List Obtains OSHPD Approval for Unique Chilled Beam System

by Wendy Walker

List Obtains OSHPD Approval for Unique Chilled Beam System Image 1

List Engineering receives a State of California OSHPD (Office of Statewide Healthcare and Planning) Alternate Method of Compliance approval for use of an active chilled beam system in a local hospital. 

The project involved replacing a 1980s-era diagnostic center with a USP 797 conforming pharmacy. The area was an older space with an infrastructure still useable, but undersized for the new airflow requirements. The old codes, low ceilings and small air handling unit created capacity challenges for the existing plant. List Engineering designed a system using active chilled beams (ACB) to provide zoned cooling and use the existing air handling unit and main ducts.

“Because the application of the ACB system includes features that are not exactly consistent with the California Mechanical Code, we had to obtain an Alternate Method of Compliance from the Office of Statewide Health Planning and Development,” said Ron Blue, List Engineering’s owner and head engineer.

The challenge was in demonstrating that the ACB would meet the needs of the new project and not compromise the functional requirements of the current California Mechnical Code.

Plate and frame heat exchangers are used to generate lukewarm chilled water (58°F, instead of the central system 42°F chilled water) which avoids condensation issues. The ACB contains a heating coil and a cooling coil, but no moving parts. Maintenance is limited to the occasional vacuuming of the coil face.

Control valves are mounted alongside the ACB. Primary air is delivered to each ACB which induces room air to pass through the device. Room exhaust removes the latent heat gain from the space leaving a proper temperature and relative humidity level in the room. 

Besides the chilled beam features, three clean rooms were also included to support the pharmacy program. While not a feature in this application, the use of the lukewarm chilled water offers possible energy-saving strategies that can be used in other applications.