Portland Museum of Art Mechanical and Electrical System Upgrades

Portland, Maine

Two of the three buildings that make up this small city’s art museum were recently restored and opened again after a two-decade period of being closed — one built in the early 1800s and the other in the early 1900s. Both are on the National Register of Historic Places, so strict guidelines were followed to ensure that the integrity of the buildings were not compromised. In addition, museum accreditation requirements stipulate maintaining a relative humidity level of 40 to 50 percent at all times so that artwork will not be harmed.

Harriman engineers were asked to design new mechanical systems that would protect both the buildings and the artwork in the museum’s collections and provide energy efficient operations.

A detailed analysis of the McLellan House, built in 1801, was completed to determine the effects of condensation on the masonry structure, which is considered a piece of art in itself. Engineers calculated the dew points at various temperature and humidity values and determined that a relative humidity of 29 to 30 percent had to be maintained in order to keep the masonry from deteriorating. In the L.D.M. Sweat Memorial Galleries, built in 1911, however, the relative humidity of 40 to 50 percent required for the display of art could be maintained.

The building’s direct digital control system makes it easy for the museum’s facilities department to monitor and adjust temperature and humidity in various parts of the museum, and track trends for energy efficiency.

The installation of pipes and duct work had to be carefully planned so that they were completely hidden and so that none of the intricate wood trim was damaged or altered. Designers creatively used the chases of non-functioning fireplaces to hide some ducts and pipes and installed others by lifting and replacing floorboards. Channels were carefully cut into the two-inch thick bearing walls for pipe routing. And in a 30-ft.-high rotunda with octagon walls, unused corners became areas where ducts could be placed.