HVAC and Plumbing Considerations for Converting Offices to Surgery Centers

As the U.S. office real estate market continues to reel from widespread vacancies, building owners nationwide are eager for solutions as the number of office workers fails to return to pre-pandemic levels. Atypical tenants like healthcare providers are increasingly attractive to office landlords. Ambulatory surgery centers (ASCs) are a great fit for this environment due to the square footage they require. The healthcare industry is also experiencing a rise in outpatient care facilities in a bid to provide more convenient care to patients, creating a perfect storm for ASCs to occupy office spaces.

While there are clear financial and sustainability benefits to adaptive reuse rather than building from the ground up, there are some challenges associated with placing surgery environments in buildings that are designed for office functions and other B Occupancy uses. From a building systems perspective, these include HVAC and plumbing, electrical service, and fire barrier separation. This article covers HVAC and plumbing considerations whereas subsequent articles will cover the rest.

Maintaining Ideal Temperature and Humidity

There are several HVAC considerations when placing an ASC in a former office building or retail environment. Most crucial is the fact that operating rooms (ORs) require more stringent HVAC requirements. Guidelines from the Facility Guidelines Institute (FGI) mandate a maximum temperature of 68 degrees Fahrenheit for ORs and 60% maximum relative humidity. This is in line with the fact that most surgeons want their ORs to be cooler and lower humidity. ORs also require a minimum of MERV 14 final filters.

To achieve these temperatures, semi-custom, direct expansion rooftop units (RTUs) or a chilled water system are required. As a result, using the existing building’s HVAC is not usually possible and additional equipment is often needed. Equipment can either be placed on grade or on the roof, and either location will require either pipe or duct runs to the space. This can quickly increase the cost of the project and should be carefully evaluated early in design.

Furthermore, most climates require humidification to prevent OR humidity from falling below 20%. There are a lot of options to consider when selecting humidifiers including gas or electric, indoor or outdoor, and treated water or untreated water. The ideal type is dependent on the local climate, building constraints, and the level of control requested by surgical staff.

• Ensuring Sufficient Plenum Space
  • Plenum space is another challenge for ASC renovations. Most office buildings have minimal plenum space since the return is not required to be fully ducted. FGI requires the return to be ducted for an ASC, thus more plenum coordination is necessary. ORs typically have 10-foot ceilings and large ductwork is required to ensure laminar airflow is provided. This can be challenging in 13-foot floor-to-floor height buildings. A solution to this lack of space can be a premanufactured OR ceiling system that allows for side duct connections. However, additional costs must be considered.

Supplying Adequate Water

Equipment and fixtures that require plumbing are more frequent within ASCs than in offices or the typical retail environment. Occasionally, the building water service is not adequate and would require either being upsized or a dedicated water line to the space. The increased fixture quantity will also necessitate more sanitary drainage and will thus require either more piping to be installed over existing tenant spaces (if not on the ground floor) or more slab cutting to install.

Engaging an Expert

Given the potential HVAC and plumbing costs associated with converting an office space to an ASC, it’s shrewd to have mechanical and plumbing engineers conduct a site assessment during lease negotiations to get the full picture of the existing building systems and the upgrades that may be needed. This approach can help ensure the project is viable before signing on the dotted line.

Henderson Knows Healthcare

Henderson has been designing healthcare projects for more than 25 years and understands that each facility, campus, and project requires a unique approach. With that great responsibility comes the need to design solutions for patient safety, complex equipment, facility infrastructure, and patient experience. Our experts are on the frontlines helping healthcare providers navigate modern technology, complicated code requirements, and the emergence of neighborhood ASCs – all while taking patient care and safety as seriously as our clients do. To learn more about our Health Sector, click here.