Why choose galvanised ductwork for a commercial kitchen hood?

Galvanised ducting, tubing and conduit form the backbone of the extraction network for a commercial kitchen hood. Galvanised steel withstands the heat from the kitchen duct and resists corrosion far better than untreated sheet metal, making it the reference material for a network that needs to last for years without failing. Our range brings together rigid spiral ducting, semi-flexible ducting, flexible ventilation hose, elbows, inspection hatches and nut, bolt and sealing kits, so you can build a complete network without chasing ten different suppliers.

Rigid spiral ducting, semi-flexible ducting or flexible hose: which should you choose?

The rigid galvanised steel duct, available in 1 metre lengths or 2 metre lengths, remains the sturdiest choice for a main network, whether exposed or concealed: it's the one that takes the most handling and wear over time. Rigid spiral ducting is available in several diameters (sized 500, 560, 630, 710 and 800), letting you adapt the network to higher airflow rates, typically for commercial or communal installations.

The semi-flexible ducting, sold in 3 metre lengths, is useful for a section of network that needs to work around an obstacle or absorb a slight offset, where a rigid elbow would be too awkward to fit. The 10 metre flexible ventilation hose is intended more for commercial mechanical ventilation networks, for short connections between grilles and the main network: it doesn't replace rigid ducting on a kitchen extraction network subject to heavy grease loading, where rigidity and ease of cleaning matter most.

Elbows, inspection hatches and connection accessories

To change direction without reducing airflow, the range includes a 90° galvanised elbow and a 45° galvanised elbow, both guaranteed for 1 year. A 45° elbow generally creates less pressure loss than a 90° elbow, worth bearing in mind if your network already includes several changes of direction.

The galvanised inspection hatch, manufactured in Europe, makes it easier to access the duct for cleaning and maintenance: a commercial kitchen network gets dirty quickly, so it's best to be able to access it without dismantling everything. The nut, bolt and sealing kit, manufactured in France and guaranteed for 1 year, secures the joints between sections of the network: a small detail that prevents air leaks and performance loss on an otherwise well sized network.

Points to check before ordering

• Duct diameter: this must match the target extraction rate. As a general guide, and depending on the network (length, elbows, pressure losses), typical reference points are around Ø160 for 800 m³/h, Ø200 for 1,200 m³/h, Ø250 for 1,800 m³/h, Ø315 for 3,000 m³/h, Ø355 for 3,500 m³/h and Ø400 for 4,000 m³/h. A diameter that's too small increases air velocity, noise and pressure losses.
• Length and number of elbows: the longer and more winding the network, the higher the pressure losses. Keep the route as direct as possible.
• Type of duct for each section: rigid spiral ducting for the main network, semi-flexible ducting for a section that needs to adapt to installation constraints, flexible hose for short connections in commercial mechanical ventilation.
• Access for maintenance: fit an inspection hatch at key points in the network so it can be cleaned without dismantling everything.
• Sealing of joints: a poorly matched or missing nut, bolt and sealing kit lets air escape at the joints and reduces actual airflow at the end of the network.

Need help choosing your ducting?

Let us know the motor airflow rate, the length of the network, the number of elbows and the available diameter. We'll be able to point you towards the right galvanised duct diameter for your installation.