Plumbing Engineering responsibilities overlap into the professional engineering areas of Civil Engineering, Mechanical Engineering, Chemical Engineering, Fire Protection Engineering, and Process Engineering. Traditionally the Plumbing Engineer performs the calculations, sizes the equipment, and prepares the plumbing design and construction documents under the supervision of a licensed Mechanical, Fire Protection or Civil, Professional Engineer.
In most states the Mechanical Engineer supervises the Plumbing Engineers’ responsibilities in the following areas: (61G15, Florida Administrative Code)
- Design of Process and Fluid Flow Systems
- Design of Plumbing Systems
- Design of Heat and Energy Transfer Systems
The Plumbing Engineer supports the Civil Engineer for the plumbing systems outside the building including storm water, sewer, natural gas, fire suppression water, domestic water, irrigation water, and other special water and waste systems.
The Plumbing Engineer plays a different role in the design of the Fire Suppression sprinkler systems for a facility. The whole building approach to the design of the building is very important when incorporating fire protection requirements into a facility. The design professionals, including the Plumbing Engineer, will rely on the recommendations of the Fire Protection Engineer. The Fire Protection Engineer will develop building hazard classifications coordinating with the different fire protection requirements for a facility. The Plumbing Engineer will work in concert with the Fire Protection Engineer when fire protection systems requiring water is required. For example, in some buildings the Fire Protection Engineer can highlight options where the building can be designed in a way it will not require automatic water based sprinkler systems without compromising building safety. In these cases the Fire Protection Engineer can inform the design team using the whole building approach that the building is more efficient and will cost less to the owner including a water-based automatic sprinkler system into the building design.
In these cases including automatic water-based sprinkler systems will reduce the amount of materials and construction required in a building and as a result reduces the cost of the building and meets one of the qualifications for a sustainable building. This close collaboration using the whole building approach is a benefit when the design, construction, and maintenance teams of a facility apply for permits and certifications, because they have a coordinated fire protection plan for the facility.
The plumbing engineer is involved in the whole building design of a water-based fire suppression system. In a typical facility the city water main will supply water for the fire suppression system. The plumbing engineer will need to coordinate with the civil engineer, water department, and fire department the details of connecting the fire water to the city water main.
Fire hydrants, valves, alarms, and fire department connections are designed for the site. When the water main enters the building there is alarm and backflow devices designed by the plumbing engineer. In larger building standpipes are installed usually in exit stairs with fire department connections for fire department personnel to connect hoses and suppress the fire in the building during a fire event.
Automatic sprinkler systems are connected to the building standpipes that will supply water to the sprinkler heads distributed throughout the building. In taller building fire pumps are required to boost the city water pressure and flow to the fire department connections and sprinkler systems. The plumbing engineer plays a key role to include water demands for a sprinkler system with the water demands for a plumbing system.
Sports facilities are a good example of highlighting the importance of coordination. During a football game fans were standing in line using the toilet facilities, creating a large demand from the city water system. At this same time a grill left burning in the parking lot during a tail gate party started a small fire. When the fire department arrived there was not enough water pressure in the fire hydrants to supply water to their hoses to extinguish the fire. In these cases, it is important to have a plumbing engineer looking at the plumbing design of the whole building.
When the design professionals, including the plumbing engineer, have developed the basic parameters of water based fire suppression systems for a building the hydraulic calculations for the fire suppression system begin. In some states the plumbing engineer prepares preliminary calculations as described by NFPA 13. In other states the licensed fire protection contractor is responsible for these calculations. In either case the plumbing engineer will review and comment on these calculations before the system is installed..