15515 - HVAC-26July2011.pdf

KRSM: 062067, 062068, 062069, 072070 B-2005, B-2013, B-2024 Section 15515 HVAC piping

HEATING AND COOLING PIPING, SYSTEMS AND EQUIPMENT 15515-1

DIVISION 15000 - MECHANICAL

SECTION 15515 - HEATING AND COOLING PIPING, SYSTEMS AND EQUIPMENT

PART I - GENERAL

1.01 RELATED DOCUMENTS:

A. All pertinent sections of Section 15000 - General Mechanical Requirements are a part of the work described in this section.

B. All pertinent sections of Section 15060 - General Pipes and Fittings are a part of the work described in this section.

C. Other Specification sections related to Insulation, System Commissioning, Testing and Balancing.

1.02 SCOPE OF THE WORK: Work shown on the drawings and required by these specifications including incidental work classified as "best practices of the trade".

A. Chilled water systems.

B. Heating water systems.

C. Steam systems.

D. Other work as indicated.

1.03 QUALITY ASSURANCE:

A. Manufacturer's Qualifications: Firms regularly engaged in the manufacture of hydronic piping products and equipment of types, materials and sizes required, whose products have been in service for not less than 5 years.

B. Installer's Qualifications:

1. Firm with at least 3 years history of successful experience on projects of similar nature.

2. Licensed as a firm in the Contractor state of origin.

3. Have a publicly registered bonding capacity of sufficient amount to cover this work and all other work in progress by the Contractor.

4. All workmen employed on the project shall carry state licenses as journeyman or apprentice pipe fitters with additional certification for welders.

C. Standards: Comply with applicable sections, follow recommended practices.

1. State Boiler and Pressure Vessel Regulations

2. ASME Codes for Boilers and Pressure Vessels

3. State and Local Plumbing and Mechanical Codes

4. International Building Code/International Mechanical Code

5. ASHRAE Handbooks

HEATING AND COOLING PIPING, SYSTEMS AND EQUIPMENT 15515-2

1.04 SUBMITTALS:

A. Product Data: Submit manufacturer's technical literature indicating source, brand, type, model, performance characteristics, installation instructions, etc.

B. Shop Drawings: Submit scaled layout drawings of heating and cooling piping and equipment for equipment rooms, tunnels, exposed runs and other congested ares.

Coordinate with other trades.

C. Record Drawings: See Section 15000.

D. Operation and Maintenance Information: Provide information for all equipment including a comprehensive system operating description. See Section 15000.

E. Instruction of Contracting Officer's Personnel: Participate in specified instruction. See Section 15000.

1. As part of the overall project warranty, furnish individual manufacturer warranties for each piece of equipment for a period of not less than one year from date of Contracting Officer's beneficial use (substantial completion).

2. Warrant the overall assembly of equipment, materials and labor comprising these systems.

1.05 TESTS:

A. Isolate sections of piping and equipment and pressure test to 175 psi or 1-1/2 times the maximum potential pressure of the system, but not to exceed the test pressure rating of a system component.

1. Conduct an air pressure test, using a soap solution to check for leaks. Establish the pressure, close off the pressure source and let stand for 24 hours. Given constant temperature, there should be no drop in pressure.

2. After the air test, fill the system with water, raise to test pressure and inspect for leaks.

3. Repair all leaks. Repeat tests. Report and certify all tests.

B. Test other system components as needed to verify proper assembly and installation.

C. Participate in overall system test and balance work.

PART II - PRODUCTS

2.01 PIPING AND FITTINGS - CHILLED WATER AND HEATING WATER SYSTEMS:

A. Schedule 40 black steel, A-53 or A-106, with malleable steel threaded fittings up to 2" size and forged steel welding fittings 2-1/2" and larger.

B. Type K or L hard copper with wrought copper fittings, solder joints.

C. Use either copper or steel throughout, do not mix materials.

2.02 PIPING AND FITTINGS-STEAM SYSTEMS:

A. Steam piping for up to 100 psig pressure, shall be Schedule 40 black steel, A-53, Grade A or A-120, with malleable steel threaded fittings up to 2" size and forged steel welding fittings 2-1/2" and larger.

HEATING AND COOLING PIPING, SYSTEMS AND EQUIPMENT 15515-3

B. Condensate piping shall be Schedule 80 black steel, A-53, Grade A or A-120, with malleable steel threaded fittings up to 2" size and forged steel welding fittings 2-1/2" and larger.

2.03 GENERAL SERVICE VALVES: (See Section 15100)

2.04 MISCELLANEOUS VALVES AND SPECIALTIES:

A. Air Vent Valves: Stockham B-64, 300 psi working pressure, 3/8" bronze or Crane No. 88.

B. Gauge Valves: Crane #88 bronze needle valve or Trerice gauge needle valve.

2.05 VALVE INSTALLATION:

A. All valves shall be installed in locations which will allow easy operation and facilitate maintenance.

B. Gate and globe valves shall be installed with stems horizontal or above the horizontal.

2.06 DRAINS AND OVERFLOWS: Piping of any size from drains and overflows shall be installed using standard weight galvanized steel piping with standard weight galvanized malleable fittings free from fins and burrs, with standard pipe threads. Drains and over flows shall be terminated over floor drains or drain funnels adjacent to equipment.

2.07 GLYCOL MAKE-UP UNIT: Provide glycol and glycol makeup unit complete with the following:

A. Polyethylene feed tank mounted on a steel frame with accommodations for mounting a pump underneath. Tank shall have a hinged lid and all interconnecting piping to pump including strainer.

B. Level switch to deactivate pump and activate alarm on low level.

C. Control panel to house switching device for pump, audible alarm, HOA switch for pump, lights to indicate power and low level, pushbutton for alarm silence. Enclosure shall be NEMA 12. Control panel shall be mounted on the tank stand.

D. Rotary gear pump of bronze construction. Capacity shall be 3 GPM at 30 psig head.

E. 1/2" bronze, solenoid valve mounted in the feed line from the pump to the system. The valve shall be activated the same time as the pump.

F. Pressure switch set at 14 psig adjustable to activate the pump and solenoid valve. Pump shall be deactivated at 17 psig adjustable. Pressure sensing shall be made in the main chilled water line on the discharge side of the pump.

G. 1/2" bronze, relief valve mounted on the system side of the solenoid valve and piped back to the tank.

H. MANUFACTURERS: Glycol make-up unit shall be manufactured by the following manufacturers:

1. Power Engineering Company

2. Aurora

3. Pacific

4. Neptune

I. INSTALLATION:

1. The glycol make-up units shall be installed in accordance with the drawings, the manufacturer's printed instructions and approved shop drawings. The units shall be mounted on a concrete pad and firmly attached to the concrete pad.

HEATING AND COOLING PIPING, SYSTEMS AND EQUIPMENT 15515-4

2.08 CHILLED WATER AND HEATING WATER PUMPS:

A. GENERAL: Pumps shall have capacity and total head as indicated on the drawings and pump shall be selected at or near peak efficiency. Additional pump capacity shall be provided for the chilled water pump to accommodate extra water requirements for water cooling the compressor motor if required for the unit furnished. Pump curve shall rise continuously from maximum capacity to shutoff. Shutoff head shall be approximately 20 percent greater than design head.

B. TYPE: Pumps shall be end-suction, non-overloading, centrifugal type.

C. CONSTRUCTION: Shaft seal shall be mechanical-seal type. Impeller shall be statically and dynamically balanced. Each pump casing shall be designed to withstand the discharge head specified plus the static head on system plus 50 percent of the total, but not less than 862 kPa (125 psig). Pump casing and bearing housing shall be close grained cast iron. High points in the casing shall be provided with manual air vents; low points shall be provided with drain plugs. Impeller, impeller wearing rings, glands, casing wear rings, and shaft sleeve shall be bronze. Shaft shall be carbon or alloy steel, turned and ground. Bearings shall be ball-bearings, roller-bearings, or oil-lubricated bronze-sleeve type bearings, and be efficiently sealed or isolated to prevent loss of oil or entrance of dirt or water. Pump and motor shall be mounted on a common cast iron base having lipped edges and tapped drainage openings or structural steel base with lipped edges or drain pan and tapped drainage openings. Pump shall be provided with shaft coupling guard. Pump motor shall have the required capacity to prevent overloading with pump operating at any point on its characteristic curve. Pump speed shall not exceed 1,750 rpm. Pump shall be accessible for servicing without disturbing piping connections.

D. MECHANICAL SHAFT SEALS: Seals shall be single, inside mounted, end-face-elastomer bellows type with stainless steel spring, brass or stainless steel seal head, carbon rotating face, and tungsten carbide sealing face. Glands shall be bronze and of the water-flush design to provide lubrication flush across the face of the seal. Bypass line from pump discharge to flush connection in gland shall be provided, with filter or cyclone separator in line.

2.09 STEAM CONVERTOR:

A. Heat exchangers shall be multiple pass shell and U-tube type as indicated, to provide low temperature hot water for the heating system when supplied with steam at the temperatures and pressures indicated. Temperature and pressure for shell and U-tube exchangers shall not exceed 338 degrees F and 100 psig for steam. Exchangers shall be constructed in accordance with ASME-16 and certified with ASME stamp secured to unit.

U-tube bundles shall be completely removable for cleaning and tube replacement and shall be free to expand with shell. Shells shall be of seamless steel pipe or welded steel construction and tubes shall be seamless tubing as specified below unless otherwise indicated. Tube connections to plates shall be leakproof. Saddles or cradles shall be provided to mount shell and U-tube exchangers. Frames of plate and frame type exchangers shall be fabricated of carbon steel and finished with baked epoxy enamel.

Design fouling factor shall be .001.

B. STEAM HEAT EXCHANGERS, SHELL AND U-TUBE TYPE: Exchangers shall operate with steam in shell and low temperature water in tubes. Shell and tube sides shall be designed for 150 psig working pressure and factory tested at 300 psig. Steam, water, condensate, and vacuum and pressure relief valve connections shall be located in accordance with the manufacturer's standard practice. Connections larger than 3 inches shall be ASME 150 pounds flanged. Water pressure loss through clean tubes shall not exceed 3 psi and water velocity shall not exceed 1.8 m/second (6 fps) unless otherwise indicated. Minimum water velocity in tubes shall be not less than 1 fps and assure turbulent flow. Tubes shall be seamless copper or copper alloy, constructed in accordance with ASTM B 75 or ASTM B 395, suitable for the temperatures and pressures specified. Tubes shall be not less than 3/4 inch unless otherwise indicated.

Maximum steam inlet nozzle velocity shall not exceed 6000 fpm.

HEATING AND COOLING PIPING, SYSTEMS AND EQUIPMENT 15515-5

PART III - EXECUTION

3.01 GENERAL SYSTEM INSTALLATION:

A. Arrange system in a neat, orderly and functional manner. Maintain access around all equipment.

B. Plan ahead for seismic restraint and vibration isolation.

C. Verify adequate ventilation for heat producing equipment, watch out for possible freezing conditions.

D. AIR VENTS AND LINE DRAINS: Provide air vents at all high points of piping systems with vent line extended to valve installed in accessible location 5'-0" above the floor, vent line extended to drain. Provide drain valves at all equipment and at low points in the system, extend drain lines to drain tunnel or floor sink.

E. Provide pressure gauges and thermometers and pressure/temperature plugs as indicated on the flow diagrams, piping plans and equipment details.

F. Provide shot type chemical feeder for the closed loop heating water system. Five (5) gallon minimum size or larger as indicated.

3.02 EXPANSION AND CONTRACTION:

A. General: Provide for expansion and construction of all piping systems with anchors, guides, loops, expansion joints, grooved joints, etc.

3.03 CHEMICAL TREATMENT CHILLED WATER AND HEATING WATER SYSTEMS:

A. Completely clean, flush and fill each new piping system. Isolate new piping sections as required to clean new systems.

B. Use a chemical vendor treatment schedule similar to the following, but to be verified compatible with the existing system materials. Survey existing system and determine extent of treatment needed.

1. Fill, circulate, drain system, clean strainers.

2. Fill, introduce sodium triphosphate or suitable degreaser, circulate, drain, flush.

3. Fill introduce oxygen scavenger/inhibitor such as sodium borate-nitrite with phenopthalien, circulate.

4. Maintain inhibitor/scavenger concentration for entire first year, replace if lost.

5. Verify treatment program of existing systems and use compatible materials.

3.04 GLYCOL FOR CHILLED WATER SYSTEM:

A. Glycol Inhibitor Solution: Commercial propylene glycol (Dow Chemical Dow Frost or equal from Union Carbide or Huntsman) shall be used. Proper inhibitor maintenance must be performed in order to prevent corrosion of the glycol system. A chemical treatment such as Betz inhibitor 590 or Bets Entec equivalent shall be used. Automotive anti-freeze is unacceptable and must not be used in an environmental control system.

B. Fill the system with the required quantity of propylene glycol through the charging valve following these steps:

1. Determine the glycol to water ratio.

2. Premix the water glycol solution before adding it to the system. Do not add water and then glycol to the system.

3. Consult and follow manufacturer's recommendations.

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C. Perform tests determining strength of glycol solution before system is turned over to the Contracting Officer. Provide test prior to end of first year of operation and replenish as required.

END OF SECTION 15515