FM-approved High-Density Polyethylene (HDPE) fire pipes are engineered for superior fire protection systems, offering durability, corrosion resistance, and reliable performance in fire suppression applications.
Corrosion & Chemical Resistance – Unlike metal pipes, HDPE resists rust and chemical degradation, ideal for harsh environments1.
Lightweight & Flexible – Easier to install than rigid metal piping, reducing labor costs and time.
High Impact Strength – Maintains structural integrity under stress, crucial for fire safety systems.
FM Approval Assurance – Meets rigorous standards for fire resistance, hydraulic performance, and long-term reliability.
Sprinkler systems
Standpipes
Industrial fire protection
FM-approved HDPE fire pipes provide a cost-effective, long-lasting alternative to traditional materials like CPVC or steel, with superior resistance to environmental and operational stresses
Official website: www.phtopindustry.com | www.phpipes.com
Contact us: Email:inquiry@phtopindustry.com | Whatsapp:+86 15093100892
Company address: Room 802, 8th Floor, Building 5, Jinyin Modern City, Jinshui District, Zhengzhou City, Henan Province, China
HDPE (High-Density Polyethylene) pipes are widely used in municipal engineering due to their excellent corrosion resistance, flexibility, and long service life. To ensure project quality and durability, the following key points must be strictly observed during installation:
1. Material Inspection
Check pipe appearance: uniform color, free of bubbles, cracks, dents, or other defects.
Stiffness requirement: Municipal drainage pipes should have a ring stiffness ≥ 4000 N/m² (SN4).
Pipe end flatness: Straightness tolerance should be less than 3‰.
2. Trench Excavation
Width requirement: Pipe outer diameter + 0.3 m (for above-ground connections) or + 0.5 m (for in-trench connections), with a minimum width ≥ 0.7 m.
Base treatment: Avoid disturbing the natural soil; backfill and compact with graded gravel if over-excavated.
Groundwater control: Lower the water table to 0.3–0.5 m below the trench bottom.
1. Connection Methods
Butt Fusion (DN ≥ 75 mm): Temperature 210 ± 10°C, voltage stabilized at 200–220 V.
Electrofusion (for confined spaces): Suitable for pipe wells and restricted areas.
Socket Fusion (DN ≤ 63 mm): Control heating time to avoid excessive melt flow.
2. Special Environmental Considerations
Summer installation (DN ≤ 110 mm): Use a serpentine layout to compensate for thermal expansion.
Outdoor installation: Apply shading measures to prevent UV degradation.
Low-temperature environments (below -10°C): Use special low-temperature-resistant pipes.
3. Pipe Laying
Lowering method: Use non-metallic slings (secured at 1/4 of the pipe length from the end); never use center lifting.
Foundation treatment: Use gravel bedding (50–200 mm thick); avoid concrete foundations.
1. Backfilling Requirements
Layered backfilling: Use medium-coarse sand for pipe sides, compaction ≥ 90%.
Mechanical backfilling restriction: Only allowed above 0.7 m from the pipe crown.
Symmetrical backfilling: Backfill both sides simultaneously to prevent deformation.
2. Quality Inspection Standards
Pressure test: Use water as the medium, maintain pressure for 30 minutes.
Joint inspection: Butt fusion beads should be uniform (height ≥ 2 mm).
Alignment control: Horizontal deviation ≤ 1.5 mm/m, total length ≤ 25 mm.
1. Safety Risk Prevention
Static electricity protection: Anti-static measures required in flammable environments.
Trench safety: Install supports to prevent collapse.
Large-diameter pipes (DN ≥ 400): Require special construction plans to control rebound risks.
2. Connection with Manholes
Flexible connection: Use rubber gaskets to prevent leaks.
Anti-settlement treatment: Enhance compaction within 1 m of the manhole.
Table: Key Control Indicators for HDPE Pipes in Municipal Engineering
Item | Standard Requirement | Test Method |
Ring stiffness | ≥ SN4 (4000 N/m²) | Pressure test |
Fusion temperature | 210 ± 10°C | Infrared thermometer |
Backfill compaction | ≥ 90% (pipe sides) | Sand replacement method |
Leak tightness | 0.8 MPa/30 min, no leakage | Hydrostatic test |
By strictly adhering to these technical requirements, HDPE pipeline systems can achieve optimal performance in municipal engineering. It is recommended to conduct pre-construction technical briefings and establish a complete quality traceability system (e.g., RFID tagging) for full lifecycle quality control. For special geological conditions or large-diameter pipes (e.g., DN ≥ 800 mm steel-reinforced pipes), refer to the manufacturer’s specialized construction guidelines.
Official website: www.phtopindustry.com | www.phpipes.com
Contact us: Email:inquiry@phtopindustry.com | Whatsapp:+86 15093100892
Company address: Room 802, 8th Floor, Building 5, Jinyin Modern City, Jinshui District, Zhengzhou City, Henan Province, China
Ring stiffness is a core indicator for measuring the ability of a pipeline to resist deformation under external pressure (such as soil pressure, traffic load), with the unit of kN/m², indicating the deformation resistance of the pipeline under vertical load.
Formula:
Ring stiffness (SN) = EID3Ring stiffness (SN) = D3EI
EE: Material elastic modulus
II: Pipe section moment of inertia
DD: Pipe diameter
International general standards (such as ISO 9969, ASTM D2412) classify ring stiffness into the following grades:
Grade | Ring Stiffness (kN/m²) | Application Scenarios |
SN2 | ≥2 | Low-load areas (e.g., green space drainage) |
SN4 | ≥4 | Light-duty roads, residential drainage |
SN8 | ≥8 | Municipal roads, general traffic areas |
SN12.5 | ≥12.5 | Heavy vehicle traffic (e.g., highways) |
SN16 | ≥16 | Ultra-deep burial or extreme load conditions |
Pipe structure:
Solid wall pipe: high stiffness, suitable for high-pressure scenarios (such as SN8 and above).
Double-wall corrugated pipe: hollow structure is lightweight, but can reach SN4-SN8 through corrugated design.
Steel belt reinforced pipe: composite steel belt support, can reach SN12.5-SN16.
Material density: The density of HDPE raw material (usually ≥0.941g/cm³) directly affects rigidity.
Wall thickness design: Under the same diameter, increasing wall thickness can significantly improve ring stiffness.
Buried depth <1m: SN4 (such as courtyard drainage).
Buried depth 1-3m: SN8 (municipal road).
Buried depth >3m or heavy load: SN12.5-SN16 (need to be calculated in combination with soil quality).
Dynamic load: areas with frequent traffic need to increase by 1-2 levels (such as SN8→SN12.5).
Laboratory test: Perform three-point loading test according to ISO 9969 to measure the deformation rate of pipes.
On-site verification: Deformation rate detection is required after construction (usually required to be ≤5%).
Certification standards:
National standard: GB/T 19472.1 (buried polyethylene double-wall corrugated pipe)
European standard: EN 13476 (structural wall pipe system)
Misunderstanding 1: The higher the ring stiffness, the better?
→ Excessive pursuit of high stiffness may increase costs, and it is necessary to balance load requirements and economy.
Misunderstanding 2: HDPE pipe flexibility = low stiffness?
→ Structural design (such as corrugation, reinforcement layer) can take into account flexibility and high stiffness.
Construction points:
Backfill materials should use coarse sand or gravel to avoid sharp stones damaging the pipe wall.
Layer compaction to prevent local stress concentration.
Pipe Type | Typical Ring Stiffness (kN/m²) | Characteristics |
HDPE Double-Wall Corrugated Pipe | SN4–SN8 | Lightweight, economical, suitable for general drainage |
HDPE Steel Belt Reinforced Pipe | SN8–SN16 | Ultra-high strength, ideal for deep burial or heavy load conditions |
PVC Solid Wall Pipe | SN2–SN4 | High rigidity but poor impact resistance |
Concrete Pipe | ≥20 | Heavy and costly to install |
The ring stiffness level of HDPE pipe directly determines its engineering applicability. When selecting, it is necessary to comprehensively evaluate the burial depth, load, soil quality and cost. For high-demand scenarios (such as municipal trunk roads), it is recommended to choose SN8 or above and match it with a steel belt reinforcement structure to ensure long-term stability.
Official website: www.phtopindustry.com | www.phpipes.com
Contact us: Email:inquiry@phtopindustry.com | Whatsapp:+86 15093100892
Company address: Room 802, 8th Floor, Building 5, Jinyin Modern City, Jinshui District, Zhengzhou City, Henan Province, China
Puhui Industry is a well-known manufacturer of high-density polyethylene (HDPE) pipes in China. Its products are widely used in municipal water supply, agricultural irrigation, mining transportation and other fields. HDPE pipes have become an ideal choice for modern infrastructure construction due to their corrosion resistance, long life and diverse connection methods.
Puhui Industry provides a variety of HDPE pipes, and the price varies depending on factors such as pipe diameter, pressure level, and wall thickness. The following are reference prices for some products:
75mm diameter HDPE pipe: The price is about $0.20 to $2.10 per meter, suitable for water supply, gas transportation, mining and other fields.
300mm diameter HDPE pipe:
Ordinary type (low pressure level, thin wall): about 200 to 300 yuan per meter.
Medium type (medium pressure level, standard wall thickness): about 300 to 400 yuan per meter.
900mm diameter HDPE pipe: The price is about $0.40/meter, suitable for large water conservancy projects and municipal projects.
1400mm to 1600mm diameter HDPE pipe: The price is about $0.36/meter, suitable for extra-large engineering projects.
The price of HDPE pipes is affected by many factors, including:
Diameter and wall thickness: The larger the diameter and the thicker the wall, the more raw materials are required, and the price increases accordingly.
Pressure rating (SDR): The higher the pressure rating, the greater the internal pressure the pipe needs to withstand, and the manufacturing cost increases accordingly. Raw material cost: The fluctuation of HDPE raw material price directly affects the price of the final product.
Production process and certification: Products that use advanced production technology and obtain international certifications (such as ISO, CE, WRAS, ROHS) have more guaranteed quality and relatively higher prices.
Transportation and tariffs: For export products, transportation costs and import tariffs will also have an impact on prices.
Due to the variety of specifications of HDPE pipes, it is recommended that you contact us directly to obtain a detailed quotation before purchasing. You can contact us in the following ways:
Official website: www.phtopindustry.com
Email: inquiry@phtopindustry.com
WhatsApp: +86 15093100892
Provide your specific needs (such as pipe diameter, pressure level, application scenario, etc.) so that we can provide you with the most suitable products and quotations.
Puhui Industry is committed to providing high-quality HDPE pipes and accessories to customers around the world. With its rich production experience and strict quality control, it has won wide market recognition. Whether it is municipal engineering, agricultural irrigation or industrial transportation, Puhui's products are a trustworthy choice.
High-Density Polyethylene (HDPE) pipes are widely used in water supply, drainage, gas, and chemical industries due to their advantages such as corrosion resistance, impact resistance, and long service life. The welding methods for HDPE pipes mainly include Butt Fusion and Electrofusion, ensuring a leak-free and high-strength pipeline system.
1. Preparation
Inspect equipment: Ensure the hot melt welding machine (heating plate, clamps, hydraulic system) is functioning properly.
Clean pipe ends: Use alcohol or a non-woven cloth to remove dirt, grease, and oxidation from the pipe ends.
Align pipes: Secure the pipes with clamps to ensure flat and aligned ends, with misalignment ≤10% of wall thickness.
2. Heating Phase
Set temperature: The heating plate temperature is typically 200–220°C (adjust based on pipe specifications).
Apply pressure:
Insert the heating plate between the pipe ends and apply initial pressure (0.1–0.2 MPa).
Observe the bead height; once it reaches the standard value (e.g., ~2 mm for DN110 pipes), reduce pressure and maintain heating time (refer to the table below).
Pipe Diameter (mm) | Heating Time (sec) | Changeover Time (sec) | Cooling Time (min) |
DN63 | 30–40 | ≤5 | 6–8 |
DN315 | 120–150 | ≤8 | 20–25 |
3. Changeover and Fusion
Quickly remove the heating plate: Complete within 5 seconds to avoid heat loss.
Apply fusion pressure: Immediately apply butt pressure (0.15–0.3 MPa) to ensure thorough material bonding and uniform bead formation.
4. Cooling and Inspection
Natural cooling: Maintain pressure until the cooling time ends (see table). Do not move the pipes during this period.
Check the weld: The bead should be symmetrical, without cracks or depressions.
1. Preparation
Select electrofusion fittings: Ensure the fittings match the pipe specifications (e.g., DN110 electrofusion coupler).
Mark insertion depth: Mark the insertion line on the pipe end to avoid improper fitting placement.
2. Cleaning and Assembly
Remove oxidation layer: Use a scraper to remove 0.1–0.2 mm of the pipe surface to expose fresh material.
Install fittings: Insert the pipe into the electrofusion coupler up to the marked line and secure with clamps to prevent misalignment.
3. Power-On Welding
Input parameters: Scan the barcode or manually enter welding parameters (voltage, time) from the fitting label.
Start welding: The machine will heat automatically. Observe the indicator holes for molten material overflow.
4. Cooling and Testing
Natural cooling: Cooling time should be ≥ specified duration (typically 10–30 minutes).
Leak test: Verify sealing integrity through air or hydrostatic pressure tests.
Environmental requirements: Avoid working in strong wind, rain, or low temperatures (<–5°C). Use windbreaks if necessary.
Quality checks:
Butt fusion bead height tolerance ≤10%.
Electrofusion indicator holes should show uniform material rise.
Safety measures: Wear heat-resistant gloves and goggles to prevent burns or arc flash injuries.
Uneven bead: Caused by uneven heating plate temperature or insufficient pressure. Recalibrate equipment.
Poor electrofusion joint: Due to incomplete oxidation removal. Re-scrape and reweld.
Mastering Butt Fusion and Electrofusion techniques is essential for ensuring long-term stability of HDPE pipeline systems. Operators should undergo professional training and strictly follow welding parameters.
(This guide applies to HDPE pipes from DN20–DN1200 mm. For PVC pipes, adjust temperature to 170–190°C.)
For detailed parameter tables or operation videos, contact us for technical support!
Official website: www.phtopindustry.com | www.phpipes.com
Contact us: Email:inquiry@phtopindustry.com | Whatsapp:+86 15093100892
Company address: Room 802, 8th Floor, Building 5, Jinyin Modern City, Jinshui District, Zhengzhou City, Henan Province, China