Factory PE-RT (EVOH) Pipes for Greenhouse Heating: Specifications and Selection Guide

For greenhouse heating, I recommend selecting PE-RT (EVOH) pipe by system temperature, operating pressure, oxygen-barrier requirements, installation method, and supplier documentation—not by pipe price alone. A PE-RT (EVOH) pipe combines temperature-resistant polyethylene of raised temperature resistance with an EVOH oxygen-barrier layer, making it suitable for many low-temperature hydronic heating circuits when the design conditions are correctly matched. Before requesting a quotation, buyers should prepare the required diameter, wall thickness, design temperature, pressure, coil length, connection method, and applicable standards.

If you are looking for more details, kindly visit our website.

At HTIAN, I help agricultural project buyers evaluate these details before production. The final product selection should always be confirmed against the heating design, heat-source conditions, local regulations, and the manufacturer’s declared performance data.

Who This Guide Is For

This guide is intended for greenhouse owners, heating-system installers, agricultural contractors, distributors, and engineering procurement teams sourcing factory PE-RT (EVOH) pipes. It is especially useful when the project includes under-bench heating, perimeter heating, root-zone heating, or low-temperature floor circuits. It can also help buyers compare quotations that appear similar but use different materials, dimensions, barrier structures, and service terms.

I focus here on technical and commercial questions that should be answered before ordering. The purpose is not to assign one universal pipe size to every greenhouse, because heat load, circuit length, pump selection, water quality, and temperature control vary from project to project.

What Is PE-RT (EVOH) Pipe?

Basic Construction and Function

PE-RT is a polyethylene material designed for elevated-temperature service, while EVOH is an ethylene vinyl alcohol layer used as an oxygen barrier. In a heating pipe, the EVOH layer is normally protected within a multilayer construction, with bonding layers used where required by the product design. This structure is intended to reduce oxygen diffusion into a closed hydronic system.

Reduced oxygen ingress can help limit conditions that contribute to corrosion of susceptible ferrous components, such as steel heat exchangers, pumps, and fittings. However, the pipe is only one part of the system; water treatment, air elimination, system layout, and component selection also affect long-term performance. I therefore advise buyers to request the manufacturer’s declared oxygen-permeation data rather than assuming that every PE-RT pipe has the same barrier performance.

Typical Greenhouse Applications

• Under-bench heating for plant-growing areas
• Perimeter heating near greenhouse walls and doors
• Root-zone or propagation-bed heating
• Low-temperature floor or slab heating
• Radiant circuits connected to boilers, heat pumps, or other hydronic sources

PE-RT (EVOH) pipe is generally considered for systems where flexibility, corrosion resistance, and efficient installation are important. It is not automatically suitable for direct exposure to ultraviolet radiation, aggressive chemicals, uncontrolled steam, or temperatures and pressures outside its rating. In those conditions, a different material or additional protection may be necessary.

Important Specifications to Review

Material, Barrier, and Dimensional Structure

Ask whether the pipe is single-layer PE-RT, multilayer PE-RT with an EVOH barrier, or another construction. Confirm the position of the barrier layer, the bonding arrangement, the outer protective layer, and the intended connection system. A visible colored layer alone is not sufficient evidence of oxygen-barrier performance.

For reference, common hydronic pipe dimensions may include 16 × 2.0 mm and 20 × 2.0 mm, but these are examples rather than a universal recommendation. The correct size depends on required flow, circuit length, permissible pressure loss, available pump head, and the heating design. I recommend asking for a dimensional tolerance statement and a product drawing before approving a purchase order.

Temperature and Pressure Rating

Many greenhouse heating systems operate at moderate water temperatures, but the actual design condition may change during startup, frost protection, or abnormal operation. A quotation should state the continuous operating temperature, maximum design temperature, and pressure rating for the specific pipe dimension. A temperature figure such as 70°C or a pressure figure such as 6 bar must never be treated as valid unless it is linked to the exact product construction and service life assumptions.

Buyers should also check whether the rating applies to continuous service, short-term exposure, or a particular design class. If the heat source can produce higher temperatures than the greenhouse circuit requires, a mixing valve, buffer tank, or other control strategy may be necessary. The pipe supplier should review this interface rather than evaluating the pipe in isolation.

Oxygen Permeation and Applicable Standards

For closed hydronic heating, ask whether the EVOH pipe is designed to meet a recognized oxygen-barrier requirement, such as the limit referenced by DIN 4726. A commonly cited benchmark is an oxygen permeability below 0.1 g/m³·day at 40°C, but buyers should verify the test method, test temperature, product construction, and current edition of the applicable standard. I do not recommend accepting a general “oxygen-proof” statement without supporting technical documentation.

You will get efficient and thoughtful service from HTIAN(uk,es,iw).

Other documents may include dimensional standards, material declarations, pressure-test records, and quality-control procedures. The exact standards depend on the destination market and application. HTIAN can review the buyer’s required specification and identify which documents should be included with the quotation and shipment.

How to Select the Right Pipe

Step 1: Define the Heating Circuit

Start with the heat source, supply and return temperatures, target indoor conditions, and estimated heat load. Then define the circuit layout, maximum loop length, pipe spacing, and allowable pressure loss. For a multi-zone greenhouse, separate circuits may be needed for different crops, benches, perimeter areas, or propagation zones.

Step 2: Match Diameter to Flow Requirements

Pipe diameter should be selected through hydraulic calculation rather than visual preference. A smaller pipe may be easy to handle but can create higher pressure loss over long circuits, while a larger pipe may reduce resistance but increase material and installation cost. I recommend providing the supplier with the required flow rate or heating capacity so the quotation can be checked against the engineering design.

Step 3: Confirm Connections and Installation Conditions

Confirm whether the project uses compatible compression fittings, press fittings, or another approved joining method. The pipe’s outer layer, ovality, dimensional tolerance, and bending behavior can affect connection reliability. Also determine whether the pipe will be installed inside the greenhouse, underground, within a slab, or exposed to sunlight and mechanical contact.

Step 4: Review Environmental Exposure

Greenhouses can expose materials to moisture, fertilizers, pesticides, temperature cycling, and ultraviolet radiation. Ask for the recommended protection method if the pipe will receive direct sunlight or contact with agricultural chemicals. If the installation environment is unusually aggressive, request a compatibility review before mass production.

Step 5: Request a Complete Commercial Quotation

A useful quotation should identify the product structure, dimensions, color, coil length, packaging, quantity, delivery term, payment terms, production lead time, and available documents. For example, a buyer may require 16 × 2.0 mm pipe in 500 m coils, but the final coil length should be confirmed according to winding equipment, transport limits, and installation requirements. The buyer should also ask whether sample approval is available before the full order.

Common Purchasing Mistakes

• Choosing a pipe solely by outside diameter without checking wall thickness
• Assuming every PE-RT pipe includes an EVOH oxygen barrier
• Comparing pressure ratings without comparing temperature conditions
• Ignoring UV exposure and chemical contact inside the greenhouse
• Ordering before confirming fitting compatibility
• Requesting a price without specifying coil length, quantity, and destination

Another frequent mistake is treating the nominal pipe rating as the complete system rating. The weakest component may be a fitting, manifold, valve, pump connection, or control device. I recommend reviewing the entire circuit and confirming that all components are suitable for the same design temperature and pressure.

Supplier Evaluation Checklist

When comparing factory suppliers, evaluate more than catalog images and unit price. Ask whether the supplier can provide a product datasheet, dimensional information, material description, batch identification, inspection process, and packaging photographs. For export orders, also confirm labeling, carton or pallet configuration, loading quantity, and documentation required by the destination market.

At HTIAN, my approach is to clarify the application first and then prepare a quotation based on the requested specifications. We can discuss PE-RT (EVOH) pipe construction, dimensions, coil packaging, fitting requirements, private labeling where available, and export coordination. Any certification, test report, or compliance document should be confirmed for the exact product and market rather than assumed from a general company statement.

Key Takeaways

• PE-RT (EVOH) pipe is a multilayer heating-pipe option that combines temperature-resistant polyethylene with an EVOH oxygen-barrier layer.
• The correct product depends on temperature, pressure, flow, circuit length, installation environment, and connection method.
• Common dimensions such as 16 × 2.0 mm or 20 × 2.0 mm are only starting references; hydraulic design must determine the final choice.
• Buyers should verify oxygen-permeation data, dimensional tolerances, test methods, and exact product ratings.
• A complete RFQ should include dimensions, coil length, quantity, application, destination, fittings, packaging, and required documents.

Conclusion: What to Send Before Requesting a Quote

The best factory PE-RT (EVOH) pipe for greenhouse heating is the one whose material structure, oxygen-barrier performance, dimensions, temperature rating, pressure rating, and connection method match the actual heating design. I do not recommend selecting solely by the lowest price or by a general product description. Technical confirmation is especially important when the system uses long circuits, elevated temperatures, heat pumps, boilers, or direct greenhouse exposure.

To request a practical quotation from HTIAN, send the application, pipe diameter and wall thickness if known, design temperature and pressure, estimated quantity, preferred coil length, fitting type, packaging requirements, destination port, and any required standards or documents. I can then help organize the specification and identify which details still require engineering confirmation. This preparation reduces quotation revisions and gives both the buyer and supplier a clearer basis for production and delivery.

For more information, please visit Factory PE-RT（EVOH） Pipes.