Coupon System – Pyramid Technical Services

Coupon System

Corrosion Coupon

Coupon Holder

Corrosion Coupons

(For Periodic and Offline Corrosion Analysis)

Corrosion coupons are precision-engineered test specimens used to assess the actual corrosion rate, mechanism, and type in process systems. Each coupon is made from a material chemically equivalent to the monitored pipeline or vessel, ensuring accurate and representative data.

After a specified exposure period, the coupons are retrieved, cleaned, and analyzed. Measurements of weight loss and surface morphology provide insight into the corrosion rate and mode—such as uniform, pitting, or crevice corrosion.

Key Features :

Fabricated to accurate metallurgical and dimensional tolerances.
All surfaces are free of cold work—carefully ground or machined to ensure consistent performance.
Offered in multiple geometries and metallurgies to accurately simulate a variety of service conditions.
Each coupon is serialized, pre-weighed to four-decimal precision, and sealed in VCI packaging for a corrosion-free shelf life of up to one year.
Designed to meet NACE and ASTM G1/G31 standards, ensuring reliable and precise corrosion rate determination.

Corrosion Coupons (for Offline Evaluation)

Samples are introduced into the process stream via access fittings or coupon holders, left exposed for a specified period, and then retrieved for laboratory analysis.

Various types of Corrosion Coupons:

Flush Disc Coupon

For flush-mounted applications where protrusion into the flow is not permitted, such as piggable lines

Strip Coupon (3”, 6”)

Standard flat-type coupon for general corrosion rate evaluation

Ladder Strip Coupon

Shorter sections mounted in series to evaluate corrosion at multiple points

Multi-Disc Coupon

Stacked circular discs for assessing uniform or localized corrosion at different depths

Cylindrical Coupon

Designed for application where direction of flow and turbulence influence corrosion rate

Scale Coupon (3”, 6”)

Precisely machined with varying hole diameters to collect and analyze scale deposits

Stress Coupon

Used to monitor stress corrosion cracking tendencies in susceptible alloys.

Technical Highlights:

Material Options: Carbon Steel, Stainless Steels (304, 316, 321, 410, duplex), or as per client’s preferred Metallurgy.
Surface Finish: Ground, Directional Sanded, or Bead-Blasted.
Insulation Options: Nylon, Teflon®, or Ceramic (based on temperature rating).
Packaging: Individually supplied – labeled and sealed in VCI bags.
Temperature Ratings:
- Nylon: up to 120°C
- Teflon®: up to 260°C
- Ceramic: up to 800°C

Applications :

For Pipeline and Vessel Corrosion Rate Evaluation
For Material Compatibility Testing
For Coating and Inhibitor Efficiency Validation
For Scale and Deposit Analysis
For Stress Corrosion Testing Under Field Conditions

Coupon Holders

(For Corrosion Coupons – Intrusive Corrosion Monitoring)

Coupon holders are precision-engineered devices designed to securely mount corrosion coupons and position them at the desired location inside the pipeline or vessel.

Each holder attaches directly to the solid plug assembly of a 2-inch access fitting using a left-hand threaded connection, enabling safe insertion and retrieval under actual operating pressure.

Pyramid offers a complete range of coupon holders compatible with mechanical and hydraulic access systems, ensuring flexibility for all monitoring applications—whether for general corrosion, localized corrosion, scale deposition, or multiphase flow assessment.

Various types of Coupon Holders:

1. Flush Disc Coupon Holder

Used for mounting flush disc coupons in pipelines where the coupon must not protrude into the flow stream, such as piggable lines.

Key Features :

Maintains a flush profile with the pipe wall.
Ideal for high-velocity systems and pigging operations.
Provides consistent wall-contact corrosion measurement.
Includes Teflon® insulation washers and mounting screw.
Available in fixed and adjustable designs for precise placement.

Applications :

For Clean Pipelines
For Lines that require un-obstructed Pigging
For Corrosion studies at Pipe Wall surface

2. Strip Coupon Holder

Designed to support 3-inch or 6-inch strip coupons, enabling top-of-line, mid-line, or bottom-of-line corrosion evaluation.

Key Features :

Single-blade (tongue) holder for mounting one or two strip coupons.
Provides vertical positioning options for different flow regimes.
Standard lengths from 2.25″ to 24″ (custom lengths available)
Includes all mounting hardware.
Manufactured from 316 Stainless Steel.

Applications :

For Uniform Corrosion Rate Measurement
For In Sour Service and Sweet Service Monitoring
For Systems with Predictable Flow Profiles

3. Multi-Disc Coupon Holder

Engineered for simultaneous monitoring at three vertical positions – top, mid, and bottom of the pipeline.

Key Features :

Holds multiple disc coupons on a central rod.
Ideal for multiphase or stratified flow.
Nitrile O-rings and Delrin spacers provide complete insulation.
Available in lengths from 4″ to 36″.

Applications :

For Identifies Top-of-Line Corrosion (TOL)
For Measures Bottom-of-Line Corrosion (BOL)
For Assesses Mid-Line Corrosion (MOL)
For Detects Corrosion Under Stagnant Conditions or Gas Pockets

4. Ladder Strip Coupon Holder

A specialized holder for six strip coupons (three pairs) mounted on a stepped blade.

Key Features :

Monitors corrosion progression at multiple depths simultaneously.
Minimum length 10.25″ for 5.25″ access fittings.
316 stainless steel blade with precision-spaced holes.
Ideal for large-diameter pipelines (≥ 8″).
Includes six sets of mounting hardware.

Applications :

For Multi-Point Corrosion Profiling
For Vertical Corrosion Distribution Studies
For Gas-Liquid Stratification Monitoring

5. Cylindrical Coupon Holder

Holds cylindrical coupons for evaluating corrosion impacted by flow direction, turbulence, and localized velocity effects.

Key Features :

Rotationally exposed geometry for realistic flow interaction.
Suitable for high-flow and turbulent zones.
Available in standard and customized lengths.
Used widely in injection points, elbows, risers, and manifolds.

Applications :

For Test Racks and Side-Stream Corrosion Studies
For Pipeline Internal Corrosion Monitoring
For Corrosion Inhibitor Performance Evaluation
For Systems Where Plant Shutdown or Flow Diversion Is Possible
For Baseline Corrosion Rate Determination
For Oil, Gas, Water, and Chemical Process Services

6. Scale Coupon Holder

Holds coupons drilled with multiple hole sizes to collect and analyze scale, fouling, and deposition trends for effective process monitoring.

Key Features :

Supports 3″ or 6″ scale strip coupons.
Captures scale particles of different sizes.
Useful for evaluating scale inhibitors and cleaning cycles.
Suitable for areas with high solids or precipitation risk.

Applications :

For Services With High Scaling Tendency
For Produced Water and Water Injection Systems
For Cooling Water and Desalination Units
For Scale Inhibitor Performance Evaluation
For Low-Flow or Dead-Leg Areas
For Monitoring Combined Scale and Corrosion Mechanisms

General Technical Specifications:

Material: 316 Stainless Steel (other alloys on request)
Compliance: NACE MR0175 / MR0103
Connection: Left-hand threaded nut to solid plug assembly
Temperature Capability: Based on insulation type
- Nylon: up to 120°C
- Teflon®: up to 260°C
- Ceramic: up to 800°C
Lengths:
- Multi-Disc Holders: 8″ to 48″
- Ladder Holders: ≥ 10.25″

Applications :

For General Corrosion Monitoring
For Localized Corrosion Detection (TOL/BOL/MOL)
For Scale Deposition Analysis
For Multiphase Flow Corrosion Studies
For Verification of Corrosion Inhibitor performance
For High-Velocity and Piggable/Non-Piggable Pipeline Monitoring

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