HVAC (heating, ventilation, and air conditioning) is the technology of indoor and automotive environmental comfort. HVAC system design is a major sub discipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer. Also the mechanical systems are to be introduced in our research including potable, drainage, firefighting and medical gases. This work is an introduction for a second part of this project which discuss the HVAC, and mechanical systems for a Musllum hospital building located in Ramallah city beside the Ersal fuel station, the building consist of seven floors, two basements, ground floor, and other four floors, each floor of the building include Diverse sections, and applications, which make the building Appropriate for design since it contain all the mechanical system, and a large HVAC system. The project is going to discuss the basics methods that we will follow in the second project to calculate the heating, and cooling load, also the design recommendation, and steps that will be followed; additionally the project gives all the information that needed to get a perfect design for the hospital. ASHREA code is to be used for heating and cooling calculation. Moreover NFPA code also is needed for medical gases and firefighting systems. On the other side the equipment that’s needed for our design is to be well mentioned.