The rupture of a high-pressure natural-gas pipeline can lead to outcomes that can pose a significant threat to people and property in the immediate vicinity of the failure location. The dominant hazards are thermal radiation from sustained fire and collapse of buildings from explosion inside or in a partially confined area enclosed by buildings. A simplified equation has been developed that relates the diameter, the operating pressure and the length of pipeline to the size of the affected area in the event of a full-bore rupture. The equation is based on release rate, gas jet and heat flux from fire to estimate the hazard area. Hazard area is directly proportional to the operating pressure raised to a half power, and to the pipeline diameter raised to five-fourths power, but inversely proportional to the pipeline length raised to a quarter power. The simplified equation will be a useful tool for safety management of high-pressur natural-gas pipelines. (C) 2002 Elsevier Science Ltd. All rights reserved.