HCD Plus desiccant dehumidifier controls film vault climate

The Munters solution

McMurray Stern, a design build contractor offering high density shelving and mobile filing systems was brought in by Pacific Title Archives to offer a solution. First, in order to control temperature and humidity, and minimize offgasing in the vault, McMurray Stern consulted with archival expert, Peter Dahlbeck of Dahlbeck Engineering Company, a Munters representative, to design a dehumidification system for installation just outside of the vault vestibule.

The Munters HCD-600 Plus custom-designed dehumidification and filtration system was selected as it can remove moisture from the air through a desiccant rotor and guarantee precise humidity control by modulating face and bypass dampers. Munters’ patented HoneyCombe® wheel is a self-regenerating desiccant rotor. When the air to be dried passes through the rotor, the desiccant removes the water vapor directly from the air and holds it while the wheel rotates. As the moisture-laden desiccant passes through the reactivation sector, the water vapor is transferred to a heated air stream, which is exhausted to the outside. The process is continuous, allowing for uninterrupted dehumidification, optimizing performance while minimizing operating costs.

“The storage standards for color film are the most stringent,” said Dahlbeck. “To extend the life of the collection, control of the relative humidity is most critical. Munters unique desiccant technology controls humidity at a low temperature that is economically feasible.” With pre-engineered add-on modules, the HCD Plus provided fast and cost-effective manufacturing and the flexibility to customize equipment that had been defined by the end user’s needs.

The 2,000 scfm system keeps the vault at a precise temperature of 45°F with a relative humidity of 25% to ensure the preservation of safety film reels. The low-temperature storage helps to preserve film at a level where the humidity is manageable. The unit also does over four air changes per hour and removes pollutants and particles by carbon and HEPA filtration. The vault is regulated by a passive smart system, which automatically monitors climate activities and sends a notification if there is a breach or change inside. This provides a level of security that facilitates a quick response in case of emergency to ensure that content condition is maintained.

Quick turnaround
The film, stored in canisters, is held on twenty mechanically assisted, mobile carriages inside of the vault that operate on a recessed-rail unit, manufactured by Spacesaver. The recessed-rail tracks are laid to allow the carriages to be easily navigated so the canisters can be accessed, while taking up little space.

Proposing a quick timeline and following through as planned was crucial to the storage vault construction. By selecting Munters’ modular, HCD Plus system, McMurray Stern was able to quickly provide a custom, packaged air processing system. The entire project took two months, a quick turnaround that was tailored to Pacific Title Archives’ requirements.

“We’re very happy with [McMurray Stern],” said John Bragg, Branch Manager of Pacific Title Archives. “From start to finish, they were perfect in everything. They did everything on time, actually finishing ahead of schedule.”