MECHANICAL, ELECTRICAL, PLUMBING ASSESSMENT

Transcription

1 MECHANICAL, ELECTRICAL, PLUMBING ASSESSMENT PREPARED FOR: LANE COUNTY PUBLIC WORKS 3040 NORTH DELTA HIGHWAY EUGENE, OREGON July Final SYSTEMS WEST ENGINEERS, INC. m e c h a n i c a l a n d e l e c t r i c a l c o n s u l t i n g e n g i n e e r s 411 HIGH STREET EUGENE, OREGON Phone: Fax: M023.01

2 TABLE OF CONTENTS LANE COUNTY PUBLIC WORKS MEP ASSESSMENT SECTION 1 EXECUTIVE SUMMARY PAGE 1.1 EXISTING CONDITIONS Heating, Ventilating, and Air Conditioning Plumbing Systems Electrical Systems RECOMMENDATIONS Heating, Ventilating, and Air Conditioning Systems Central Plant Upgrades Building Upgrades Plumbing Systems Electrical Systems COST SUMMARY IMPLEMENTATION SECTION 2 EXISTING CONDITIONS 2.1 HEATING, VENTILATING, AND AIR CONDITIONING SYSTEMS Central Plant General Chillers Boiler Pumps Distribution Systems Controls Makeup Water/Expansion Control Systems Wells Maintenance Building Hydronic Systems Central Air Handling Systems Secondary Air Handling Systems Controls Administration Building Hydronic Systems Central Air Handling Systems Secondary Air Handling Systems Conditions Survey Table of Contents Page 1

3 2.1.4 Fleet Systems Hydronic Systems Radiant Floor Systems Secondary Air Handling Systems Controls Warehouse Hydronic Systems Main Storage Area Air Handling Unit Office Area Fan Coil Units Miscellaneous Equipment Storage Buildings Building B Building C Building D Building F Building H Paint Storage Building Heat Recovery Ventilator Vehicle Exhaust Fan Truck Wash Building Steam Boiler Jet Pump Electric Unit Heater PLUMBING Domestic Hot Water Systems Piping Fixtures Water Closets and Urinals Lavatories Wash Fountains Sinks Showers Miscellaneous Fixtures Fleet Services Shop Compressed Air Fleet Services Oxygen and Acetylene Distribution System ELECTRICAL SYSTEMS Maintenance Building and Testing Lab Power Distribution Lighting Conditions Survey Table of Contents Page 2

4 2.3.2 Administration Building Power Distribution Lighting Fleet Services Power Distribution Lighting Warehouse Power Distribution Lighting Asphalt and Gravel Storage Power Distribution Lighting Paint Building Power Distribution Lighting Storage Buildings A-G Power Distribution Lighting Storage Building H Power Distribution Lighting SECTION 3 RECOMMENDED UPGRADES 3.1 HEATING, VENTILATING, AND AIR CONDITIONING SYSTEMS Central Plant Heating Water System and Boiler Upgrades Chiller Replacement Chilled Water System Reconfiguration and Upgrade Expansion Tank and Makeup Water Upgrades Control System Upgrades Maintenance Building Hydronic Systems Central Air Handling Systems Secondary Air Handling Systems Administration Building Hydronic Systems Central Air Handling Systems Secondary Air Handling Systems Conditions Survey Table of Contents Page 3

5 3.1.4 Fleet Services Building Hydronic Systems Secondary Air Handling Systems Warehouse Main Storage Area Air Handling Unit Office Area Fan Coil Units Storage Buildings Paint Storage Building Heat Recovery Ventilator Truck Wash Building HVAC Cost Summary PLUMBING Domestic Hot Water Systems Piping Fixtures Water Closets and Urinals Lavatories Wash Fountains Sinks Showers Miscellaneous Fixtures Fleet Services Shop Compressed Air Fleet Services Oxygen and Acetylene Distribution System Plumbing Cost Summary ELECTRICAL Electrical System Testing Panel Replacements Electrical Cost Estimate SECTION 4 IMPLEMENTATION 4.1 GENERAL APPROACH POTENTIAL PROJECT PHASING Phase 1 Initial Heating System Renovation Phase 2 Central Chilled Water Upgrades Phase 3 Final Heating Plant Upgrade Phase 4 Administration and Maintenance Building Upgrades Phase 5 Maintenance Building, Fleet Services, Remaining Buildings SCHEDULE Conditions Survey Table of Contents Page 4

6 FIGURES 2.1 Central Plant Schematic a and 2.2b Boiler Chilled Water and Condenser Water Pumps Distribution Systems Small Diameter Pipe Corrosion Administration Building HWS Piping Well Tank Isolation Valve HWS Piping Corrosion HWS Pipe Sample CHWS Piping Corrosion CHWS Pipe Sample HVU-1 Pipe Corrosion Maintenance Building CHWS Pump Leak Maintenance Building HCU-1 Schematic Administration Building HCU-1 Schematic Hazardous Maintenance Access Administration Building Central Plant Schematic Recommended Revisions Lane County Yards Upgrade Schedule Gantt Chart TABLES 1.1 Lane County Yards Cost Estimate Summary Lane County Yards HVAC Cost Estimate Summary Lane County Yards Plumbing Cost Estimate Summary Lane County Yards Electrical Cost Estimate Summary Lane County Yards Cash Flow Summary APPENDIX A Inventory of Existing Equipment APPENDIX B Cost Estimates Conditions Survey Table of Contents Page 5

7 SECTION 1 EXECUTIVE SUMMARY SYSTEMS WEST ENGINEERS, INC. Systems West Engineers was retained by Lane County to provide an assessment of mechanical, electrical, and plumbing systems serving each of the buildings at the Lane County Public Works Delta Facilities located at 3050 Delta Highway North, Eugene, Oregon. The assessment predicts major equipment replacement schedules and identifies opportunities to improve building performance and reduce facility energy use. Section 1 includes a summary of report findings. Following sections include a description of existing conditions, recommendations for facility upgrades, and a discussion of potential implementation approaches. A detailed inventory of existing equipment is included as Appendix A. 1.1 EXISTING CONDITIONS The Lane County Public Works Delta Facility was constructed around 1977 and includes approximately 173,300 square feet of enclosed space including the Administration Building, Maintenance and Testing Building, Fleet Services, Warehouse, Paint Storage, and a variety of accessory buildings. The facility was constructed with generally high quality equipment; however, much of the equipment has reached the end of its service life, and some portions of the heating, ventilating, and air-conditioning systems are very problematic. A brief description of building systems follows. More detailed information can be found in Section 2 Existing Conditions Heating, Ventilating, and Air Conditioning CENTRAL PLANT SYSTEMS Heating water and chilled water are produced in a central mechanical plant and distributed to the Administration, Maintenance, Fleet Services, and Warehouse Buildings for space heating and cooling. The original plant was highly innovative and uses well water as an energy source or a heat sink depending on whether the overall complex is in heating or cooling. Such systems were popular in the area around the time the facility was constructed, because, when operating correctly, the systems are extremely energy efficient. In addition, the approach consumes no fossil fuels on site except when operating in an emergency backup mode. As a result, the overall facility carbon footprint is exceptionally low. Many of these systems have been abandoned because of problems with the well source. However, wells have not been an issue at the site because of the proximity to the Willamette River and a favorable gravel aquifer. Continued well reliability is expected, and remaining with the current general central plant approach is recommended. Conditions Survey Section 1-1

8 However, the system has one fundamental flaw. The original system configuration injected well water directly into heating water and chilled water piping systems where it was routed through the complex piping to building mechanical systems. Well water contains considerable oxygen and also tends to carry some sediment. The combination of sediment and corrosion has caused serious problems in building systems. System piping leaks are common, and coils located in smaller air systems are often completely plugged. System capacity has degraded to the point that systems must operate continuously for the entire heating season, and even then, heating is marginal at best during cold weather. In addition to problems related with piping corrosion, some critical central equipment has failed and most of the remaining equipment has exceeded its service life. In particular, one of the two central heat recovery chillers is not operating and the backup boiler has failed. The failures leave heating of the entire facility to a single heat recovery chiller. The chiller has been reliable but operates many hours per year and is rapidly reaching the end of its life. If the chiller fails, no heat can be provided unless the non-operating chiller can be brought back on line. Since it has not been operated for a number of years, re-starting the machine is likely to be difficult, if not impossible, and it may take considerable time to restore heat to buildings. Beyond the issues discussed above, most central plant equipment is around 34 years old. While a majority of the original equipment was high quality, the age is significantly beyond expected service life. In some cases, replacement parts are either not available or are becoming more difficult to obtain. Replacement of most equipment will be required to provide the targeted future life of 20 years. BUILDING SYSTEMS A wide variety of building systems are installed with many tailored to meet specific process needs. The most prevalent are large, central air handling systems serving the Administration Building and much of the Maintenance Building. The systems are a dual-duct configuration and are primarily constant volume. In each system, the air handling unit produces both heated air and cooled air for distribution to terminal units adjacent to areas served. The units mix the heated air and the cooled air to the temperature required to meet space demand. The continued mixing of a constant volume of heated and cooled air is very inefficient. Remaining equipment appears appropriate for the use, but initial equipment quality and current condition vary widely. In the majority of cases, equipment has exceeded its service life by many years, and replacement is recommended to ensure reliability. However, in some cases, equipment was of very high initial quality or service was moderate, and it appears the units can remain in service for an extended period if they are refurbished Plumbing Systems Plumbing systems were of very high initial quality. Fixtures and piping have an almost infinite life, and major upgrades to provide reliable service are not required. Most work can be completed as part of normal maintenance Electrical Systems In general, electrical systems were of high initial quality, but given the age of the facility, much of the equipment is nearing the end of its service life. In a few areas, a number of remodels have been performed, and there is little 120 volt circuit capacity available in existing panels. Conditions Survey Section 1-2

9 1.2 RECOMMENDATIONS Recommended upgrades fall into two general classifications: Upgrades needed to correct system deficiencies, improve effectiveness, or increase efficiency. Upgrades needed to replace or repair equipment that is no longer effective or reliable. Following is a general discussion of recommended upgrades. More detailed descriptions are included in Section Heating, Ventilating, and Air Conditioning Systems Central Plant Upgrades System Revisions Major system revisions in the central plant include: Isolate the chilled water system from the well system to prevent system corrosion and the introduction of sediment into chilled water piping. Replace PVC plastic piping between the central plant and buildings to repair leaks and allow systems to operate at higher temperature without the potential for damage. Add a primary heating water pump on the backup boiler to improve operation and prolong boiler life. Replace facility secondary heating and chilled water pumps with pumps capable of meeting the pressure drop in distribution piping and building systems, and convert all systems to variable flow. The approach will improve energy efficiency and eliminate building pumps, which will reduce maintenance requirements. Upgrade the existing facility direct digital control system to the most current version to ensure that equipment retains manufacturer support and to allow remote monitoring and control. Replacement or Repair Virtually all of the original central plant equipment is beyond its service life. In addition, introduction of well water in both the heating and chilled water systems has caused extensive corrosion on all piping and equipment that contains steel. The corrosion has seriously damaged piping, and the presence of corrosion products in the water has affected the performance and remaining life of most equipment. Given these factors, replacement of most equipment is recommended. Major work items include: Repair the backup boiler and modify boiler piping. Replace the offline chiller and associated accessories and trim. Replace all heating water and chilled water piping 2-inch and smaller. Provide complete water treatment including: o Provide an initial system flush on a building-by-building basis, starting with the central plant. This would involve installation of a temporary bypass to isolate the central plant, installation of a basket strainer to catch debris, and circulation of a chemical mixture designed to scour corrosion products from the heating water piping. o Install a chemical feeder, side-stream centrifugal separator, and cartridge filter to provide long-term cleaning. Conditions Survey Section 1-3

10 Replace central plant pumps. Replace existing isolation valves, air vents, strainers, pressure relief valves, and other system trim. Replace plant expansion tanks and makeup water systems. Replace existing pneumatic control valve actuators and obsolete controllers, and revise plant control sequences Building Upgrades System Revisions Major system revisions in buildings will include: While the central plant configuration is inherently very energy efficient, a significant portion of the facility is conditioned by air handling equipment that is just the opposite. As previously mentioned, the Administration and Maintenance Buildings are primarily conditioned by central air handling systems configured in a dual-duct arrangement. The arrangement generally provides very good temperature control but is no longer allowed in new building construction because of excessively high energy consumption. To address this issue, replacement with a variable volume reheat configuration is proposed. Work would include: o Provide a new air handling unit. o Re-connect the existing hot and cold deck supply ducts to the new AHU discharge plenum. Both ducts will be used for cooled air supply. o Demolish existing terminal units and provide new VAV terminal units with heating water reheat to replace existing terminal units in core zones or zones with moderate exterior exposure or heating load. o Provide fan-powered VAV terminal units with heating water reheat to replace existing terminal units in high ceiling areas and zones with large exterior exposure or heating load. The central air handlers were designed to provide a set minimum amount of outside air for ventilation. By design, the ventilation rate provided was much lower than the amount required by current code, and an increase in ventilation is recommended. Also, since outside air rates are limited, the units cannot cool using outside air (economizer cooling). Addition of 100% outside air capability would address both of these problems. Building pumps will be removed unless required for freeze protection since new central plant pumps will be sized to meet building pressure losses. Replacement or Repair Remaining mechanical equipment was a mix of high quality and moderate quality components. Moderate quality components are past their service life and should be replaced. It appears that much of the high quality equipment can be refurbished and provide a considerable remaining service life. In particular, it appears that many of the original fan units can be reused. Equipment replacement requirements are described in detail in Section 3. Other major building work would include: Replace all building heating and chilled water piping 2-inch and smaller. Replace remaining pneumatic control systems and obsolete direct digital controllers. Conditions Survey Section 1-4

11 1.2.2 Plumbing Systems In general, plumbing systems include high quality fixtures and fittings and most repairs can be provided as equipment fails. Equipment recommended for replacement includes only some domestic water heaters and most hot water re-circulation pumps Electrical Systems The existing electrical does not appear to have been tested for proper operation. Since the majority of equipment is more than 30 years old, a complete system test is recommended. The test would consist of testing all main and large sized branch breakers in switchboards and distribution panels for overcurrent, ground fault, and short circuit tripping operation. A representative sample of panelboard breakers should also be tested. Where equipment fails the test, additional repair will be required. A few existing panel have damaged covers or equipment. An example is Panel B in Storage building B. These panels should be replaced. 1.3 COST SUMMARY Estimated upgrade costs are summarized in Table 1.1 below. Direct construction costs include contractor costs only and do not include Owner expenses such as management, staff relocation, and similar items. Design fees are budget prices only and may vary significantly from the figures shown depending on the method of implementation and the exact services required by the Owner. Table 1.1 Report Section Section Title Lane County Yards - Cost Estimate Summary Direct Construction Cost Design Fees TOTAL HVAC Systems $2,407,500 $361,125 $2,768, Plumbing Systems $144,300 $21,645 $165, Electrical Systems $55,000 $8,250 $63,250 TOTALS $2,606,800 $391,020 $2,997, IMPLEMENTATION Generally, there are two approaches that can be used to minimize the impact on building users. The first approach relocates building users to temporary quarters allowing a Contractor complete access to the project site. This approach is relatively simple and allows the work to be completed in a short time but adds significant cost to provide temporary space and to relocate staff during the construction period. As a second approach, it is possible to construct the work while the buildings are occupied if staff can tolerate space temperatures and ventilation rates that may be less than ideal. Under Conditions Survey Section 1-5

12 this scenario, work in the central plant and in building mechanical spaces could be completed at any time, while work in occupied spaces would be performed at night. Contractors would have to clean and return spaces to a useable condition each morning and provide temporary lighting and other services as needed. This method eliminates the need to relocate building users, but the impact on building function is substantial and the length of the project is considerably increased. Ultimately, a combination of these two approaches often provides the best solution. As much work as possible, including work in the central plant and in main mechanical rooms, would be completed without interrupting staff. Work in occupied areas would be completed by moving staff to local temporary float spaces that are set up in a portion of the building or a nearby facility. Depending on the available size of the float space, the work is divided into segments small enough to be accommodated by moving personnel from their normal stations to the float space. Work must be carefully sequenced to keep systems operational to the extent possible and reduce the need to provide temporary services that ultimately increase cost. To lessen impact, the schedule of individual phases must take into account seasonal variations in load. As a rule, this dictates that work on heating systems occurs from mid spring, through the summer, into early fall. Conversely, work on cooling systems will occur from fall, through winter, into early spring. A potential phasing sequence is described in detail in Section 4. Conditions Survey Section 1-6

13 SECTION 2 EXISTING CONDITIONS SYSTEMS WEST ENGINEERS, INC. Section 2 includes a description of existing mechanical, plumbing, and electrical systems that currently serve the Lane County Yards facility. The section also includes a condition and comments section for each significant system or piece of equipment. The section provides information on equipment condition, expected remaining life, suitability for current use, and other significant details. Additional equipment information can be found in Appendix A Equipment Inventory. 2.1 HEATING, VENTILATING, AND AIR CONDITIONING SYSTEMS Following is a discussion of existing heating, ventilating, and air conditioning systems serving the facility Central Plant The existing central plant is located in the Maintenance building and provides heating water and chilled water for use in the Maintenance building, Administration building, Fleet Services, and Warehouse facilities for space heating and cooling. Following is a general plant narrative and a description of major plant components General Description: The plant is based on a direct well, geothermal concept that uses well water as an energy source when heating and a heat sink when cooling. A schematic of the plant is shown as Figure 2.1. Conditions Survey Section 2-1

14 FIGURE 2.1 The primary source of heating and cooling is two heat recovery chillers that can simultaneously produce chilled water at the chiller evaporator and heating water at the chiller condenser. With this capability, the chillers can capture energy gained from cooling and use it for heating elsewhere. If the facility heating load happens to match the cooling load, the plant is perfectly balanced, and use of well water is not required. If there is an overall cooling demand, well water is used in two ways. First, it is introduced directly into the chilled water system where it is further cooled by the chiller then circulated to the buildings. Since the chilled water temperature is lower than the temperature leaving cooling coils in the building, chilled water is rejected to waste after use. The approach allows well water to provide around 50% of space cooling with the remaining provided by chiller compressors. Second, well water is used in a heat exchanger to cool the chiller condenser loop thereby removing excess heat resulting from the overall cooling process. If there is an overall facility heating demand, well water is used as an energy source. Again, well water is introduced into the chilled water system where it is cooled. Cooling the well water produces heat, which is rejected at the chiller condensers and used for space heating. In this case, since there is more heating load than cooling load, some or all of the chilled water is directed to waste instead of out to buildings for space cooling. During times of moderate outside temperature when there is little or no heating load, well water is used directly in a free cooling mode. In this mode, chillers are not operated, and all cooling Conditions Survey Section 2-2

15 is provided by well water alone. A boiler is installed to provide supplemental heating when required to meet facility load. Condition and Comments: In general, the heat recovery chiller approach is highly efficient and can provide a significant energy cost savings over a more conventional system. However, in our opinion, the original plant arrangement included a fundamental flaw. Specifically, well water was circulated directly in building heating and cooling piping. Well water includes considerable oxygen and tends to be highly corrosive. Since the system continuously adds more well water, there is no way to chemically treat the system, and piping systems have been seriously degraded. Corrosion rates are proportional to the fluid temperature, and heating water systems have been considerably more impacted than chilled water systems. The original system was installed in During a chiller replacement project in 1988, heat exchangers were added to isolate the heating water piping from the well water piping. Unfortunately, enough damage had already occurred so that piping systems still leaked considerably, and chemical treatment of heating water systems still could not be performed. Overall, the change probably extended the life of systems but, ultimately, did not correct the problem. Another result of the introduction of well water into the piping system was the introduction of sand and other sediment. While water delivered by the system appears to be relatively clean in comparison to many well systems, there is always some amount of sediment. Over time, the sediment accumulates at low spots in piping systems and impedes flow. This has been observed in the outlet piping from the Fleet Services Building chilled water system where obstructions dramatically reduced water flow. It seems highly likely that this condition is prevalent throughout the chilled water system and, to a somewhat lesser degree, the heating water system. In short, the system approach can provide exceptional energy efficiency. However, problems, primarily with delivery piping, prevent the system from operating at its full potential Chillers Description: Initially, a single heat recovery chiller was installed in the plant. In 1988, the chiller was replaced with two, 80 ton heat recovery machines with reciprocating compressors. The machines were somewhat problematic, and one of the two, chiller CH-2, was replaced in 2001 with an 82 ton chiller with dual, rotary screw compressors. Condition and Comments: Following is a list of specific comments: Reportedly, CH-2 is operating effectively and has been very reliable. According to the American Society of Heating, Refrigeration, and Air Conditioning (ASHRAE), the expected median service life of a water-cooled chiller is 20 years. Using this figure, chiller CH-2 should have a remaining useful life of 10 years. However, for a heat recovery machine operating as the sole primary heating and cooling source for a facility, the 20 year figure is very generous. A review of equipment run time shows the unit has operated for 40,200 hours. According to a manufacturer's representative, the expected median service life for this machine is 20 to 25 years, but the figure is based on 2000 hours of operation per year. Assuming a 20 year life at 2000 hours of operation per year, the total run time before equipment should be replaced would be 40,000 hours. We conclude that the machine is approaching the end of its useful life, and, given the Conditions Survey Section 2-3

16 high annual run time, we would expect reliable service for only another two to three years. The 1988 chiller is no longer used. Maintenance personnel report that the 1988 chiller has a refrigerant leak. As a result, the refrigerant has been removed, and the machine has been retired from service. Reportedly, it may be possible to replace the refrigerant and restart the unit in an emergency, although, given the age of the machine, this cannot be considered a certainty. Loss of one chiller leaves the plant with marginal capacity to meet actual building demand. We note that the sum of the cooling coil capacity shows a peak load of 143 tons, which is 170% of the capacity of the operable machine. While there is almost certainly a safety factor in the original design, it seems unlikely to be that large. We conclude that the peak building load would exceed the capacity of a single chiller if all building systems were operating as intended. The marginal capacity of the plant is also likely to contribute to the inability of building systems to meet peak demands imposed by start-up. Currently, buildings must operate 24 hours per day, 7 days per week during the heating season since buildings cannot recover from a shutdown in a reasonable time period. The additional operating time significantly increases facility operating costs Boiler Description: The original plant included a scotch-marine boiler with heat exchangers in the supply to each building to supplement heat produced by the chiller plant. The original boiler was seldom used, and the boiler and heat exchangers were removed. Subsequently, a 2,000,000 Btu/hr condensing boiler was added back into the system. Condition and Comments: The boiler heat exchanger has failed, and the unit is not operational. Additional comments follow: Based on past experience, this model and manufacturer of boiler is generally of high quality and typically is quite reliable. The boiler was installed in 1999 making the unit 12 years old. The typical life for boilers is in excess of 20 years, and the unit should have significant remaining life although the equipment has not been reliable. Reportedly, the heat exchanger has failed two or three times. Figures 2.2a and 2.2b show the disassembled boiler and the inside of the failed heat exchanger. We expect there are three primary reasons for the high failure rate: o Corrosion products from elsewhere in the system haved coated the heat exchanger surfaces requiring higher temperatures on the flue gas side to provide the same boiler output. Higher operating temperatures can reduce boiler life. o Since the heating water system leaks, the system cannot be chemically treated and there is a significant amount of potable water added to the system for makeup. The stainless steel heat exchanger in the boiler may be subject to stress cracking in the presence of chlorine used to sanitize the potable water. o The boiler is connected directly in series with the heating water supply piping. Potentially, the amount of flow delivered to the buildings at low loads may fall below the manufacturer s recommended minimum. Conditions Survey Section 2-4

17 FIGURES 2.2A FIGURES 2.2B After the boiler heat exchanger failed, the unit was disassembled, and an estimated cost for repairs was prepared by the manufacturer's representative. However, repair was not pursued. The heat exchanger must be replaced to allow the boiler to operate. Conditions Survey Section 2-5

18 Pumps Description: Pumps are generally base-mounted, end-suction configuration and appear to be original equipment. See Figure 2.3. Condition and Comments: In general, the pumps are of high quality and are fully operational. However, the pumps are original equipment making them 34 years old. ASHRAE published median service life for base-mounted pumps is 20 years, although, in our experience, the expected median service life should be closer to 30 to 35 years for this configuration and quality. Regardless, the pumps are close to the end of their life. Given the age of the pumps, replacement parts are difficult to find. In addition, discussions with repair organizations indicate that refurbishing the pumps will be only slightly less expensive than replacement. Overall, replacement is favored over refurbishment Distribution Systems FIGURE 2.3 Description: Above grade piping is generally schedule 40 black steel. Documents indicate that below-grade piping from the mechanical room to remote buildings including Administration, Fleet Services, and the Warehouse is schedule 40 polyvinyl chloride (PVC). Isolation of equipment and piping sections is provided by a combination of gate and butterfly valves. Condition and Comments: The condition of existing piping was briefly discussed in the above general section. Additional comments follow: Small diameter piping sections removed because of leaks or loss of flow show severe Conditions Survey Section 2-6

19 corrosion. In some cases, corrosion products have completely blocked piping. An example noted during the initial investigation is shown as Figure 2.4. FIGURE 2.4 Leaks in heating water piping are common with most found in small piping although leaks have occurred in larger piping. In our experience, this is a typical progression. Since the corrosion rate is identical between large and small piping and since the wall thickness of larger piping is greater than small piping, the small piping sections tend to rust through first. Although the heating water system has been converted to a closed loop and well water is no longer introduced into the heating water network, leaks in heating water piping make it impossible to chemically treat the systems, and piping will continue to degrade. The corrosion rate of steel piping is dependent on fluid temperature, and chilled water is not as corroded as the heating water piping. However, considerably more well water has been directed through the chilled water system since start-up, and it appears that sediment has settled in system low points throughout. As mentioned, this was observed in the outlet piping from the Fleet Services Building where obstructions dramatically reduced chilled water flow. In addition, it is likely that such sediment has coated coil heat transfer surfaces reducing heat transfer rates and system capacity. As mentioned, the below grade piping from the central plant to the Administration, Fleet Services, and Warehouse buildings is PVC. There are significant known leaks in the heating water piping. It is not possible to identify the specific cause of the leaks, but a contributing factor may have been the temperature of water circulated. We note that Conditions Survey Section 2-7

20 PVC has full strength rating at 73 o F and is easily capable of withstanding normal operating pressures at that temperature. However, if the fluid temperature is raised to 140 o F, pipe strength is reduced to only 20% of the full strength rating. Currently, it appears that the supply water temperature is not raised above 120 o F. Reportedly, however, supply water temperature has been maintained as high as 140 o F when the boiler was operational. In short, supply water temperature has been higher than appropriate for the piping type, and damage may have resulted. A potential confirmation was found at the heating water piping entrance into the Administration Building mechanical room. The piping appeared to have been deformed, likely as the result of high temperature. See Figure 2.5. FIGURE 2.5 Conditions Survey Section 2-8

21 System valves are problematic. A significant number have frozen in place, and many more do not shut off properly. Given the number of failed valves, it is very difficult to isolate equipment for service. Valve failure is partly due to the age of equipment, but the amount of system corrosion is also a large contributor. See Figure 2.6. FIGURE 2.6 Conditions Survey Section 2-9

22 Results of Additional Testing: As previously discussed, it was apparent during the field survey that piping is corroded and contains considerable sediment from the introduction of well water. However, the extent of the damage could not be determined using a visual inspection only and Lane County obtained additional destructive testing to better establish existing conditions. As part of the testing process, sections of larger diameter heating and chilled water piping in the Adminstration, Maintenance, and Fleet Services Buildings were removed for examination. Piping samples were sectioned to allow thickness to be measured, and corrosion products were cleaned from internal surfaces to provide an indication of the type of corrosion occuring. Results follow. The amount of corrosion found in larger heating water pipe samples is significant as shown in Figure 2.7. While there is sufficient free area in the large size pipe shown to allow adequate flow, the rough surface presented by rust tubercles will increase pressure loss in piping and require higher than necessary pumping costs. It is also clear that smaller piping with the same thickness of corrosion products would be seriously occluded and potentially even completely blocked. FIGURE 2.7 Heating water pipe pitting is significant although pits do not exceed 0.04 inches in any sample. For larger size piping, remaining wall thickness would be approximately 74% to 80% of original. Generally, this remaining thickness will provide a piping strength that is adequate for continued use provided that current deficiencies are corrected and proper chemical treatment can be performed. However, piping that is 2-inch and smaller was constructed using threaded fittings. Wall thickness is significantly reduced where Conditions Survey Section 2-10

23 threads are cut during construction. Assuming that piping corrosion is the same as found in the worst case sample, remaining wall thickness at threads in 2-inch pipe would be approximately 29% of the original wall thickness. The remaining percentage for smaller piping would be even less. A section of piping where corrosion products have been removed is shown as Figure 2.8. FIGURE 2.8 Conditions Survey Section 2-11

24 As shown in Figure 2.9 below, the amount of corrosion on chilled water piping is significant less than on heating water piping. It seems unlikely that any piping in the chilled water system is blocked as the result of corrosion alone. FIGURE 2.9 Conditions Survey Section 2-12

25 The degree of pitting on the chilled water piping is also less than on heating water piping. Clearly, larger piping is acceptable for reuse. See Figure 2.10 FIGURE 2.10 Conditions Survey Section 2-13

26 We note that the condition of piping in the Fleet Services Building serving heating and ventilating unit HVU-1 is not explained by the samples. These relatively short sections of piping have experienced many leaks as shown in Figure 2.11 below where pipe repair clamps are designated by arrows. Based on the condition of the samples from other areas, we expect that this is an isolated problem that may result from a local galvanic corrosion cell, a localized chemical or biological contaminate that increases corrosion rate, or a batch of low quality steel. FIGURE 2.11 Conclusion: The initial survey and subsequent testing show that larger size piping can be reused although cleaning is recommended to reduce pressure drop and limit the possibility that corrosion products will break loose and cause other system problems. Cleaning will also help remove sediment. However, the wall thickness of 2-inch and smaller piping installed with threaded fittings is marginal at best. Replacement of all such piping is recommended to ensure long-lasting, reliable service Controls Description: The original facility was constructed with a Honeywell Delta 1000 control system. The system provided start/stop and some monitoring of equipment but performed few control functions. Most control functions were performed by pneumatic systems. In 2000, the control system was upgraded to a new Trane direct digital control system. The system was connected to existing start/stop and monitoring points in all buildings. In addition, control of the entire central plant was added to the system along with limited control of major air handling equipment throughout the facility. Conditions Survey Section 2-14

27 Condition and Comments: The Trane control components are operable and in reasonably good condition although some controllers are obsolete and replacement parts may soon not be available. Where DDC control has been added, existing pneumatic actuators have been reused. The actuators are well beyond their median service life Makeup Water/Expansion Control Systems Description: The heating water system is equipped with an expansion tank and makeup water control system. The expansion tank is an open style without bladder. Condition and Comments: The existing system is problematic. Reportedly, the plant operator must drain the tank frequently to maintain expansion volume. To reduce the drain down requirement, the makeup water pressure has been reduced. However, reduced makeup water pressure may lead to air in the system causing air binding and loss of flow at coils Wells Description: Currently, the central plant is connected to three wells with approximate outputs of 200 gallons per minute (gpm), 205 gpm, and 54 gpm. Condition and Comments: Reportedly, the wells are reliable, and little debris is found in the system strainer where well water enters the plant. Additional discussion follows: Well pump 1 was recently replaced and is in good condition. Maintenance staff was not aware of the age and condition of well pumps 2 and 3. Reportedly, the total delivered flow was measured by maintenance staff at 479 gpm. The total flow is adequate to allow both chillers to operate in full heating or full cooling simultaneously. The wells operate from level controls mounted on a large, vented, concrete-lined, steel well water tank located in the mechanical room. The well water inlet valve to the tank is frozen in place, and the handle has been broken off in an attempt to isolate the tank. Without operable isolation valves, it is difficult to drain the tank for inspection, and the internal tank condition is unknown. However, unless the tank concrete lining has failed, considerable life should remain. Reportedly, the tank level controls have not been reliable Maintenance Building A description of systems serving the Maintenance Building follows Hydronic Systems Description: Heating water and chilled water is provided from the central plant to the building s distribution system, and includes heating and chilled water pumps and distribution piping. Condition and Comments: Overall, building hydronic systems are in extremely poor condition. Additional discussion follows: The building heating water and chilled water circulation pumps are both an in-line centrifugal configuration. The ASHRAE published median service life for similar pumps is 10 years. In our experience, this figure should be closer to 20 years if equipment is properly maintained. These pumps are 34 years old and are clearly past their expected Conditions Survey Section 2-15

28 median service life. We note that leaking seals are common. See figure FIGURE 2.12 Four in-line centrifugal heating water and chilled water circulation pumps were installed in 2000 and 2001 to serve four single-zone air handling units. As previously, mentioned, these pumps should have a median service life close to 20 years if properly maintained. P-1A, P-1B, P-2A, and P-2B are in good condition and can be expected to provide useful service for as much as 10 more years. As discussed under the central plant section, system piping is corroded due to the introduction of well water into the distribution system. Much, of the smaller building piping is significantly blocked with corrosion products or sediment significantly reducing system heating and cooling capacity. Corrosion and debris within the distribution system has also had a considerable impact on isolation valves, pressure relief valves, automatic air vents, and other system trim. Many components are no longer functional or are significantly compromised Central Air Handling Systems GENERAL Description: A dual-duct, central air handling system serves a large majority of building spaces. The system includes a central fan unit that delivers both heated air and cooled air through duct systems to all areas of the building. Terminal units are installed near areas served. The terminal units mix heated air and cooled air to the temperature needed to match local demand. Booster fans BF-1, BF-2, and BF-3 are used to return air back to the central fan room. BF-1 Conditions Survey Section 2-16

29 serves the testing lab and provides a constant return air rate. Booster fans BF-2 and BF-3 serve the remaining building and can return all air to the central fan or divert a portion of the return air to fan powered terminal units. To accommodate changes in return air flow to the central air handling systems, the central fan is equipped with inlet vane dampers to vary supply air rate. A fixed amount of outside air is provided to the air handler for ventilation. The outside air system includes an additional booster fan and air-to-air heat exchanger to allow ventilation air to be preheated using toilet exhaust. Condition and Comments: In general, the condition of system components varies from poor to good, and overall system function is marginal. Some considerations include: The system is constant volume with both heated air and cooled air delivered to terminal units near areas served. At terminal units, heated air and cooled air are mixed to the temperature needed to maintain load. While temperature control using this strategy is good, the continuous mixing of heated and cooled air is highly inefficient and is no longer allowed by Code except under special conditions. Space use has changed in some areas, and air distribution to these locations may not be adequate to meet revised load. The system was designed with ventilation rates that are no longer considered to be adequate and do not meet current ventilation code. The existing ventilation rate is approximately one-third to one-half of current code rates. The system was designed without the capability to cool using outside air (economizer cooling), and the maximum outside air rate is limited to the ventilation rate. MAIN AIR HANDLER Description: Air handling unit HCU-1 includes a supply fan, return fan, pre-filter, roll-type main filter section, and discharge plenum section. The discharge section includes parallel heating and cooling coils allowing the unit to produce both heated air and cooled air for building conditioning. HCU-1 is located inside mechanical room 427. Return air and ventilation air are ducted to the room and not directly to the unit inlet. A schematic of the system is included as Figure Conditions Survey Section 2-17

30 FIGURE 2.13 Condition and Comments: In general, the unit is of lower initial quality than many air handling units found elsewhere in the facility and is in relatively poor condition. Additional comments and details follow: ASHRAE median service life for centrifugal fans is 25 years. Given the initial fan quality and the service, this figure appears reasonable. Equipment age is 34 years, and the unit is significantly past normal median service life. The unit is equipped with inlet vane dampers controlled to maintain a fixed pressure in the discharge ductwork. The inlet vane dampers function, but do not appear to be capable of moving to 100% open position. The damper actuator has limited travel, and only appears to be able to move the inlet vanes to a 50% open position. Fan volume appears to be significantly lower than if dampers were wide open. The reduced airflow may limit system heating and cooling output to below design. Fan speed was measured at 1593 rpm. This is a very high speed for a fan of this type. The high speed tends to add stress to components and reduces expected equipment life. Fan vibration is significant indicating that fan wheels are out of balance. The unit was originally equipped with a pre-filter, an automatic roll filter, and an electrostatic carbon filter bank. The roll filter advanced when a differential pressure sensor exceeded a certain value. The pre-filter and main filter are still used, but the main filter is now manually advanced by maintenance staff. The carbon filter bank is no longer used. Conditions Survey Section 2-18

31 RETURN AIR BOOSTER FANS Description: A combination of under-floor and above ceiling ductwork systems return air back to the air handler mechanical room. The ductwork systems include three constant volume booster fans BF-1, BF-2, and BF-3. As previously described, BF-2 and BF-3 can also return air to the heating side of fan powered terminal units. Condition and Comments: The fans are of high quality and in generally good condition. The ASHRAE median service life is 25 years. However, given that the use is low pressure, there are no coils, and the initial quality is good, we expect that the fans have significant remaining life, particularly if the units are refurbished. OUTSIDE AIR SYSTEM Description: Booster fan BF-4 provides outside air directly to the mixed air plenum for HCU-1. Condition and Comments: BF-4 is of high quality and in generally good condition. The ASHRAE median service life is 25 years. However, given that the use is low pressure, there are no coils, and the initial quality is good, we expect BF-4 to have significant remaining life, particularly if it is refurbished. Additional comments follow: Originally, BF-4 was paired with an air-to-air heat exchanger that operated in conjunction with a central toilet room exhaust fan. By design the amount of air exhausted from the toilets was made equal to the building ventilation rate. Outside air was routed through the heat exchanger where it was pre-heated by toilet exhaust. However, there were no filters on the heat exchanger, so it became plugged. The heat exchanger was removed by maintenance staff, and the ductwork was modified accordingly. TERMINAL UNITS Description: Conditioned air is delivered to office and work spaces throughout the building by dual-duct terminal units (TUs) and fan-powered terminal units (FPTUs). The dual-duct TUs, also called mixing boxes, are constant volume devices connected to both the hot and cold ducts from the central air handler. The TUs mix hot and cold air to supply the correct temperature air to satisfy room setpoint temperature and are typically used in internal spaces and areas with moderate heating loads. Each TU has a single pneumatic actuator connected to dampers that adjust the proportion of hot and cold air entering the mixing box as needed to meet space load. The FPTUs are similar but also have internal fans and units that are connected to both the return air ductwork from BF-2 and BF-3 and the cold duct. FPTUs are used to serve spaces with high ceilings or high heating loads. The cold duct connections for each FPTU are controlled by pneumatically-actuated dampers. The FPTUs re-circulate air from their respective zones and add cold air as needed to satisfy cooling demand. Supplemental heat for each FPTU is provided by a heating water reheat coil in the downstream ductwork. Condition and Comments: The TUs and FPTUs are of fair quality and in generally good condition. The ASHRAE median service life is 20 years, and the TUs and FPTUs are beyond their median service life. In addition, the units do not have a means of controlling the volume of airflow, only the relative proportions of hot and cold air. The approach is less energy efficient than more current designs that vary airflow to match space demand. Conditions Survey Section 2-19