A comprehensive strategy for combating thermal runaway in telecommunications equipment enclosures

Thermal runaway is a potentially hazardous problem associated mainly with valve-regulated lead-acid (VRLA) batteries. There are many previous papers and studies on the causes of thermal runaway, as well as a few ideas on how to prevent thermal runaway. However, there has been no paper on a comprehensive strategy for combating thermal runaway. US WEST has settled on, and is implementing a multi-pronged strategy. This paper lays out the basic details of that strategy in the interest of beating the problem. The basic strategies consist of the following: temperature compensation and/or current limiting; proper ventilation of both controlled and uncontrolled environments including customer premises; temperature control of the battery environment, including “uncontrolled” cabinets; adequate remote alarming; gas monitoring; battery monitors capable of detecting thermal runaway; regular battery maintenance and replacement; pursuit of alternatives to VRLA batteries; prioritization of sites; and removal of batteries in some customer premises