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SSC-Natick Press Release

U.S. Army Soldier Systems Center-Natick
Public Affairs Office
Kansas Street
Natick, MA 01760-5012

Contact: Chief, Public Affairs Office
(508) 233-5340

Date: October 9, 2003
No: 03-33

Heaping on heat
New ‘family’ showers warmth in tents safely, efficiently

NATICK, Mass. -- Heating tents safely, effectively and efficiently is now much simpler thanks to the Family of Space Heaters (FOSH) developed by Product Manager-Force Sustainment Systems located at the U.S. Army Soldier Systems Center here.

The FOSH uses the latest advances in combustion, power generation and microprocessor technology to provide comfort and protection for soldiers, supplies and equipment in tents during cold weather operations in the field.

The FOSH replaces the old M-1941 “Pot Belly” and M-1950 “Yukon” heaters from the World War II-era and eliminates the serious operational deficiencies and safety hazards associated with these antiquated heaters.

While many seemingly attractive commercial space heaters are available in today’s marketplace, they are unjustified from a safety, performance and economic perspective, and military units should replace their stock of these heaters with standard vented military heaters.

Commercial unvented kerosene or propane-fueled heaters that release exhaust directly into the living space present a serious risk of injury or death to soldiers.

Kerosene heaters “are intrinsically dangerous and should not be used in field environments,” according to the U.S. Army Center For Health Promotion and Preventative Medicine. Army Regulation 420-96 restricts the use of unvented space heaters in living quarters or enclosed locations where soldiers sleep, and the U.S Army Safety Center advises commanders not to allow the use of these heaters where soldiers work or sleep.

Besides safety hazards, commercial heaters do not meet military requirements that are satisfied with the FOSH. Some of the key capabilities of the FOSH include:

Operation without electrical power.
Multi-fuel operation on diesel, JP-8, JP-5, kerosene, wood or coal.
Efficient, clean-burning combustion requiring little maintenance.
Operation in temperatures down to minus 60 degrees F.
Self-contained, lightweight, portable, rugged and simple to operate.
Venting exhaust outside the tent.
Interfaces with and meets heating requirements for all standard military tentage.
The FOSH consists of the Space Heater Small (SHS), Space Heater Medium (SHM) or H45, Space Heater Arctic (SHA) and Space Heater Convective (SHC).

The SHM, SHA and SHS are non-powered radiant heaters that operate inside the tent, and the SHC is a self-powered convective heater that operates outside the tent. The Thermoelectric Fan (TEF) is a FOSH accessory used with the SHM and SHA heaters to circulate heated air inside the tent.

The SHM, SHA and SHS heat through radiation and natural convection. They use a newly-developed vaporizing burner tube technology that overcomes major combustion and safety problems plaguing the non-powered heater industry during the past 50 years.

In the old-type heaters, fuel would pool in the bottom of the burner to be vaporized and burned. If fuel entered faster than it could be vaporized, the burner would flood and the operator would end up with a “runaway” heater.

The patented burner design vaporizes all fuel within the confines of a tube and eliminates the pooling of raw fuel during operation and the possibility of flooding the pot. It also provides a multi-stage liquid-to-vapor combustion process that results in much cleaner, more efficient combustion requiring much less burner maintenance.

A patented multi-fuel control valve is incorporated into each heater, which provides a new capability to compensate for dissimilar fuel viscosities and maintain a consistent flow rate among the various types of liquid fuels and temperatures encountered in the field. The addition of a sight glass also allows the operator to view the flame and heater operation without the need to open the lid.

The SHC is the most advanced of all four heaters. It is a self-powered, thermoelectric heater that provides forced hot-air circulation without external power normally supplied by a field generator.

The SHC generates its own electrical power, without any moving parts, through thermoelectric modules located in the combustion chamber that convert waste heat into electricity. The internal generation of electrical power gives the SHC the extra capabilities of single switch operation, completely automatic safety and temperature controls, operation without the need for a fire guard and significantly higher combustion efficiencies all without an external power supply.

To troubleshoot, the SHC comes equipped with a remote intelligent control box that tells the operator when there’s a problem and how to fix it.

All fielded FOSH units are available through the Defense Supply Center Philadelphia (DSCP). Listed below are some of the specifications of the individual heaters. Costs are estimated.

Space Heater Small: Intended for the Soldier Crew Tent, the SHS has a maximum output of 12,000 BTU and completely self-stores all its accessories. NSN: 4520-01-478-9207. Dimensions: 16” L x 9” W x 14” H. Weight: 35 pounds. Cost: $660.

Space Heater Arctic: Designed to heat the 5 and 10-man Arctic tent and other shelters with a floor area of 100-200 square feet, the SHA has a maximum output of 25,000 BTU and is completely self-storing. NSN: 4520-01-444-2375. Dimensions: 17” L x 9” W x 17” H. Weight: 41 pounds. Cost: $780.

Space Heater Medium: The barrel-shaped SHM or H45 is intended for the larger GP, MGPTS, MCPS and TEMPER tents and delivers a maximum of 45,000 BTU. An 80,000 BTU model with the same footprint should be available in about two years. NSN: 4520-01-329-3451. Dimensions: 18” diameter x 24” tall. Weight: 65 pounds. Cost: $550.

Space Heater Convective: The SHC can be used with any tent and has an output of 35,000 BTU. A 60,000 BTU model with a similar dimensions and weight should be available in about two years. NSN: 4520-01-431-8927. Dimensions: 40” L x 14” W x 18” H. Weight: 78 pounds. Cost: $6,700.

For more information about the Soldier Systems Center, please visit our website at

This page last updated on 28 February 2003.