Retrofitting historic structures with modern building systems can be one of the most difficult aspects of a historic restoration and renovation project. Building teams often struggle to 'squeeze' new HVAC equipment and ductwork, water pipe, electrical wire, and telecom and fiber-optic cable into tight spaces.
If a building's interior space is deemed a historic landmark, a mechanical, electrical and plumbing (M/E/P) retrofit job can be even more difficult, because the interior cannot be altered.
The newly restored Fairhaven (Mass.) High School is a case in point. Led by Boston-based architect Flansburgh Associates, the project involved modernizing the 1906 school while making few intrusions to its ornate interior.
'The structure was not forgiving because the walls are solid masonry with plaster applied directly,' says Samuel Bird, construction architect with Flansburgh. 'Solutions included running wire behind slate blackboards and in closets. In some cases, the plaster was on furring, allowing enough space to snake wiring through. Literally, every wire required an investigation.'
Bird says, however, that the building team benefited from progressive construction methods used to construct the school. For instance, existing duct chases that had been built directly into the masonry structure provided a vertical distribution path for ventilation, electrical wiring and data cabling. Moreover, all of the existing wiring was installed in conduits, making it easier for new wire to be pulled through.
Finally, the building team reused much of the building's existing steam heat system. 'We replaced the boilers and radiators, but the existing piping was still viable, which minimized costs and disruption to the interior,' Bird says.
Converting the gymnasium into a library also presented challenges. This was particularly the case in finding space to house HVAC equipment for the 6,000-sq.-ft. area.
'We found space between the ceiling and the roof,' says Bird. 'The pyramid-shaped ceiling was sloped less steeply than the roof, which created space about 6 feet high - just enough to install the HVAC equipment.'
Richard Barcori, mechanical engineer with Albany, N.Y.-based A/E Einhorn Yaffee Prescott (EYP), says one of the most difficult aspects of a M/E/P retrofit is routing ductwork, especially if the building has low floor-to-floor heights.
'We can hide pipe inside a 4-in.-thick wall, but trying to route and hide a 10-by-24-in. duct is much more difficult,' he says. 'So we'll often specify fan-coil units to provide heating and cooling on a room-by-room basis to minimize ductwork.' EYP is employing this technique for the renovation of the Washington State Capitol building in Olympia.
A similar approach was employed during the renovation of the Main Administration Building at the University of Notre Dame. (See 'Reviving a revered landmark,' October 2000, page 54.)
The challenge for Dan Dickenson, mechanical engineer with A/E Ellerbe Becket, Minneapolis, was to design a cost-effective HVAC system without compromising the appearance of the interior. Dickenson says the firm chose to install four air-handling units - one in each quarter of the building - instead of a more traditional central unit.
'Smaller units allowed us to use smaller duct runs, and reduced noise and vibration,' he adds.
Barcori also worked on the renovation of Princeton University's Blair and Buyers Residence Hall (see 'Gothic revival,' October 2001, page 46.), where tight spaces required the use of an existing mechanical corridor in the basement to house and distribute utilities.
'Due to low floor-to-floor heights and limited ceiling plenums, the building was essentially wired vertically versus horizontally,' says Barcori. 'Instead of trying to run the utility lines horizontally on each floor, which would have reduced ceiling heights, the basement serves as the horizontal distribution area, and utility lines rise up three stories at a couple of dozen spots.
'We're currently working on another dormitory at Princeton - Hamilton Hall - that presents a different set of challenges,' adds Barcori. 'For instance, Blair and Buyers is a wood-frame structure, so we had stud and joist space to hide utility lines. Hamilton Hall has flat-slab construction and terra-cotta interior walls, which provide virtually no space to hide infrastructure.'
The solution, says Barcori, will most likely involve replacing some of the structure's nonload-bearing terra-cotta walls with stud-frame walls. 'Even though we'd like to minimize costs and disruption to the existing appearance, this will give us a path to get vertically from either the floor below or within the same floor from the ceiling down to floor level,' he adds.
Another challenge, says Barcori, is finding ways to intake and exhaust air without compromising an historic exterior. 'What we'll have to do sometimes is install several air handling units that exhaust air at a number of lower-profile outlets - such as a reclaimed chimney or an existing airway - versus having one large air-handler exhaust air out of a louver that is intrusive to the building's appearance.'