What is Hospital HVAC?

Hospital HVAC systems are special systems that control air, temperature, and humidity to keep hospitals safe, clean, and comfortable. Hospital HVAC systems are different from regular ones because they help stop the spread of germs and keep the air healthy to breathe. Hospital HVAC system use strong filters to clean the air, control how it flows between rooms, and make sure the temperature and humidity are just right. Hospital HVAC keeps patients, doctors, and nurses safe and healthy. Hospital HVAC systems are designed to work well in different hospital rooms, like operating rooms and isolation rooms, making the hospital a safe place for everyone.

How Hospital HVAC System Differ from Building HVAC?

HVAC design in Hospitals buildings is focused on making the air safe and comfortable for patients and staff. Here’s what makes its HVAC System different from regular building HVAC :

Airflow Control

The air must not move freely between different hospital areas. Each department needs its air kept separate to avoid spreading germs or smells.

Special Ventilation and Filtration

The system should pull in fresh air from outside and clean it properly. This helps eliminate bad smells, germs, viruses, dangerous chemicals, and other harmful stuff in the air. Good ventilation makes sure the air stays clean and safe to breathe.

Different Temperature and Humidity

Different areas in a hospital need specific temperatures and levels of humidity. It is vital to control these settings to keep everyone in the facility comfortable and safe.

Preventing Germ Spread

The system will help stop germs from moving through the air. It will keep the place clean and safe for everyone.

Importance of Hospital HVAC SYSTEM

Hospitals need a lot of outside air for ventilation, which must be cooled, dehumidified, reheated, humidified, and filtered for safe use.

Infection Control in Hospitals

Hospitals are full of harmful germs, so their HVAC design needs to keep patients safe from infections. To do this, hospitals should focus on being clean, secure, reliable, and energy-efficient. Germs can spread in three main ways:

1. Contact Transmission

2. Droplet Transmission

3. Airborne Transmission

Contact Transmission

This is the most common way infections spread in hospitals. It happens in two ways:

Direct contact

Germs pass directly from one person to another through touch.

Indirect contact

Germs spread through contaminated objects like tools or dressings.

Droplet Transmission

This happens when an infected person coughs, sneezes, or talks, releasing droplets that can land on another person’s eyes, nose, or mouth. Because these droplets do not stay in the air for long, special HVAC systems are unnecessary for droplet control.

Airborne Transmission

Tiny droplets or dust in space can carry germs. These tiny particles can stay in the air for a long time and move with it. Good HVAC systems are important to stop germs from spreading. These systems help clean the air by removing these particles, making the environment safer for everyone.

Types of Airborne Transmission:

Droplet nuclei

When a person coughs or sneezes, droplets quickly dry and shrink to a size that stays in the air for a long time. These need to be controlled by unique HVAC systems.

Dust

Contaminated dust can hold germs and cause infections even after the infected person is gone. HVAC systems help remove this dust from the air.

What are Isolation Rooms

Isolation rooms are used to stop the spread of infections from an infected patient to others. These rooms need proper HVAC systems to handle air movement. There are two main types of isolation rooms:

Airborne Infection Isolation (AII) Rooms

Protective Environment (PE) Rooms

Airborne Infection Isolation (AII) Rooms

These rooms are used for patients with tuberculosis, chickenpox, or measles. They are also used in emergency departments and intensive care units.

Protective Environment (PE) Rooms

for patients with weak immune systems, such as those who have had organ transplants or cancer patients receiving treatments like chemotherapy, maintaining clean air is very important

HVAC systems are essential for infection control in hospitals. They manage airflow, filter harmful particles, and ensure a safe environment for all patients and staff.

How Does the Above Classification Affect HVAC Designers?

The main difference between AII (Airborne Infection Isolation) rooms and PE (Protective Environment) rooms is the air pressure inside them:

Protective Environment (PE) Rooms:

These rooms are set to have positive air pressure compared to the surrounding areas. This means that air flows out of the room to prevent outside air from coming in. PE rooms need more than 12 air exchanges per hour, and the air supply must pass through HEPA filters to make sure it is very clean.

AII Rooms (Isolation Rooms):

These rooms are kept at negative air pressure. This makes air flow into the room and prevents the air inside from escaping to other areas. Like PE rooms, AII rooms also need more than 12 air exchanges per hour, but here, all the air is removed and not recirculated.

Both types of rooms need to have devices that monitor the air pressure to make sure it stays at the set level. The doors should close by themselves, and all openings like windows, ceilings, walls, and floors need to be well-sealed.

This means HVAC designers must carefully plan systems that can manage these different pressures, ensure proper air exchange rates, use HEPA filters where needed, and include monitors to keep track of pressure. Good sealing and proper door function also need to be checked during design and installation.

These requirements help keep patients and medical staff safe by managing how air moves in and out of these rooms.

What are the HVAC control parameters for isolation rooms?

HVAC designers need to ensure isolation rooms are properly designed to keep everyone safe these are different parameters

Air Pressure Control

· What It Means: In an isolation room, the air pressure inside the room needs to be different from the air pressure outside. This difference helps to keep harmful germs or contaminants from spreading.

· How It Works: If the room has lower pressure than the outside, air will flow into the room and keep germs from escaping. If the room has higher pressure, air flows out to keep outside contaminants from coming in.

Air Exchange Rate

· What It Means: The air in the room should be replaced regularly with fresh, clean air. This is known as the “air exchange rate."

· How It Works: For isolation rooms, the air exchange is often set higher than usual to ensure that any germs or particles in the air are removed quickly.

HEPA Filters

· What It Means: HEPA filters are powerful air filters that can trap tiny particles, including bacteria and viruses.

· How It Works: HVAC systems in isolation rooms use HEPA filters to clean the air before it enters or leaves the room. This helps keep the air as germ-free as possible.

Air Pressure Monitors

· What It Means: Air pressure monitors check if the room is at the right pressure level.

· How It Works: These monitors are set up to alert staff if the pressure is too high or too low. This helps make sure the room is always safe for both patients and medical staff.

Door and Seal Checks

· What It Means: Doors and seals need to close tightly to prevent any air from leaking in or out.

· How It Works: HVAC designers and hospital staff must check that doors close properly and that seals around the room are secure. This keeps the room airtight and ensures that air only flows where it’s supposed to.

Why This Matters

All of these factors help protect patients and staff by controlling the airflow in and out of isolation rooms. This way, harmful germs stay contained, and the air remains safe to breathe.

Wrte types of room in hospitals?

Patient Rooms

1. General Patient Room: Where patients stay for regular care or to recover.

2. Private Room: A room for one patient to give privacy and reduce infection risk.

3. Semi-Private Room: A room shared by two patients, usually with a curtain in between.

4. Isolation Room: For patients with contagious diseases. Air is controlled so germs don’t spread outside the room.

Operating Rooms (OR)

1. General Operating Room: A clean room where surgeries are done.

2. Specialty Operating Room: A room for specific surgeries like heart or brain surgery.

3. Hybrid Operating Room: A room with surgery and imaging equipment, so doctors can do certain procedures with real-time images.

Intensive Care Units (ICU)

1. General ICU: For very sick patients who need constant monitoring.

2. Neonatal ICU (NICU): For premature or sick newborns.

3. Pediatric ICU (PICU): For very sick children and infants.

4. Cardiac ICU (CICU): For patients with serious heart problems.

5. Surgical ICU: For patients recovering from major surgeries.

Emergency Room (ER) / Emergency Department (ED)

1. Triage Area: Where staff check how serious each patient’s condition is.

2. Trauma Room: For treating serious injuries.

3. Treatment Bays: Small areas for treating less serious cases.

4. Observation Rooms: For short-term monitoring of patients who don’t need to be admitted.

Labor and Delivery Rooms

1. Labor Room: Where mothers go during labor, before giving birth.

2. Delivery Room: A room for childbirth.

3. Postpartum Room: Where mothers and newborns stay to recover after birth.

4. Neonatal Nursery: For monitoring and caring for newborns after birth.

5. LDR Room (Labor, Delivery, and Recovery): A room where mothers can go through labor, delivery, and recovery all in one place.

Recovery Rooms / Post-Anesthesia Care Units (PACU)

· PACU: For patients waking up from anesthesia after surgery. They stay here until they are fully awake and stable.

Imaging Rooms

1. Radiology Room: For X-rays and other imaging tests.

2. MRI Room: A room with MRI machines for detailed body scans.

3. CT Scan Room: For CT scans, which show detailed images of the body.

4. Ultrasound Room: Used for ultrasound scans, often during pregnancy.

5. Nuclear Medicine Room: For scans using tiny amounts of radioactive material.

Diagnostic and Treatment Rooms

1. Exam Room: For routine check-ups and assessments.

2. Endoscopy Room: For procedures that look inside the body, like a colonoscopy.

3. Cardiology Room: For heart tests, like EKGs and stress tests.

4. Dialysis Room: For patients with kidney problems to get dialysis treatment.

Procedure Rooms

1. Minor Procedure Room: For small surgeries that don’t need a full operating room.

2. Cath Lab (Catheterization Laboratory): For heart procedures like inserting a catheter.

3. Bronchoscopy Room: For examining the airways with a special tool.

Isolation Rooms (Negative and Positive Pressure)

1. Negative Pressure Room: Keeps germs inside the room to stop them from spreading.

2. Positive Pressure Room: Keeps germs out to protect patients with weak immune systems.

Specialty Care Rooms

1. Burn Unit Room: Special room for burn patients to prevent infections.

2. Psychiatric Room: A safe room for mental health patients.

3. Chemotherapy Room: For cancer patients receiving chemotherapy.

Support and Administrative Rooms

1. Nurse Station: Where nurses keep an eye on patients and handle records.

2. Pharmacy: Where medicines are stored, prepared, and given out.

3. Supply and Equipment Storage: For keeping medical supplies and equipment.

4. Staff Lounge: A break room for hospital staff to rest.

5. Waiting Room: Where family and friends wait to visit patients.

6. Consultation Room: Private room for doctor-patient discussions.

Therapy and Rehabilitation Rooms

1. Physical Therapy Room: For exercises to help patients recover strength.

2. Occupational Therapy Room: For therapy that helps with daily living skills.

3. Speech Therapy Room: For therapy that helps with speech and language.

Public Areas and Lounges

1. Lobby: The main entrance with desks and seating for visitors.

2. Cafeteria: Dining area for patients, visitors, and staff.

3. Chapel or Meditation Room: A quiet space for prayer or meditation.

HVAC Standards and Environmental Requirements for Different Hospital Rooms

Patient Rooms

General Patient Room:

· Area per person: Approximately 120-150 square feet per bed (ASHRAE 170).

· Sensible Heat Gain per Person: 250 Btu/hr.

· Latent Heat Gain per Person: 200 Btu/hr.

· Lighting Load Density: 1.0 W/ft² (ASHRAE 90.1).

· Outdoor Air per Person: 25 CFM (ASHRAE 170).

· Air Changes per Hour: 6 ACH for comfort and infection control (ASHRAE 170).

· Relative Humidity: 30-60% (ASHRAE 170).

· Indoor Air Quality Index: Should meet the minimum standards of ASHRAE 62.1.

· Humidification and Dehumidification Set Points: Humidification at 30% minimum, Dehumidification up to 60%.

Private Room:

· Similar to general patient rooms in all parameters but with a focus on higher privacy and infection control.

Semi-Private Room:

· Similar to general patient rooms in most values but may require adjustments for shared space.

Isolation Room:

· Area per person: 150 square feet or more (CDC).

· Sensible Heat Gain per Person: 250 Btu/hr.

· Latent Heat Gain per Person: 200 Btu/hr.

· Lighting Load Density: 1.0 W/ft².

· Outdoor Air per Person: 30 CFM for increased ventilation (ASHRAE 170).

· Air Changes per Hour: 12 ACH for high contamination control (ASHRAE 170).

· Relative Humidity: 30-60%.

· Indoor Air Quality Index: Higher standards due to airborne infection risks (ASHRAE 62.1).

· Humidification and Dehumidification Set Points: 30-60% to avoid dry or too humid conditions.

Operating Rooms (OR)

General Operating Room:

· Area per person: 400-600 square feet (ASHRAE 170).

· Sensible Heat Gain per Person: 250-300 Btu/hr.

· Latent Heat Gain per Person: 200-250 Btu/hr.

· Lighting Load Density: 2.0 W/ft² due to intense lighting for surgical procedures.

· Outdoor Air per Person: 20 CFM.

· Air Changes per Hour: 20 ACH to maintain sterile conditions (ASHRAE 170).

· Relative Humidity: 20-60% (ASHRAE 170).

· Indoor Air Quality Index: Must be high to ensure a sterile environment.

· Humidification and Dehumidification Set Points: Humidification set above 20% to avoid static, dehumidification below 60%.

Specialty Operating Room:

· Similar values to general operating rooms with specific requirements for temperature and humidity depending on the type of surgery.

Hybrid Operating Room:

· Requires precise temperature and humidity controls, similar to general operating rooms, with extra attention to HVAC to prevent condensation on imaging equipment.

Intensive Care Units (ICU)

General ICU:

· Area per person: 200-250 square feet per bed (ASHRAE 170).

· Sensible Heat Gain per Person: 250 Btu/hr.

· Latent Heat Gain per Person: 200 Btu/hr.

· Lighting Load Density: 1.5 W/ft².

· Outdoor Air per Person: 25 CFM.

· Air Changes per Hour: 12 ACH for infection prevention and airflow control (ASHRAE 170).

· Relative Humidity: 30-60%.

· Indoor Air Quality Index: Must be high to ensure patient safety.

· Humidification and Dehumidification Set Points: 30-60% RH.

Neonatal ICU (NICU):

· Area per person: 120 square feet per infant.

· Sensible Heat Gain per Person: 150 Btu/hr.

· Latent Heat Gain per Person: 100 Btu/hr.

· Lighting Load Density: 1.0 W/ft² with dimming options.

· Outdoor Air per Person: 15-20 CFM.

· Air Changes per Hour: 6-12 ACH (ASHRAE 170).

· Relative Humidity: 30-60%, critical for infant health.

· Indoor Air Quality Index: High quality to protect immune-compromised infants.

Emergency Room (ER) / Emergency Department (ED)

Triage Area:

· Area per person: 50 square feet per person (CDC).

· Air Changes per Hour: 6 ACH for comfort and ventilation.

Trauma Room:

· Air Changes per Hour: 15-20 ACH (ASHRAE 170).

· Relative Humidity: 30-60%.

· Outdoor Air per Person: 20 CFM for adequate ventilation.

Treatment Bays:

· Similar values to general patient rooms with Air Changes per Hour at 6 ACH.

Observation Rooms:

· Typically requires 6 ACH with 30-60% humidity levels for short-term monitoring.

Labor and Delivery Rooms

Labor Room:

· Air Changes per Hour: 6 ACH.

· Outdoor Air per Person: 15 CFM.

Delivery Room:

· Air Changes per Hour: 12-15 ACH to maintain cleanliness (ASHRAE 170).

Postpartum Room:

· Air Changes per Hour: 6 ACH for comfort and air quality.

Recovery Rooms / PACU

Post-Anesthesia Care Unit (PACU):

· Air Changes per Hour: 6 ACH, with 100% outdoor air (ASHRAE 170).

· Relative Humidity: 30-60%.

Imaging Rooms

Radiology and MRI Rooms:

· Air Changes per Hour: 6 ACH for comfort (ASHRAE 170).

· Relative Humidity: 30-60%.

Diagnostic and Treatment Rooms

Exam Room:

· Air Changes per Hour: 6 ACH.

Dialysis Room:

· Air Changes per Hour: 6 ACH with high outdoor air to reduce chemical exposure risks.

Isolation Rooms (Negative and Positive Pressure)

Negative Pressure Room:

· Air Changes per Hour: 12 ACH.

· Outdoor Air per Person: 30 CFM for infection control (CDC and ASHRAE 170).

Positive Pressure Room:

· Air Changes per Hour: 12 ACH.

· Relative Humidity: 30-60%.

Specialty Care Rooms

Burn Unit Room:

· Air Changes per Hour: 15 ACH with HEPA filtration (CDC).

Chemotherapy Room:

· Air Changes per Hour: 12 ACH to maintain safe air quality (CDC and ASHRAE 170).

Public Areas and Lounges

Lobby and Waiting Areas:

· Air Changes per Hour: 6 ACH for comfort and air quality (ASHRAE 62.1).

FAQ

What is the main purpose of a hospital HVAC system?

To control air, temperature, and humidity, keeping the hospital safe, clean, and comfortable for patients and staff.

How does hospital HVAC prevent the spread of germs?

It controls airflow, uses strong filters to clean the air, and separates air between different areas.

What is the difference between positive and negative pressure rooms?

• Positive pressure keeps germs out by pushing air out of the room.
• Negative pressure keeps germs in by pulling air into the room.

Why are isolation rooms important in hospitals?

They stop infections from spreading by controlling how air moves in and out of the room.

What is the role of HEPA filters in hospital HVAC systems?

HEPA filters clean the air by trapping tiny particles like germs and dust, ensuring safe air to breathe.