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Zhejiang Sanli Pipe Technology Co., Ltd.
Pipe Buying Guides & FAQ for Importers
SANLI Underfloor-Heating Knowledge Base

Pipe Buying Guides & FAQ for Importers

Selection, factory-audit, logistics and pricing guides for importers, buyers and contractors worldwide (updated regularly).

01

Industry

Read the market and your supplier: export markets & trends, factory audits, EAC/ISO/CE, duty & customs, Incoterms & pricing.

19 articles
01

Market trends

Annual observations of the global underfloor-heating and pipe market, regional demand shifts and supply-chain dynamics.

See all (6 articles)
03

Supply chain & trade

Factory audit, MOQ, OEM, container loading, HS code, Incoterms, RFQ and landed cost — the full procurement playbook.

See all (10 articles)
02

Products

PEX-AL-PEX, PE-RT, PP-R and brass fittings — OEM, MOQ and container-loading plans from one factory.

8 articles
06

Selection & buying decisions

PEX-AL-PEX / PEX / PE-RT / PB / PP-R / copper compared side-by-side — putting Sanli on your shortlist.

See all (4 articles)
03

Technology

Material science and engineering: PEX vs PE-RT, oxygen barrier & DIN 4726, temperature and pressure, sizing, loops and layout.

5 articles
09

Application scenarios

Global underfloor-heating scenario map: pipe selection by region × building type × heat source.

In production
  • Global scenario map: region × building × heat source
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G

Glossary

Key pipe-industry terms and standards (PEX-AL-PEX, PE-RT, EVOH, DIN 4726, PN/SDR, EAC/GOST) in one place.

18 terms
PEX-AL-PEX (multilayer pipe)
Five layers: PE-X / adhesive / welded aluminium / adhesive / PE-X. The aluminium layer gives a 100% oxygen barrier, low thermal expansion and shape retention. Standards: EN ISO 15875, GOST R 52134.
PE-RT (polyethylene of raised temperature)
Thermoplastic polyethylene; heat-fusible and recyclable, very flexible and easy to coil — cost-effective for low-temperature underfloor heating. Standards: EN ISO 10508 / GOST 32415.
PE-Xa / PE-Xb (cross-linking method)
Distinguished by cross-linking method: PE-Xa is peroxide (Engel) cross-linked (~70–87% degree, with a memory effect), PE-Xb is silane cross-linked. Cross-linking raises heat and pressure resistance but rules out heat fusion — use press or slide-sleeve joints.
EVOH (oxygen-barrier layer)
An ethylene-vinyl alcohol layer co-extruded onto the pipe wall to stop oxygen diffusing into closed heating systems, meeting DIN 4726; usually covered by a protective outer layer.
DIN 4726
The German standard limiting oxygen permeation through plastic heating pipe (to roughly <0.325 g/m³·day) so that steel and copper components in the system are protected.
PN (nominal pressure)
Nominal Pressure — the design working-pressure class referenced to 20 °C (e.g. PN10, PN20). The allowable pressure falls as temperature rises and must be derated for the duty.
SDR (standard dimension ratio)
The ratio of outside diameter to wall thickness (SDR = dn/en). A lower SDR means a thicker wall and higher pressure rating; SDR and PN together set the rating.
Press fitting / slide sleeve
A stainless-steel or brass fitting compressed cold with a dedicated tool to form a seal — no heat fusion required; the standard jointing method for PEX and PE-RT.
Manifold
A brass or stainless-steel assembly that distributes the heat-transfer fluid to the heating loops and collects the return, often with flow balancing and thermostatic heads.
See full glossary →
Q

FAQ

Quick answers to the questions buyers ask most before ordering.

15 questions

What is the difference between PEX-AL-PEX and PE-RT pipe, and which is better for underfloor heating?

SANLI PEX-AL-PEX composite pipe has an aluminium layer that blocks oxygen and cuts thermal expansion, so it holds its shape and suits heating loops and radiators. PE-RT from China manufacturer SANLI is flexible, heat-fusible and lower cost, making it a good fit for low-temperature underfloor heating. For standard water-based UFH choose PE-RT, and for higher temperature or stiffer runs choose PEX-AL-PEX.

Do I need an oxygen-barrier pipe for underfloor heating, and why?

Yes, a closed water heating system needs an oxygen-barrier pipe because oxygen ingress corrodes boilers, manifolds and steel parts. SANLI supplies PE-Xa and PE-RT pipe with a 100% oxygen barrier meeting DIN 4726. This protects the plant and extends the service life of the underfloor heating.

What temperature and pressure can these pipes handle?

SANLI underfloor-heating pipes are typically rated for a working temperature of about 60-70 °C and short-term peaks up to roughly 90-95 °C. Working pressure depends on the PN class and pipe size, commonly 6-10 bar for heating. Confirm the exact temperature and pressure ratings for your design from the SANLI technical data sheet.

What is the maximum coil or loop length without joints?

SANLI supplies PEX-AL-PEX and PE-RT pipe in coils up to 100 m with no joints, cutting the number of connections under the floor. The maximum single loop length depends on diameter, typically up to about 100-120 m for 16 mm and shorter for larger sizes. These figures are indicative, so confirm the exact loop length with SANLI for your project.

What is your minimum order quantity (MOQ)?

The standard SANLI MOQ is about 1,000 metres per pipe specification, and mixed containers with different diameters and colours are welcome. Samples and pallets follow separate terms. Confirm the exact MOQ in metres in your quote.

Can you OEM or private-label the pipe?

Yes, as a China manufacturer with 20+ years and 20 production lines, SANLI offers OEM and private-label work: your brand printing, custom pipe colour, labels and pallets. Branded products carry their own MOQ. Confirm the printing details and minimum batch with SANLI.

Do you provide free samples?

SANLI provides free pipe and fitting samples so buyers can assess the quality. The buyer only pays the courier freight. Request samples carrying SANLI marking to verify the material.

Which payment terms do you accept?

SANLI normally works on T/T with 30% deposit and 70% balance before shipment, and also accepts sight L/C. Trade Assurance is available for a first order to protect the transaction. Final payment terms are confirmed in the contract.

How long is the production lead time?

The standard SANLI production lead time is roughly 15-25 days after the deposit, depending on volume and specification. During the peak heating season the 20 lines run fuller, so the time can extend. Confirm the exact lead time for your quantity and season.

Which Incoterms do you quote and can you ship to Central Asia?

As a China manufacturer, SANLI ships on EXW, FOB Ningbo, FCA, CPT and DAP terms. Rail delivery to Almaty or Tashkent takes roughly 18-30 days, indicative. Confirm the exact route, transit time and Incoterm for your destination in the quote.

What certifications do your pipes have?

SANLI's management systems are certified to ISO 9001:2015 (reg. 0350124Q30689R0S), ISO 14001:2015 (0350124E20450R0S) and ISO 45001:2018 (0350124S30433R0S), issued by Xingyuan Certification Centre (CNAS C035-M, IAF-MRA) and valid to 3 July 2027. Every number is verifiable at CNCA and on IAF CertSearch and is listed on our Certificates page (https://sanlipipe.com/en/certificates.html). Our pipes also carry CE and SKZ marking for European requirements and EAC conformity for the EAEU market; product-level numbers are issued per order and supplied with your shipment.

Is EAC certification required to sell in Kazakhstan or Russia?

Yes, selling pipe in Kazakhstan, Russia and other EAEU countries requires TR EAEU conformity and an EAC declaration or certificate. As a China manufacturer, SANLI supplies EAC-marked product for this market. Confirm the exact conformity form for your HS code when ordering.

What is the approximate price per metre?

Pipe price per metre depends on the type (PEX-AL-PEX or PE-RT), diameter, order volume and trade terms, so it is quoted to spec. Send us your parameters, quantity and destination, and we'll return an accurate quote within 24 hours; larger batches and mixed containers usually lower the unit cost.

How do I estimate how many metres of pipe I need for a project?

Divide the heated floor area by the pipe pitch and add a allowance for the feed runs: metres = area / pitch + waste. For example, 100 m² at a 0.15 m pitch gives about 667 m plus 10-15% for tail and header runs. Use the SANLI knowledge calculator page for a quick estimate.

What is the warranty and how is quality controlled?

SANLI rates its pipes for a service life of up to 50 years when used within specification, with a warranty per product type. Quality is backed by 26 inspection steps and a per-coil test before shipment across 20 production lines. Confirm the warranty terms for your specification in the contract.

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