What is a C4 400°C 1/2h motorized cabinet?

A C4 400°C 1/2h motorized cabinet is a motorized extraction fan unit classed to keep running at 400°C for 30 minutes. This classification applies to certain ventilation installations in public-access buildings and residential blocks, when the project configuration requires it. It is not decided case by case: always check the regulations applicable to your building before making a decision.

C4 or F400/120: don't get them mixed up

The C4 classification (400°C / 30 min) and the F400/120 classification (400°C / 120 min) cover different durations and are never interchangeable. A cabinet rated to hold out for half an hour at high temperature does not necessarily replace a unit approved for two hours, and vice versa. If you're unsure which classification your project requires, have it confirmed before placing your order.

What airflow rate should you choose for your C4 cabinet?

The airflow rate (in m³/h) is selected based on the volume to be ventilated, the number of connected grilles, the duct diameter and the pressure losses of the network. Our range of C4 cabinets covers flow rates from around 500 m³/h (Nather cabinet 500 m³/h) to over 13,000 m³/h (Saftair DOF 450R 13,000 m³/h), with intermediate steps from Cairox (700, 1300, 1800, 2500, 2800, 4000, 4600 m³/h) and two-speed models from Saftair to adapt to load variations. The stated flow rate remains a motor reference figure: a long duct run, numerous elbows or an undersized duct diameter will reduce the actual flow rate delivered at the outlet.

Single-phase or three-phase: which power supply?

The small and medium flow rates in the range run on single-phase 230V, including the Nather cabinets and most of the Cairox EC Regulo units. For higher flow rates, the Saftair cabinets switch to three-phase 380V, a supply to arrange in advance with your existing electrical installation.

Range comparison table

C4 cabinet and day-to-day ventilation

Outside of any fire situation, a C4 motorized cabinet provides air extraction under normal operation: it is connected to the grilles via a duct network and then discharges the air outside. Regular maintenance of the grilles, accessible ducts and the cabinet itself keeps the network performing well over time.

Points to check before ordering

• Required flow rate: to be sized according to the volume to be ventilated and the number of grilles, taking into account the network's pressure losses (length, elbows, diameter).
• Electrical supply: 230V single-phase for most of the range, 380V three-phase for high-flow Saftair units.
• Exact classification required: C4/30 (400°C/30 min), C4/60, C4/90 and F400/120 (400°C/120 min) are not interchangeable, to be checked with us.
• Size and weight: high-flow three-phase units weigh several hundred kilos (up to 312 kg for the DOF 450R): plan ahead for access to the plant room.
• Flow adjustment: a fan speed controller potentiometer allows fine adjustment on certain models.

Complete your order with

• G3 filter box for pre-filtration upstream of the network.
• Replacement G3 filter for maintaining the pre-filtration box.
• Acoustic insulation roll to limit sound transmission from the network.
• Commercial and residential mechanical ventilation, the parent category for our full range of professional mechanical ventilation.

Need help choosing your C4 cabinet?

Let us know the flow rate you need, the diameter and length of the duct network, the number of elbows and, if possible, send us a plan or photos of the installation. We'll be able to point you towards the C4 cabinet that matches your configuration.