Common Plumbing Design Mistakes 41-50
Click on an item below to view additional information and suggestions on how to avoid the mistake .

 41.  Food disposal discharge into grease trap.
            a) Route waste from disposals into sanitary waste system, bypassing grease trap.
 42.  Improper grease interceptor sizing.
            a) Verify local code requirements.
            b) Provide interceptor detail and sizing information on drawings.
 43.  Non-compliant waste provisions for swimming pool drainage.
            a) Verify local code requirements.
            b) Verify flow rate of pool discharge.
            c) Provide sanitary drain for backwash and storm drain for main pool drain.
 44.  Insufficient clearance for plaster trap.
            a) Coordinate with owner for plaster trap size requirement.
            b) Coordinate with architect to verify space availability when trap is to be located within casework.
            c) Consider and accomodate service access require.
 45.  Improper use of automatic flushing devices.
            a) Do not specify automatic devices for specimen toilets.
            b) Do not specify automatic devices for emergency room toilets.
 46.  Omission of dielectric connections.
            a) Specify dielectric couplings, unions or flanges for all connections between ferrous
                 and non-ferrous piping.
 47.  Failure to coordinate building drain inverts with site sewer inverts.
            a) Coordinate with civil engineer and verify elevations of sanitary and storm sewers.
 48.  Improper design of domestic hot water circulation system.
            a) Route circulating hot water distribution mains within 25 feet of each fixture.
            b) Specify automatic pressure compensating flow control valves for balancing control.
            c) Design circulating pump with capacity to overcome return piping friction losses.
            d) Do not provide aquastats. System should circulate constantly to minimize legionella growth.
            e) Verify return piping arrangement requirements with master thermostatic mixing valve
                 manufacturer's installation recommendations.
 49.  Unclear information on documents concerning water meter installation.
            a) Contact water department and verify whether utility company or contractor provides water meter,
                 vault and tap into main. Clarify this information on drawings.
            b) Verify with water department the meter type and size to be provided.
 50.  Failing to provide emergency power for critical plumbing equipment.
            a) Determine which plumbing equipment should be provided with emergency power for life safety
                 and/or owner requirements.
            b) Coordinate with electrical engineer to provide appropriate service connections.