15A - Mechanical Marriott Hotel - International
? Heating Hot Water Supply and Return: Insulate piping with 37 mm (1? inches) minimum thick fibrous glass insulation with vapor barrier.
? Seams and Joints: Continuously glued with insulation contact adhesive.
? Chilled Water, Exterior Piping: Insulate as required above and cover with an aluminum-clad jacket.
? Valves and Fittings: Insulate as required above and cover with one-piece, PVC, molded jacket covers.
? Freeze Protection of Condenser Water System: Where required by environmental conditions, and drain down is not possible, provide electric heat-trace and insulate condenser water piping same as required above for chilled water piping with aluminum clad jacket.
7. Vibration Isolation: Provide flexible pipe loops to
maintain the functional integrity of the mechanical piping systems during and after a seismic event. Provide to accommodate seismic displacements for vertical piping between floors, where piping passes through building seismic or expansion joints, or where supported piping connects to equipment mounted on vibration isolators. Provide flexible pipe loops for horizontal piping across building seismic or expansion joist to accommodate the resultant building drift. Provide UL approved flexible piping connectors on gas / fuel fired equipment to prevent damage to connections caused by piping stress where piping connects to equipment with rigid supports. 8. Valves: Design the piping distribution system with valves
located to permit repairs without shutting down more than one piping riser at a time.
Where possible, locate balancing, isolation and shut-off valves over back-of-house areas to allow remote, accessible service that is not visible to public and guests. Shut-off Valves: Provide shut-off valves for each piece of piped equipment to permit replacement, accessible service and repair without disturbing other equipment that is not dependent on operation of the equipment to be serviced. Provide full-port ball valves or butterfly valves for the following applications:
? In supply and return piping to all equipment and on both sides of 2-way control valves to permit service and replacement.
? In chilled water supply, chilled water return, hot water supply and hot water return lines at the base of all risers (including fan coil risers).
? At major branch take-offs for isolation of systems. ? Gate valves are not allowed for shut-off.
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Marriott Hotel - International
Mechanical - 15A
Balancing (Flow Control) Valves: ? Type: Hays Fluid Control (#2516 or equal) constant flow
device with Pressure Temperature (P/T) ports to determine pressure drop and water flow.
? Location: At base of return risers and on return of each
piece of equipment with shut-off valves on each side. Control Valves: Provide in the following locations:
? 2-way modulating control valves on air handling units
except 3-way at last air handling unit on major piping mains.
? 2-way control valves on fan coil units except 3-way on
the top floor.
? Size 2-way control valves to handle differential pressure
without blow-by.
9. Strainers: Provide strainers with drain valve at each air
handling unit coil for drain-down. Provide drain valve at the base of return risers.
10. Equipment Connections: Provide connections at the
following locations:
? Flanged or Screwed Unions: On both sides of 2-way
control valves.
? Di-Electric Unions: At connections of dissimilar metals. 11. Piping Identification: Provide the following:
? Plastic Nameplates: Identify air handling units, pumps,
heat exchangers, tanks, chillers, cooling towers, water treatment devices and control panels.
? Brass Tags: Identify small devices, including in-line
pumps and valves.
? Plastic Pipe Markers: Snap-on type for chilled water,
condensate drain, heating hot water and domestic hot water piping.
12. Air Vents: Provide the following:
? Manual type preferred located at system high points.
? Automatic Type: If required, place at system high points
in accessible ceiling spaces and other locations with vent port hard-piped to nearest floor drain. G. Air Side Systems
1. Design Considerations: Provide air conditioning for
habitable Public and Back-of-House spaces.
? Air Handling Unit (AHU) Locations: For ease of access
and maintenance, no AHU may be installed above ceilings. Locate AHU’s in either mechanical rooms or mechanical mezzanines, not outside.
? Outside Air Intakes: Locate in fully secured areas; 3 m
(10 ft.) minimum above grade and away from: + Exhaust
+ Traffic / trucks
+ Ability to contaminate
Design Standards - Copyright, Marriott International, Inc. January 2005 15A - 13
15A - Mechanical Marriott Hotel - International
? Mechanical Rooms: May be used as a return air plenum, but in all cases, unconditioned outside air shall be ducted to inlet of air handling units. Avoid access to mechanical spaces from public areas. Design equipment in locations to avoid using ladders for access and maintenance.
? Zoning: Zone air handling systems by type of occupancy and time of operation to allow shutdown of equipment or reset of temperature when heating and cooling is not required.
? Rooftop Air Handling Units (AHU’s): If required, locate rooftop AHU’s immediately above conditioned space with minimum two 90° elbows on supply and return duct to minimize potential noise generation.
? Variable Air Volume (VAV) Systems: Use VAV systems with variable speed drives to serve areas with similar occupancies and hours of operation but different load conditions (Ballrooms, multiple retail shops and gift shops, and administrative offices). Do not use VAV systems in laundries and kitchens.
? Contactors: Provide totally silent type (solid-state or mercury) contactors for air handling units, fan coil units, fans and electric heaters in or adjacent to public spaces and guestrooms.
? Smoke Control: For AHU’s that are part of the smoke control system, provide auxiliary contacts on the control panel to receive signal from the fire alarm system.
? Indoor Pools: Provide dehumidification type AHU’s designed and constructed for pools with reheat for proper temperature and humidity control. Locate supply air not to blow directly on glass windows.
? Region Requirements: In tropical climates consider use of:
+ Separate air-handling units for pre-conditioning all
outside air.
+ Run-around coils for reheat.
+ Recirculating only units controlled by humidistat, in
areas of potentially heavy infiltration.
+ In coastal areas or corrosive environments,
construct coils and fins of copper mechanically bonded to copper tubes. Provide corrosion protection for HVAC equipment and ductwork.
2. Supplemental A/C:
? Provide chilled water fan coil unit for primary cooling with back-up Direct Expansion (Dx) split system air conditioning units to provide 24 hour air conditioning for At Your Service (AYS), liquor storage rooms, PMS computer room, telephone equipment room, elevator machine rooms and refrigerated trash rooms.
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January 2005
Design Standards - Copyright, Marriott International, Inc.
Marriott Hotel - International
Mechanical - 15A
? Provide Dx split systems for Bakery and Butcher Shop. ? Connect Dx split systems to emergency power.
? For projects with exterior elevators, provide packaged air
conditioning and heating unit mounted on the top of the elevator cab. Manufacturer is Air-x-cel.
3. Exhaust Systems:
? General: Provide for pool equipment rooms, garages,
toilet rooms, ice / vending rooms, maintenance shops, locker rooms, electric rooms, kitchen hoods, bars, laundries, employee cafeteria and other areas producing odors, fumes or excessive heat and as required by governing code. ? Guestroom Towers: Provide exhaust in Service Elevator
Foyer, Laundry Chute Room, Housekeeping, Ice / Vending and Electric Rooms.
? Toilet Exhausts: Size for minimum pressure drop
differences across length of riser. See additional requirements under Ductwork in this Module.
? Refrigeration Compressor Room: Provide minimum
exhaust of 340 m3 / hr (200 cfm) to maintain 32o C (90o F).
4. Combustion Air: Provide in compliance with manufacturer’s
requirements and governing codes for gas or oil fired appliances including boilers, pool heaters and dryers.
? Cold Climates: Preheat combustion air at the intake
louvers to 4° C (40° F) to prevent freezing conditions in the central plant. Provide unit heaters for general space conditioning.
? Fan Operation: If provided by a fan, interlock fan with
boiler controls to ensure proper supply of combustion air prior to boiler firing.
5. Ventilation: Provide mechanical ventilation to non-conditioned spaces to maintain a minimum winter temperature of 12o C (55o F) and maximum summer temperature of 32 o C (90 o F). 6. Fans:
? Type: Typically, centrifugal type, except garage fans
which may be propeller or other low noise fan.
? Drive: Typically belt drive, except dedicated smoke
control fans are direct drive. ? Motor Horsepower: Exceed brake horsepower
requirements by 10% for airfoil and backward inclined fans and 20% for forward curve fans.
? Smoke Control: For fans that are part of the smoke
control system, provide auxiliary contacts on the starter to receive signal from the fire alarm.
Design Standards - Copyright, Marriott International, Inc. January 2005 15A - 15
15A - Mechanical Marriott Hotel - International
H. Public and Back-of-House AHUs
1. AHU Type: Provide factory packaged vertical or
horizontal type draw-thru low-pressure constant volume or variable air volume (VAV) units.
2. Fabrication: Double wall construction with closed cell
insulation and positive drain type stainless steel drain pan.
3. Components: Supply fan with double-width double-inlet
air-foil fans, hot water preheat coils with 2-way valves, chilled water cooling coils with 2-way valves, hot water reheat coils with 2-way valves (for humidity control), combination filter/mixing boxes with low velocity filters, motorized dampers and automatic temperature controls. ? Equip VAV AHUs with variable frequency drives (VFDs) and premium duty motors rated for inverter duty.
4. Return Fan: Provide with motor operated dampers on
return, outside air and relief air ducts, when required for airside economizer.
? Select fan with capacity to match supply air.
? Consider use as smoke exhaust fan if capable of exhausting 8 air changes per hour in smoke mode. Provide VFD as necessary.
5. Freeze-Stats: Utilize freeze-stats to protect coils from
freezing by shutting down fans and closing outside air dampers. 6. VAV Systems:
? Locate static pressure sensor at last VAV box and high pressure limit at AHU.
? Provide minimum of four inlet diameters of straight duct on VAV boxes for accurate sensing of velocity pressures on box controller.
? Locate VAV boxes either in mechanical plant rooms or above accessible ceilings, preferably in back of house areas, for service and maintenance. Where heat is required, outfit VAV boxes with hot water heating coils (or electric reheat coils) with 2-way control valves.
? Where possible, avoid locating VAV boxes in egress corridors that may be in conflict with hotel staff or guest circulation paths.
7. Sizing:
? Public Areas: Provide cooling coils serving public areas designed to provide 11.1oC (52oF) or less air at cooling conditions and with reheat capacity to provide 22.2oC (72oF) at 50% RH.
? Design Supply Rate: Minimum of six air changes per hour.
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January 2005
Design Standards - Copyright, Marriott International, Inc.
万豪酒店设计标准DS-MHR-Intl-2005Jan-M15-MEP
