SPECIAL NOTICE
Y -- VA-241-10-RP-0332 Project #631-08-106 Demolition and construction of newly designed boiler plant. Set A Side for Service Disabled Veteran Owned Small Businesses ***Answers for RFI 2 Addendum***
- Notice Date
- 6/9/2010
- Notice Type
- Special Notice
- NAICS
- 236210
— Industrial Building Construction
- Contracting Office
- Department of Veterans Affairs;VAMC Northampton;Acquisitions-90;421 North Main Street;Leeds MA 01053-9764
- ZIP Code
- 01053-9764
- Solicitation Number
- VA24110RP0332
- Response Due
- 6/17/2010
- Archive Date
- 8/8/2010
- Point of Contact
- Jane LaBorde
- E-Mail Address
-
ct
- Small Business Set-Aside
- N/A
- Description
- REVISIONS TO SPECIFICATIONS ITEM 1:Specification Section 23 50 11, ADD the following: 2.9 FEEDWATER DEAERATOR TANK AND ACCESSORIES A.Fully packaged, piped and wired, Pressurized (14-35 kPa) (2-5 psi) unit designed to heat and deaerate boiler feedwater by direct contact with low pressure steam.Spray type deaerating section. Horizontal feedwater storage tank. Provide accessories including vacuum breaker, safety valve, water inlet and overflow controls and control valves, water level indicators and alarms and other devices as specified and shown. B.Performance and Operating Characteristics: 1.Oxygen Content of Feedwater Output: 7 parts per billion maximum over turndown range with minimum and normal feedwater input temperatures as listed. 2.Turndown: 20/1. 3.Required Maximum Feedwater Flow Output: 16,000 lb/hr. 4.No carbon dioxide in feedwater output; maximum steam vent loss 1/2 percent of input steam at maximum load. 5.Feedwater Input Temperature: Minimum temperature is 15 °C (60 °F) and normal range is 60 - 82 °C (140 - 180 °F). 6.Water Pressure Loss Through Spray Valves: 48 kPa (7 psi) maximum. 7. Steam Pressure Loss in Unit: 7 kPa (1 psi) maximum. C. Feedwater Storage Capacity to the Overflow Line: Sufficient for twenty minutes operation at maximum required feedwater output with no input water, unless shown otherwise on the drawings. Overflow line (elevation) shall be set by feedwater deaerator manufacturer so that there is no water hammer when water is at this level. D. Construction: 1. Storage Tank and Deaerator Pressure Vessels: a.Conform to ASME Boiler and Pressure Vessel Code, Section VIII. Design for saturated steam at 200 kPa (30 psi) with 3 mm (0.125 inch) corrosion allowance. b.Carbon steel, ASTM A285 Grade C or ASTM A516 Grade 70. Weld metal strength shall approximate the strength of the base metal. All welds shall be double-vee type. No single vee welds allowed. Weld undercut not allowed. All welding must be constructed to allow future internal weld inspections, utilizing non-destructive-testing methods. c.Post Weld Heat Treatment (PWHT) to stress-relieve pressure vessel to 620 °C (1150 °F) not to exceed ASME hold-time or temperature. d.Provide 100 percent radiography of all longitudinal and circumferential welded seams. Test nozzle-to-shell welds by wet magnetic-particle method. Hydrostatically test final assembly at 1.3 times design pressure. e. Furnish completed applicable ASME Forms U-1, U-1A or U-2. 2. Spray Valve Assemblies: Spring-loaded, guided stem, stainless steel and Monel, removable. Spring-loaded, guided stem types not required on spray-type units that operate with recycle pumps at constant flow rates through the spray valves. 3.All other parts in deaerator section exposed to undeaerated liquids or gases must be constructed of stainless steel, cupro-nickel or equivalent. 4.Provide two 300 mm (12 inches) x 400 mm (16 inches) elliptical manways in storage tank, located below the normal water level, but near the tank centerline, and away from the deaeration section or internal piping. Manway locations must allow unrestricted access to tank interior with no interference from internal equipment and piping and with easy access from outside the tank. Second manway is to facilitate the annual internal inspections. 5.Provide access openings in deaeration section to allow inspection and replacement of spray valve assemblies. 6.Support: Steel saddles or legs welded to storage tank. 7.Nameplates: Attach to bracket projecting beyond field-applied insulation. Provide all ASME pressure vessel nameplate information as required by the Code along with information identifying the designer and manufacturer of the storage tank and the deaeration section. 8.Pipe Connections: a.Threaded for sizes 50 mm (2 inches) and under. b.Flanged, 1025 kPa (150 psi) ASME, for sizes above 50 mm (2 inches). c.Vortex breaker in boiler feedwater pump suction connection. d.Overflow Pipe: 1)Overflow pipe inside tank terminating 150 mm (6 inches) below low level alarm set point. Operation of overflow control system must not allow water level to fall to the level of the overflow pipe inlet. 2)Overflow pipe sizing, based on required maximum feedwater flow output of feedwater deaerator: Feedwater Flow Rate(kg/sec)Feedwater Flow Rate(klb/hr)Overflow Pipe Minimum Size (mm)Overflow Pipe Minimum Size (in) 0 thru 3.80 thru 30753 3.9thru 7.631 thru 601004 E. Pumps: 1.Pumps: Three required, each full flow capacity of deaerator. High efficiency, multi-stage diffuser type. Provide shutoff valves to isolate each pump, provide inlet strainer with valved blowdown on each pump, provide check valve and discharge isolation valve on each pump. Provide tee connection at each pump inlet to allow field piped deaerator bypass. Provide pressure gages on suction and discharge of each pump. Refer to Section 23 09 11, INSTRUMENTATION AND CONTROL FOR BOILER PLANT for gage requirements. 2.Motors: High efficiency, open drip proof. Non-overloading at any point on pump head-flow performance curve. For efficiency and power-factor requirements, refer to Section 23 05 11, COMMON WORK RESULTS FOR HVAC AND STEAM GENERATION. F. Steam Safety Valve: Mount on feedwater deaerator pressure vessel. Set pressure 100 kPa (15 psi). Capacity as shown. If not shown, minimum capacity 0.12 kg/sec (900 lb/hr). For safety valve construction requirements, refer to Section 23 21 11, BOILER PLANT PIPING SYSTEMS. G.Oxygen and Non-Condensable Gas Venting: Straight vertical pipe extending through roof from deaeration section. Provide gate valve in vent pipe, with hole drilled in wedge. Hole size selected by feedwater deaerator manufacturer for normal venting with gate valve closed. H.Thermometers and Pressure Gages: Refer to Section 23 09 11, INSTRUMENTATION AND CONTROL FOR BOILER PLANT for construction requirements. Provide thermometers on deaeration section and on storage tank. Provide compound gage with shut-off valve and siphon on deaerator. I.Vacuum Breaker: Sized by deaerator manufacturer to protect unit. Bronze swing check valve, rated for 1030 kPa (150 psi), PTFE seat, stainless steel hinge pin. J.Water Sample and Chemical Feed Probes: Type 304 or 316 stainless steel, multi-ported, minimum length 300 mm (1 foot), accessible for removal from exterior of tank. K.Cleaning and Painting: Remove all foreign material to bare metal. Coat exterior of pressure vessel with rust-preventative primer. Refer to Section 09 91 00, PAINTING. Do not coat interior of pressure vessel. L.Insulation: Field-applied. Refer to Section 23 07 11, HVAC, PLUMBING, AND BOILER PLANT INSULATION. M.Seismic Design: Refer to Section 13 05 41, SEISMIC RESTRAINT REQUIREMENTS FOR NON-STRUCTURAL COMPONENTS. Design the entire assembly and anchorage to building to resist seismic forces and be fully operational after the seismic event. N.Water Level Indicators: 1.Gage Glasses: Red line type, overlapping glasses if multiple glasses are utilized. Provide automatic offset-type gage valves that stop the flow if a glass is broken. Drain cock on lower gage valve. Gage glass protecting rods. 2.Vertical pipe type header shall be connected to top and bottom of storage tank with tank isolation valves and valved header drain. Viewable gages shall cover entire diameter of tank. 3. Minimum rating 120 degrees C, 200 kPa (250 degrees F, 30 psi). O.Low Level Alarm Switch: Float type unit with hermetically sealed mercury switch. Locate external to tank on a vertical header with valved tank connections and valved drain. Switch elevation shall be at the tank centerline. Minimum rating 120 degrees C, 200 kPa (250 degrees F, 30 psi). Provide signals to computer workstation specified in Section 23 09 11, INSTRUMENTATION AND CONTROL FOR BOILER PLANT. P.High Level Alarm Switch and Overflow Control Switch: 1.A differential pressure type level transmitter providing monitoring and level alarms, separate from the low level alarm switch function. Overflow control float (trap) shall automatically open when the water level rises approximately 100 mm (4 inches) above the high water alarm level. Provide low level, high level and overflow signals to computer workstation specified in Section 23 09 11, INSTRUMENTATION AND CONTROL FOR BOILER PLANT. 2.Transmitter shall have "Smart" HART protocol programmable electronics, sealed diaphragms, direct sensing electronics, no mechanical force or torque transfer devices, external span and zero adjustment. Controller shall have proportional plus reset control, adjustable proportional band, reset rate and level set points. Provide manual-automatic control station on main instrument panel. Control station shall indicate actual water level, normal and emergency level set points and valve positions. The water level controller (CV-4) shall be the same make and model as the combustion controls. Q.Steam pressure reducing station (PRV-1) shall be a steam pressure reducing valve with cast iron body and flanged connections. The valve shall be of self contained unit capable of reducing 15 psig saturated steam to the operating pressure of the deaerator at the design flow rate. R.Emergency Make-Up Fill: A flanged 3" diameter nozzle shall be provided as a provision for emergency manual fill of the deaerator. S. Unit shall be Cleaver Brooks Model SS or approved equal. END
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