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Unidirectional flow in theatre plays a crucial role in sterility and preventing hospital-acquired infections during surgery.

In addition, clean air distribution is fundamental to the health and safety of the surgery team and also provides a comfortable working environment.

What is Unidirectional Flow?

Unidirectional flow is characterised by streamlines that do not cross over each other but rather move parallel to one another and in one direction.

It is also characterised by low momentum convection and high momentum diffusion.

With unidirectional flow, the motion of the particles is orderly as particles close to a solid surface will move in straight lines, parallel to the surface.

Unidirectional Air Flow in Theatres

There are three main sources of airborne particles or contaminants in clean air environments:

• Contamination by occupants
• Infiltration
• Ventilation systems

Patients who are undergoing invasive surgery are more susceptible to infection. Therefore, clean air is absolutely critical in operating theatres.

In order to create positive air pressure, the air inside the operating room should always be kept at a higher pressure than in adjacent areas and passages.

Positive air pressure prevents the flow of air from less sterile areas into clean air environments.

Unidirectional Flow in Theatres and HEPA Filters

Unidirectional flow is a type of low velocity, orderly ventilation system. However, these systems still require a high efficiency particulate air (HEPA) filter to provide maximum efficiency and sterility.

Technically speaking and in terms of contamination control, unidirectional air flow systems are the best option for operating theatres. This is because they result in the smallest percentage of particulates impacting the surgical site.

Vivid Air Unidirectional Flow Theatre Unit

Below are some of the specifications of our unidirectional flow units:

VA5027 Unidirectional Flow Theatre Unit

• The unit will be equipped with peripheral lighting supplied by 8 (eight) off fluorescent lights with easy access through removable Perspex covers
• The unit shall supply sterile air under ISO Class 5 conditions as per ISO 14644-1 delivered through a specially designed double layer distribution membrane (CG Screen) over the entire work area
• The air supply though the distribution screen shall be at a uniform velocity of between 0,3m/s and 0,5m/s along parallel streamlines with minimal turbulence between where the air enters and exits the room
• The CG Screen frame shall be manufactured from stainless steel to prevent corrosion

For a full list of specifications, click here

VA5033 Unidirectional Flow Theatre Unit

• The unit can be flush mounted with the ceiling or protruding from the ceiling by 200 / 300mm.
• The CG Screen shall be easily removable for cleaning and maintenance purposes
• Each laminar Flow theatre shall be equipped with 4 (four) off 99,997% efficiency high volume HEPA filters, each capable of handling an air volume of 4 000 m³/h. The HEPA should be housed in leak proof mild steel epoxy powder coated housing above the slab with non-shedding transition pieces between the HEPA filter housing and theatre plenum.

For a full list of specifications, click here

Vivid Air – Manufacturers of Clean Air Equipment South Africa

At Vivid Air, we value the importance of clean air and manufacture high-quality equipment to meet the minimum requirements for all clean air environments.

Our unidirectional flow units for theatre are built according to the relevant ISO standards, ensuring optimal function in operating theatres and minimising the risk of infection.

To find out more about our clean air equipment, or for more information about our unidirectional flow theatre units, please contact us.