Final answer:
In plumbing engineering, a soil-or-waste stack for buildings more than four storeys high will require additional specifications like increased diameter or venting to comply with plumbing codes and ensure the system's proper functioning and safety.
Step-by-step explanation:
The question pertains to the field of plumbing engineering, particularly the design and specification of soil or waste stacks in multi-story buildings. In plumbing, a soil-or-waste stack is a vertical pipe that conveys sewage from toilets or waste from other plumbing fixtures to the building drain or building sewer. According to plumbing codes, which may vary by region, specific requirements are set for buildings of different heights. For a stack that receives discharge from more than four storys, a number of provisions may apply, such as the need for increased pipe diameter, additional venting, or more frequent cleanouts. These measures are put in place to ensure the proper functioning of the plumbing system and to prevent issues like blockages or backflow that could affect the health and safety of the building's occupants.