When an emergency occurs in a building, congestion avoidance becomes a very serious localisation issue, which is often ignored. If the emergency involves the outbreak of fire, the rescue team must establish the easiest and quickest exit route from the building. Any delay could be very dangerous, potentially even resulting in fatalities. To avoid congestion, an effective Emergency Rescue Localisation (ERL) system is essential to help rescue teams determine the easiest exit route from the building. This paper proposes an ERL methodology, based on the Inertial Measurement Unit (IMU).In this system, the IMU helps to determine and obtain positioning data from a building's interior. This study describes the application of the ERL system for an indoor situation in detail.