When it comes to plumbing and fire protection systems, ProPress copper fittings are one of the most trusted solutions on the market. Contractors choose them for quick installation, durability, and leak-free performance.

But many buyers still ask key questions about ProPress pressure ratings, specifications, UL/FM certifications, and sizing before ordering. This guide answers those questions — and shows you why you should buy from us and save over 50% compared to brand-name suppliers for the exact same UL/FM-certified parts.

What Is the Maximum Operating Pressure for ProPress Fittings?

The maximum operating pressure for most ProPress copper fittings depends on pipe size and application:

• ½" – 2" copper tube: rated up to 200 PSI for water applications

• 2½" – 4" copper tube: rated up to 175 PSI for water applications

For an easy reference, check the official ProPress pressure rating chart when planning your installation.

💡 Pro Tip: Our Copper Press-Fit Collection includes UL/FM-certified fittings that meet these same ratings — at over 50% off brand-name prices.

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ProPress Zero Lead Valves – Pressure Rating and Specs

For potable water systems, ProPress Zero Lead valves are required. Their specifications typically include:

• Maximum Operating Pressure: 200 PSI
• Hydrostatic Test Pressure: 600 PSI
• NSF-61-G Compliance: Safe for drinking water

Shop our Ball Valve Press-Fit Copper — UL/FM certified and ready to ship at a fraction of what you’d pay elsewhere.

Minimum Distance Between ProPress Fittings

A common installation question: what is the minimum distance between ProPress fittings?Leave at least one pipe diameter between fittings (e.g., 1" of straight pipe for 1" tube).

This spacing ensures proper pressing and avoids tool interference.

When planning layout, stock up on the right fittings:

• 90° Elbow Press-Fit Copper
• Tee Press-Fit Copper
• Union Press-Fit Copper

Largest Diameter of Soft Drawn Copper for ProPress

Installers often ask: what is the largest diameter of soft drawn copper that may be used with ProPress fittings?

• Soft drawn copper tube is approved for use up to 1".
  
• For sizes above 1", use hard drawn copper.
  
• Check the official Viega ProPress fitting take-off PDF for detailed specifications.

Hydrostatic Test Ratings & Operating Temperatures

Your system’s reliability depends on using fittings that can handle testing and temperature swings:

• Rated Hydrostatic Test Pressure: 600 PSI
  
• Operating Temperature Range for FKM Sealing Elements: -4°F to 284°F
  

These ratings make ProPress fittings ideal for both residential and commercial water systems, hydronic heating, and fire protection piping.

Do Press-Fit Copper Fittings Have to Be UL/FM Certified?

If you’re working on a fire sprinkler system, yes — fittings must be UL/FM listed to comply with NFPA 13 and local fire codes.

We proudly stock UL/FM Certified ProPress-compatible fittings, including:

Coupling Press-Fit Copper

Male Adapter Press-Fit Copper

Female Adapter Press-Fit Copper

Shop UL/FM Certified Copper Fittings and Save

Why Buy From Us?

UL/FM Certified Stock – Meets all fire protection and plumbing requirements.

Over 50% Savings – Same quality and certifications as big-name brands.

Full Copper Fittings Selection – Couplings, Elbows, Caps, Valves, and more.

Fast Shipping – Get your order when you need it.

Stop overpaying for press-fit copper.

👉 BUY NOW and Get Certified Fittings for Half the Price