Marriott Hotel - International
Mechanical - 15A
? Region Requirement: Consult with A&C Engineering for
these requirements.
+ Plate and frame heat exchanger with same flow rates and pressure drops as one chiller, piped in parallel for waterside economizer (free cooling).
+ Where ambient wet bulb temperatures exceed 25.6oC (78oF) consult chiller manufacturer for specifications of chillers using higher temperature condenser water supply.
4. Pumps for Chilled Water System:
? Design: Perform accurate system head calculations with prudent but not excessive consideration of safety factors to eliminate operation in an overload condition and eliminate excessive differential pressures across valves. ? Type: Centrifugal base mounted, 1,750 rpm. End-suction type for capacity of 63 l/s (1,000 gpm) and below and split case type for capacity greater than 63 l/s (1,000 gpm).
? Sizing: Select for maximum efficiency, minimum 10% larger than calculated brake horsepower with flows to match equipment.
? Primary Chilled Water: One constant speed, constant volume pump for each chiller plus one additional pump for standby with piping and valves for cross connection to other pumps.
? Condenser Water: One constant speed, constant volume pump for each chiller plus one additional pump for standby with piping and valves for cross connection to other pumps.
? Secondary Chilled Water: Minimum two pumps (one
standby) for the air handling unit zone and two pumps (one standby) for guestroom fan coil unit zone. Equip all pumps with variable frequency drives and premium duty motors rated for inverter duty. Locate pressure sensors in most remote area of building away from chiller plant. ? Piping: Provide line-size shut-off valve and suction
diffuser on pump suction and triple-duty valve on pump discharge.
? Mounting: Install pumps on 10 cm (4 inch) high concrete
housekeeping pads with concrete inertia bases and spring isolators. Provide braided stainless steel flexible pipe connectors at suction and discharge of each pump to isolate the piping system.
5. Water Cooled Refrigeration Equipment: <10> Provide
water cooled coolers, freezers and ice machines.
? Preferred System: Chilled water return in normal mode
Provide separate dry cooler, pumps and automatic valves connected to emergency back-up power <15C>.
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15A - Mechanical Marriott Hotel - International
? Connect refrigeration equipment to emergency back-up power. <15C>
? In projects with air-side economizer, provide separate condenser water system and connect to emergency back-up power.
? Provide each unit with water supply of 0.1 l/s (1.5 gpm) per hp.
? Consult Marriott A&C Engineering for project specific requirements.
E. Central Heating Plant
1. Design Considerations: A central heating plant is
preferred because of its energy and operating efficiency. The plant consists of high efficiency, gas fired, hot water boilers with a hydraulically separate primary / secondary hot water pumping system with “bridge”, expansion tank, air separator, and shell-and-tube heat exchangers for heating hot water (also for humidity control), and double wall shell-and-tube heat exchanges for domestic hot water, laundry and kitchen systems.
? Location: Strategically locate heating plant to minimize pipe and conduit lengths, but outside of conditioned area, preferably at grade to facilitate maintenance. Locate heating plant equipment above water table and protect from flooding.
? Region Requirements: Consult with Marriott A&C Engineering to determine these requirements. Based on geographic location and availability of factory trained local service personnel and spare parts, additional boiler(s), heat exchangers or pump(s) may be required.
2. Boilers:
? Quantity: Minimum two piped in parallel.
? Type: Modular, gas or oil fired closed combustion chamber water-tube boilers.
? Sizing: Quantity required to meet simultaneous peak load for heating and if appropriate, domestic hot water, laundry hot water and kitchen hot water. See plumbing Module <15B> for domestic hot water, laundry hot water and kitchen hot water requirements. ? Efficiency: Minimum 85%.
? Water Temperatures: Design so that return boiler water temperature is minimum 60oC (140oF) to eliminate the possibility of condensation in boilers.
? Water Circulation: Minimum through boiler to comply with manufacturer but not less than 0.0632 l/s (1 gpm) per 34,815 kJ (33,000 BTU) of boiler input.
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Marriott Hotel - International
Mechanical - 15A
+ Continuous water flow through boiler(s) under all operating conditions to minimize thermal shock conditions.
+ Position pipe so automatic valves do not bypass water around boiler.
? Region Requirements: Consult with Marriott A&C
Engineering to determine these requirements. + Gas or fuel oil fired steam boilers.
+ Steam to hot water, shell-and-tube heat exchangers. ? Controls: Provide manufacturers' stand alone digital
based microprocessor to provide stop, start, capacity control, and energy efficiency optimization (including associated pumps) lead/lag control, and boiler/burner staging and contact points for external connection of DDC control system.
3. Pumps for Heating Hot Water System:
? Design: Perform accurate system head calculations with
prudent but not excessive consideration of safety factors to eliminate operation in an overload condition and eliminate excessive differential pressures across valves. ? Type: Centrifugal base mounted, 1,750 rpm. End-suction type for capacity of less than 63 l/s (1,000 gpm) and split case type for capacity greater than 63 l/s (1,000 gpm).
? Sizing: Select for maximum efficiency, minimum 10%
larger than calculated brake horsepower with flows to match equipment.
? Primary Hot Water: One constant speed constant volume
for each boiler plus one additional pump for standby with piping and valves for cross connection to other pumps.
? Secondary Hot Water Pumps: Multiple zoning to consist
of minimum two pumps (one standby) for each of the following systems; fan coil system, AHU system, domestic hot water system and laundry hot water system.
Equip pumps with variable frequency drives and premium duty motors rated for inverter duty. Locate pressure sensors in most remote areas of the building. ? Piping: Provide line-size shut-off valve and suction
diffuser on pump suction triple duty valve on pump discharge.
? Mounting: Install pumps on 10 cm (4 inch) high concrete
housekeeping pads with concrete inertia bases and spring isolators.
? Provide braided stainless steel flexible pipe connectors
at suction and discharge of each pump to isolate the piping system.
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15A - Mechanical Marriott Hotel - International
4. Miscellaneous:
? Exterior Walls: On exterior walls with large glass areas where heat loss exceeds 390 Watts/m (400 BTUh/ft.), provide low silhouette hot water fin tube radiation units in an architectural enclosure. Coordinate with Marriott Interior Design on unit selection and enclosure design.
? Stairwells: Provide heating in stairwells to maintain minimum 10° C (50° F). In enclosed stairs, of certain regions and where guest use is included in the design as a consistent route to other property spaces, provide cooling between 24 to 29° C (75 to 85° F) for guest comfort, otherwise provide ventilation.
? Front Entrance Vestibule: In cold climates, provide heat in vestibule to maintain minimum 10o C (50o F). F. Piping Systems
1. Water Treatment: Provide automated water treatment to
prevent premature pipe failure and loss of efficiency and heat transfer in chilled water, condenser water and heating hot water systems.
? Water Analysis: Obtain a complete current water analysis from the local water authority during the design process.
+ Address issues of corrosion, scale formation,
biological growth, and suspended solid matter.
+ If a complete current water analysis is not
available, obtain a water sample to submit to a laboratory approved by Marriott A&C Engineering. ? Chilled Water System: Design a complete automatic shot feeder system with bulk chemical storage for corrosion inhibitors and antimicrobials. ? Condenser Water System: Design a complete automatic system with total dissolved solids meter with flow-through cell, a chemical proportioning pump, a solenoid controlled adjustable flow bleed valve, automatic blow-down and bulk chemical storage for corrosion inhibitors, deposit dispersements, antimicrobials and pH adjustment chemicals.
? Heating Hot Water System: Include in the design complete automatic shot feeder system with bulk chemical storage for corrosion inhibitors and antimicrobials.
2. Testing:
? For future periodic inspection by operating personnel, provide a full line size flanged spool piece with a shut-off valve on each side of spool on main chilled water supply, condenser water supply and heating hot water supply lines.
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Marriott Hotel - International
Mechanical - 15A
? Provide full line size valved bypass around each spool
piece.
3. Pipe Material: Provide the following:
? HVAC Systems: Either schedule 40 black steel (welded,
screwed or grooved), type “L” copper, or schedule 40 CPVC. Use of CPVC is limited to pipes of under 75 mm (3 inch) and do not install CPVC piping outside. Galvanized pipe may not be used for HVAC systems. ? Di-electric Unions: Must be provided for connections of
different materials.
? Solder for Copper: 95/5 tin antimony lead solder. 4. Pipe Sizing: Size water piping based on the following:
? 50 mm (2 inch) and Smaller: 1.2 m/sec (4 fps) maximum
velocity in chilled, hot and condenser piping.
? 50 mm (2 inch) and Larger: 2.4 m/sec (8 fps) maximum
velocity in chilled, hot and condenser piping.
? Pressure Drop: 11.96 kPa (4 ft of water column) per 30.5
m (100 ft) maximum pipe pressure drop in any system.
5. Pipe Supports: Provide clevis or Uni-strut trapeze hangers
with spacing for steel or copper piping system supports based on pipe diameter plus provide supports on both sides of changes in direction and at both sides of valves and fittings.
? 50 mm (2 inch) and Smaller: 1.8 m (6 ft.) maximum.
? 50 mm (2 inch) to Less than 150 mm (6 inch): 3 m (10 ft.)
maximum.
? 150 mm (6 inches) and Larger: 4.5 m (15 ft.) maximum. ? Provide clevis or Uni-strut trapeze hangers with
maximum spacing of 1.2 m (4 ft) for PVC piping.
? Provide copper coated, steel riser clamps for use with
copper pipe at floor penetrations.
? Hanger Shields: Provide at each hanger for insulated
piping.
6. Pipe Insulation: Provide continuous insulation for piping
systems as follows.
? Chilled Water Supply, Return and Condensate Drains:
Closed cell thermal insulation of thickness based on pipe diameter as follows:
+ 18 mm (3/4 inch) Pipe: 18 mm (3/4 inch) minimum. + 25 mm (1 inch) to 50 mm (2 inches) Pipe: 25 mm (1 inch) minimum. + 50 mm (2 inch) and Larger Pipe: 35 mm (1? inch) minimum.
+ In low humidity climates, rigid glass fiber insulation with vapor barrier may be used for interior cold piping, with approval from Marriott A&C Engineering.
Design Standards - Copyright, Marriott International, Inc. January 2005 15A - 11
万豪酒店设计标准DS-MHR-Intl-2005Jan-M15-MEP
