Hydrostatic Test Additives for Ultimate Protection

A hydrostatic test is a critical procedure used to verify the structural integrity of pressure vessels such as pipelines, heat exchangers, storage tanks, and ship voids. While this testing method is essential for safety and compliance, it introduces a significant risk: corrosion.

When left unprotected, the presence of water and ionic contaminants during a hydrostatic test can rapidly corrode metal surfaces, jeopardizing long-term system performance. That’s why ZERUST® Hydrostatic Test Additives are engineered to deliver unparalleled corrosion protection during and after testing.

Why Use Additives in a Hydrostatic Test?

During a hydrostatic test, water is pressurized inside a vessel to detect leaks and ensure mechanical reliability. However, untreated water contains dissolved ions, oxygen, and minerals that can lead to:

• Rust formation on ferrous metals
• Pitting and scale buildup
• Long-term internal corrosion
• Environmental discharge concerns

ZERUST® has developed a suite of hydrostatic test fluid additives that counteract these threats with safe, globally compliant, and high-performing formulations tailored to different metal types and testing environments.

ZERUST® Hydrostatic Test Additives: Product Overview

1. Axxatec™ HST-20L

For ferrous metals | Anti-rust + Hard water scale prevention

ZERUST®/EXCOR® Axxatec™ HST-20L is a powerful water treatment concentrate formulated to deactivate ionic contaminants that cause rust and scale during hydrostatic testing. Ideal for pressure vessels composed of ferrous metals, this additive ensures temporary corrosion protection during and post-test.

Key Features:

• Deactivates ionic contaminants to prevent rust and deposits
• Not compatible with aluminum, zinc, galvanized, or yellow metals
• Non-flammable and solvent-free
• Compliant with TSCA, RoHS, and REACH
• Environmentally safe; can be reused or discharged per regulations
• Ideal for: pipelines, steel tanks, ship voids, and heat exchangers made of ferrous metals

Ideal for: pipelines, tanks, and vessel systems made of ferrous metals where hard water is used or where a dry, powder format is preferred.

Tip: For systems that contain aluminum or yellow metals, use Axxatec™ HST-20L in conjunction with Axxatec™ HST-M100.

2. Axxatec™ HST-M100

For mixed-metal systems | Broad-spectrum protection

When your hydrostatic test involves aluminum, copper, brass, or a mix of metal alloys, Axxatec™ HST-M100 is the ideal additive. This water-soluble solution provides corrosion protection for a wide range of metals and continues to inhibit corrosion after the test is complete.

Key Features:

• Compatible with aluminum, copper, brass, and ferrous metals
• Water-soluble and low-foaming
• Meets TSCA, RoHS, and REACH compliance
• Dry-to-touch finish post-testing
• Non-flammable, solvent-free, and easy to flush

Ideal for: heat exchangers, ship voids, and tanks containing mixed-metal components

Tip: When testing only ferrous metal systems, pair with AxxaVis™ HST-10 for enhanced cost-efficiency.

3. AxxaVis™ HST-10

For ferrous metals | Powder-based corrosion inhibitor

AxxaVis™ HST-10 is a water-soluble powder additive that transforms hard water into a corrosion-safe testing medium for ferrous metal vessels. It’s an excellent option for industrial operations that rely on hard or variable water sources.

Key Features:

• Deactivates ionic contaminants to prevent rust and scale
• Designed for ferrous metals only
• Powder format allows for convenient mixing and storage
• Compliant with global environmental and safety standards
• Non-hazardous, non-flammable, and solvent-free

Ideal for: facilities using hard water or requiring a powdered additive format

Tip: For systems involving yellow/red metals, use AxxaVis™ HST-10 alongside Axxatec™ HST-M100 for full-spectrum protection.

Environmentally Compliant. Operationally Efficient.

All ZERUST® hydrostatic test additives are formulated with environmental stewardship in mind. These products:

• Meet global compliance standards (TSCA, RoHS, REACH, ECHA SVHC)
• Are safe for discharge in most regulated environments
• Reduce operational costs through reusability in select applications
• Offer non-flammable, solvent-free safety for operators and equipment

Choosing the Right Additive for Your Hydrostatic Test