Principles of planning for suitable utility are:
1. Roominess
2. Furniture Requirements
3. Groupings
4. Circulation.
1. Roominess: It refers to suitable proportioning of length, width and height of rooms in the building to get maximum benefit from the minimum dimensions. Length to width ratio should be 1.2 to 1.5. If it is nearly square lot of area is wasted for movement, while, it is more than 1.5, it gives the tunnel effect. Doors for rooms should be properly located so that utility and privacy are maximum.
Cupboards and lofts should be provided to increase roominess. Proper colours to wall and floor also give roominess effect. Light colour gives effect of more space.
2. Furniture Requirements: In planning residential, office, laboratory, hospital buildings positions of required furniture should be drawn and then room dimensions, positions of doors, windows, wardsities etc. planned. In case of planning a hostel room for two students it may need centrally placed
door while if it is for three students, it should be near the end of front wall. Positions of cots, study
tables and cupboard should be drawn and room planned. In designing a living room, positions of sofa,
chairs, T.V. show case etc. should be drawn and size of the room and positions of doors fixed. Availability
of circulation area should be checked. Thus the furniture requirement influences the planning of a building to a great extent.
3. Grouping: Grouping means disposition of various rooms in the building for the convenience of users and their utility. A dining room should be close to the kitchen, white sanitary block should be away from kitchen, but convenient to bedrooms. In case of offices, administrative department is located centrally. In factories, various sections are located such that product moves in one direction to get finally assembled after least movement. In residential buildings grouping is to achieve comfort, privacy and efficiency while in the case of other buildings it is to achieve economical service.
4. Circulation: Circulation means the space to be provided for movement from room to room or floor to floor. Passages, lobbies, halls provided serve horizontal circulation while stairs and lifts serve vertical circulation. Within a room also a portion of it serve for circulation while some other portion serve for utility. The following points should be considered in planning circulation:
(a) They should be straight.
(b) They should be sufficient.
(c) They should be sufficiently lighted and ventilated.
(d) Stairs should be easily accessible to all the users.
(e) Sanitary services should have access for every user through passage lobby.