Airflow paths in healthcare facilities

Air is the primary carrier of moisture, contaminants, heat and most of the viable and non-viable contaminants in health care facilities such as surgical suites, patient rooms and isolation rooms.  Hospital-acquired infection is a public health issue with high levels of morbidity and mortality. Disease can be transmitted by air, by direct/indirect contact or a combination of both routes. The transmission through the air is harder to control than the direct transmission, but one where the engineering sciences can play an important role in limiting the spread.

A key system that should not be overlooked in the surgical suite is heating, ventilation and air conditioning. Proper HVAC air flow can help protect patients from infection.   Air quality is essential to the health of patients.

Air flow into the surgical suite and removal of air through the exhaust vents remove airborne microorganisms to help control infection. A preventative maintenance program with regular inspection is absolutely essential.  An isolation facility aims to control the airflow in the room so that the number of airborne infectious particles is reduced to a level that ensures cross-infection of other people within a healthcare facility is highly unlikely.

There are factors in reducing airborne-induced infections:

• Proper Air Quality: Humidity and temperature should be carefully maintained. This may be achieved by control of the quantity and quality of intake or exhaust air.
• Proper Air filtration: HEPA filters.
• Proper Air Volume Changes: The recommended air volume to and from the surgical suite is 25 volume changes per hour. Diluting infectious particles with large air volumes is really important.
• Proper Air Differential Pressure: It’s important to maintain different air pressures between adjacent areas, designing airflow patterns for specific clinical procedures.
• Proper Air Flow Direction: Even opening doors and personnel moving about the room can cause turbulence that stirs up previously settled particles.

People working at hospitals need to understand the safety issues involving surgical HVAC systems. Proper air flow can help prevent infections and avoid equipment breakdowns.

Most studies on the transmission of infectious airborne disease have focused on patient room air changes per hour (ACH) and how ACH provides pathogen dilution and removal. The logical but mostly unproven premise is that greater air change rates reduce the concentration of infectious particles and thus, the probability of airborne disease transmission. Several studies indicate that the design of a ventilations system and the resulting airflow patterns play a more important role than just the supply airflow rate or ACH alone.

OPIA Operaciones e  Ingeniería de Avanzada de Centroamérica S.A can help healthcare  facilities through our services:

• Computational fluid Dynamics simulations: It’s a three dimensional computational model that can evaluate the impact of HVAC design configuration on the airflow patterns, temperature distribution and resulting thermal comfort of the patient and obviously the probable flow path of the airborne particles released over the patient.
• Installation, testing and balancing of HVAC systems.
• HEPA/ULPA filters leak testing and report.

Ask our engineers and we gladly advise you.