When Working in Confined or Enclosed Spaces, such as Basements, Tunnels, Pits or Shafts, Poor Air Quality can put the Health of Workers at Significant Risk.

If you are working on a top-down construction project, you will need to ventilate the basement levels using positive pressure ventilation systems. RVT offer a wide range of high pressure centrifugal and axial fans offering airflows of up to 120,000m³/h.

Please speak with one of our experienced hazard control consultants, who can assess your site conditions, such as hazards, zone classification, airflow and pressure needs, and recommend the right ATEX fan and ducting setup.

Our ATEX fans comply with the ATEX Directive (2014/34/EC), and some models are independently dual‑certified to IECEx standards as well, giving confidence in both their electrical and mechanical safety.

Typical applications include:

• Hot‑work fume extraction (welding, burning)
• Ventilation inside hazardous zones (e.g. gas or vapour zones)
• Confined space ventilation when there is a risk of explosive atmospheres
• Extraction of dust, gases, vapours from tanks and vessels

Yes, many of our ATEX ventilation fans are mobile and designed for project flexibility. For instance, the VENTEX® Centrifugal Fan 300M ATEX can easily be moved around as work progresses.

RVT provides a range of ATEX ventilation fans, including centrifugal and axial models. These are designed for use in potentially explosive atmospheres (e.g., zones with flammable gases, vapours, or dust).

Yes, fans such as VENTEX® Centrifugal Fan 450S ATEX have ATEX and IECEX dual certification for Zone 1/22 inside the fan and Zone 1/21 outside the fan.

An ATEX-rated fan has been certified for use in potentially explosive atmospheres.

Our team of experts can support you by designing the right ventilation or extraction setup for your project, helping you choose the correct fan sizes, ducting, and control options to suit your hazard and airflow requirements.

Yes, we have ATEX-certified centrifugal fans, such as the VENTEX® Centrifugal Fan 300M ATEX

Our centrifugal fans are ideal for:

• Extracting hot or volatile fumes (e.g. paint, solvents)
• Dust extraction and filtration
• Long-distance ventilation such as inside tunnels or basements
• Providing fresh air to confined space work areas

Yes, several of our fans are portable, including VENTEX® Centrifugal Fan 200P, and also VENTEX® Centrifugal Fan 300M which has wheels and a handle. These fans are easy to move around a project as work progresses.

Our VENTEX® Centrifugal Fan 800S industrial centrifugal fan can move up to 52,200 m³/ hr of free air

Because of the design of the centrifugal fan, the motor is placed outside the airflow path, so air (which might be hot or abrasive) doesn’t pass over the motor. This makes them safer for extracting hot fumes, flammable gases, or dust.

This is a very broad question and the answer depends on what type of environment you are working in, the size of the work space, the types of activities you are undertaking, and what contaminants you are dealing with (eg. dust, fumes, DEEEs, gases etc.).

However, generally speaking there are two ventilation methods for controlling airborne contaminants on site; supply and/ or extraction. Positive pressure ventilation systems can be used to supply a constant flow of clean air into a work space which will displace any contaminated air. Alternatively, if you have a specific activity that is generating the airborne contaminants, a local exhaust ventilation system (portable LEV) can be used to extract and filter the contaminated air out of the work space. Quite often, a combination of the two methods will work well; use an appropriate extraction ventilation system with capture hood to capture and extract the contaminants at the source of the activity, then force in clean air to dilute the residual contaminants in the air.

Learn more about best practice ventilation

According to Section 3 of the government guidance, “Transmission characteristics and principles of infection prevention and control” by Public Health England:

“A single air change is estimated to remove 63% of airborne contaminants. After five air changes, less than 1% of airborne contamination is thought to remain.”

The exact number of air changes required depends on the environment and the activities being carried out; higher-risk situations demand more frequent air changes. In particularly sensitive settings, Public Health England recommends 6 -12 air changes per hour to effectively control airborne contaminants.

Typically, Centrifugal fans are the best fans to use for basement ventilation, because they are quiet, compact and perform well even when using long duct runs or duct runs with multiple bends (as is often required to be the case), however, each basement project is unique with different activities, access points, depth and volume of excavation etc, so therefore requires a tailored approach.

For railway tunnels, centrifugal fans are often the preferred option as they can be situated outside the tunnel, ensuring that they do not get in the way or block access for vehicles and machinery. Centrifugal fans also maintain high pressure over long duct runs, so they can deliver clean air deep into long tunnels.

Axial fans are better for moving high volumes of air over short distances, whereas centrifugal fans are better at maintaining high pressure over long duct runs. Despite a lower flow rate, centrifugal fans create a steadier flow, resulting in a significantly higher static efficiency. Centrifugal fans are also typically quieter than axial fans, and even with attenuators fitted are more compact. The best fan to use therefore depends on the requirements of the project.

A centrifugal fan has its motor positioned to the side of the fan casing and uses a curved, snail-shaped impeller to move air. This design typically produces higher pressure but lower airflow compared with an axial fan of the same motor size. An axial fan, by contrast, has its motor located in the centre of the casing, with air passing directly around it to achieve higher volume flow at lower pressure.

Yes, we offer for hire the VENTEX® 300P ATEX IECEx axial fan, which is certified for both electrical and non-electrical safety to operate in Zone 1 and Zone 2 hazardous environments.

Our axial fans are ideal for:

• High-volume ventilation, e.g. in tunnels, basements or top-down construction projects
• Extracting or supplying air in large enclosures, warehouses, or during top-down construction
• Confined space ventilation
• Creating negative pressure in conjunction with a filtration systems for dust or fume control

Yes, we have portal axial fans for hire. This includes VENTEX® Axial Fan 300P which weighs less than 15kg and has a carry handle for easy transport. We also have

VENTEX® Axial Fan 450M which has castor wheels so it can be rolled into position and easily moved around as a project progresses.

Our VENTEX® Axial Fan 1250S‑HP high airflow industrial fan can provide up to 86,000m³/hr airflow

It depends on several factors, including the type of environment, the size of the workspace, the activities being carried out, and the nature of the contaminants, such as dust, fumes, diesel engine exhaust emissions, or gases.

In general, there are two main approaches to ventilation for controlling airborne contaminants.

Positive pressure ventilation which introduces a steady flow of clean air into the workspace, displacing contaminated air.

Extraction of contaminants at a specific source via a local exhaust ventilation (LEV) system.

Often, a combination of both methods works best, using an extraction system with a capture hood to remove contaminants at the source, while simultaneously supplying clean air to dilute any remaining pollutants in the workspace.

In section 3 of the government guidance titled 'Transmission characteristics and principles of infection prevention and control', Public Health England explain that;

"A single air change is estimated to remove 63% of airborne contaminants, after 5 air changes less than 1% of airborne contamination is thought to remain".

The number of air changes required will depend on the environment you are working in and the activities you are conducting; the higher the airborne risk, the more air changes required.

In sensitive environments, Public Health England recommends 6 - 12 air changes per hour.

Typically, Centrifugal fans are the best fans to use for basement ventilation, however we have also used our largest high power Axial fans to create a fresh air ventilation system, forcing fresh air into many top-down construction basement projects. Each basement project is unique, with different activities, access points, depth and volume of excavation etc, and therefore requires a tailored approach.

Centrifugal fans are often the preferred option as they can be situated outside the tunnel, ensuring that they do not get in the way or block access for vehicles and machinery, however, we have also supplied large, high power axial fans, for several tunnel projects. Please get in touch to discuss your specific requirements with a hazard control expert.

Axial fans are ideal for moving large volumes of air over short distances, while centrifugal fans excel at maintaining high pressure across longer duct runs. Although centrifugal fans generally have a lower airflow, they produce a more consistent flow, resulting in significantly higher static efficiency. Ultimately, the choice between installing an axial fan or centrifugal fan depends on the specific requirements of the project.

An Axial fan has its motor located in the middle of the fan casing, and the airflow passes around it. A centrifugal fan has its motor located to the side of the fan casing, with a ‘snail’ shaped impeller. Typically a centrifugal fan will provide less airflow but at higher pressure than an axial fan with the same size motor.