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Operating Theatres

Vertical laminar air flow - The most efficient way of controlling microbe levels in an operating theatresali

"The purpose of ventilation in the operating theater is to minimize the risks to patients and wounds of contaminants from human and other unsterile sources. Air ventilation also removes any anesthesia gases that escape into the air." (Ekono Oy. Energy Savings and Hospital Hygiene, Helsinki 1990)  


Research fingings about air conditioning in operating theatres 

The findings below were taken from an EKONO Oy study done for the Hospital Association of Finland, "Energy Savings and Hospital Hygiene," Helsinki 1990.The rates for post-operative infections after orthopedic knee and hip surgery are twice as high for surgery performed in theaters with conventional ventilation systems as compared to theaters ventilated with laminar air flow through a perforated cover.

Compared to conventional turbulent ventilation, vertical laminar flow can decrease the number of post-operation infections by half. In several studies made of air-exchange systems for entire operating theaters, the superiority of vertical laminar air flow has been conclusively established.

In laminar air flow, the entire air mass circulates in one direction and displaces the existing air in the operating area.

In a ventilation system based on vertical laminar flow, the incoming air is blown straight down through microfilters above the operating table.

The downward air flow prevents air masses from mixing in the work area. Air in the operating area is changed 400 times per hour and at least 20 times per hour in the entire room.

20% of the air mass is vented out of the room and replaced by fresh air. 80% of the air in the room is circulated, filtered with the replacement air and blown back into the room. In this way, increased amounts of fresh air are not needed compared to conventional systems, which keeps energy costs down


Kojair laminar flow unit is a flexible, total solution

The Kojair laminar flow unit is factory-tested and ready-to-use. An operating theater module can include general lighting, gas, oxygen and electrical connections and exhaust fittings. The blowers can be located in the same room as the hospital A/C machinery.

When a laminar flow unit is placed in a modernized space, the filter units in the operating theater can house the circulating fans. In this way, replacement air can be supplied through the existing air-conditioning system.

Kojair Tech Oy has supplied air conditioning to operating theaters since 1983. A major part of our production is marketed abroad. Our diverse and extensive experience from all the different areas of clean-air needs are a part of the product.

Kojair Tech Oy is a comprehensive supplier. We are able to keep any system we supply running reliably. Every Kojair laminar flow unit has been completely tested and can be delivered fully installed and ready to use.

Effective air conditioning in operating theatres is a good investment


The operating theater is the source of more than one quarter of all infections from hospital sources. This contributes to the ever-higher costs of medical care in the form of longer hospital stays and higher insurance payments. Effective air conditioning in the operating theater is a key preventive measure, along with advanced surgical techniques and the correct use of antibiotic prophylaxis.

Air ventilation technology is especially important for orthopedic, neuro-, heart and micro-surgery, all of which demand exceptionally sterile conditions. According to research, direct contact and airborne contaminants account for 98% of the micro-organisms that come into contact with the wound during major surgery. On the other hand, infections acquired after surgery requiring less-sterile conditions are usually caused by micro-organisms outside the operating theater.

When operations requiring extremely sterile conditions are performed daily, and hospital stays are increased an average of two weeks by infections, effective air conditioning in operating theaters quickly pays for itself. The difference in price between a conventional turbulent ventilation system and a laminar flow unit is covered in just a few months by improved hygiene and lower health care costs.


WALL BLOWERS 196 48 25-70
ALANDER CEILING 247 56 25-89

Microbe levels in operating theaters equipped with different air ventilation methods; surgical team wearing conventional, cotton surgical gowns. Slit sampler or filter measurements.

Operating theatres with Individial  Climatized Zones

Read article: 

Laminar Air Flow ( LAF ) in Operating theatres with Individual Climatized, Ventilated and Ultra Clean Air Zones, an international patented system

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