Satish Kamble, GM-MEP Design, HOSMAC explains the codes and standards and importance of good indoor air quality in healthcare
Importance of good indoor air quality
Indoor Air Quality (IAQ) is strongly connected to the health and wellbeing of individuals. As per various studies and scientific reports; it is said that an individual breathes about 12,000 liters of air everyday. This breathable air that’s free of health threatening pollutants can lead to a higher quality of life, lower risk of respiratory illnesses, and a reduced risk of various chronic conditions.
Exposure to hazardous airborne agents due to poor air quality present in indoor spaces can cause adverse effects such as respiratory and cardiovascular diseases, which can possibly lead to cancer. The general illnesses include dryness and irritation of eyes, nose, throat and skin, headaches, fatigue, shortness of breath, among others.
The complex hospital environment requires special attention to ensure a healthy IAQ to protect patients and healthcare workers against hospital-acquired infections (HAI) and occupational diseases.
Basic characteristics of the indoor air quality of a building can be mainly decided on various gaseous composition, temperature, relative humidity and airborne contaminant levels. Indoor air is considered to be healthy when the it does not contain contaminants in harmful concentrations.
Codes and standards for healthcare IAQ
As per ANSI/ASHRAE Standard 62.1 – Acceptable IAQ is air in which there are no known contaminants at harmful concentrations as determined by cognizant authorities and with which a substantial majority (80 per cent)of the people exposed do not express dissatisfaction.
In order to maintain IAQ level in the clinical area of hospitals “ANSI/ASHRAE/ASHE Standard 170-2021 – Ventilation of Health Care Facilities” is to be followed. The purpose of this standard is to define ventilation system design requirements that provide environmental control for comfort, a sepsis and odour in healthcare facilities.
Additionally, maintaining good IAQ in critical areas like OT, ICU, isolation rooms, NICU etc. depends on various parameters like, temperature RH%,Air Changes per hour Filtration level, positive / Negative pressurisation of area with respect to adjacent area.
Let’s take a dip into these parameters:
Temperature & RH percentage: This is an important parameter for the comfort of patients and working staff. The survival of viruses, bacteria, and fungi in the air is influenced by temperature and relative humidity. Thus environmental control in hospitals is important because of infectious disease transmission from the aerosol or airborne infection.
Following are the temperature & RH percentage per ANSI/ASHRA Standard 170-2021:
- For Critical Application (OT,ICU,PE room) : 18 Deg. C to 23 Deg. C (DBT) / 55 ± 5 percent
- For special Critical Application (NICU) : 26 Deg. C to 27 Deg. C (DBT) / 55 ± 5% (RH)
- For Corridor Application : 26 ± 1 Deg. C (DBT) / 55 ± 5% (RH)
Air change per hour: Hospitals are full of potential contaminants ranging from viruses, bacteria, Volatile Organic Compounds (VOCs) to common dust. Proper ventilation and the exchange of air is the best way to reduce the presence of these pollutants, maintaining a healthy living and working condition.
Following are the Total Air Change per Hour requirement as per ANSI/ASHRAE/ASHE Standard 170-2021:
- Critical care (ICU) – 6 TACPH
- Laboratories – 6 TACPH
- OT – 20-T ACPH
- Patient room – 4 TACPH
- Isolation room -12 TAPCH
Filtration level: Hospitals are unique in that infections reign wherever a person goes, and the fact that there are contained environments in which infected people are in close proximity with non-infected people, creates a cauldron in which the spread of infection is relatively quick.
Airborne contaminants can have a serious effect on patients who have suppressed or weakened immune systems, and who are much more susceptible to lower grade airborne bacteria and viruses that would not affect people with healthy immune systems.
Filtration level for different areas as per ANSI/ASHRAE/ASHE Standard 170-2017:
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Three stages of filtration consisting of Pre-filters, Microvee (fine filter) & Terminal HEPA filters up to 0.3 micron particle size (Operating rooms, Protective Environment rooms).
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Two stages of filtration consisting of Pre-filters & Microvee filters (fine filter) up to 5 micron particle size for clinical areas.
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Single stage of filtration consisting of normal washable filters up to 10 micron particle size (For all non-clinical areas).
Pressurisation: Certain rooms within a healthcare building should be positively or negatively pressurised with respect to surrounding areas. Positively pressurised rooms (i.e. for transplant patients, OT etc.) are usually designed to protect a patient, clean supplies, or equipment within the room. Negative pressurised rooms (i.e. infectious isolation room etc.) is used to contain airborne contaminants within a room and to avoid spreading to other adjacent area.
IAQ is an important component when designing hospitals and healthcare facilities. Proper consideration must be taken to ensure that clean and fresh air is brought into the building, that the indoor air is maintained within specific air quality parameters. Also, the air should not allow to contaminate other indoor and outdoor spaces.
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