Fire-fighting plastic-coated steel pipe

Product Introduction

Fire-fighting plastic-coated steel pipe, with carbon steel pipe as the base pipe, both inner and outer walls are sprayed with epoxy resin EP powder. The outer wall of fire-fighting specific products is red. It is a dedicated pipe material for fire hydrant and automatic sprinkler systems, replacing traditional hot-dip galvanized steel pipes.

• Structural Composition

1. Base pipe: longitudinally welded pipe, seamless steel pipe (GB/T3091, GB/T8163), material Q235B, 20# steel
2. Inner coating: epoxy resin powder, anti-corrosion, smooth inner wall without scaling
3. Outer coating: epoxy resin powder, fire-fighting specific red coating

Key distinctions:

• Fire-fighting plastic-coated: single-layer epoxy powder on both inner and outer surfaces; mainly used for indoor building and corridor fire protection pipe networks.
• TPEP steel pipe: outer 3PE three-layer polyethylene + inner epoxy powder; mainly used for buried municipal water transmission, not used as indoor fire sprinkler main pipe material.
• Product advantages: smooth inner wall, low water flow resistance, not prone to scaling or rusting; flame-retardant coating, resistant to water corrosion; eliminates galvanized pipe rusting that blocks sprinkler heads; design service life of 30-50 years; high pressure rating, suitable for high-pressure fire-fighting water supply.
• Application fields: building fire hydrant systems, automatic sprinkler fire extinguishing systems, foam fire-fighting systems; also applicable to water supply and drainage, and reclaimed water pipelines.
• Executive standards

1. GB/T 5135.20-2010 "Automatic Sprinkler Fire Extinguishing Systems - Part 20: Coated Steel Pipes" (mandatory fire-fighting standard, essential for acceptance inspection)
2. CJ/T 120-2016 "Water Supply Plastic-Coated Composite Steel Pipes"
3. GB50974-2014 "Technical Code for Fire Protection Water Supply and Hydrant Systems"

• Medium working temperature: 0-80℃; short-term ≤95℃, not suitable for steam.
• Nominal pressure: PN1.0MPa, PN1.6MPa, determined by the base pipe wall thickness.
• Diameter range: DN15-DN600; fixed length 6m.

Coating Technical Parameters (GB/T5135.20-2010)

Table

3. Common Connection Methods

1. Threaded connection: DN15-DN100, for small-diameter sprinkler pipelines;
2. Groove coupling connection: DN65-DN300, most commonly used in fire-fighting projects;
3. Flange connection: full diameter range, for pump rooms and equipment connections;

⚠️On-site welding is not permitted! Welding high temperatures will burn and damage the inner and outer epoxy coatings; if welding is absolutely necessary, repair treatment must be performed on both inner and outer surfaces of the pipe ends after welding, otherwise acceptance inspection will fail.

4. Construction Precautions

1. Cutting must be done with an abrasive cut-off machine; gas cutting is prohibited; after cutting, deburr the pipe ends thoroughly and repair damaged coatings;
2. Strictly prohibit high-temperature baking or direct welding torch exposure on the pipe;
3. Avoid impact and scratching of the coating during handling and installation;
4. For buried applications, the outer epoxy of fire-fighting plastic-coated pipes has weak resistance to crushed stone impact; for long-distance buried applications, TPEP steel pipes are preferred.

5. Quick Comparison Table of Four Pipe Types

Table