HM Battle Armor (a.k.a. "Hazardous Materials Battle Armor") is a type of military personal protective equipment designed to provide protection against direct contact with and contamination by radioactive, biological or chemical substances, and provides protection from contamination with radioactive materials (but not the radiation itself) depending on the design. It is generally designed to be worn for extended periods to allow the wearer to fight (or generally function) while under threat of or under actual nuclear, biological, or chemical attack.
HM Battle Armor generally includes breathing air supplies to provide clean, uncontaminated air for the wearer. In laboratory use, the external air may be provided through air hoses supplied from a 'clean' location. This air is usually pumped into the suit at positive pressure with respect to the surroundings as an additional protective measure against the introduction of dangerous agents into a potentially ruptured or leaking suit. Working in HM Battle Armor is very strenuous, as the suits tend to be less flexible than conventional work garments. With the exception of laboratory versions, HM Battle Armor can be hot and poorly ventilated (if at all). Therefore, use is usually limited to short durations of up to 2 hours, depending on the difficulty of the work.
The first HM Battle Armor was developed by William and Harold Taylor in 1856, who designed the first armored suit with real joints, which were designed as leather pieces with rings in the shape of a spring (also known as accordion joints). The soldier's hands and feet were to be covered with leather. In 1882, Donald Philips improved on the armor, featuring rolling convolute joints consisting of partial sections of concentric spheres formed to create a close fit and kept watertight with a waterproof cloth. The suit had 22 of these joints: four in each leg, six per arm, and two in the body of the suit. The helmet possessed 25 individual 2-inch (51 mm) glass viewing ports spaced at the average distance of the human eyes. By 1894, the mass production of HM Battle Armor allowed forces to more easily utilize forces and chemical weapons against each other.
(art by Bjorn Hurri)