High-temperature · up to +180 °C
NORFLEX SIL 408 special wall 2 mm
NORFLEX SIL 408 special wall 2 mm is a food-approved silicone hose in small dimensions (ID 2-3 mm). The highly flexible silicone construction tolerates continuous operation between -60 and +180 C - one of the highest temperature capacities for food-approved hoses. The hose is used for precise liquid transfers in pharmaceutical industry, laboratories and medical technology.
- -60 to +180 C
- Silicone resistance
- Food-approved
- Steam-sterilisable
- Precise transfers
- Liquid/gas
Why this hose?
Silicone is the material with the unique combination of three properties: extreme temperature resistance (-60 to +180 C), food and medical compatibility, and breadth of chemical resistance. Few other elastomers can meet all three requirements simultaneously.
The special wall 2 mm variant is specifically developed for small dimensions (ID 2-3 mm) where a stiffer wall construction would limit flexibility. 2 mm wall on a 2 mm ID hose is already a substantial wall thickness - more would make the hose too stiff for ordinary use.
The high temperature capacity is decisive for SIP (sterilisation-in-place) cycles in pharmaceutical production. Steam at 121-134 C is standard for medical equipment sterilisation - the silicone hose tolerates this with large margin and can run thousands of cycles without material degradation.
Where it is used
Pharmaceutical production uses the hose in tablet press, dosing and transfer installations where small volumes must be controlled precisely. The high temperature capacity allows sterilisation cycles with steam without removing the hose from installation.
Medical technology uses the variant in diagnostic and analytical installations where small volumes of biological liquids or reagents must be transferred. Food approval is typically a minimum requirement in these applications.
Laboratories and research installations use the hose in bench-top instruments and automated sample handling installations. The hose's transparency is a major advantage - operators can visually verify flow, blockages or bubble formation.
NORFLEX SIL 408 is colloquially known as a silicone hose or pharma hose.
Technical specifications
The hose's key specifications are summarised briefly below. The special wall 2 mm variant is the smallest in the NORFLEX SIL 408 series.
| Material | Silicone (food-approved) |
|---|---|
| Wall thickness | 2 mm |
| Reinforcement | None (pure silicone wall) |
| Colour | Transparent |
| Temperature range | -60 to +180 C |
| Steam sterilisation | 121-134 C for 15-30 min cycles |
| Available dimensions | ID 2 mm (OD 6 mm) and ID 3 mm (OD 7 mm) |
| Food approval | REACH + RoHS (specific EU 1935/2004 category on request) |
| Standard roll length | 50 m |
| Manufacturer SKU | 4082163 |
Dimensions and ordering
The table shows the available standard dimensions. The special wall 2 mm variant is limited to two dimensions (ID 2 mm and ID 3 mm) - the rest of the NORFLEX SIL 408 series covers larger dimensions.
| Inner Ø |
Outer Ø |
Wall thickness |
Max. length |
Weight |
Roll |
Article no. |
|---|---|---|---|---|---|---|
| 2 | 6 | 2 | 50 | 0.03 | 50 | 40890202163 |
| 3 | 7 | 2 | 50 | 0.04 | 50 | 40890302163 |
Fields without a value (—) are not specified in the manufacturer's factsheet. Overpressure and underpressure values are recommended operating limits; the product can be subjected to higher loads on request. Bend radius is measured along the inside of the hose bend.
Standards and compliance
The hose is manufactured to European standards for food-approved silicone hoses and general quality systems.
- EU 1935/2004. General framework regulation for materials in contact with food. Manufacturer declaration on file for specific categories.
- FDA 21 CFR 177.2600. American food contact approval for silicone elastomers. Relevant for export to USA.
- (GMP) EU 2023/2006. Good Manufacturing Practice for food contact materials.
- USP Class VI. American pharmaceutical classification for biocompatible materials. Standard for silicone hoses for medical and pharma applications.
- ISO 10993. Biocompatibility for medical equipment. Test protocol for materials in contact with biological liquids.
- RoHS Directive (2011/65/EU). Restriction of hazardous substances.
- REACH (EC 1907/2006). Registration of chemical substances.
Documentation and downloads
Additional documents about this hose, its compliance and installation. Click to download as PDF in a new tab.
Help with material selection
Although this hose isn't ATEX-relevant, these two articles provide useful background on electrical resistance and industrial safety — important if you later combine the hose with electrical equipment or work in mixed environments:
The invisible weakest link
Why a conductive or antistatic hose isn't sufficient on its own — and what grounding means for the complete system.
Know your ohm
The difference between antistatic and conductive, which resistance limits apply where, and how to measure them correctly.
Industries that use it
NORFLEX SIL 408 special wall 2 mm is used in small-dimension pharmaceutical and laboratory applications where the highest temperature capacity and food approval must be combined.
Pharmaceutical industry and medical technology is the core market. Small-dimension silicone hoses are essential for precise liquid transfers in production of medicines, vaccines and diagnostic products. Silicone is one of the few elastomers that meets both the requirement of food/medical compatibility and higher temperatures often required in sterilisation cycles.
Food and beverage industry use the variant for micro-dosing of additives, flavourings and colours. The small dimensions (2-3 mm ID) allow precise control of volumes in automated production installations.
Laboratories and research installations use the hose for reagent transfers, sample handling and bench-top instrumentation. The high temperature capacity (180 C) makes the hose well-suited to autoclave sterilisation between uses.
Custom lengths and assemblies
The hose can be delivered cut to desired lengths. The standard roll can be supplemented with shorter pieces or multiple rolls by arrangement.
At Particulair we advise on couplings and sizing. Send us a sketch of your application and we will assess the right variant and length.
Frequently asked questions
What is 'special wall 2 mm'?
The NORFLEX SIL 408 series has several wall thickness variants (2 mm, 3 mm, 15 mm, 25 mm). Special wall 2 mm is the smallest variant with 2 mm thinner wall, making it extra flexible and lightweight. The thinner wall suits smaller dimensions (2-3 mm ID) where stiffer construction would limit flexibility.
How warm does the hose tolerate?
-60 to +180 C in continuous operation. It is one of the highest temperature capacities for food-approved hoses. For ordinary CIP cleaning (60-90 C) or steam sterilisation (130-140 C) the hose is well within its comfort zone.
Which dimensions does this variant come in?
Two dimensions: ID 2 mm (OD 6 mm) and ID 3 mm (OD 7 mm). These are very small dimensions suited to precise liquid transfers in pharmaceutical and laboratory applications. For larger dimensions we recommend the other NORFLEX SIL 408 variants (3, 15 or 25 mm wall).
Are silicone hoses food-approved?
Standard medical-grade silicone is not automatically food-approved - requires explicit certification per EU 1935/2004. The NORFLEX SIL 408 series is food-approved; specific categories vary per variant. For these small dimensions contact us for precise approval.
Can the hose be steam-sterilised?
Yes - silicone is well-suited to steam sterilisation. The hose tolerates 121-134 C (typical SIP cycle) for 15-30 minutes at a time. Thousands of cycles are technically possible - service life is primarily limited by flexibility cycles and daily handling, not sterilisation cycles.
Which couplings are recommended?
For these small dimensions we recommend luer-lock or screw couplings that are standard in pharmaceutical and laboratory. Standard hose clamps are too coarse for small dimensions. We offer pre-assembled configurations - contact us.
What is the difference between silicone and PUR for food?
Silicone (like NORFLEX SIL 408) is preferred at higher temperatures (above 100 C) where PUR would degrade. PUR (like ARMOFLEX PU FOOD) is preferred at lower temperatures where abrasion resistance is more important. Both are food-approved, but in different operating conditions.
How long does the silicone hose last?
Silicone is one of the most durable elastomers. Service life depends on thermal and flexibility cycles - daily industrial use typically gives 10-15 years in continuous installations, shorter with frequent manual handling.