Flame-retardant
PROTAPE® PVC 371 (MD)
Highly flexible PVC ventilation hose with spring steel wire embedded in the wall, flame-retardant according to NF P 92-503 M2 and fabric-reinforced. Designed for ventilation in vehicles and the construction industry as well as welding fume extraction. Service range from −10 °C to +80 °C, short-term peak up to +110 °C. The MD variant is medium-duty — lighter than the HD variant but stiffer than the LD.
- Flame-retardant NF P 92-503 M2
- −10 to +80 °C
- Short-term +110 °C
- Highly flexible 6:1
- Fabric-reinforced
- Cut to length
Why this hose?
PROTAPE® PVC 371 (MD) is a medium-duty ventilation hose. It's designed for airborne ventilation where flexibility and easy handling are needed, while still providing a flame-retardant cover that meets NF P 92-503 M2.
The spring steel wire embedded in the wall gives shape stability without making the hose heavy. Combined with the PVC wall and fabric reinforcement, you get a hose that springs back after bending and tolerates both negative (vacuum) and positive pressure within the specified limits.
The MD variant sits in the middle of the PROTAPE® PVC 371 range. The LD variant is lighter and more compressible; the HD variant is heavier and tolerates higher mechanical load. Choose MD when you need a versatile ventilation hose that isn't too stiff to route, and that meets flame-retardant requirements.
Where it is used
The hose is typically installed in vehicle cabins as a ventilation or extraction connection between fan and outlet. It's also used in construction for temporary ventilation solutions on building sites where flame-retardance is required.
In the welding industry it's a well-known choice as a connection from welding station to extraction unit. Fume temperature is typically within the +80 °C continuous limit; for peak loads up to +110 °C the hose tolerates it short-term.
In HVAC installations (heating, ventilation, air conditioning and refrigeration) it's used in smaller dimensions as flexible connectors between fixed pipework and equipment.
In everyday talk we usually call it a flame-retardant ventilation hose — used where air needs moving without the hose cover itself becoming the fire source.
Technical specifications
Technical specifications for PROTAPE® PVC 371 (MD). Values are the manufacturer's standard at 20 °C unless otherwise stated.
| Material | PVC wall, fabric-reinforced, with spring steel wire |
|---|---|
| Colour | Grey |
| Inner diameter | 50–600 mm |
| Temperature (continuous) | −10 to +80 °C |
| Temperature (peak) | +110 °C |
| Flame retardance | NF P 92-503 M2 |
| Compressibility | 6:1 (highly flexible) |
| Conformity | RoHS, NF P 92-503 M2 |
| Cut to length | Yes |
| Manufacturer SKU group | 3713400 |
Dimensions and ordering
Standard dimensions for PROTAPE® PVC 371 (MD) from inner diameter 50 mm to 600 mm. Working pressure and vacuum decrease as expected with increasing diameter. The weight column shows hose weight per running metre.
| Inner Ø |
Outer Ø |
Wall thickness |
Working pressure |
Vacuum |
Bend radius |
Max. length |
Weight |
Article no. |
|---|---|---|---|---|---|---|---|---|
| 50 | 56 | 0.25 | 0.265 | 0.16 | 30 | 20 | 0.13 | 37100503400 |
| 60 | 65 | 0.25 | 0.22 | 0.12 | 36 | 20 | 0.18 | 37100603400 |
| 70 | 76 | 0.25 | 0.2 | 0.1 | 42 | 20 | 0.21 | 37100703400 |
| 75 | 83 | 0.25 | 0.175 | 0.09 | 45 | 20 | 0.22 | 37100753400 |
| 80 | 87 | 0.25 | 0.165 | 0.09 | 48 | 20 | 0.24 | 37100803400 |
| 90 | 96 | 0.25 | 0.15 | 0.075 | 53 | 20 | 0.26 | 37100903400 |
| 100 | 109 | 0.25 | 0.13 | 0.055 | 60 | 20 | 0.3 | 37101003400 |
| 110 | 118 | 0.25 | 0.12 | 0.05 | 66 | 20 | 0.27 | 37101103400 |
| 120 | 128 | 0.25 | 0.11 | 0.045 | 72 | 20 | 0.29 | 37101203400 |
| 125 | 133 | 0.25 | 0.105 | 0.04 | 75 | 20 | 0.31 | 37101253400 |
| 140 | 148 | 0.25 | 0.095 | 0.04 | 84 | 20 | 0.34 | 37101403400 |
| 150 | 159 | 0.25 | 0.09 | 0.04 | 90 | 20 | 0.37 | 37101503400 |
| 160 | 168 | 0.25 | 0.085 | 0.02 | 96 | 20 | 0.39 | 37101603400 |
| 180 | 189 | 0.25 | 0.07 | 0.02 | 107 | 20 | 0.44 | 37101803400 |
| 200 | 208 | 0.25 | 0.065 | 0.02 | 120 | 20 | 0.49 | 37102003400 |
| 250 | 260 | 0.25 | 0.05 | 0.015 | 150 | 20 | 0.61 | 37102503400 |
| 254 | 264 | 0.25 | 0.05 | 0.015 | 153 | 20 | 0.61 | 37102543400 |
| 300 | 311 | 0.25 | 0.045 | 0.01 | 180 | 20 | 0.76 | 37103003400 |
| 305 | 315 | 0.25 | 0.045 | 0.01 | 183 | 12 | 0.77 | 37103053400 |
| 350 | 361 | 0.25 | 0.04 | 0.01 | 210 | 12 | 0.87 | 37103503400 |
| 356 | 367 | 0.25 | 0.04 | 0.01 | 214 | 12 | 0.88 | 37103563400 |
| 400 | 410 | 0.25 | 0.035 | 0.005 | 240 | 12 | 1 | 37104003400 |
| 406 | 416 | 0.25 | 0.035 | 0.005 | 243 | 12 | 1.02 | 37104063400 |
| 500 | 512 | 0.25 | 0.03 | 0.005 | 300 | 12 | 1.26 | 37105003400 |
| 508 | 519 | 0.25 | 0.03 | 0.005 | 305 | 12 | 1.28 | 37105083400 |
| 600 | 614 | 0.25 | 0.02 | 0.005 | 360 | 10 | 1.51 | 37106003400 |
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
PROTAPE® PVC 371 (MD) conforms to the following standards:
- NF P 92-503 M2. French standard for flame-retardant construction materials; M2 corresponds to the "hard-to-ignite" category that is the usual norm for ventilation hoses in public buildings and vehicles.
- RoHS. Directive 2011/65/EU on the restriction of hazardous substances in electrical and electronic equipment.
- REACH (EC 1907/2006). The manufacturer's REACH declaration is available for download in the Documentation section below.
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
PROTAPE® PVC 371 (MD) is used across industries where air needs moving — without the hose cover itself becoming the fire source:
In the vehicle industry the flame-retardance isn't just a nice-to-have — it's often a requirement for components close to engine or exhaust, where short-term temperature peaks can occur.
In construction it's mostly about temporary installations on sites where fire authority requirements for materials must be respected. The hose's combination of flexibility and flame-retardance makes it easy to route around obstacles without compromising safety.
In welding it's often the connector between a mobile extraction unit and the welding station itself — robust enough to handle daily handling, but light enough to move with the workplace.
Custom lengths and assemblies
The hose is delivered on rolls in standard 10 m and 20 m lengths. We cut to length and assemble with couplings or sleeves, so you receive a finished assembly ready to install.
For larger volumes of identical assemblies, we can set up a serial run — giving you repeatable assembly and consistent performance across the delivery.
Frequently asked questions
Is PROTAPE® PVC 371 (MD) ATEX-approved?
No. The hose has no conductive or antistatic properties and is therefore not approved for ATEX zones. For ATEX zones, choose a conductive or antistatic hose instead — for example PROTAPE® PUR 332 SE (LD) (antistatic + flame-retardant) or AIRDUC® PUR 351 EC (MD) (conductive).
What does M2 mean in NF P 92-503 M2?
M2 is the French fire class for materials that are "hard to ignite". The scale runs from M0 (non-flammable) through M1, M2, M3 to M4 (easily flammable). M2 is the usual norm for ventilation hoses in public buildings and vehicles.
What's the difference between MD, LD and HD in the PROTAPE® PVC 371 range?
LD (Light Duty) is the lightest with the most compressibility (6:1). MD (Medium Duty) is the versatile variant — it balances flexibility and strength. HD (Heavy Duty) is the heaviest with higher mechanical resistance to impact and wear.
Does it tolerate hot air from welding?
Yes, within limits. Welding fume is typically below +80 °C (continuous limit) when it reaches the hose via a hood. For high-energy processes where temperature briefly reaches +110 °C the hose tolerates it too, but not continuously. For continuous service above +80 °C choose PROTAPE® PVC 371 HT (LD).
Can I order it in a specific length?
Yes. The hose is delivered on rolls in 10 m and 20 m lengths, and we cut to length and fit couplings as a finished assembly. If you prefer the hose as a loose delivery, we can also supply complete rolls.
How tightly can the hose be bent?
Bend radius is shown in the dimension table for each inner diameter — for example 30 mm for Ø 50 mm and 360 mm for Ø 600 mm. The bend radius is measured along the inside of the hose; bending tighter risks the hose kinking or compressing, which reduces airflow.
Which couplings fit it?
The hose is a standard product and fits the usual coupling systems for 50–600 mm inner diameter ventilation hoses. We can supply it with permanently fitted couplings (clamp ring, hose band or bayonet) as a finished assembly — tell us which system you're working with.
Is it food-grade?
No. The PVC wall is not certified to EU 10/2011 or FDA and must not be used for food or beverage transport. For food purposes choose a silicone or PUR-based food-grade hose — for example NORFLEX® SIL 408 or AIRDUC® PUR 351 FOOD (MD).