Confined Spaces and Manholes

Why ventilate a confined space?

The top reason is to prevent people from becoming extremely ill, or even dying in a worst case scenario. The second most important reason is to create a comfortable working environment. This is why ventilation for confined spaces needs careful consideration.

We sell fans and accessories for confined space ventilation. This includes fans for explosive environments. Used correctly, they help keep workers safe and productive.

What is a confined space?

Any space with limited entrance and exit points may be a confined space. Examples include tunnels, storage tanks and grain silos. They're places with little-to-no natural airflow, and that makes them hazardous places to work.

Confined space hazards

Fresh air is about 20% oxygen, and according to OSHA, humans need at least 19.5% air to be safe. Less than that and you'll lose consciousness and potentially suffocate. Carbon dioxide, (produced by breathing,) is heavier than air so will pool near the floor in enclosed spaces that lack ventilation. Carbon monoxide, a byproduct of running gasoline-powered equipment, is around the same density as air so doesn't pool like CO2. It will however displace air from an enclosed space, with potentially lethal results.

Processes used in confined spaces can produce their own hazards. Welding, bead or grit blasting and paint spraying all generate fumes and dust that should be removed. Flammable or explosive fumes may be present in some confined spaces like oil tanks. In addition, confined spaces can get extremely hot. Workers, particularly if wearing heavy PPE, can quickly dehydrate and even lose consciousness.

Ventilating for safety

Employers have a duty to ensure the safety of their workers. Any time someone has to work in an enclosed space it's essential to follow all relevant codes and instructions. (Check with OSHA or relevant state authorities to learn which apply to your particular situation.)

Confined spaces are ventilated with a suitable fan. These are usually axial fans, although in specialized cases venturi-type blowers may be used. Typically the fan is placed outside the confined space and moves air in to or out of it through ducting.

As covered in OSHA regulation 1910.146, positive pressure ventilation is usually preferred. This is when the fan pushes air into the confined space. However, there may be situations where negative pressure ventilation (pulling out of the space,) is better. Fans we sell can be used in either mode.

Calculating the ventilation needed

This depends on the number of air changes per hour (ACH) required. OSHA has no specific requirements although some states and local authorities do have ACH targets. Once the ACH is known it's a simple matter to calculate the CFM needed.

Fan types

Nearly all confined space fans are of the axial design. This makes it easy to connect appropriate ducting. Most are electrically-powered but gasoline and pneumatically driven fans are also available.

Standard Confined Space Fans

Generally portable, these are powered from a 110V supply and can work either in positive or negative pressure modes. A wide range of CFM's are available.

High Volume Confined Space Fans

Often used as smoke ejectors, these will move high volumes of air rapidly.

Gas-Powered Confined Space Fans

These address the problem of not having an electrical supply available. Always set up gas-powered fans outside of the confined space and make sure the fumes cannot be drawn into the ducting.

12V Confined Space Fans

These are intended for when a vehicle electrical supply is the only option. That makes them easy to deploy on a remote job site.

Intrinsically-safe confined space fans

Intrinsically-safe fans are powered by compressed air. This eliminates potential ignition sources, making them a good fit when flammable fumes may be present.

Explosion-Proof Confined Space Fans

These electric fans are designed in a way that prevents sparks. They are for use in places with a risk of fire or explosion.

Keep workers safe and comfortable

Confined space working is potentially dangerous and ventilation must always be considered. We sell fans for both positive and negative pressure ventilation and to deal with flammable, toxic and inert gases.

Industrial Fans Direct carries the right ventilating fan or blower for your work within a confined space or manhole work. Whether your project involves cleaning, painting, welding, or repairing tanks, rail cars, mills, granaries, silos, tunnels, septic tanks, ditches or other small or confined area we have the ventilation equipment necessary to help make the space a cleaner, healthier and safer environment for workers. We offer the confined space blowers and ventilators in; standard 120 volt AC models, 12 volt DC models, pneumatic and intrinsically safe models, hazardous location or explosion proof models for atmospheres and environments where flammable or ignitable fumes, gases and or dust may be present.

You will find quality brands like Allegro Safety, RamFan by Euramco, Americ, Pearson Industries, Canarm, Ventamatic and Xpower Manufacturing.

There are many options available, so selecting a fan to ventilate a confined space can be difficult. If in doubt as to what will work best, call the experts at Industrial Fans Direct: 866 727 1060.