April 7, 2022

HI-FOG Mist Fire Suppression System Protects Remote Alaskan Cathedral

Fire poses one of the greatest risks to historic places, but its prevention and extinguishment can also present a high risk to historic materials. Installing a traditional sprinkler system can negatively impact the character of a historic place, and the high volume of water used to quell fires can oversaturate fragile features. In the 1990s, a new solution was developed in Finland to mitigate the risk of fire, reduce subsequent water damage, and prevent major disruptions from installation: HI-FOG mist fire suppression systems. This innovative technology has protected historic places worldwide, including a historic cathedral in the remote community of Unalaska on the Aleutian Islands of Alaska.

Designated as a National Historic Landmark in 1971, Holy Ascension of Our Lord Cathedral is one of the oldest Russian Orthodox churches in Alaska. The cathedral’s history dates to the 1750s when Russian Orthodox missionaries started preaching to European fur traders and Alaska Natives. The current cruciform cathedral was built in 1896, replacing earlier churches on the site. Few modifications have been made to the cathedral despite ongoing use by the congregation, community, and visitors.

photo by: National Park Service for ROSSIA.

Site view of Holy Ascension of Our Lord Cathedral following restoration following installation of HI-FOG mist fire suppression system.

Holy Ascension has faced a heightened risk of fire throughout its history. The wooden cathedral hosts worship services that involve lighting many candles. Housed within the cathedral is a priceless collection of historic church icons and artifacts, transported to the Aleutian Islands over rivers, mountain ranges, and the ocean in treacherous conditions. Fire could destroy the church and its collection in the approximately five minutes it would take firefighters to respond.

Since 2013, the congregation, in partnership with Russian Orthodox Sacred Sites in Alaska (ROSSIA), a nonprofit focused on preserving Alaskan churches and religious iconography, has discussed upgrading fire protection at Holy Ascension. Congregants and stakeholders worried that Holy Ascension could burn down like other churches in Alaska, including St. Michael’s Cathedral in Sitka.

HI-FOG Mist as Fire Prevention

While Holy Ascension installed its first fire alarm system during a 1996 restoration and replaced these alarms around 2015, the cathedral never invested in any type of fire suppression system. ROSSIA proposed installation of a HI-FOG mist fire suppression system, which worked well at another National Historic Landmark, Holy Assumption Church in Kenai, Alaska.

As fire protection expert Jack Watts explained in the National Trust for Historic Preservation’s publication Fire Safety in Historic Buildings, HI-FOG mist fire suppression systems have many advantages for historic places compared to traditional sprinkler systems. By using high pressure water to penetrate the seat of the fire, cool the air, block heat, and starve the fire from oxygen, this system uses much less water, avoiding potential damage to fragile historic materials and collections. Additionally, the system can function even during harsh weather conditions or power outages because it relies upon pumps operated by compressed nitrogen as opposed to utility electric service.

HI-FOG mist fire suppression systems can also have fewer negative impacts on the character-defining features of historic structures. To evaluate alterations and additions to historic buildings, preservationists often use the Secretary of the Interior’s Standards for Rehabilitation, which state that the “historic character of a property shall be retained and preserved. The removal of historic materials or alteration of features and spaces that characterize a property shall be avoided.” The tubing for HI-FOG mist fire suppression systems is substantially smaller, less intrusive, and requires less cutting and patching of historic fabric during installation than regular sprinkler piping. The mist sprinklers for this system can be discreetly integrated into the ceiling without greatly altering the visual or material character of the building.

Considering these benefits, ROSSIA moved forward with a capital campaign for a HI-FOG mist fire suppression system at Holy Ascension. The organization received funding from sources including the National Park Service and the National Fund for Sacred Places, a program of Partners for Sacred Places in collaboration with the National Trust for Historic Preservation, with support from the Lilly Endowment Inc., that offers financial support and technical assistance to community-serving historic houses of worship. The installation of the fire suppression system began in 2019.

Insulated CONEX with pressurized canisters as part of installation of HI-FOG mist fire suppression system at Holy Ascension of Our Lord Cathedral | Credit: Yukon Fire Protection Systems.

A Closer Look At Installation

The HI-FOG mist fire suppression system installed at Holy Ascension was tailored to the size and needs of the space. Twenty-five gas pump units (GPUs) powered via compressed air or nitrogen and stored in pressurized containers are connected to the cathedral via a stainless-steel, insulated piping system in an underground utility tunnel. Water is then transported to 75 mist sprinklers installed in the ceiling of the cathedral’s occupiable areas. Considering Alaska’s climate, contractors used a dry system at Holy Ascension. Pipes are only filled with water when a fire alarm is triggered, and a releasing control panel is activated. The dry system causes a slight lag in water reaching the mist sprinklers but prevents the pipes from freezing.

The storage location of the GPUs, water tank, and other mechanical equipment presented a unique challenge. Holy Ascension does not have a mechanical room or even a bathroom within the cathedral and has limited storage space, so placing the system within the building without causing adverse effects to the historic fabric was not possible. Contractors considered installing the system in a parking lot bunker, existing small outbuildings, and a neighboring building. Ultimately, the team used a CONEX shipping container on the cathedral lawn.

Since Unalaska is a major North American shipping hub, shipping containers are part of local vernacular architecture. Holy Ascension’s new insulated CONEX was shipped 800 miles from Anchorage and outfitted with a historic-looking façade to match the character of the surrounding buildings. The 200-square-foot CONEX was placed on a foundation 20 feet away from the cathedral, connected via the utilidor. Archaeologists conducted an assessment before workers laid the foundation and dug the trench for the utilidor to ensure limited disturbance of historic materials.

photo by: Marc Daniels

Insulated trench running between CONEX and the cathedral as part of installation of HI-FOG mist fire suppression system at Holy Ascension of Our Lord Cathedral.

Despite delays resulting from the COVID-19 pandemic, ROSSIA and Holy Ascension completed the installation of the fire suppression system in late 2021. David Gregory, a ROSSIA board member who was highly involved in this project, spoke to the impact of the project: "The installation of the fire mist system has been a wonderful addition. The Parish has always lived in fear that a fire would destroy our beloved cathedral. Now we can rest easier knowing we have one of the best fire systems for protecting our historic church." ROSSIA also looks forward to opening up Holy Ascension to tours now that cruise ships are starting to operate again.

photo by: National Park Service for ROSSIA

CONEX under construction as part of installation of HI-FOG mist fire suppression system at Holy Ascension of Our Lord Cathedral.

The success of ROSSIA and Holy Ascension in completing this project demonstrates how stewards of all historic sites, no matter how remote, can work towards ensuring fire safety and protection. Installing new, large-scale fire suppression systems may not always be necessary or feasible. However, there are many steps owners and stakeholders can take to become more prepared in case of fire, including conducting their own fire inspection, preemptively connecting with emergency responders, and documenting the building’s important features and contents. Even a small step can help protect historic buildings, objects, and the people who use them.

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Emily Kahn is the former associate manager of the National Fund for Sacred Places at the National Trust for Historic Preservation.

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