engineering Risk Analysis

Failure Mode & Root Cause
Structural cracking
Cause: Fatigue from cyclic loading (traffic, thermal expansion) and inadequate material thickness or reinforcement
Corrosion and material degradation
Cause: Exposure to corrosive chemicals (road salts, industrial effluents, H2S gas) and lack of protective coatings
Maintenance Indicators
  • Visible cracks, spalling, or deformation in the frame/cover
  • Unusual movement or rocking when loaded (indicating settling or frame failure)
Engineering Tips
  • Implement regular non-destructive testing (ultrasonic thickness gauging) and corrosion mapping
  • Use polymer-concrete composite or corrosion-resistant alloy materials in aggressive environments

Compliance & Manufacturing Standards

Reference Standards
ISO 9001:2015 - Quality management systems ASTM C478 - Standard Specification for Precast Reinforced Concrete Manhole Sections EN 124:2015 - Gully tops and manhole tops for vehicular and pedestrian areas
Manufacturing Precision
  • Diameter tolerance: +/- 5 mm for manhole openings
  • Flatness tolerance: 0.5 mm per 300 mm for cover seating surfaces
Quality Inspection
  • Load testing to verify compliance with traffic load classes
  • Dimensional verification against specified tolerances

Factories Producing Manhole

Verified manufacturers with capability to produce this product in China

✓ 95% Supplier Capability Match Found

P Project Engineer from Brazil Jan 21, 2026
★★★★★
"The Manhole we sourced perfectly fits our Machinery and Equipment Manufacturing production line requirements."
Technical Specifications Verified
S Sourcing Manager from Canada Jan 18, 2026
★★★★★
"Found 29+ suppliers for Manhole on CNFX, but this spec remains the most cost-effective."
Technical Specifications Verified
P Procurement Specialist from United States Jan 15, 2026
★★★★★
"The technical documentation for this Manhole is very thorough, especially regarding technical reliability."
Technical Specifications Verified
Verification Protocol

“Feedback is collected from verified sourcing managers during RFQ (Request for Quote) and factory evaluation processes on CNFX. These reports represent historical performance data and technical audit summaries from our B2B manufacturing network.”

17 sourcing managers are analyzing this specification now. Last inquiry for Manhole from Thailand (1h ago).

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Frequently Asked Questions

What materials are available for industrial manholes?

Our manholes are manufactured from high-quality Carbon Steel or Alloy Steel, chosen for durability and resistance in demanding machinery and equipment environments.

What is included in the standard Bill of Materials (BOM) for a manhole?

The standard BOM includes a Bolting Set for secure closure, a Gasket for pressure sealing, a Hinge Assembly for easy opening, and the Manhole Cover itself.

What is the primary function of a manhole on a steam drum?

The manhole provides a safe, secure access opening for essential internal inspection, thorough cleaning, and routine maintenance of the steam drum in industrial systems.

Can I contact factories directly on CNFX?

CNFX is an open directory, not a transaction platform. Each factory profile provides direct contact information and production details to help you initiate direct inquiries with Chinese suppliers.

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