Prescription for hospital, health care HVAC success
Hospital and health care facility projects are especially important due to their sensitive nature. The HVAC system—especially indoor air quality—must have reliable design.
Michael Chow, PE, CxA, LEED AP BD+C, Member/Owner, Metro CD Engineering LLC, Powell, Ohio
George Isherwood, PE, Vice President, Peter Basso Associates, Troy, Mich.
Michael Lentz, Associate, RMF Engineering, Baltimore
CSE: What unique requirements do hospitals and health care facilities’ HVAC systems have that you wouldn’t encounter on other structures?
Isherwood: Equipment redundancy is more common in health care facilities than in other structures. This is due to the failure events that may occur and endanger patients if redundant systems are not properly designed, installed, and commissioned.
Lentz: Redundancy and reliability are the largest requirements that I see. Most health care facilities require some means of redundancy in their HVAC systems so they can still adequately serve patient and critical spaces during an equipment malfunction or failure. The amount of redundancy is always something that has to be weighed and measured against the project budget and the type of program space that is being built. For example, 100% redundancy for the HVAC system is more suitable for operating rooms and patient spaces than material holding or administrative offices. How you achieve this type of redundancy is also something that is unique to each facility. Is the redundancy a standby air handling unit, a standby supply fan, a fan wall assembly, or a manifold system that can withstand the loss of partial supply air?
CSE: What HVAC techniques or tools have you used to reduce the possibility of hospital-acquired infections (HAIs)?
Lentz: Strict pressurization requirements between different program areas within the hospital, and filtration and separation of different program areas within the hospital. For example, applying 100% exhaust to the emergency department waiting rooms. Any airborne infection isolation room exhaust is treated with high-efficiency particulate air (HEPA) filtration. All critical spaces, such as operating rooms, recovery areas, and sterile processing departments, are equipped with return or exhaust air terminal units in order to maintain correct pressurization within the program area, even if there is a loss of supply air to the space.