Selection Criteria for Stainless Steel Press Systems – A Press Inox vs. B Press Inox

In water, heating, industrial, and technological installations, stainless‑steel press fittings are becoming an increasingly popular choice. Thanks to fast installation, corrosion resistance, and suitability for demanding operating conditions, stainless steel has become a strong alternative to copper and plastic systems.

Conex Bänninger offers two INOX press systems: <A> Press Inox 304 and >B< Press Inox 316L. Although both systems are based on the same press technology, they differ in application areas, material characteristics, and certification.

Application and Operating Environment

A Press Inox 304

A Press Inox 304 is designed for water and heating installations in residential and commercial buildings.
It performs reliably in standard operating conditions, such as:

• cold and hot water,
• heating systems,
• non‑aggressive industrial installations,
• rainwater drainage systems.

This system is not approved for potable water.

>B< Press Inox 316L

>B< Press Inox 316L is intended for more demanding environments where installations are exposed to higher temperatures, higher pressure, or chemical agents. It is designed for:

• potable water and solar installations,
• heating and solar heating systems,
• chilled‑water systems, compressed air, and technical media,
• process installations in the food, cosmetics, chemical, and pharmaceutical industries.

Its increased corrosion resistance makes it suitable for the most challenging operating conditions.

Material Properties and Sealing

The fundamental difference lies in the type of stainless steel used:

• <A> Press Inox 304 is made of AISI 304 (1.4301) — suitable for water and heating installations but not for potable water.
• >B< Press Inox 316L is made of AISI 316L (1.4404) with a minimum of 2% molybdenum, providing excellent resistance to chlorine and other aggressive substances. It is fully approved for potable water.

Both systems are equipped with a black EPDM O‑ring with Press Indicator (PI) functionality, allowing installers to detect unpressed connections at 0.1–6 bar.

Available sizes: DN15–DN108.

Certification

B< Press Inox 316L holds certifications such as DVGW, WRAS, KIWA, ITB, PZH,
allowing it to be used in potable‑water systems, compressed‑air networks, and solar installations.

A Press Inox 304 holds certifications including WRAS and ITB, but due to material limitations (304 steel), it is not approved for potable water.

Before selecting a system, always consult the latest technical documentation and project requirements.

Tool Compatibility and Installation Differences

Although both systems rely on press technology, they require different jaws and specific installation rules.

>B< Press Inox 316

• DN15–DN54 → B-profile jaws
• DN76–DN108 → M‑profile press collars

A Press Inox 304

• DN15–DN54 → M‑profile jaws
• DN76–DN108 → M‑profile press collars

Pre‑Installation Checklist

Before starting installation, ensure that:

• the tools are approved by the manufacturer,
• jaws match the selected press system,
• the pipe insertion depth is correct.

Despite visual similarities, fittings are not interchangeable between systems.

How to Select the Right System

Both A Press Inox 304 and >B< Press Inox 316L rely on the same proven press technology.
However, they differ significantly in technical parameters, corrosion resistance, certification, and application scope.

When selecting the correct system, consider more than the price — durability, safety, and project requirements should be the priority.

Choose Press <A> Press Inox 304 if:

• you are installing systems in residential or commercial buildings,
• the project does not involve potable water or aggressive environments,
• you need a cost‑effective solution with fast installation.

Choose >B< Press Inox 316L if:

Tthe installation must meet hygienic standards (e.g., potable water),

• the environment involves harsh conditions (chemicals, steam, chlorine),
• you require high corrosion resistance and certified long‑term performance.

Full Product Range

• A Press INOX 304 (link)
• B Press INOX 316L (link)

Need Support?

The Conex Bänninger Technical Team will help you choose the right system for your installation, tools, and project.

Contact our Technical Advisors (see the CONTACT tab) or the Technical Department: [email protected]