Ultraclean, Metal-free Lab Designed for Columbia University

This hood design was a prototype that has never been used in any known application.

ANGELA LOPICCILO

By: Angela LoPiccilo,Pete Daniele

Columbia University has recently commissioned a new ultraclean laboratory for Professor Sir Alex Halliday, founding dean and director of the Columbia Climate School, and director of the Earth Institute. The laboratory was constructed in the Gary Comer Geochemistry building of Lamont-Doherty Earth Observatory.

Halliday’s research required a custom, metal-free laboratory. The specific acids used in his team’s research will corrode any metal in close proximity, with or without direct contact, and contaminate the high precision metal isotope research being conducted. These acids will also degrade most color additives, including the additive used to manufacture standard white polypropylene. White polypropylene is more attractive, but will leach a powdery dust when attacked by these specialized acids. Natural polypropylene, which has an opaque beige color, was the optimal material for this laboratory because of its excellent acid resistant properties. The architectural firm, Payette of Boston, and the Columbia University team offset the industrial look of natural polypropylene by including design elements such as a bold floor color as well as a color accented backsplash for the cabinetry. The lab was also designed with floor to ceiling windows looking out onto the evergreen trees adjacent to the building, giving some warm natural feel to the space. 

The mechanical challenges of the laboratory were more difficult to circumvent. The Gary Comer building is one of the most advanced acid digestion laboratories in the US. However, the ambitious design requirements presented the team with some interesting challenges. The lab was to be divided into two acid digestion modules and a balance room. The space needed to be an ultraclean lab with a total of 12 laminar flow hoods for acid digestion and two fume hoods. The number of hoods drove requirements for extremely high supply and exhaust for the space, which would have strained existing building systems, significantly increased utility cost for the building, and dramatically increased the building’s carbon footprint. 

The team settled on a two-fold solution. The first was to redirect as much air to the space as the building could spare by rearranging ductwork in adjacent laboratories. The second, and more challenging, was to design custom fume hoods for the space that would maximize cleanliness and minimize exhaust air requirements while maintaining safety. Payette, Columbia, and the lab end-users designed the vertical exhausting laminar flow hoods for this lab.

Each of these new hoods was a vertical sash laminar flow hood. The hoods were designed with ULPA filters (ISO 14644) in the top faces to draw in pre-filtered room air to direct into the hood as a laminar down draft, eliminating the requirement for room exhaust. Each hood included a dual work chamber, one for preparing samples and one for acid digestion. This cut the required number of acid digestion hoods from 12 to six, as each hood served a dual purpose. Each module had a sash monitor and a multi-speed fan; when a sash opened the fan in the adjacent module ramped down, and only one sash could be opened at a time. Redirecting air to the open module allowed the hoods to maintain a high level of cleanliness while maintaining exhaust in the closed module. The hoods were all connected to the building wide system for exhaust. 

LM Air was hired to construct the custom hoods. This hood design was a prototype that has never been used in any known application, and LM Air was able to build on the design for maximum energy efficiency. The hoods were constructed from natural polypropylene like the rest of the lab. Each was constructed with energy efficient EC motors and incorporated a laser eye sash monitor system, which reads the height of the sash to gradually and proportionally slow the supply air in the adjacent chamber. The complex system worked seamlessly and cleanliness testing of the hoods yielded excellent results. The project was managed by Protecs, Inc. 

Angela LoPiccilo is with Columbia University, and Pete Daniele is with LM AIR.