| Capital Projects Home Page |
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| Division 15 Mechanical |
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| 15-4 | Plumbing |
| B. | Industrial Water Systems |
| 1. | The term industrial water is defined in this use as water that is not potable due to contamination, either actual or potential. |
| 2. | The industrial water system shall serve all points of water use that could cause contamination by their backflow into the domestic water system. |
| 3. | Where an industrial water system is selected for a project, protect the domestic water system by installation of two approved reduced pressure backflow prevention devices in parallel at the point of connection. |
| 4. | Detail the installation of the devices in an accessible location with the lower a minimum of 1' above the floor and the upper a maximum of 5'. Provide adequate drainage below the devices for testing or malfunction, via floor drains. |
| 5. | Each outlet or connection to the industrial water system shall be posted with a sign reading Industrial Water - Do Not Drink. These may be waterproof clothtape with printing protected by clear vinyl and self-adhesive back; 1/4" high, black letters on yellow background. |
| 6. | Where hot water outlets are required in an industrialized system, provide either a separate water heater in the industrial system or a separate backflow preventer in all branch connections which may be taken from the domestic hot water system. Selection will depend on the number, extent and location of hot water outlets requiring industrialized water. If separate backflow devices are specified, give operating temperature for proper selection. |
| C. | Connections To Kitchen Equipment |
| 1. | Kitchen equipment is normally furnished under the specification section for kitchen equipment. |
| 2. | Include a schedule in the plumbing drawings for the rough-in and final connections to all kitchen equipment. |
| 3. | Coordinate the furnishing of all equipment trim, such as traps, faucets and valves, with the kitchen equipment drawings and specifications. |
| 4. | Provide a pressure regulating valve, pressure gauge, pressure relief valve, thermometer and shock absorber in the 180° rinse line to the dishwasher connection. |
| D. | Connections For Laboratory Equipment And Casework |
| 1. | Include the rough-in for all laboratory equipment and casework (benches) in the plumbing drawings and specifications. Terminate rough-ins with valved services and plugged drains. |
| 2. | Coordinate with laboratory casework and equipment specifications to make sure final plumbing connections are properly accounted for and specified in the appropriate specification section. |
| E. | Meters |
| 1. | Provide two meters in parallel for each building domestic cold water service. Locate meters inside the building in an accessible location to permit reading and maintenance. |
| 2. | Specify disc or turbine type meters for normal flow and compound type for cases where there is a large range of flow. Provide single or double registers reading in cubic feet. |
| 3. | Provide strainers and isolating valves at meters to permit operation with one meter out of service. See Appendix. |
| 4. | Size each meter for 100% of the estimated building cold water demand. Do not include fire sprinkler demand. Because of meter failure, 100% demand on both meters must be met. Research buildings must have full demand met at all times. |
| 5. | Meter cold water makeup to cooling towers if the refrigeration system capacity is greater than 50 tons. |
| 6. | Meter the cold water fill line serving steam to space heating hot water shell and tube heat exchangers (to monitor leaks in the tube bundle). |
| F. | Water Pressure Regulations |
| 1. | Provide two water pressure regulators in parallel for each building, regardless of existing static pressure. System shall maintain a maximum of 80 pounds per square inch at the lowest point of use. |
| 2. | Locate regulators in the mechanical room for ease of maintenance. Provide proper drainage for pressure relief valve and leaks. |
| 3. | Size each regulator with a rated capacity at the reduced pressure for 100% of the estimated cold water building demand. No device shall be sized with inlets or outlets smaller than size of supply piping. |
| 4. | Provide low and high pressure gauges, strainers, pressure relief valve and isolating valves at regulators to permit operation with one regulator out of service. See Appendix. |
| 5. | Adjust pressure differential settings so that one regulator will operate on low demands and the second open on increased demands. |
| 6. | Where no regulation is required by present static pressure, set PRVs to no more than present static pressure. |
| 7. | Note that regulators must be provided to meet the building water demand. There may be low, medium and high volume demand at various pressure requirements. As many as three regulators in parallel may be required. |
| G. | Back Flow Prevention |
| 1. | The University of California at Berkeley adheres to State requirements (California Code of Regulations Title 17: Group 4) and adopts the standards and recommendations set forth by the University of Southern California: Foundation for Cross-Connection Control and Hydraulic Research - Manual of Cross-Connection Control (9th edition, August 1993 or subsequent revisions). The proper design, selection, installation and maintenance of cross-connection control devices is imperative, particularly in a university/mixed-use environment, for the protection of potable drinking water and distribution systems. Appropriate backflow prevention assemblies shall be selected from the most current USC-FCCCHR List of Approved Backflow Prevention Assemblies and shall be inspected and periodically tested as specified by the manufacturer by a certified tester. |
| 2. | Provide backflow protection at any building water system where there are connections, actual or potential, to a contaminating liquid. Examples include laboratory hose cocks and connection from domestic system to HHW makeup and cooling towers. |
| 3. | Backflow may be prevented by installing a backflow prevention device at each individual point of possible contamination, where devices such as vacuum breakers or air gaps may be employed, or at a single point where an industrial water piping system takes off from the domestic water piping. Industrial water used in labs for experiments is assumed to be non-contaminated. The industrial system must be protected from HHW, cooling towers, etc., by additional RP devices. |
| 4. | Select the type of backflow prevention system appropriate to each individual case. Generally, a separate industrial water system will be justified in buildings having numerous outlets that are susceptible to contamination. A chemistry or laboratory building is a good candidate for a separate industrial system. |
| 5. | Discuss the requirements for backflow prevention for any building off campus with Capital Projects (CP) and the utility company. |
| H. | Backflow Prevention Devices |
| Select appropriate backflow prevention devices for the intended service. The following devices are listed in approximate decreasing order of effectiveness and reliability. |
| 1. | Air-Gap Separations (a physical break between the supply pipe and a receiving vessel): The air gap shall be at least twice the diameter of the supply pipe, measured vertically above the overflow rim of the vessel with a minimum clearance of 1". This provides the maximum degree of protection and should be used wherever a non-pressurized supply is acceptable. It must be used where sewage or toxic substances are involved. |
| 2. | Reduced-Pressure Backflow Preventers: Use for protection of all direct or indirect connections where the device may be subject to back pressure and for isolating industrial water systems from the domestic water system. Locate in an accessible location. Where spillage is unacceptable, discharge with an air gap into a floor drain. Install backflow preventer at least 12" above floor or ground. Test cocks must be accessible. |
| 3. | Pressure-Type Vacuum Breaker: Use only as protection for direct or indirect water connections to all types of polluted or contaminated liquids where the vacuum breakers are not subject to back pressures. These units may be installed under continuous line pressure. Install in an accessible location. Where spilling into room is objectionable, it shall be specified as modified with drain connection and waste. |
| 4. | Anti-Siphon Ballcocks: Use for tank-type water closets and urinals. The outlet of the backflow preventer shall be at least 1" above the opening of the overflow pipe. |
| 5. | Vacuum Breakers for Flush Valves: Occurs at toilets or urinals. Specify installation at least 4" above the overflow rim. |
| 6. | Double Check Valve Assemblies: Use to protect direct or indirect water connections where contaminants entering the system would not constitute a health hazard. Examples include steam, air, foods and beverages. |
| I. | Roof, Floor And Areaway Drains |
| 1. | Include provisions in the specifications for coordination of drain and clean-out elevations and other work such as concrete and waterproofing. |
| 2. | The architect shall carefully coordinate with the mechanical engineer in the selection of drains for appearance (as in toilet rooms, terraces and other visible locations); type of clamping ring (built-up and single-ply roofing); size and type of waterproofing flange (for liquid applied systems); two-level drains; type of strainer, including removable internal strainers or buckets; gravel guards (ballasted or built-up roofs); method of anchorage to roof deck; movement due to seismic or deflection (steel framing systems) - ensure that movement is accommodated in leader below roof ‹ not at roof membrane. |
| 3. | Locate toilet room floor drains out of foot traffic below water closet partitions or between urinals. |
| 4. | Specify galvanized beehive type roof and areaway drains. |
| 5. | Where floor drains are roughed in for future use, cover with a flush plate and gasket for protection against fume leakage. |
| 6. | Provide trap primers to retain trap seals on floor drains installed in areas where floors are not washed periodically or there is no regularly used water outlet to replenish trap seal. Do not make a general statement to install as required, where required, etc. |
| 7. | All floor drains to have 3" or larger traps plus trap primers. |
| 8. | All horizontal drain runs to have cleanouts on the end of the run on every floor. |
| 9. | Main drain stacks must have cleanouts installed on each floor. |
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