Return to 90 South: Part II
The ins and outs of the fire suppression systems in the Antarctic.
Captain Robert F. Scott and four others reached the geographic South Pole on Jan. 18, 1912, only to find out that a team of Norwegian explorers was the first earth humans to make it there. The Norwegian explorers, led by Captain Raold Amundsen, reached the South Pole on Dec. 14, 1911, and safely returned. Not so for Scott and his men, all of whom perished during their return trek.
From the United States Antarctic Program (USAP) Participant Guide, published by the National Science Foundation (NSF): (The Amundsen-Scott South Pole Station), at the geographic South Pole, is on the polar plateau at an elevation of 9,300 feet. It is situated on a 9,000-foot thick plateau of ice. It is 850 nautical miles south of McMurdo. The station is drifting with the ice sheet at about 33 feet a year.
The original station was built in 1956-1957, and is now buried beneath the snow. The second station, located under a geodesic dome, was completed in 1975. The dome was dismantled in 2009-10 and removed from the continent. The current station was dedicated on Jan. 12, 2008.
The winter population is around 45 and the summer population averages 150.
The mean annual temperature is 56 F. Average monthly temperatures range between –18 F in the summer and –76 F in winter. The record high of 9.9 F was recorded in December 2011, and the record low of –117 F was recorded in June 1982.
On Feb. 3, 2017, the NSF design review team boarded the Hercules LC-130 transport aircraft at McMurdo Station headed for the South Pole Station. The aircraft and crew are attached to the New York Air National Guard, their home base being Schenectady. The LC-130 is equipped with retractable skis that allow it to land on snow and ice runways, as well as on conventional runways. The LC-130 departs from the snow runway at Willy field, which is about eight miles from downtown McMurdo, for the three-hour flight to the South Pole Station.
Though the station is at 9,300 feet elevation, the lower barometric pressure at the pole makes it feel like 10,500 feet.
At this elevation, one must take precautions against developing altitude sickness. Though the oxygen content in the air at the pole is the same as at sea level (about 21 percent), the decreased barometric pressure at pole altitude makes less oxygen available to be absorbed into the blood stream. To combat altitude sickness, one is instructed to take it easy the first day or two, drink lots of water, and avoid alcohol and tobacco. Also, to help with acclimation to the altitude, visitors are offered Acetazolamide, a medication that can reduce the symptoms of altitude sickness.
The current South Pole Station was designed for NSF under a contract with the Naval Facilities Engineering Command, Pacific Division at Pearl Harbor, Hawaii. The project architect was Ferraro Choi Associates Ltd. of Honolulu, Hawaii. The design of fire suppression and fire alarm and detection systems for the facility was provided by PDC Consulting Engineers of Anchorage, Alaska. The project was constructed by Raytheon Polar Services of Denver, Colorado. Construction was completed in 2010.
The elevated station consists of a two-story portion sitting above the snow surface on columns. The elevated station contains berthing, food service, offices, a science lab, hydroponics garden, recreational spaces (including a small gym and basketball court), an emergency power plant and other support spaces.
The elevated station is divided in to two pods, Pod A and Pod B. Each pod has four wings. Columns several feet above the snow surface support the elevated station. The station is elevated to delay the inevitable inundation by the increasing snow pack. Snow accumulates at a rate of about one foot per year; there is also a significant amount of snow drift. To further extend the life of the station, the building exterior has an aerodynamic design, which helps prevailing winds slow the accumulation of snow from drifting beneath the structure. Also, the station structure can also be raised with a system of jacks to add even more service life to the building. Adjacent to the elevated station are arched structures below the surface that contain the main power plant, cargo facility, fuel storage, and a vehicle maintenance garage/shop area (see photo depicting a section drawing through the station). The elevated station and below surface facilities are connected by an aluminum clad stair tower, known as the “beer can.”
In addition to the elevated station and the arches there a several outlying facilities for specific scientific programs.
The total floor area of the elevated station is approximately 65,000 square feet.
The station was constructed in four phases. The first phase consisted of Pod A Wings A-1 and A-2 and the Vertical Tower (the Beer Can), which leads to the buried arches. This phase contains a berthing wing and the kitchen/dining facility and was occupied in 2003.
Pods A and B serve as areas of refuge for each other (see photo). The horizontal link connecting the two pods provides a 3-hour fire barrier separation. Berthing Wings A-1, A-4, and B-3 are separated from the elevated station by a one-hour fire barrier. As a further contingency, Wing B-4 is intended to be the “life boat.” It is separated by 1½ hour fire barrier, and contains berthing and its own emergency power plant and communications area.
The elevated station is provided with automatic sprinkler protection throughout. The sprinkler system was originally installed as double-interlock pre-action system. It was recently converted to an all wet pipe system.
The water supply for the sprinkler system consists of a stainless-steel pressure tank containing approximately 5,000 gallons of water. A dedicated air compressor maintains a pressure of 150 psi in the pressure tank.
The elevated station sprinkler system has three wet pipe risers: One riser serves Pod B, one riser serves the kitchen and dining area in Pod A, and one riser provides protection for the remaining portion of Pod A.
Sprinklers are closed head, quick response type sprinklers. Except for the sprinkler risers, which are black steel, the piping consists of Type L copper tubing.
There are three occupancy hazard classifications identified. The berthing areas, offices, recreation and dining areas are considered light hazard. The kitchen and utility spaces are considered ordinary hazard Group 1. Storage areas are considered ordinary hazard Group 2. The system is hydraulically designed using the density/area method of NFPA 13.
The fire alarm, detection and communications system for the elevated station consists of an addressable fire alarm panel and an emergency voice communications system (ECS).
Notification appliances consist of speakers and visual alarm strobes. Complete automatic detection is provided throughout the station. Open area photoelectric smoke detectors are provided in most areas including sleeping areas, offices, corridors and the dining area. Heat detectors are provided in storage areas and certain utility and shop spaces.
The fire alarm and detection system provides supervision of sprinkler flow and tamper switches and tank supervisory devices.
The emergency communication systems can broadcast 21 different pre-recorded messages. These are all fire emergency messages, which announce the location of the alarm by wing and provide some instruction to occupants. For alarms in Pod A, occupants are instructed to relocate to the gymnasium in Pod B. For alarms in Pod B, occupants are instructed to relocate to the dining area in Pod A. The elevated station ECS is also linked to the station public address system and can broadcast a message indicating the location of alarms to all areas, including the elevated station, buildings in the arches and to major outlying facilities.
There are also other fire suppression systems and equipment in the elevated station.
Wet chemical fire extinguishing systems are provided in the kitchen for the two kitchen exhaust hoods. The two emergency generators in the emergency power plant are protected with a local application carbon dioxide fire extinguishing system. This system is activated manually by CO2 release stations and automatically by cross-zoned heat detectors.
In the below surface facilities generators in the main power plant are protected by a carbon dioxide fire extinguishing system.
In outlying facilities, clean agent fire suppression systems protect critical electronic equipment. Portable fire extinguishers are located throughout the facility. General use extinguishers consist of multi-purpose dry chemical stored pressure extinguishers. Clean agent extinguishers are also located in areas where appropriate.
During the summer, there is a crew of full-time firefighters, which with the aid of volunteers, provide emergency response.
Fire suppression systems for the South Pole Station work with the fire alarm and detection system, other fire protection features provided in the station construction, and an emergency plan to provide life safety at the southernmost location on our planet.
Samuel S. Dannaway, P.E., FSFPE, is a licensed fire protection engineer and mechanical engineer with bachelor’s and master’s degrees from the University of Maryland Department of Fire Protection Engineering. He is a past president and Fellow of the Society of Fire Protection Engineers. He is vice president of Fire Protection Technology at Coffman Engineers Inc., a multi-discipline engineering firm with over 360 employees across eight offices. Dannaway can be reached at firstname.lastname@example.org.