The rules for Qasr Salat is described below.
If a person crosses his area (village, city boundary) with the intention of traveling 48 miles or about 77.25 kilometers away from his place of residence, he will be considered as a Shariah traveler.
A maximum of 14 days tour will be considered as Shariah tour. In this case he/she visit somewhere other than his/her permanent or temporary residence (workplace, dormitory etc.).
For the Shari’ah traveler, one has to perform the prayers during the journey. He/She will perform two rak’ats in Fajr, two rak’ats in Zuhr, two rak’ats in Asr, three rak’ats in Maghrib and two rak’ats in Isha.
References: Raddul Muhtar 2/128, Raddul Muhtar 1/835, Raddul Muhtar 1/642, A’laus Sunan 7/191, Badayous Sanaye 1/104.