Air Handler Design Considerations for Medical Facilities
By Chris Schoonover, PE, LEEP AP, BCxP
SBM has completed many air handling unit (AHU) projects in occupied medical facilities. Recent clients include St. Elizabeth’s Hospital in Youngstown, St. Mary’s Medical Center in West Virginia, Summa Akron City Hospital, Cleveland Clinic – Akron General, and Cleveland Clinic – Medina Hospital. We were recently asked about some of the specific challenges, and while some of these apply to any air handling repairs, most of them are especially critical in a healthcare setting.
Patient safety - Ensure that all design, pre-construction, and construction activities consider the needs of the patients and applicable infection control risk assessment (ICRA) procedures. This is priority number one.
Shutdown schedule - The number of days, hours, or minutes that a system can be shutdown will dictate the planning of the new unit design. It also determines measures which may need to take place including phased construction, temporary (rental) air handlers, etc.
ASHRAE 170 compliance - Many times “like-for-like” AHU replacements are requested but it is important to determine whether the current systems are capable of providing adequate ventilation and filtration. Sometimes a preliminary scope validation is warranted. It may also be important to consider the age of the controls and air terminals since replacements of those components may need to go hand-in-hand with the project.
Redundancy - Will the new air handler need to have future capacity? Will it need to have multiple fans and/or coils? Many firms specify these but may not always include adequate means of isolation or sequences of operation to ensure they work as desired.
Rigging and structural coordination - Do not presume existing structures are adequate for new equipment unless it is extremely well documented. We have designed projects where inclusion of a structural analysis, even when the new equipment was supposed to be lighter, prevented an overloading situation. Working with a rigging contractor during design helps ensure that the schedule and phasing planned will be able to be executed. While we may need to defer the rigging plan to the contractor for insurance purposes, it does not alleviate the design team from considering where and for how long cranes and platforms will need to be utilizing the project site.
Commissioning (Cx) - Whether the expectation is for the engineer to commission the system or a third party, it is strongly recommended that a commissioning process be defined as early as possible so that the facility gets the most benefit from it.
Budget - No project is successful if the owner cannot afford it. SBM frequently assists hospitals performing capital plan budgets, and can provide detailed estimating, including cashflow projections, when designing projects.
SBM is passionate about generating solutions for these types of projects and we are experienced at proactively identifying challenges that can arise. Our design, construction administration, and commissioning skills on projects of this nature have brought praise from clients.
Contact SBM if you have a project in need of a consultation.