Flexible polyethylene duct for hygienic and efficient ventilation systems
The REC FLEX HDPEA flexible duct allows for quick and reliable routing of the ventilation system while ensuring a high level of hygiene. The antistatic and antibacterial inner layer (>99% biocidal effect) prevents the accumulation of dust and microorganisms, while the smooth surface minimizes pressure loss. Made of durable polyethylene, crush-resistant, and perfect for installation above suspended ceilings or embedded in floors.
Fast and easy installation due to the corrugated outer surface, which allows the duct to be bent easily without extra elbows. The smooth inner layer with antibacterial and antistatic coating ensures cleanliness (compliant with ISO 22196 standard) and requires minimal maintenance. High ring stiffness allows the duct to be installed not only above plasterboard ceilings but also cast into concrete floors.
The REC FLEX duct system is designed for mechanical ventilation with heat recovery. The system connects the air handling unit through silencers to distribution boxes (LFT series), from which flexible ducts route air radially to individual rooms (to plenum boxes). This radial connection guarantees a balanced airflow and eliminates cross-talk noise between adjacent rooms.
REC FLEX is produced in 75 mm and 90 mm outer diameters. The 75 mm ducts are typically used in standard residential spaces (allowing for minimal ceiling drop, starting at 90 mm), where multiple runs can be connected to a single box for higher airflow if needed. The 90 mm ducts are chosen when a larger air volume needs to be supplied while reducing air velocity and aerodynamic noise.
The system ducts feature high ring stiffness and hygienic properties meeting the EN 17192 standard requirements, ensuring an ATC 2 (D) airtightness class.
| Parameter | Value |
|---|---|
| Duct type | Flexible uninsulated (Semi-rigid) |
| Material | High-quality polyethylene (HDPE) |
| Properties | Antistatic, Antibacterial (>99% biocidal effect) |
| Temperature range | -20 to +50 C (installation from -5 to +50 C) |
| Fire class | E (per EN 13501-1) |
| Roll length | 50 m (+/- 0.5 m) |
The exact diameter selection depends on the required air volume in the room. The recommended air velocity is up to 3 m/s.
| Parameter | 75 mm | 90 mmSelected |
|---|---|---|
| Inner diameter (ID) | 63 mm | 75 mm |
| Outer diameter (OD) | 75 mm | 90 mm |
| Min. bend radius | 0.29 m | 0.33 m |
| Recommended airflow (up to 3 m/s) | up to 31.6 m3/h (8.8 l/s) | up to 47.7 m3/h (13.25 l/s) |
| Weight (per m) | 0.30 kg/m | 0.42 kg/m |
Installing the REC FLEX SYSTEM is intuitive and fast, requiring no special complex tools. This duct is ideal for both flexible routing above suspended ceilings and embedding into floor structures.
It is recommended to cut the duct with a specific pipe cutter or a sharp knife at an exact right angle between the corrugations so the cut is clean and burr-free. It is important not to leave sharp edges that could damage the sealing ring. Avoid storing the rolls in direct sunlight for extended periods.
Before connecting the duct to a distribution (LFT) or plenum (LDL) box, an original RE75 or RE90 rubber sealing ring must be placed over the end of the duct (typically in the second groove). The duct is then simply pushed into the box spigot until it clicks into place (using the box's integrated clips), ensuring Class D airtightness.
Ducts should be routed avoiding sharp angles. The minimum bend radius is 0.29 m for the 75 mm duct and 0.33 m for the 90 mm duct. The distance between duct support brackets (e.g., perforated tape or plastic clamps) must not exceed 1 meter. When fastening, it is crucial not to over-tighten and deform the duct.
Because the duct itself is uninsulated, external insulation must be applied when routing it through unheated spaces (e.g., uninsulated attics) to prevent heat loss and condensation. Cap off any unused box spigots using special PL series blanking plugs.
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Don't forget to pair the REC FLEX HDPEA flexible ducts with LFT distribution boxes, LDL plenum boxes, and the appropriate RE sealing rings for a successful system assembly.
Read honest, verified experiences from our professional installers and clients. Based on 1 review.
I decided to install the entire ventilation system in my house myself. Really glad I went with these flexible ducts – they were extremely easy to cut and route through tight spaces without needing any specialized tools. The ducts are elastic, don't kink, and hold their shape well. Everything worked out on the first try, and the system runs perfectly and quietly!
