EN 10255 Medium Series Galvanized Steel Tube DN50 with Grooved Ends for Fire Service

Engineered to provide ultimate reliability and rapid installation for modern active fire protection networks, this EN 10255 Medium Series Galvanized Steel Tube is a premier choice for commercial and industrial fire services. Utilizing a DN50 (2-inch equivalent, 60.3mm OD) steel tube manufactured in strict compliance with the European EN 10255 standard, it features a robust 3.6mm wall thickness (Medium Series) for exceptional pressure handling.
The tube is hot-dip galvanized both internally and externally to EN 10240 standards, providing a highly durable, corrosion-resistant zinc barrier. Supplied with factory roll-grooved ends conforming to AWWA C606, this pipe is designed for rapid mechanical coupling, ensuring a leak-free, high-pressure seal for commercial wet or dry fire sprinkler distribution lines.

Features & Advantages

Full EN 10255 Compliance: Built to European standards for non-alloy steel tubes, ensuring certified material traceability, strict dimensional tolerances, and high structural safety for critical fire suppression networks.

Premium Hot-Dipped Galvanizing (EN 10240): Coated with a dense, metallurgically bonded zinc layer that prevents internal scaling and rust, guaranteeing unimpeded water flow over decades of stagnant water exposure.

Factory Roll-Grooved Ends: Precisely cold roll-grooved to AWWA C606 specifications, allowing for rapid, weld-free mechanical jointing using standard grooved couplings, cutting field installation times in half.

Medium Series Wall Integrity: The 3.6mm wall thickness offers robust mechanical strength, high ring stiffness, and high burst pressure capacity, perfectly rated for commercial fire protection mains.

Technical Specifications

Specification Item	Detailed Description
Product Name	EN 10255 Medium Series Galvanized Steel Tube
Standard Specification	EN 10255 (Non-alloy steel tubes suitable for welding and threading)
Weight Series	Medium Series (equivalent to former BS 1387 Class B)
Manufacturing Process	ERW (Electric Resistance Welded) followed by Hot-Dip Galvanizing
Nominal Diameter (DN)	DN50 (equivalent to 2 Inch)
Outer Diameter (OD)	60.3 mm (Minimum 59.6 mm – Maximum 60.8 mm)
Wall Thickness (WT)	3.6 mm (0.142 inches)
Galvanizing Standards	EN 10240 (internal/external quality class), EN ISO 1461, ASTM A53
Zinc Coating Thickness	Minimum average of 55 to 70 microns (zinc weight ≥ 350 g/m²)
End Connection	Cold Roll-Grooved Ends conforming to AWWA C606 dimensions
Standard Length	5.8m, 6.0m, or customized as per project logistics

Product Applications

Automatic Fire Sprinkler Wet Systems: Highly reliable horizontal distribution lines and branch piping supplying sprinkler heads.

Dry Pipe & Preaction Sprinkler Networks: Excellent protection against localized oxygen and moisture corrosion caused by trapped condensation in dry-pipe lines.

Building Fire Water Mains: High-strength subterranean or riser pipes connecting primary fire pumps to building manifolds.

Industrial Fire Hydrant Loops: Rugged, corrosion-resistant low-pressure water mains for warehouse and factory fire protection loops.

Rigorous Quality Control & Manufacturing Process

Our DN50 EN 10255 Medium galvanized tubes undergo a highly standardized manufacturing and testing process:

ERW Base Tube Verification: Checking the dimensions, wall thickness (3.6mm), and weld seam of the raw steel tubes to ensure full compliance with EN 10255 Medium specifications.

Molten Hot-Dip Galvanizing: Immersing the pickled and pre-fluxed tubes into a molten zinc bath maintained at approximately 450°C, ensuring a tough, protective zinc-iron alloy layer inside and out.

Precision Roll Grooving: Utilizing specialized computer-controlled cold roll-grooving machinery to shape the pipe ends into standard AWWA C606 grooved profiles without cutting away the steel mass.

Hydrostatic Leak Testing: Every tube is subjected to a 100% factory hydrostatic pressure test at the specified pressure limits to verify the seam and tube body sealing integrity.

Frequently Asked Questions (FAQ)

Q1: What does “Medium Series” represent under the EN 10255 standard?

A: EN 10255 classifies steel tubes primarily into Medium Series (wall thickness of 3.6mm for a DN50 pipe) and Heavy Series (wall thickness of 4.5mm). The Medium Series offers the most popular and highly economical balance of steel weight and mechanical strength, fully certified for fire water pressures in commercial and residential buildings.

Q2: Why are grooved ends preferred over threaded or welded connections in fire services?

A: Welding inside buildings creates high fire hazards (hot works) and requires certified welders. Threading reduces the steel wall mass, which can weaken the joints. Grooved ends allow for extremely rapid, weld-free mechanical assembly using flexible or rigid grooved couplings. This connection method absorbs piping thermal expansion, reduces noise transmission, and cuts installation labor by over 50%.

Q3: How does hot-dip galvanizing to EN 10240 protect fire sprinkler pipes?

A: EN 10240 specifies strict quality classes for the internal and external zinc layers on steel tubes. Our hot-dip process ensures a thick, continuous 55–70 micron coating both inside and outside the tube. This prevents internal water tuberculation (rust scaling) that can clog sprinkler heads, while shielding the exterior from atmospheric moisture and condensation.

Q4: Can this EN 10255 DN50 galvanized pipe be used in dry-pipe sprinkler systems?

A: Yes. Dry pipe systems are filled with pressurized air or nitrogen and are highly vulnerable to localized corrosion caused by pooling condensation and trapped oxygen. The thick EN 10240 hot-dipped zinc lining provides an outstanding chemical barrier that completely halts oxygen-induced pitting, making it highly recommended for dry-pipe fire lines.