– The Role of Air Conditioning in Hospitals and Health Clinics

Hospitals, clinics and other healthcare facilities play a vital role in society, providing treatment and care for citizens. What is equally vital is the role of heating, ventilation and air conditioning (HVAC) in these buildings. We have previously discussed the importance of Indoor Air Quality (IAQ) and its effects on health. When IAQ is not optimal, it can worsen allergies and other respiratory issues, causing flare ups and sensitivities. This is true for any type of building that is frequented by people, but it becomes especially necessary in the case of healthcare facilities, where patients with compromised health may visit, where staff need to be protected from infections, and where delicate operations may be performed.

In this article we are going to discuss the particular challenges of healthcare facility buildings from an HVAC point of view, and how each element (temperature, humidity, ventilation and air filtration) helps keep a healthy environment. 

Particularities and Challenges of Healthcare Facilities

Public buildings can all have their own challenges and particularities to deal with in terms of HVAC system design. In healthcare buildings it is even more important to guarantee not only comfort, but safety and health as well. Here is what makes healthcare facilities different from other buildings:

• Hospitals and clinics tend to have separate spaces for different functions and, as such, they also have different HVAC requirements. There are wards, staff rooms, waiting rooms… Each of them has individual temperature, humidity and ventilation standards.  Some areas are considered critical, such as operating rooms, isolation rooms, and laboratories. These rooms usually need more accurate control of all climate elements.

• Technology and equipment in hospitals in clinics consume a great deal of energy, not to mention that HVAC systems need to run 24 hours a day. According to the Department of Energy (DOE), an average hospital uses 2.5 times more energy than other commercial buildings. To reduce the energy consumption impact, individualized controls are needed to turn down unoccupied spaces and apply special conditions at nighttime.

• When it comes to HVAC systems in public spaces, the main focus may be put on comfort; but in the case of hospitals and clinics, safety and health are on the front line. As diseases and infections are treated, these need to be contained and prevented from spreading to immuno-compromised patients and to healthy visitors and staff. One of the key elements for ensuring safety is ventilation and air exchange strategies, as well as removing exhaust air effectively.

• Comfort and climatization also have health benefits for patients. Adverse environmental factors can aggravate inpatients’ conditions, or delay recovery. Safeguarding patients from heat and cold for thermal comfort may even be related to lower mortality rates in hospitals, according to the findings of a study published in the BioMed Central Journal (BMC).  

• Healthcare facilities may also have to deal with higher concentrations of volatile organic compounds (VOCs) and chemical fumes from laboratories and handling of medicine and other treatment components. The presence of these particles is related to low IAQ, and it becomes paramount to manage it through ventilation and air filtration. 

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) has one of the most comprehensive lists of references for HVAC guides and applications in different buildings. During recent years, HVAC design for healthcare has shifted its focus on areas to prevent the spread of airborne infections; such as the improvement of isolation rooms, enhanced air filtration requirements, revisions on exhaust systems, etc. ASHRAE has compiled a design manual for expert guidelines specifically for hospitals and clinics, with best practices regarding temperature, ventilation, air filtration, etc. In the following sections, we will take a look at some of their recommendations.

Temperature

Temperature is closely related to health, both physical and mental. As mentioned above, extreme climate conditions can be detrimental to patients’ health and recovery journey. According to ASHRAE, air conditioning can accelerate recovery and can be regarded as a therapy factor. For example, heat is considered a threat for the elderly, children, and people with preexisting health conditions; specifically, cardiac patients and persons with thyroid conditions are more sensitive to heat and have difficulties with heat regulation. On the other side, patients that undergo surgery or operations can be more susceptible to hypothermia. Air conditioning with a focus on temperature control is key in these cases, which are just a few examples of how patients can benefit from air conditioning.

Keeping a comfortable temperature allows for a more pleasant environment, both for staff and visitors. In the case of staff, temperature and productivity are much more connected than we may think, a point we have previously explored in our article about job performance. Healthcare staff face elevated stress on a daily basis and guaranteeing thermal comfort can help with performance and decision-making. From the point of view of visitors, ensuring they feel comfortable while at the facility can reduce the negative feelings that may arise from having to visit an ill friend or relative.

Temperature can also affect the activity of bacteria and viruses, some can be inhibited by low temperatures, while for others it is the opposite. Finally, other considerations for temperature are maintenance of equipment and preservation of medicine and other treatment components, which usually have their own temperature requirements; although, generally speaking, they usually require colder temperatures (or need dedicated freezer rooms).

Humidity

When it comes to relative humidity (RH) at healthcare facilities, it becomes slightly more challenging to regulate it than in other buildings. The reason is that the same humidity level can have positive effects on some persons, and negative effects on others. ASHRAE’s general recommendation for indoor humidity is to keep it below 60%, but not excessively dry. This general recommendation cannot be applied to healthcare facilities, where rooms may need different relative humidity depending on their function and type of treatment patients may receive there. Some patients that are on treatment for respiratory issues benefit from a warm, humid climate to alleviate their discomfort; while others see an improvement in their symptoms when RH is at 30% (which is considered dry).

In relation to medical equipment, medicines and treatment, low humidity can create static electricity or increase the fire hazard risk of flammable chemicals.

Another challenge regarding humidity is that dust and particles tend to float and remain airborne for longer in dry environments, which makes cleaning and keeping infections at bay difficult if proper measures are not taken. It is also worth mentioning that some bacteria and viruses thrive and spread in high humidity environs. It has been observed that infections increase in hospitals when RH is lower than 40%. This brings us to the next point, ventilation, which is how germs and contaminants in the air are kept in check.

Ventilation

Even in other indoor environments, ventilation is one of the key elements for ensuring a healthy space. In the case of hospital and health clinic ventilation, it is even more critical as it is used to control airborne particles and keep infections from spreading. Due to these increased needs, requirements and regulations for ventilation in healthcare are more rigorous than for other public buildings. There are different ways in which ventilation helps improve IAQ. One of the most common ones is through air exchanges, by which fresh outdoor air is treated and introduced indoors. ASHRAE’s general recommendation is ensuring 0.35 air exchanges per hour (ACH); but as healthcare facilities have higher standards, the recommendation for the sector ranges between 2 and 12 ACH, the higher rate being for airborne infection isolation rooms (AIIR). Through air exchanges, the concentration of air pollutants also becomes diluted.

A less known way ventilation works is through positive and negative air pressure. This technique is used from small clinics to large hospitals, and it consists of changing air pressure to regulate the passage of fresh air into the room. Positive pressure rooms have higher air pressure inside than their surrounding areas; this way, air easily escapes the room, but outdoor air will not get back in. This is useful for sterile environments where bacteria and viruses need to be prevented from entering. These rooms usually keep immuno-compromised patients safe from outdoor infections. Negative pressure rooms work in the opposite way, as they have lower air pressure than other rooms, and prevent air from escaping, while letting fresh outdoor air in. Negative pressure rooms usually function as AIIR, to treat patients with infectious conditions and protect staff and other patients from contagion.

One point to note is that natural ventilation is usually avoided in these controlled areas, especially when taking into account that air conditioned areas have a lower concentration of microbes than naturally ventilated rooms (according to a study that observed the spread of microbial contamination in hospitals).

Filtration

Air filtration constitutes a barrier against airborne infections, as well as to reduce particles and dust in the air that may exacerbate respiratory conditions. The American Society for Health Care Engineering (ASHE) gives exhaustive guidelines for air filtration in specific areas. High-Efficiency Particulate Air (HEPA) filtration systems have become one of the most known standards for filters in recent years. HEPA filters have an efficacy of 99.97% against particles of 0.3 microns of diameter. This size of particulate matter poses one of the main challenges because of its evasiveness.

Large hospitals have to manage preventing spread of airborne pathogens that may be resistant to antibiotic treatment. Infection in healthcare facilities is a well-known issue:: higher presence of contagious pathogens increases the risk of nosocomial infections, which is the term used to describe infections acquired during hospitalization. Through filter testing and use of adequate filters for each space, these issues can be managed effectively.

Hitachi Air Conditioning for health and safety

As we have seen, complying with the high standards of air conditioning in healthcare facilities is vital to the wellbeing of patients, and the safety of staff and visitors. Hitachi’s range of commercial air conditioners features the Variable Refrigerant Flow systems (VRF), which offer individualized comfort in different zones, without compromising energy efficiency. The Heat Recovery VRF system aims to simultaneously provide cooling and heating in different rooms, by reusing exhaust heat from cooling one space, to heat another space.

As the ventilation system is such an important element in healthcare, ventilation can be upgraded through integration of a custom Air Handling Unit (AHU) by DX-Kit to the VRF system. DX-Kit offers a wide range of capacity, adapted to the needs of each installation.

Find Hitachi’s VRF system range and their key features here.