Exclusive RK Infra distributor

Flexible pre-insulated PE‑Xa pipes: 770 m without a single joint

PE-Xa · PUR EN 15632-2 · Austria

The pipe arrives in a coil and goes into the trench as one continuous line, with no welded joints and no expansion loops. We select the line and send a quote within an hour.

0,021W/m·K insulation
770 mmaximum coil
115°Cand up to 16 bar
Select a pipe RK Infra factory, 42 s

Three lines for your temperature and pressure

PE-Xa service pipe · PUR insulation 0.021 · corrugated jacket

Three RK flexible pre-insulated pipes in cross-section: FibreFlex Pro with an orange, FibreFlex with a yellow and HeatFlex with a red service pipe

This is where your pipe is made

The RK Infra plant in St. Valentin, Austria. Production halls, lines and the finished-coil yard in 42 seconds.

  • 50+ yearsof making pre-insulated pipes
  • Up to 770 min one piece per coil, straight from the plant
  • ISO 9001 · TÜVand EN 15632-2 for flexible pre-insulated pipes

Choose who you are and see what we take off your plate

Municipalities with donor funding, international funds and lenders, project consultants

What hurts

  • Audit and a transparent supply chain
  • Hard grant deadlines and the heating season
  • Impact that can be measured and reported

What we bring

  • Exclusive RK Infra distributor: certificates issued to us on the manufacturer’s authorisation
  • DSTU, EN 15632-2, plant ISO 9001 and TÜV: a document package in Ukrainian and English
  • λ 0.021 and no corrosion: savings in heat losses and failures can be calculated
Get the document package

What a flexible pre-insulated pipe is

A flexible pre-insulated pipe has three layers bonded at the plant: a cross-linked polyethylene PE-Xa service pipe, cyclopentane-blown polyurethane insulation and a corrugated PE-LLD jacket. It bends, so it is delivered in coils and laid without welding. There is nothing in it to rust.

Insulation thermal conductivity, W/m·K lower means warmer

Polyethylene foam0.040-0.045
CO₂-blown polyurethane0.023-0.033
Cyclopentane PUR, RK0.021

Typical values; RK: 2026 catalogue

Cross-section of an RK flexible pre-insulated pipe: PE-Xa service pipe, aramid reinforcement, PUR insulation, corrugated jacket 01 02 03 04
  1. PE-Xa service pipedoes not rust, smooth inside
  2. Aramid reinforcementin FibreFlex: up to 16 bar
  3. PUR insulation0.021 W/m·K, CFC-free
  4. PE-LLD jacketcorrugated: bends and withstands soil load

Selection in a minute

Which pipe your project needs

A few answers and you see which system and pipe line fit. We send a quote within an hour during Kyiv business hours.

1 / 5
What are you supplying?

Five lines for different temperatures and pressures

Coil of HeatFlex flexible pipe with a red service pipe

HeatFlex

District networks and building connections. Also available as twin-pipe DUO.

DUOSupply and return in one jacket: one trench instead of two. Most often chosen up to Ø75. Sizes 25+25/91 – 75+75/202 mm.

Temperature
up to 95 °C
Pressure
6 bar
Sizes, mm
25/76 - 125/182
Service life
50 years
Coil
up to 770 m
All sizes, UNO and DUO

UNO, single pipe, insulation IS1

Service / jacket, mmCoil, m
25/76770
32/76770
40/91570
50/111410
63/126300
75/142220
90/162150
110/162150
125/18286

DUO, twin pipe, insulation IS1

Service pipes / jacket, mmCoil, m
25+25/91570
32+32/111410
40+40/126300
50+50/162150
63+63/18286
75+75/20280

IS2 reinforced insulation too.

Coil of FibreFlex flexible pipe with a yellow service pipe

FibreFlex

When HeatFlex is short on pressure: aramid reinforcement, same 0.021 insulation.

DUOSupply and return in one jacket: one trench instead of two. Most often chosen up to Ø75. Sizes 25+25/91 – 90+90/225 mm.

Temperature
up to 95 °C
Pressure
10 bar
Sizes, mm
25/76 - 160/225
Service life
50 years
Coil
up to 570 m, Ø160 up to 150 m
All sizes, UNO and DUO

UNO, single pipe, insulation IS1

Service / jacket, mmCoil, m
25/76570
32/76570
40/91570
50/111410
63/126300
75/142220 (440)
90/162150 (300)
110/162150 (300)
125/18286 (170)
140/20280 (160)
160/22575 (150)

DUO, twin pipe, insulation IS1

Service pipes / jacket, mmCoil, m
25+25/91570
32+32/111410
40+40/126300
50+50/162150 (300)
63+63/18286 (170)
75+75/20280 (160)
90+90/22575 (150)

IS2 reinforced insulation too.

In brackets: project coil.

Video: installing large diameters
Coil of FibreFlex Pro flexible pipe with an orange service pipe

FibreFlex Pro

Where only steel was used before: up to 115 °C.

Temperature
up to 115 °C
Pressure
10 bar
Sizes, mm
32/76 - 160/225
Service life
50 years
Coil
up to 570 m, Ø160 up to 150 m
All sizes
Service / jacket, mmCoil, m
32/76570
40/91570
50/111410
63/126300
75/142220 (440)
90/162150 (300)
110/162150 (300)
125/18286 (170)
140/20280 (160)
160/22575 (150)

IS1 standard insulation; IS2, DUO too

In brackets: project coil.

Coil of FibreFlex Pro 16 flexible pipe rated for 16 bar

FibreFlex Pro 16

The highest pressure among RK flexible pipes: 16 bar at 115 °C.

Temperature
up to 115 °C
Pressure
16 bar
Sizes, mm
50/111 - 110/162
Service life
50 years
Coil
up to 410 m
All sizes
Service / jacket, mmCoil, m
50/111410
63/126300
75/142220 (440)
90/162150 (300)
110/162150 (300)

IS1 standard insulation; IS2, DUO too

In brackets: project coil.

Coil of PEX Sanitary flexible pipe for hot water

PEX Sanitary

Domestic hot water: SDR 7.4 service pipe.

Temperature
up to 95 °C
Pressure
10 bar
Sizes, mm
20/76 - 63/126
Service life
50 years
Coil
up to 770 m
All sizes
Service / jacket, mmCoil, m
20/76770
25/76770
32/76770
40/91570
50/111410
63/126300

IS1 standard insulation; DUO too

RK Infra catalogue 2026All lines, sizes, coil lengths, fittings and pressure losses. 16 pages, in Ukrainian. Download PDF 4.9 MB

Flexible or steel

Compare a metre of finished route, not a metre of pipe

Steel pre-insulated pipe770 m = 65 bars of 12 m
welded joint expansion loop 12 m bar welded joint expansion loop 12 m bar

0 welded joints plus expansion loops

RK flexible770 m = 1 coil Ø25-32
one coil bends around obstacles, no elbows no joints to the end of the coil manhole / utility one coil no elbows needed no joints

0 joints, no expansion loops needed

RK flexibleSteel pre-insulated
Trench

narrow, the pipe bends around obstacles

wider, bends need fittings

Expansion

absorbed by the pipe itself

compensators or U-loops

Corrosion

none: there is no metal in the pipe

the main cause of failures

Installation

unroll the coil and press the fittings

welding and inspection of every joint

Under roads

trenchless: directional drilling or pulling through

open cut or a casing with welding

Limits

up to 115 °C, 16 bar, Ø160

above Ø160 up to 95 °C: PP-RCT; above 115 °C: steel

Trunk mains above Ø160, boiler rooms and above-ground runs are done in the second system we supply: PP-RCT Aqua-Plus. For underground networks up to Ø160 we price both options.

Select a pipe

Large-diameter FibreFlex in the trench

Reinforced 10 bar pipe up to Ø160: the coil is unrolled along the route, with joints only at the ends of the section. Full on-site installation, 2.5 min.

  • Up to 160/225 mmservice pipe and jacket, in a coil
  • 10 bar · 95 °Caramid reinforcement, 0.021 insulation
  • 0 welded jointswithin one coil
Green Aqua-Plus manifolds and risers in a boiler room

Our second pipe system

PP-RCT Aqua-Plus: boiler rooms, substations and heating networks in one system

Pre-insulated and bare pipes, fittings, adapters, valves and manifolds by Interplast from Ø20 to Ø315. For boiler rooms, substations, networks with many nodes, above-ground and indoor runs. For underground networks up to Ø160 we price both options.

  • Ø20-315
  • pre-insulated and bare
  • fittings, valves, manifolds
  • 10-year warranty
See Aqua-Plus

The route goes in in four steps

Press fitting installation, 8 min video

Before your first project we walk the crew through working with flexible pipe and fittings.

Supplied together with the pipe

  • Compression fittings up to 6 bar, assembled with an ordinary hex key
  • RK press fittings and press tools
  • Tees, elbows, couplings, transitions to steel and thread
  • CLICK joint insulation with no glue or heat shrink
  • Wall penetration seals and building entry bends
  1. 01

    Narrow trench

    A sand bed, as wide as the pipe needs, not as wide as a welder needs.

  2. 02

    Unroll the coil

    The pipe is guided by hand around obstacles, with no fittings.

  3. 03

    Connect the fittings

    Compression fittings are tightened with a hex key, press fittings are pressed with a tool. No welding on the route.

  4. 04

    Backfill

    The jacket carries the soil load and the pipe absorbs its own expansion.

Installer tightening a brass compression fitting on a PE-Xa pipe with a hex key

Joints made with a wrench

RK brass compression fittings: couplings, elbows, tees. The clamp is tightened with one bolt and an ordinary hex key, with no press tool, welding or power on the route.

  • 1 boltper clamp
  • up to 6 barHeatFlex networks
  • 0 weldinginstallation in any weather

For 10 and 16 bar (FibreFlex, Pro) we use RK press fittings and supply the press tool as well.

RK brass compression fittings: coupling, tee and elbow with hex-bolt clamps, and a hex key

8 000+ km

of TRS flexible pre-insulated pipe in Eastern European heating networks since 2004.

Austrian plant, exclusive supply

Aerial view of the RK Infra plant in St. Valentin, Austria
RK Infra St. Valentin, Austria. Making pre-insulated pipes for over 50 years. ISO 9001, TÜV, EN 15632-2.
Flexible pipe winding drum at the RK Infra plant
The pipe is wound into coils at the plant and arrives on site in one piece.

Supplying heating and hot water networks in Ukraine since 2018. Exclusive RK Infra distributor: the Ukrainian certificates of conformity for HeatFlex and FibreFlex were issued to us on RK Infra’s authorisation.

22 km of HeatFlex and FibreFlex in 2025–2026: reference list

Reference list

Heating networks we supplied in 2025–2026

RK Infra HeatFlex and FibreFlex flexible pre-insulated pipes: technical support, full component supply and delivery for every project.

  • 22 kmof pipe, linear length
  • 26projects in 2025–2026
  • 9cities and communities
  • Ø160/250largest diameter

We work with municipal utilities, public institutions and defence and security agencies. This includes supplying pipe for projects of units of the National Guard of Ukraine and the Ministry of Defence of Ukraine, so we know what public-sector clients require in documentation and delivery quality.

  • Kramatorsk06–09.2026Heating network, underground125/180, 110/160, 90/160, 75/125, 63/110, 50/110Municipal utility
  • Kropyvnytskyi03–08.2026Heating network, underground160/225, 90/140, 75/125, 63/110, 50/90, 40/75, 32/63Industrial company
  • Kyiv08.2026Heating network, underground110/200, 90/160Private client
  • Bila Tserkva01–05.2026Heating network, underground63+63/200Energy company
  • Martusivka, Kyiv region01.2026Heating network, underground50+50/180 – 75+75/225Construction company
  • Kryvyi Rih06–11.2025Heating network, underground40/90 – 160/225Municipal utility
  • Kherson07–09.2025Heating network, underground and above-ground160/250, 125/225, 110/200, 90/160, 75/140, 63/125Donor-funded project, CHP plant
  • Bila Tserkva07–09.2025Heating network, underground75/140, 63/125Energy company
  • Sencha, Poltava region09.2025Heating network, underground90/160, 25+25/90Private client
  • Kyiv09.2025Heating network, underground110/160 (HeatFlex)Health resort
  • Svaliava, Zakarpattia region06.2025Heating network, above-ground125/200Private client
  • Kramatorsk06.2025Heating network, underground110/200, 90/160, 63/125Donor-funded project

Diameters: service pipe / jacket; “63+63/200” means a twin-pipe DUO. The full reference list with client names is available on request for tender documentation.

From the plant to the trench

  1. Large-diameter flexible pre-insulated pipe being unwound from a drum at the RK Infra plant
    01RK Infra plant

    The pipe is wound onto a drum or into a coil in one piece.

  2. Flexible pipe coils loaded into a truck at the plant
    02Loading

    Coils are strapped down in the truck so the pipe arrives undamaged.

  3. Truck with flexible pipe coils and a pallet of fittings
    03Delivery

    Pipe and components arrive together, in one truck.

  4. HeatFlex Ø110/160 laid in the trench at a logistics complex in Kyiv region, 420 m route
    04On site

    Logistics complex, Kyiv region. HeatFlex Ø110/160, 420 m of route.

FibreFlex on a large project

  • Large diametersFibreFlex up to Ø160 in a coil
  • Coil next to the routeunrolled, laid, backfilled
  • No weldingjoints only at the ends of the section
ISO 9001ISO 14001ISO 45001TÜVOFI CERTTGMEN 15632-2DSTU B V.2.5-31DSTU EN ISO 15875-2CFC-free PUR

Data for your design and tender

Diameter calculator

Enter the heat load and temperatures to see the diameter, velocity and pressure loss from the RK tables.

Line

Flow rate 0 m³/h

Recommended diameter Ø90 0.0 m/s · 0 Pa/m

Criteria: specific pressure loss up to 150 Pa/m and velocity up to 1.5 m/s.

Preliminary sizing from the RK 2026 pressure-loss table. We confirm the final diameter in the calculation.

Free on Telegram

The design engineer’s kit in 10 seconds

Start the InfraSfera bot and it immediately sends the five files you need to put flexible pipe into a design.

  1. Design quick guide, in Englishlines, all sizes with coil lengths, diameter selection by heat load
  2. Technical catalogue, 78 pagesheat losses, pressure losses, laying, building entries, test reports (Ukrainian edition)
  3. RK Infra product catalogue 2026lines, fittings, components (Ukrainian edition)
  4. HeatFlex certificateUkrainian DSTU, valid to 21.06.2028
  5. FibreFlex and Pro certificateUkrainian DSTU, valid to 21.06.2028
Get the kit on Telegram

No Telegram? Leave your email below and we will send it by email.

For design engineers

Download the RK 2026 product catalogue (Ukrainian edition) right away. Get the 78-page technical catalogue with heat losses, pressure losses and building entry details in the design engineer’s kit on Telegram, or leave your email.

RK Infra catalogue 2026 PDF, 4.9 MB

Tenders and donor-funded projects

We help draft technical specifications for Prozorro (Ukraine’s public procurement system) and for donor and IFI tenders, and assemble the document package in Ukrainian and English. We answer the client’s questions.

  • DSTU B V.2.5-31:2007
  • DSTU-N B V.2.5-81:2015
  • DSTU EN ISO 15875-2:2022

Ukrainian certificates of conformity for HeatFlex, FibreFlex and FibreFlex Pro, valid until 21.06.2028.

HeatFlex certificate PDF, 2.2 MB FibreFlex & Pro cert. PDF, 2.2 MB
Discuss a tender

FAQ

Twin-pipe DUO flexible pre-insulated pipe twisted into a spiral
What is the lead time?

It depends on the line and the volume. We state the exact date in the quote together with the calculation.

Can a flexible pipe be repaired?

Yes. The damaged section is cut out and replaced with a repair coupling and fittings, no welding.

What is the minimum bending radius?

It depends on the diameter and the line. The bending radius table is in the RK technical catalogue, which we send by email or Telegram.

Can it be laid without open trenching?

Yes. Under roads, railways and water, flexible pipe is installed by horizontal directional drilling or pulled through a casing pipe. We match the method and the permissible pulling force to your route.

Is it suitable for hot water?

Yes, the PEX Sanitary line is designed for domestic hot water: SDR 7.4 service pipe, 10 bar.

What if the temperature is above 95 °C?

Use FibreFlex Pro or FibreFlex Pro 16: both are rated for up to 115 °C.

How long are the coils for large diameters?

The larger the diameter, the shorter the coil: Ø25-32 up to 770 m, Ø50 up to 410 m, Ø90-110 up to 150 m, Ø160 up to 75 m. Project coils are twice as long: Ø90-110 up to 300 m, Ø160 up to 150 m. Even Ø160 arrives in a coil, not in 12 m bars.

What is the service life?

All RK flexible pipe lines are designed for a 50-year service life.

Can you help with a tender?

Yes: technical specifications, a document package in Ukrainian and English, answers to the client’s questions. HeatFlex, FibreFlex and FibreFlex Pro hold Ukrainian certificates of conformity to DSTU B V.2.5-31:2007, DSTU-N B V.2.5-81:2015 and DSTU EN ISO 15875-2:2022, valid until 21.06.2028.

Cut-away sample of a flexible pre-insulated pipe in a black gift box with a green ribbon
Free gift

A gift from InfraSfera

A free pipe sample for your office

Show your manager and your client what a flexible pre-insulated pipe is made of: service pipe, PUR insulation and corrugated jacket in a cut-away. Free for design engineers, installers and clients.

  • Cut-away sample: every layer is visible
  • A tag with a QR code to the RK Infra 2026 catalogue
  • Free delivery within Ukraine

We will contact you to confirm the address. No mailing lists.

Contacts

Send us the route parameters, we do the rest of the maths

+38 050 415 40 35 +38 050 367 74 77 Telegram Viber WhatsApp info@infrasfera.com
Office 58, 6-A Larysy Rudenko St, Kyiv · directions

So we can send the calculation and clarify the route.

Preferred way to reach you

You can send the design file via messenger after submitting.

Exclusive RK Infra distributor · DSTU certificates valid to 2028 · supplying heating networks since 2018

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