federal electricity & water authority asset management … hvac.pdf · 2017. 2. 21. · 5.4...

WAM

Client: FEDERAL ELECTRICITY AND WATER AUTHORITY (FEWA)

Project: STANDARD SPECIFICATIONS FOR WATER WORKS

Engineer WATER DIRECTORATE / ASSET MANAGEMENT DEPARTMENT

Title: Technical Terms / Chapter 4/ Engineering Specifications / Mechanical System Specifications.

MS06-HEATING, VENTILATION AND AIR CONDITIONING SYSTEMS

Office:

DUBAI Order:

Document: MWA_PRO_07/WAM-04-MS06 Rev: OCT/2014 PAGE 1 OF 30

Federal Electricity & Water Authority

Water Directorate

Asset Management Department

STANDARD SPECIFICATIONS

FOR WATER WORKS

TECHNICAL TERMS

Chapter – 4

Engineering Specifications

Mechanical System Specifications

MS06-HEATING, VENTILATION &

AIR CONDITIONING SYSTEMS

WAM Client: FEDERAL ELECTRICITY AND WATER AUTHORITY (FEWA)





Office: DUBAI Order: Document: MWA_PRO_07/WAM-04-MS06 Rev:

OCT/201 4

PAGE 2 OF 30

MS06-HEATING, VENTILATION & AIR CONDITIONING SYSTEMS

TABLE OF CONTENTS

1. GENERAL

2. CAPACITIES, RATINGS, SIZES, QUANTITIES AND MATERIALS

3. APPLICABLE STANDARDS AND CODES

4. DESIGN PARAMETERS.

4.1 Outdoor Design Conditions

4.2 Indoor Design Conditions

4.3 Heating

4.4 Cooling

4.5 Humidification

4.6 Fresh Air Ventilation

4.7 Filtration

4.8 Control and Alarming

4.9 Noise Limits

4.10 Electrical Power Supply

5. DUCT WORK, GRILLES AND DIFFUSERS

5.1 Ductwork

5.2 Ductwork Hangers

5.3 Ductwork Supports

5.4 Dampers - General Requirements.

5.5 Butterfly, Bifurcating and Multi leaf Dampers

5.6 Fire Dampers

5.7 Flexible Joints

5.8 Flexible Connections

5.9 Air Intakes and Outlets

5.10 Access Doors

5.11 Ductwork Test Points

5.12 Grilles

5.13 Diffusers

5.14 Sand Trap Louvers

6. AIR CONDITIONING AND VENTILATION EQUIPMENTS

6.1 Package Air-Conditioning Unit

6.1.1 General

6.1.2 Casing

6.1.3 Filter Section

6.1.4 Compressors

6.1.5 Refrigerant Circuits

6.1.6 Evaporator Coil

6.1.7 Condenser Coil

6.1.8 Condenser Fans and Motors .

6.1.9 Supply Fans

6.1.10 Controls

6.1.11 Capacity control

6.1.12 Electrical Requirements







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6.1.13 Operating Characteristics

6.1.14 Testing and Inspection

6.2 Ducted Split Air Conditioning Units (AHU/ FCU)

6.2.1 Air Cooled Condensing Units

6.2.2 Air Handling Unit

6.2.3 Electrical Requirements

6.2.4 Operating Characteristics


6.3 Decorative Type Split Air Conditioning Unit

6.3.1 Indoor Fan Coil Unit

6.3.2 Evaporator Coil and Drain Pan .

6.3.3 Evaporator fans and motors

6.3.4 Filters

6.3.5 Electrical controls

6.3.6 Controls

6.3.7 Outdoor Condensing Unit

6.3.8 Casing

6.3.9 Refrigerant Controls

6.3.10 Compressor

6.3.11 Condensor Coil

6.3.12 Electrical Requirements .

6.3.13 Operating Characteristics .


6.4 Extract Ventilation Units

6.4.1 General

6.4.2 Roof Ventilators

6.4.3 Wall Propeller Exhaust Fans

6.4.4 Wall Mounted Mixed Flow Fans

6.4.5 In-line Fan

6.4.6 Centrifugal Fans/Blowers

6.4.6.1 Fan Casing

6.4.6.2 Fan Inlet.

6.4.6.3 Fan Impellers

6.4.6.4 Shafts for Belt-Driven Fans.

6.4.6.5 Bearing for Belt-Driven Fans.

6.4.6.6 Base Frames for Belt-Driven Fans.

6.4.6.7 Twin Fan Unit

6.4.6.8 Control Options

6.4.6.9 Casing

6.4.6.10 Installation/Application







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7. HVAC CONTROLS

8. REFRIGERANT SYSTEMS

9. THERMAL INSULATION

10. AC AND VENTILATION CONTROL PANEL

11. ACOUSTIC AND VIBRATION ISOLATION

11.1 General

11.2 Silencers (Dissipative)

11.3 Silencers (Reactive)

11.4 Anti-Vibration Mountings

11.5 Acoustic Louvers

12. TESTING AND COMMISSIONING

13. TEST INSTRUMENTS

14. DESIGN, SHOP AND AS-BUILT DRAWINGS

15. OPERATION AND MAINTENANCE MANUALS

16. SPARES

17. WARRANTY

18. QUALITY CONTROL

18.1 Quality Control

18.2 Inspection and Testing

19. TRAINING

20. VENDOR'S DOCUMENTATION







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MS06-HEATING, VENTILATION & AIR CONDITIONING SYSTEMS

GENERAL ـ 1

The scope of these specifications is for design, manufacture, testing at manufacturer works, supply, erection, testing, commissioning, performance and reliability confirmation, warranty confirmation of the entire electrical building air conditioning and ventilation system including motor control boards, switchgear, automatic control and associated cabling according to relevant standards. This section defines the air conditioning, ventilating and cooling requirements, their performance, behaviour and appearance for this project. Design conditions given in this section of the specification are typical for the types of buildings involved. Due consideration shall be taken with regard to fire hazard areas within the plant with particular attention being paid to fire dampers and emergency plant isolation. All air conditioning refrigeration plant shall be selected with a view to future conversion to ozone-friendly refrigerants when available. All plant specified should be capable of operation in aggressive atmosphere of this region. The scope of work and the equipment to be provided shall be as given in Specific Requirements of the Project of Volume-2. It is not intended here to describe the design, arrangement or installation, or to specify each and every component required for the completeness of the system or to select each material for safe and reliable operation of the proposed systems. In general, the system shall be complete in all respect with its equipment and accessories.

2 - CAPACITIES, RATINGS, SIZES, QUANTITIES AND MATERIALS

The capacities, rating, sizes, quantities and materials specified in Specific Requirements of Project and in this specification are to be considered as the minimum requirements to be provided. It is the responsibility of the Contractor / Manufacturer to determine the required capacities, rating, sizes and quantities and select the appropriate equipment/ material based on the guidelines given in the following specifications. Any discrepancy in capacities, rating, sizes, quantities and materials specified in Specific Requirements of Project and in the following specifications, then the requirements given in Specific Requirements of the Project shall prevail.

3- APPLICABLE STANDARDS AND CODES All works and equipment provided under this contract shall be installed in strict accordance with local codes, ordinances, rules and regulations of public administrative authorities including all health and safety related codes. The current edition at the time of biding of all the publications listed below shall apply, as applicable. In case of conflict between this specification and the below mentioned standards then the more stringent requirements shall be applicable.







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Air-conditioning and Refrigeration Institute (ARI) ARI 210 Unitary Air Conditioning Equipment ARI 270 Standard for Sound Rating of Outdoor Unitary Equipment ARI 340/360 Commercial and Industrial Unitary Air-Conditioning Eqpt. ARI 410 Forced Circulation Air-Cooling and Air-Heating Coils ARI 430 Central Station Air-Handling Unit American Society for Testing and Materials (ASTM) ASTM A 53/A 53M Standard Specification for Pipe, Steel, Black and Hot Dipped coated, Welded and Seamless.

ASTM A 90/A 90M Standard Test Method for Weight of Coating on Zinc-Coated (Galvanized) Iron or Steel Articles

ASTM A 653/ A 653M Standard Specification for Steel Sheet, Zinc-Coated by the Hot- Dip Process, Lock-Forming Quality ASTM B 62 Standard Specification for Composition Bronze or Ounce Metal Castings

ASTM B 280 Standard Specification for Seamless Copper Tube for Air Conditioning and Refrigeration Field Service

ASTM C 552 Standard Specification for Cellular Glass Thermal Insulation American Society of Heating, Refrigerating, and Air Conditioning Engineer, Inc. (ASHRAE) ASHRAE 23 Methods of Testing for Rating Positive Displacement Condensing Units .

ASHRAE 20 Methods of Testing for Rating Remote Mechanical Draft Air Cooled Refrigeration Condensing Units

ASHRAE 15 Safety Code for Mechanical Refrigeration ASHRAE 52 Method of Testing Air Cleaning Devices Used in General Ventilation for Removing Particulate Matter

ASHRAE Hand Books . National Electrical Manufactures Association (NEMA). National Fire Protection Association (NFPA) NFPA 70 National Electrical Code NFPA 90A Standard for the Installation of Air Conditioning and Ventilating Systems. NFPA 220 Standard on Types of Building Construction

NFPA 255 Method of Test of Surface Burning Characteristic of Building Material Rubber Manufactures Association (RMA) RMA IP-20 Specification for Drives Using Classical Multiple V-Belts, And Sheaves

– Cross Section A, B, C and D.

Sheet Metal and Air Conditioning Contractors National Association, Inc. (SMACNA) SMACNA-06 HVAC Duct Construction Standards – Metal and Flexible Underwriters Laboratories, Inc (UL) . UL 181 Factory-Made Air Ducts and Connectors UL 207 Refrigerant – Containing Components and Accessories, Non electrical UL 1995 UL Standard for Safety Heating and Cooling Equipment. UL 900 UL Standard for Safety Air Filter Units American Association of Balancing Contractors (AABC) National Standards for Field Measurement & Instrumentation







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National Environmental Balancing Bureau Procedural Standards for Testing, Adjusting and Balancing of Environmental Systems International Organization for Standardization (ISO) ISO 9001 Quality Systems Model for Quality Assurance in Design, Development Production, Installation and Servicing ISO 9004 Quality Management and Quality System Elements Guidelines

4. DESIGN PARAMETERS. 4.1 Outdoor Design Conditions

Summer Dry bulb temperature 52ºC Wet bulb temperature 31ºC Winter Dry bulb temperature 1ºC Daily Range 14ºC Design temperature for condensor 52ºC

4.2 Indoor Design Conditions The indoor design conditions for battery rooms, telecommunication areas, electrical areas,

conference rooms and offices shall be as follows : Summer Dry bulb temperature 24ºC ± 2ºC Relative Humidity 50% ± 10% Winter Dry bulb temperature 20ºC ± 2ºC Relative Humidity 50% ± 10% The indoor conditions of the kitchen and toilet rooms will not be controlled. 4.3 Heating Heating is required to raise the temperature inside the building to the required level. The dissipated heat from personnel, lighting and electronic equipment, etc. shall not be taken as a

contribution towards heating requirements calculations. Heat losses through walls, floors and roofs shall be taken into account.

The heating system shall consist of electric heater (resistance) installed in the AHU of the split air conditioning system or in the duct, as applicable.

4.4 Cooling Cooling is required to lower temperature and humidity inside the building to the required level. Cooling requirement calculation shall take into consideration heat dissipations from the following heat sources :

Personnel

Electrical/Electronic Equipment

Lighting

Fresh air intake

Solar radiation through transparent surface such as windows

Heat transmission through walls and roof. Cooling load requirements shall be based on the method of calculation using a software programme approved by FEWA. 4.5 Humidification Humidification, if required, shall increase the relative humidity inside the building to the required level. De-humidification shall be obtained by the cooling-coil of the air conditioning system.







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4.6 Fresh Air Ventilation

Provide a minimum fresh air intake to guarantee the required number of air changes per hour, in accordance with latest revision of ASHRAE Standard 62.

Maintain an overpressure of 30Pa in order to prevent the ingress of contaminants.

No return air to be considered for battery room, kitchens, toilets etc. A minimum 5 Air changes per hour quantity shall be considered for battery room and 10 air changes per hour for kitchen and toilets. Suitable exhaust fans shall be provided.

4.7 Filtration Fresh air ventilation intake shall be provided with sand trap and with aluminium washable pre filter

for 65% efficiency and final bag filter of 95% efficiency ASHRAE dust spot test filter. 4.8 Control and Alarming HVAC control and alarm system shall be as per HVAC Vendor's standards. As a minimum the HVAC control system shall include the following:

Temperature control

Humidity control Control system shall normally operate in automatic mode. The system shall, however, be equipped

for manual operation. The air conditioning system shall, comprise a 100% backup/stand-by units. In case of failure of the

operating unit, the stand-by unit shall operate automatically. HVAC Alarms for temperature, unit failure and exhaust fans status (running/failure) shall be

individually displayed in the local HVAC panel. 4.9 Noise Limits Maximum indoor noise level 60 dBA measured at a distance of 1.5m away from any wall or

grille. 4.10 Electrical Power Supply

Electrical power supply shall be 415V, 3 phase 4 wire and 240V, 1 phase, 50Hz.

5. DUCT WORK, GRILLES AND DIFFUSERS 5.1 Ductwork All duct works shall be constructed from hot dip galvanised steel sheet in accordance with the

Specification for sheet metal ductwork DW/142 as published by Heating and Ventilating Contractors Association, London

The drawings submitted with the Tender shall indicate the pressure classification, size, velocity

and flow of each section of ductwork as defined by DW/142 and shall be constructed and installed accordingly.

Angle galvanize steel frames shall be provided where connections are made. Where angle frames

are fitted, the corners shall not be split and the ends of the ductwork shall be lapped 10 mm over the angle. The corners of the angles shall be neatly rounded unless they are to mate with items having square corners.

On bends and offsets the centre line radius shall be equal to 1½ times the width of the duct unless

space restrictions preclude this, in such case it shall be as large as possible. Where long radius







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bends are not possible, approved turning vanes shall be fitted. Where desirable for acoustic attenuation and other purposes, square bends and 'splitters' shall be provided.

Branches shall generally be taken at 45° from the side of the main duct, but where supply diffusers

are fitted the manufacturer’s recommendations regarding air approach shall be followed. All ductwork exposed to external atmosphere or corrosive fumes shall be suitably protected,

internally and externally as required. Alternatively, a suitable material such as stainless steel shall be used when agreed by the Engineer. Such alternative material shall be constructed according to the relevant code of the Heating and Ventilating Contractors Association, London and clearly indicated on the drawings. Where ducts are lined internally for acoustic attenuation the internal area shall be maintained and the sheet metal size increased accordingly.

Flexible ducting shall be used only where any duct crosses expansion joints specially approved and

full details and samples shall be submitted when seeking approval. The maximum velocity of air in ducts shall be controlled to ensure that noise levels in adjacent rooms are kept below 35 dB A .

All air ducts shall be made of 0.8 mm-minimum thickness, galvanised steel sheets galv. 227-g/m²

zinc coating. Insulation of internal supply and return air ducts shall have 25 mm thick 48 kg/m³ density and external duct shall have 50 mm thick 48 kg/m³ density aluminium foil faced glass fibre rigid slabs securely fixed to the duct work with adhesive and stick clips (min 5/m²). The final vapour barriers shall be achieved by applying at least two coats (one horizontally and one transverse) of Foster 30-36 vapour sealing solution on a layer of 0.17 kg canvas cloth wrapping which should first be dipped in solution of Foster 30-36 and equal water before wrapping the ducts with 50 mm overlap.

Roof ducts and all internal exposed ducts shall be protected with 0.8 mm thick aluminium cladding.

5.2 Ductwork Hangers Spacing of hangers shall be provided in accordance with the following table. Steel hangers may be formed by bending the ends at least 180°. Power driven fasteners, may be

used in cast concrete slabs and beam clamps may also be used. Synthetic jointing of at least 7 mm thick after loading shall be interposed between the hangers and the air ducts. As an alternative to suspending ducts from above, they may, where appropriate be supported from the floor by means of angle iron frames.

No screws, bolts or other fixing devices shall be allowed to penetrate the air duct. Hangers are to be set out in collaboration with other services to avoid encroachment and obstruction thereto.

5.3 Ductwork Supports

Ductwork will not be permitted to rest directly on portions of the building except on concrete slabs or substantial brick walls and then only with the approval of the Engineer and with adequate insulation.

The welding or bolting of supports to structural steel work will not be permitted.Duct supports shall

be slotted galvanised steel U-channel support.

Duct Size (Long size) Hanger Size & Type Max. Spacing of pairs (m)

Up to 100 8mm Ø rod 2

100 - 150 8mm Ø rod 2

150 - 300 10mm Ø rod 2

Over 300 10mm Ø rod 1.2







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5.4.1 Dampers - General Requirements Sufficient dampers shall be provided to regulate and balance the system. Dampers on grilles or

diffusers shall be used for fine or secondary control. All dampers shall be sufficiently rigid to prevent fluttering. Unless otherwise indicated the air leakage past dampers in the fully closed position shall not exceed 5% of the maximum design air flow in the duct. All duct dampers except fire dampers and self-closing dampers shall be fitted with locking devices and position indicators.

Each primary control damper shall be fitted with a non-corrodible label stating the actual airflow in

M3/s and the cross-sectional area; the position of a damper as set after final regulation and balancing shall be indelibly marked on the damper quadrant.

5.5 Butterfly, Bifurcating and Multi leaf Dampers

Butterfly dampers shall consist of two plates, edge seamed, of at least the same thickness of

material as that from which the associated duct is made and rigidly fixed to each side of a mild steel operation spindle, the end of which shall be turned and housed in non-ferrous bearings.

Bifurcating dampers shall be of 2 mm thick sheet steel for sizes up to 450 mm square; for larger

sizes the thickness shall be as indicated in the tender drawings. Damper plates shall be rigidly fixed to square section mild steel spindles the ends of which shall be turned and housed in non-ferrous bearings.

Each leaf of a multi leaf damper shall consist of two plates of material of the same thickness as the

associated duct and rigidly fixed to each side of an operating spindle, the ends of which shall be housed in brass, nylon, or impregnated sintered metal, PTFE impregnated or ball bearings.

The ends of the spindles shall be linked so that one movement of the operating handle shall move

each leaf an equal amount. An inspection door shall be provided adjacent to each multi leaf damper.

On low velocity systems only, multi leaf damper blades may be of a single plate at least 1.6 mm thick and suitably stiffened. These dampers shall have bearings and inspection doors as specified.

Quadrants and operating handles shall be of die-cast aluminium with the words 'OPEN' and 'SHUT'

cast on the quadrant. Quadrants shall be securely fixed and the damper spindles shall be close fitting in the quadrant hubs to prevent any damper movement when the damper levers are locked.

5.6 Fire Dampers

Each fire damper shall have at least the same standard of fire resistance as the wall or floor through which the duct passes and shall comply with TROX K-90 equipment and designed to DIN 4102.

Fire dampers shall be motorized and installed wherever the ductwork passes through a wall or floor.

Purpose designed installation frames shall be used in accordance with manufacturer's instructions. Each pivoted type fire damper blade shall be fixed off centre to a substantial steel spindle which

shall rotate freely in bearings supported on the outside of the casing. The damper shall close against a 25 x 25 x 3 mm angle iron stop fixed to all four sides of a rectangular casing or to the full circumference of a circular casing. Operation of any fire damper shall be indicated in the control panel.

Spring return actuator shall close fire dampers. Under normal circumstances, power should be supplied to the actuator motor, which shall hold the damper blade open. On interruption of power, the actuator should close by spring action. Closing time should not be more than 10 seconds.







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When the power supply is restored the actuator motor should open the damper and at the same time recharge the released spring.

The actuator motor shall stop automatically when the damper is fully open. A temperature switch

connected to the actuator circuit shall be provided which will close the damper when the

temperature exceeds 70C. The fire damper control/indication contacts shall be wired to suitable common junction boxes by

using fire proof cables subject to FEWA approval.

5.7 Flexible Joints Flexible joints shall be provided on fan inlet and outlet connections and elsewhere on the ductwork

where necessary. They shall be of the full cross-sectional area of the mating fan inlet or outlet or duct section. The ends of the ducts or the duct and the fan connection shall be in line.

Flexible joints shall be of the glass fibre cloth type; canvas will not be accepted. The width of the

joints from metal edge to metal edge shall be not less than 80 mm and not more than 250 mm. All flexible joints other than fan inlet connections shall be between flanged ends. The flexible

material flange shall be backed by an angle or flat iron flange and the flexible joint shall be securely held between the metal flanges. Flat iron bands used with fan inlets shall be not less than 5 mm thick. 5.8 Flexible Connections

Where flexible connections are indicated or required between rigid ductwork and particular components or items of equipment the internal diameter of the flexible duct shall be equal to the external diameter of the rigid ductwork and of the spigot served.

The use of flexible duct between rigid sections of sheet metal ductwork to change direction or plane

will not be permitted except where indicated or expressly authorised by the Engineer. The flexible duct shall have a liner and a cover of tough tear- resistant fabric equal in durability and

flexibility to glass fibre fabric and shall be impregnated and coated with plastics. It shall be reinforced with a bonded galvanised spring steel wire helix between the liner and the cover and an outer helix of glass fibre cord or equal shall be bonded to the cover to ensure regular convolutions.

Alternatively the flexible duct shall consist of flexible corrugated metal tubing of stainless steel,

aluminium, tinplated steel or aluminium-coated steel. The metal may be lined on the inside or the outside or both with plastics material.

The joints to rigid spigots shall be sealed with a brush coat of pipe jointing paste or mastic

compound. Ducts up to 150 mm diameter shall be secured with a worm drive type hose clip. Ducts over 150 mm diameter shall be secured with a band clip.

The frictional resistance to air flow per unit length of the flexible duct shall not exceed 50% more

than the frictional resistance per unit length of galvanised steel ducts of equivalent diameter. The radius ratio R/D for bends shall not be less than 2, where R is the centre line radius and D is the diameter of the flexible duct.

The leakage from any section of flexible duct shall not exceed 1% of the design airflow rate at the

static operating pressure.







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5.9 Air Intakes and Outlets A galvanised steel wire mesh screen of 20 mm diamond mesh and at least 2 mm diameter wire and

complete with a frame of galvanised steel rod with securing lugs or of flat iron shall be provided and fixed by the Contractor on the inner side of the louvers.

5.10 Access Doors

Access doors shall be provided adjacent to all items of equipment requiring maintenance or inspection.Access doors shall be of the hinged type manufactured from 1.6 mm thickness galvanised sheet steel suitably stiffened. The door shall be insulated with 50 mm thick 48 kg/m3 fibre glass.

The doors shall be provided with robust hinges on one vertical side and a suitable handle operated

lock on the other vertical side. All hinges and handle operated locks shall be cadmium plated or treated with a similar corrosion resistant finish.

All access doors shall be made airtight by the use of plastic or felt strip.

5.11 Ductwork Test Points Test points suitable for pilot tube insertion shall be provided in accordance with the Chartered

Institute of Building Services (London) Commissioning Code 'A' on two adjacent sides of rectangular ducts as determined by the access available. They shall consist of 25 mm diameter holes, fitted with a cover secured by large headed set screws, one hole being slotted to allow the cover to swing clear without being removed.

The use of plastic or rubber plugs will not be accepted. Test points shall be positioned at points

where the air flow is stable and shall include each branch duct as well as suitable locations in the main duct.

5.12 Grilles

Grilles shall be of steel, aluminium or PVC according to the application. Steel grilles shall be protected against rusting and supplied in fully finished condition. All grilles except those on exposed ducting shall incorporate an edge seal.

Velocities, net airways and distribution patterns shall give satisfactory air distribution, and be free of

draughts, stratification and noise nuisance. The Contractor shall make final adjustments to air patterns when balancing.

Damper assemblies and internal surfaces of outlets and take-off ductwork where visible through

outlet faces, shall be painted matt black. All outlets shall be fitted truly square and in alignment. Perimeter trims shall seat hard against wall

or ceiling finishes as applicable and shall properly mask the trimmed openings. Unless otherwise approved, all fixings shall be concealed.

Each supply air grille shall be complete with an opposed blade multi leaf damper. Alternatively, in

lieu of the opposed blade multi leaf damper a rhomboidal air controller may be provided; this air controller shall control both the volume of air passing and the distribution of air across the grille face. The louvers and the damper or air controller shall be adjustable from the front of the grille. For up to ten grilles, one set of any tools required for adjusting the louvers and dampers or air controllers shall be provided; from eleven to twenty-four grilles, two sets; above twenty-five grilles, three sets.

Return air grilles may have either a single set of louvers or bars (either vertical or horizontal) or a

lattice or egg crate front. Each return air grille shall be complete with an opposed blade multi leaf damper or a rhomboidal air controller operable from the front.







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5.13 Diffusers

Diffusers shall be of steel or aluminium to suit the application. Steel diffusers shall be protected against rusting and shall be stove enamelled. Diffusers, except on exposed ductwork, shall incorporate an edge seal; diffusers mounted on ceilings shall have anti-smudge rings. Pan type diffusers may be provided except where cone type diffusers are indicated.

Diffusers shall be provided with volume control dampers of the iris, flap or sleeve type, which shall

be adjustable from the front of the diffuser. Where the length of a vertical duct to a diffuser is less than twice the diameter of the diffuser an equalising deflector shall be fitted.

Linear diffusers shall include a control damper at the rear of the vanes giving volume control down

to complete shut-off and operated from the face of the diffuser. Linear diffusers for supply air shall have adjustable blades to give directional control of airflow. Where linear diffusers are mounted in a continuous line there shall be means of ensuring alignment between consecutive diffusers and of equalising pressure behind the vanes.

5.14 Sand Trap Louvers

Sand trap louvers shall be constructed from galvanised steel/ powder coated aluminium sheet not less than 1.2 mm thick mounted on angle iron supports and carried in a louver box of galvanised sheet steel of the same thickness.The base member of the box shall slope downwards to the outside of the building at an angle of 15°.

The louvers shall be of the labyrinth type designed to achieve velocity changes of the air passing

through it inducing fall-out of the sand.

6. AIR CONDITIONING AND VENTILATION EQUIPMENTS

6.1 Package Air-Conditioning Unit 6.1.1 General

The package Air-conditioning unit shall be a factory assembled, single piece compact unit comprising compressor, air cooled condenser and evaporator, all assembled on a common base and encased in a weather proof cabinet.

The base shall have slots and rigging holes to facilitate lifting and shifting of the unit. The unit shall have horizontal connections / horizontal adaptors for supply and return air ducts.

The unit shall have a corrosion resistant sloped drain pan. The unit rating shall be in accordance with ARI Standards 210/240 or 270 & 340/360.All insulation

and adhesives used shall meet NFPA 90A requirements for flame spread and smoke generation.

6.1.2 Casing The casing shall be constructed of 18G (minimum) galvanized steel, zinc phosphate bonderized and coated with an oven baked polyester paint on all externally exposed surfaces,

which shall be weather proof. Internally insulated access panels shall be provided for ease of service and maintenance. The insulation used shall be 25 mm thick, 24 kg/m3 density fiber glass acoustic insulation tightly fitted with a gasket on a rigid frame.

6.1.3 Filter Section

Standard filter section shall consist of 50mm thick high efficiency filters. Filter mount integral within unit and shall be accessible by hinged access panels.

6.1.4 Compressors

Hermetic or semi hermetic reciprocating compressor direct drive, 1750 RPM, with isolated mounting, integral suction accumulation, oil pump, oil filter screen, magnetic discs, oil level sight







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glass, oil changing valve, lubrication for each bearing, connecting rod, crankcase heater and well, double mesh suction inlet screen, high strength non-flexing ring type suction and discharge valves, large gas passages and minimum clearance volumes, electric actuated unloading, and replaceable unloaded solenoid valves. Motor shall be suction gas cooled and shall have voltage utilization range plus or minus 10 percent of nameplate voltages.

Two winding thermostats imbedded between three motor windings shall protect motor against

excessive winding temperatures. Safety controls shall include high and low pressure cut-outs, non recycling pump down and reset relay. Compressor shall conform to ARI Standard 520.

Motors shall conform to NEMA, MG-1 & MG-2 and shall be of constant speed, squirrel cage

induction, hermetically sealed high torque type with low starting current and line break protection. All controls and contactors shall be mounted in weatherproof control box.

6.1.5 Refrigerant Circuits

Each refrigerant circuit shall have independent thermostatic expansion devices, service pressure ports for high pressure, low pressure and oil pressure gauges and refrigerant line filter driers factory installed as standard. An area shall be provided for replacement suction line driers.

6.1.6 Evaporator Coil

Seamless copper tubing mechanically bonded to heavy duty aluminium fins of configurated design. All coils shall be factory pressure and leak tested at 2,070 kPa (300 Psi). Coils shall conform to ARI 410. Casing and tube support shall be 18 gauge minimum galvanized steel.

6.1.7 Condenser Coil

Configured copper fin secondary surface shall be mechanically bonded to primary surface of seamless copper tubing. Sub cooling circuit(s) with liquid accumulator(s) shall be standard, Shall be factory tested at 3,100 kPag (450 psig) air pressure, and vacuum dehydrated. Coils shall conform to ARI 410. The coils shall be coated with air dry "phenolic", thermally set "here site", or approved equal coating suitable for salty seacoast with SO2 environment.

6.1.8 Condenser Fans and Motors .

Vertical discharge, direct drive fans, statically and dynamically balanced, with corrosion resistance steel blades and zinc plated steel hubs. Motors shall be three-phase with permanently lubricated ball bearings, built-in current and thermal over-load protection, and weather tight slingers over bearings.

6.1.9 Supply Fans

Double inlet, forward curved fans mounted on common shaft with adjustable sheave drive. All fans shall be statically and dynamically balanced and tested at the factory. Supply fan test run shall be as a part of unit test. Unit shall reach rated rpm before fan shaft passes through first critical speed.

Fan shaft shall be mounted on two grease lubricated ball bearings designed for 200,000 hours

average life. Fan motor and fan assembly shall be mounted on common base to allow consistent belt tension with no relative motion between fan and motor shafts. Entire assembly shall be completely isolated from unit and fan board by double deflection, rubber shear isolators on motor sizes larger than 5 hp.

Provide fan motors with a nameplate rating of no less than 10 percent above the fan brake

horsepower and drive loss at maximum capacities at any point on the characteristic curve for forward curved fans, and 5 percent for backward curved fans.







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Each motor provided with automatic control shall be capable of making as frequent starts as the control device may demand. Motors not provided with automatic control shall be capable of making no less than 4 starts every hour.

Provide belt drives with a service no less than 1.4, arrange belt drives to permit use of speed

counters with the guards in place. Belts guards shall be furnished on units having externally mounted motors. Belt guards shall conform to OSHA (Occupations Safety and Health Administration) requirements. Construct belt guards of mill galvanized or phosphate treated and prime finish coated steel with solid slides and face, bolted to fan housing and motor rails.

Belt guards are not required on units having internally mounted motors.Provide poly phase motors

of the drip-proof, squirrel cage, induction type, in accordance with NEMA (National Electrical Manufacturers Association) MG-1. Poly phase motors shall be single voltage type or increment starting type.

Securely mount each direct connected motor in accurate alignment. The drive shall be free from

both angular and parallel misalignment when both motor and driven machine are operating at normal temperatures. Provide each belt connected motor with securely

mounted, adjustable base to permit installation and adjustment of belts. Provide 2 motor sheaves: one of the adjustable pitch type to be used for air balance, and one of the

fixed pitch type to be used for final rpm. No motors shall be equipped with bushing type bearings. All motors shall have ball bearings.

6.1.10 Controls Unit shall be completely factory wired with necessary controls and contactor pressure lugs or

terminal block for power wiring. Units shall provide an external location for mounting fused disconnect device.

The following controls shall be factory installed in the Packaged unit. Any additional controls necessary for the operation of the unit, shall also be installed by the

manufacturer. The compressors and fan motors have to be equipped with single phase preventor / power failure relay.

6.1.11 Capacity control

High Pressure Switch with manual reset Low pressure Switch Oil Safety Switch Time Delay Relay to delay the starting of each compressor Units shall be controlled by cooling thermostat.

Instruments and Controls offered for the application envisaged shall be well proven and tested in similar applications in United Arab Emirates for a minimum period of three years. Spare parts and service support shall be locally available. Makes and model numbers of all instruments and control/logic schematic shall be subject to

client/consultant approval.

6.1.12 Electrical Requirements The unit shall operate on a 415 V / 3 Ph / 50 Hz or 240 V / 1 Ph / 50 Hz power supply as applicable. All electrical wiring shall enter the unit cabinet at a single point.







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6.1.13 Operating Characteristics The unit shall be capable of operating at an ambient temperature of 52ºC.Unless stated otherwise, unit performance shall be rated at an ambient temperature of 52ºC dry bulb temperature.

6.1.14 Testing and Inspection Complete factory tests, in accordance with the applicable standards shall be performed prior to

shipment to demonstrate to FEWA/Engineer that the package AC units meet the requirements of this specification. The package units shall not be shipped unless results of test show compliance with all requirements of this specification.

6.2 Ducted Split Air Conditioning Units (AHU/ FCU)

6.2.1 Air Cooled Condensing Units

Air cooled condensing units with casing construction made of galvanized sheet metal, zinc

phosphatised with stowing enamel finish. Semi-hermetic compressors of reciprocating type must have built-in suction gas cooled motor with control system allowing safe and long-life operation.

Condensing units must be equipped with oil strainer, sight glass, replaceable core type filter drier,

shut-off valves and liquid line solenoid valve. Condenser coils shall be especially coated for corrosion protection (here site coating or equivalent). Each compressor must be mounted on spring vibration isolators with in the base frame. In addition to this, condensing units shall be mounted on vibration isolation pads of minimum 50 mm thickness.

All components must be protected from weather, heat, sand-storms, salt bearing air, etc.Units must

be completed with refrigerant piping as connection between the condensing unit and the air handling unit. Each condensing unit shall have its own HP, LP and oil pressure gauges with isolating valves. Control panel shall have all necessary safety and control devices for automatic operation. Compressors and fan motors have to be equipped with single phase preventor / power failure relay.

The compressors of these condensing units shall have a special guarantee of five years from the

contractual completion date and complete compressor have to be replaced if found defective during this guarantee period.

6.2.2 Air Handling Unit

Air handling units shall consist of double skin casing construction with minimum 25 mm panel insulation, hinged access panels, vertical/horizontal supply and return connections (factorybuilt),high efficiency bag filters, washable metallic pre-filter and all necessary safety and control devices for automatic operation. The airflow shall be performed by means of low noise fans.

The casings shall include the evaporator of copper tube and copper fins, the expansion valve, all

piping and insulation. The copper tube and copper fins shall be tin plated or by gold coated against corrosion. 6.2.3 Electrical Requirements

The unit shall operate on a 415 V / 3 Ph / 50 Hz or 240 V / 1 Ph / 50 Hz power supply as applicable. All electrical wiring shall enter the unit cabinet at a single point.

6.2.4 Operating Characteristics The unit shall be capable of operating at an ambient temperature of 52ºC.Unless stated Otherwise, unit performance shall be rated at an ambient temperature of 52ºC dry bulb temperature.







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Complete factory tests shall be performed prior to shipment to demonstrate to FEWA that that units meet the requirements of this specification. The air-conditioning units shall not be shipped unless results of test show compliance with all

requirements of this specification.

6.3 Decorative Type Split Air Conditioning Unit Contractor shall select units specifically designed for installation of indoor wall mounted fan coil unit

and outdoor floor / roof mounted condensing unit. The units shall be factory assembled including direct expansion type coil, condensate drain pan, fans, fan motors, filters and

controls all in an insulated casing. Unit shall be rated in accordance with ARI standards 210/240 and 340/360.

6.3.1 Indoor Fan Coil Unit

The unit casing shall be constructed of heavy gauge galvanized steel powder coated with a full covering to all edges and a uniform paint thickness. The casing shall be completely insulated with at least 15 mm thick fire retardant insulation.

6.3.2 Evaporator Coil and Drain Pan .

The aluminium fin surface shall be mechanically bonded to 3/8" copper tubing. The coil shall be pressure and leak tested at 400 psig, be arranged for draw-through airflow and includes an L-shaped drain pan constructed of galvanized steel and insulated.

6.3.3 Evaporator fans and motors

It shall be dynamically balanced, double inlet, double width, forward curved, three speed permanent split capacitor direct drive. Fan motors shall be protected against overload. Fan and

motor bearings shall be permanently lubricated and be easily accessible.

6.3.4 Filters It shall be washable, reusable type installed by the factory and be easily accessed by removing the unit front panel.

6.3.5 Electrical controls Magnetic evaporator fan relay and low voltage terminal board shall be factory wired and installed.

6.3.6 Controls Factory wired microprocessor type thermostat shall be provided and include an LED display

indicator, thermostat, room temperature indicator and 3-speed fan control.

6.3.7 Outdoor Condensing Unit The condensing units shall be fully charged from the factory for 7.5m of piping. The unit shall be

suitable for outdoor installation. Compressor shall be either reciprocating or rotary type. Condensing unit shall be mounted on vibration isolation pads of minimum 50mm thickness.

6.3.8 Casing Unit casing shall be constructed of heavy gauge galvanized steel and painted with a weather

resistant powder coating.

6.3.9 Refrigerant Controls Refrigerant system controls shall include condenser fan and compressor contactor.







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Compressor shall be protected against high and low pressure. A factory installed liquid line drier and low pressure switch shall be provided. Field braze connections shall be externally accessible multi-use liquid and gas line valves with

service pressure gauge ports.

6.3.10 Compressor The compressor shall be either reciprocating or rotary type. The compressor shall include internal

over temperature and pressure protection, total epoxy dipped hermetic motor windings, thermostatically controlled sump heater, roto lock suction and discharge refrigerant connections, centrifugal oil pump, steel alloy valves in valve plate assembly, and internal spring mounts.

6.3.11 Condensor Coil

The coil shall be continuously wrapped, corrosion resistant all aluminium with brazed joints. The coil shall be 3/8" O.D. seamless aluminium glued to a continuous aluminium fin. The coil shall

be protected on all four sides by louvered panels. The coils shall be coated with air dry "phenolic", thermally set "heresite", or approved equal coating suitable for salty seacoast with SO2 environment.

6.3.12 Electrical Requirements .

The unit shall operate on a 415 V / 3 Ph / 50 Hz or 240 V / 1 Ph / 50 Hz power supply as applicable. All electrical wiring shall enter the unit cabinet at a single point.

6.3.13 Operating Characteristics . The unit shall be capable of operating at an ambient temperature of 52ºC.Unless stated otherwise, unit performance shall be rated at an ambient temperature of 52ºC dry bulb temperature.

Decorative type A/C units selected shall not be less than 2 Tons cooling capacity.

6.3.14 Testing and Inspection Complete factory tests shall be performed prior to shipment to demonstrate to FEWA that that units

meet the requirements of this specification. The split Air conditioning units shall not be shipped unless results of test show compliance with all requirements of this specification.

6.4 Extract Ventilation Units 6.4.1 General

The Contractor shall supply and install where shown on the Drawings, fans as described hereinafter and of capacities indicated in the Capacity Schedule on the Drawings.

The fan motors and starters shall be in accordance with the Electrical division of these specifications. Test and rate all fans in accordance with the standards of the AMCA. All fans must bear the AMCA

certified rating seal. Make appropriate allowance for the effects on fan performance of all installation conditions including

plenum enclosures and inlet and discharge arrangements so that actual installed fan performance equals that specified.

Balance all fan wheels and all other moving components statically and dynamically. Where coating

is specified and it affects the balance of the fan wheel, perform balancing after the coating has been applied.

Drill all fan shafts on the centre line to receive a tachometer.







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Belt driven fans shall be connected to the driving motor by means of an approved V-belt drive, with

adjustable sheaves, unless otherwise designated. V-belt drives shall be designed for 50% overload capacity and the motors for such drives shall be equipped with adjustable bases or slide rails.

Bearings shall be self-aligning, grease lubricated, ball-bearing type, and shall be complete with

grease fittings, extended for easy access where necessary. Weather proof hoods should be provided for all motors and drives exposed to weather to the

approval of FEWA/Engineer. Back draft dampers, gravity type, shall be installed on the fan discharge of all fans discharging

directly to the atmosphere. Fans are to operate steadily without pulsation at design conditions. Centrifugal fan characteristic

curves must be such that the fan operation point falls below the point of no flow static pressure, to the right of the point corresponding to that of maximum mechanical efficiency, and a 15% increase in static pressure over that specified results in not more than a 15% reduction in cfm and does not affect the stability of fan operation. If necessary N accomplishes the foregoing by modifying the width of the wheel and/or by providing inlet vanes to change the characteristic curve.

Performance curves shall be submitted for each fan for approval.

6.4.2 Roof Ventilators Roof extract unit to be constructed in aluminium alloy with no rusting fixings and to incorporate outlet bird guards, air operated / gravity return shutters and service panels for access to all working parts. Fan to be single inlet high performance mixed flow type with asymmetric blade spacing, dynamically balanced after manufacture and directly driven by motor. Motor to be manufactured to BS 5000, to have sealed for life bearings and IP 55 rating. Impeller and motor to be quickly removable / replaceable without disturbing weathering or flashing arrangement. Unit shall be capable of operation in a hot (60ºC) and humid atmosphere. Unit to be finished in polyester powder paint.

Each roof ventilator shall be complete with:

Electric motor suitable for outdoor operation.

Aluminium protective cowl and body.

Metallic fixing and supporting frame.

Weather proof non fused disconnect switch under fan cowl.

Automatic Shutter. Quiet Curb, manufactured in galvanized sheet steel with perforated aluminium sheet splitters and

containing mineral wool acoustic medium.

6.4.3 Wall Propeller Exhaust Fans Wall exhaust fan shall be of the wall or window mounted type all plastic construction. Fan shall be complete with outside plastic grille, enough length of electrical flexible cord (including ground conductor) with suitable connecting end (plug, or..) to connect to electrical outlet, and wall mounted on-off switch. Fan shall have a shutter that opens and closes automatically by means of an electromagnet.







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6.4.4 Wall Mounted Mixed Flow Fans Casing to be manufactured in galvanized steel with no rusting fixings. Unit shall have a performance mixed flow impeller manufactured in aluminium, statically and dynamically balanced. The unit shall be tested to BS 848 Part 1 & Part 2.A removable access panel shall be provided for easy access to the impeller for cleaning purposes.

Motors shall comply to BS 5000 with class F insulation. Motor protection rating shall be IP 54.

Motors are to be prewired to an external terminal box through flexible conduit. All units shall be suitable for external use in a hot (60ºC) and humid atmosphere. Each unit shall be complete with short silencer and installation accessories. 6.4.5 In-line Fan The fan shall be of the centrifugal or mixed flow in-line type all aluminium construction and shall be complete with:

Electric motor mounted outside the air steam, when air temperature inside the duct is above 200ºF. (93ºC), otherwise inside air stream.

Metallic fixing frame and supports.

Dust proof, non fused disconnect switch under motor casing.

Belt drive and belt guard or as stated in Capacity Schedule.

Vibration isolators.

Aluminium air foil blades impeller with non overloading horse power characteristic.

Flexible duct connection at each end. 6.4.6 Centrifugal Fans/Blowers The fans / blowers shall be belt driven centrifugal fan of double-inlet design with backward curved blades. The fans shall be complete with belt drive, 4 pole / motor, protective screen for the inlet, flexible connection duct for the outlet, counter flange for the outlet, drain and inspection cover. Connections shall be free inlet and ducted outlet. Air intake to the fan shall be through sand trap filter louvers.

6.4.6.1 Fan Casing The fan casing is made of Galvanized sheet steel. The casing side plates are stamped in one piece. This ensures accurate location of the hole for the inlet and the mounting points for the radial supporting arms and frames. The inlets deep-pressed in the end walls of the casing contribute towards very high rigidity of the casing, thus ensuring smooth, vibration – free operation of the fan, even at high speeds. The ends and scroll plate of the casing are jointed by the thoroughly proven " Pittsburgh folding method" which produces tight, strong joints. The method guarantees high, consistent quality and good dimensional accuracy of the casing. The casing side plates are internally provided with weld nuts at all holes for securing the bearing supports and at inaccessible holes for securing the base frame. This facilitates the removal and fitting of these parts.







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6.4.6.2 Fan Inlet. The design of the fan inlet is of vital importance to the fan efficiency and sound generated by the fan. On fans with forward-curved blades, good performance is achieved by pressing the inlets directly into the side plates. On fans with backward-curved blades, the inlet must be deeper and must also extend into the impeller with a certain amount of overlap and a small, accurately predetermined radial gap.These inlet are deep-drawn in one piece and are fitted into special pressed recesses in the casing sides. 6.4.6.3 Fan Impellers The fan impellers are designed for high rigidity and strength. They are balanced to an accuracy which is better than ISO Standard 1940-1940/2, G 6.3 at the maximum speed. The impeller is secured to the shaft by means of a taper sleeve. As a result, it is always mounted as accurately on the fan shaft as it has been on the shaft of the balancing machine. The impeller and shaft together will therefore always retain the exceptional balancing accuracy achieved when the impeller was balanced. The impeller has backward-curved blades and is characterized by an extremely high efficiency (up to 86%), low sound level and a stable fan characteristic, throughout the recommended working range. The fan characteristic is very steep, which is beneficial if variations in the system resistance must cause only minor changes in the air flow. The steep curve is also highly beneficial if several fans are to operate in parallel. 6.4.6.4 Shafts for Belt-Driven Fans. The steel shafts are centre less-ground and are provided with keyways for the belt pulleys- at both ends of double-inlet fans. The shafts are designed with a high factor of safety against fatigue and for a critical speed which is at least 40% higher than the maximum fan speed. 6.4.6.5 Bearing for Belt-Driven Fans. Most fans are equipped with permanently lubricated, single-row, deep-groove ball bearings secured to the shaft by means of a taper mounting sleeve. This method of mounting ensures that the inner race of the bearing will always be concentric with the shaft, and that the bearing will not work loose. The concentricity ensures smooth, vibration-free operation and long useful life of the fan. The method of mounting also eliminates shaft damage caused by set-screws and gluing used in other methods of mounting. Due to the mounting sleeve fitted between the shaft and bearing, the bearing must be one size larger than it would have been without the sleeve. The useful life of the bearing is therefore increased by 3 to 5 times. Each deep-grove ball bearing is mounted in a rubber damper and is fitted into a bearing housing supported by a study three-arm or four-arm spider. The larger fans are equipped as standard with Plummer blocks which have self-aligning roller bearings mounted on a study bearing bracket made of welded flat iron bar. The deep-grove ball bearings are permanently lubricated, whereas the self-aligning roller bearings are fitted with grease nipples.







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All bearings are rated, with 90% probability, for a life cycle of 40 000 hours at the maximum speed. The probable mean useful life is thus 200 000 hours or more at the maximum fan speed, and appreciably longer at lower speeds. 6.4.6.6 Base Frames for Belt-Driven Fans. The base frame supports the fan, motor and belt drive. The belt drive gives rise to high loads on the shaft (600 – 1200 Newton per belt), and the loads also vary due to the irregularity of the belts. To enable the belts to be tensioned and to ensure smooth running, fans of smaller sizes are equipped with a pivoted motor bracket which, together with the base frame and fan, forms a very rigid unit. In the case of larger sizes, the fan and the motor are mounted on common longitudinal beams which are extra high to ensure maximum possible stiffness in bending. However, the beam height does not increase the overall height of the fan unit, since the fan casing is located between the beams. 6.4.6.7 Twin Fan Unit

The Twin fan shall be supplied with a square end spigot and 2 opposed outlet grilles. 6.4.6.8 Control Options The Twin fan shall have automatic fan duty sharing. In case of failure of duty unit standby unit shall come into operation automatically. 6.4.6.9 Casing Casing manufactured from heavy gauge natural aluminium alloy with top panel fully detachable. All internal inlet chamber surfaces are acoustically treated. Outlet grilles are positioned on opposing sides of the fan casing to prevent wind pressures effecting fan performance. Fan assembles incorporate forward curved centrifugal impellers directly driven by motors fitted with air flow and failure monitors. Fans are suitable for operation in ambient temperatures up to 60ºC. 6.4.6.10 Installation/Application All units are suitable for internal and external use and may be installed up to a maximum angle of 60ºC. 7. HVAC CONTROLS

The control system shall be designed to monitor and control the operation of all equipment associated with the HVAC system, in the duty and standby modes, including Air Handling Units, Condensing Units and fans. The sequence of control system shall be submitted for approval by FEWA/Engineer. The control system shall monitor all temperature and humidity (as necessary) set points. System running/standby/off/out of service should be reflected on the HVAC panel. The HVAC control system shall be interlocked with the fire and detection system, to shut down the whole HVAC plant upon receipt of a signal from the fire and gas detection system. The status of each fire damper shall be indicated on the panel.







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SPECIFICATION REQUIREMENTS a. The battery room exhaust fans shall be no sparking construction with explosion proof and shall provide adequate ventilation to prevent accumulation of explosive gas. b. The outdoor Package Air-conditioning Units, Air Handling Units and Condensing Units shall be

provided with weatherproof motors and condenser enclosure, and shall be designed to protect the fan, motor drive and coils from the harsh weather conditions.

8. REFRIGERANT SYSTEMS Pipe work for refrigerant systems shall be of refrigeration quality copper to BS 2871 table X with BS 864 part 2. All Joints shall be brazed. Fittings shall be in accordance Pipelines shall be firmly secured and measures shall be taken to prevent vibration weakening joints and connections. Pipe work shall be designed and run so that any oil in the compressor discharge refrigerant which passes through the oil separator (where fitted) is carried through the system and returned. At any point where a large quantity of oil may accumulate an oil separator and means of returning the oil to the compressor shall be provided. Valves required for compressors, liquid receivers etc. shall be of either diaphragm or bellows type or be packed valves complete with a back seating and a seal cap. Compressors shall not be connected to run in parallel (i.e., with common discharge and/or suction lines). Where, to increase availability, it is required that any compressor shall be capable of working with any condenser or evaporator, cross connections shall be provided and all major plant items shall be valved for isolation. After erection the whole of the refrigeration pipe work shall be pressurized and tested for leaks. All fittings for use with refrigeration systems shall be suitable quality copper with all joints being made either by flanges, brazing, welding or soldered capillary fittings. The Contractor shall ensure that the correct quality of brazing or soldering filter rod, together with the correct flux is used for the type of joint with due consideration for the temperature and pressure of the media flowing in the pipe work. Where reducing valves are installed in a system the low pressure, high pressure and any intermediate pressure systems shall be separately protected by safety valves set to release air as soon as the design pressure of that part of the system is reached. Safety valve outlets shall be positioned such that escaping air will not cause injury to personnel or damage to equipment. A pressure gauge shall be fitted to each air receiver, and at each pressure reducing set. 9. THERMAL INSULATION

Sheet metal supply, return & fresh air ductwork and all surfaces subject to condensation, shall be thermally insulated with insulation incorporating a vapour barrier on the outer surface. Surface of pipe work and ductwork to be insulated shall be thoroughly cleaned and degreased before the application of fixatives. Thermal insulation shall be non-corrosive to ferrous and non-ferrous metals, non-combustible, water repellent, sterile, odor free and shall not sustain vermin. Insulation of ductwork and pipe work shall not commence until the respective testing has taken place.







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Insulation of ductwork shall be approved foil faced rigid slabs of glass fibre or mineral fibre to provide the thermal insulation barrier, vapour barrier, protective and visual finishes as specified. Joints to be lapped and sealed with approved fire resistant adhesive. Insulation for pipe work shall be rigid shaped cut sections of glass fibre or mineral fibre to provide the thermal insulation barrier. Thickness of insulation shall be minimum 25 mm. Duct insulation in air conditioned spaces shall be 25 mm thick rigid slab of fibre glass with a density of not less than 48 kg/m3 and k - factor of not more than 0.38 W/mK at a mean temperature of 24ºC. Duct insulation in unconditioned spaces shall be 50 mm thick rigid slab of fibre glass with density of not less than 48 kg/m3 and a k factor of not more than 0.036 W/mK at a mean temperature of 24ºC. Insulation on pipe work and ductwork shall be built up over flanges, valves and other projections to provide not less than the specified thickness. It shall give a completely unbroken appearance to the surface of the ductwork and pipe work. Ductwork insulation shall be fixed to the duct with approved fire resistant adhesive, and where necessary, the adhesive shall be reinforced with nylon duct clips and washers of approved manufacture. Insulation sections will be close butted with butt joints and longitudinal joints sealed with an approved vapor sealant. Cavities in the ductwork and pipe work insulation surface will be filled and sealed with an approved vapor sealant. The surface finish of duct work and pipe work insulation shall be 8 ounce canvas applied using vapour barrier mastic and full coat of lapping cement, then a second coat of lapping cement over the entire canvas surface. Vapour barriers shall be continuous. Duct spigots and flexible connections shall be insulated with a 25mm thick glass fibre flexible duct insulation blanket with a facing of PVC film, tape sealed in position with an adhesive PVC tape. Duct works and piping in non conditioned area shall further be provided with 0.8 mm thick aluminium hammer cladding. 10. AC AND VENTILATION CONTROL PANEL

a) All air conditioning and ventilation system controls shall be fully automatic in operation and shall be capable of maintaining the internal conditions within the bands of temperature and humidity specified in the respective clauses of specifications.

b) Restarting of package units and ventilation fans after power shutdown shall be done a phased manner. Details shall be submitted to FEWA approval.

c) The control system shall preferably be of the electronic type capable of providing the degree of thermostatic control specified.

d) The control system shall incorporate all necessary safety interlocks for the successful operations of the plant.

e) All status indication of AC and ventilation units and temperature and humidity in all areas shall be indicated in the control panel.

f) At least 20% spares shall be provided for outgoing MCCBs, with minimum of one number in each rating.

g) The cubicle shall be free standing type manufactured from sheet steel of minimum thickness 2.5 mm and shall be painted of colour RAL 7032 out side.







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h) The incoming and outgoing cable entry shall be from bottom and suitable gland plate (non- magnetic) shall be supplied

i) All wiring inside the cubicle shall be carried out with suitably rated power cable, copper conductor, XLPE insulated, fire proof switchboard wire 0.6/1 KV with minimum cross section of 2.5 sq mm.

j) All wiring from HVAC control panel to A/C Units control devices shall be armoured cables. k) All power, instrumentation and control cables on the roof shall be on cable trays with

covers. l) Each ACB/MCCB shall employ thermal means inverse time overload protection

supplemented by an instantaneous magnetic short circuit trip. ACB shall be equipped with suitable shunt trip.

m) The control panel shall have an earth bar not less than 30 mm x 6 mm copper conductors. n) All ACB/MCCBs shall have sufficient number of auxiliary contacts (NO and NC contacts)

for status indications. o) Incomer shall be supplied with the following indicating instruments: p) One volt meter scaled 0-500 v, with volt meter selector switch, q) Three ammeters suitably scaled to read the incoming current in R, Y and B Phases, r) Current transformer of suitable ratio with class of accuracy 0.5 for connecting the

ammeters. s) All CT terminals shall have shorting, isolation and injection test facilities. t) The contractor shall be ensure that sufficient auxiliary contacts are made available in the

package units for interfacing with control panel. u) All indication lamps shall be neon type and over rated to prevent frequent failure. v) The following minimum indications/ alarms shall be provided in the control panel. A lamp

test facility shall also be incorporated. 1. AC unit on (Red). 2. AC unit off (green). 3. AC unit trip (amber). 4. AC unit filter dirty (amber). 5. AC unit faulty (amber). 6. AC unit on push button (green). 7. Ac unit off push button (red). 8. Incomer on (red). 9. Incomer off (green). 10. Incomer trip (amber). 11. Incomer on pushbutton (green). 12. Incomer off push button (red) 13. Lamp test pushbutton (black) 14. Temperature and humidity for each area 15. Fire dampers open/close indication 16. Motorized volume control dampers open/closed indication 17. Compressors on/trip indication 18. Package units fan run indication 19. Fan air flow fail indication 20. High temperature indication 21. Duty /standby selector switch for each AC system. 22. Supply, extract and fresh air fans on/off pushbuttons on

11. ACOUSTIC AND VIBRATION ISOLATION







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11.1 General The noise produced by the installation in the spaces served, in any adjacent buildings and in the

open air surrounding plant rooms shall be kept as low as possible. This shall be specially considered in the selection of fans (including those for condensers and

cooling towers), motors, fan coil units and terminal units, grilles and diffusers and the internal finish and arrangement of distribution ducting.

11.2 Silencers (Dissipative)

All silencers will be fitted with drilled angle flanges. The method of installing acoustic elements into the casing shall not cause air leaks. Acoustic elements shall incorporate full aerodynamic leading and trailing edges (not square ends), and the inert, rot and vermin-proof non-hygroscopic and non-combustible mineral wool or glass fibre acoustic medium shall be packed to a density of not less than 48 kg/M3 and retained by a perforated steel sheet facing.

Where required, for water or grease-laden duties, an impervious but acoustically transparent

membrane may be fitted behind the perforated metal facing. Silencer units shall be delivered to Site with blocked ends to prevent the ingress of rubble, etc.

during installation, and reduce the risk of damage. The direction of air flow through the silencer shall be clearly marked on the casing.

Engine Absorptive Exhaust Silencer casings shall be manufactured from suitable heavy gauge

sheet steel, with all seams and joints continuously welded. All internal splitter elements shall be manufactured from suitable gauge stainless steel, with adequate precautions taken to allow sufficient freedom of movement to overcome expansion and thermal shock.

These internal elements shall be packed with an inert, rot and vermin-proof, non-hygroscopic and

non combustible mineral wool or glass fibre acoustic medium of 96 kg/M3 density, protected by a layer of glass fibre cloth, behind the perforated steel facing. The same remarks relating to performance for duct silencers shall apply to engine silencers.

11.3 Silencers (Reactive)

The outer casings of all silencers shall be constructed from suitable heavy gauge mild steel with all seams and joints continuously welded. Acoustic elements within the silencer shall be designed and constructed with due allowance made for differential expansion and thermal shock.

All silencers shall also be fitted with suitable flanges and drain plugs and shall be manufactured and

finished with due allowance made for the operating temperature and environmental conditions. Silencers shall be delivered to Site with blocked ends to prevent ingress of rubble, etc. during

installation, and reduce the risk of damage. The direction of air flow through the silencer shall be clearly marked on the casing.

11.4 Anti-Vibration Mountings

All dynamic machinery shall be isolated from the building structure by vibration isolators and/or vibration isolation materials, which shall be purpose, designed and selected to suit the machinery.

Anti-vibration mountings of the following types shall be provided where appropriate:

(a) Caged Spring Mounts Each mounting shall consist of cast telescopic top and bottom housings containing one or more

helical steel springs, of 50 mm minimum diameter, as the principal isolation elements. The mountings shall incorporate a built-in levelling device, and resilient inserts as guides for the upper and lower housing.







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The bottom plate shall be fitted with a 6 mm thick neoprene pad bonded to it to reduce high frequency flanking. When in use with equipment having a fluid weight in excess of 25% of the total empty equipment weight a suitable hold-down or restraining device shall be incorporated.

All spring mounts shall be designed such that the lateral spring stiffness is equal to the vertical stiffness. The static deflection shall not be less than that indicated in Schedules.

The mountings shall also be selected for all items of plant with stiffness to cater for any eccentric weight distribution over the unit base. An equal static deflection shall be provided on all mounts, to avoid the possibility of flanking caused by the plant tilting and rendering one or more of the mounts 'solid'.

(b) Resilient Hangers

All resilient hangers shall be of the two element design, with helical spring and neoprene-in-shear elements mounted in a steel cage pre-drilled and tapped at top and bottom to receive threaded hanger rods.

(c) Rubber or Neoprene Mounts

The mountings shall consist of a steel top plate and base plate completely embedded in colour-coded neoprene for easy identification of rated load capacity. The mountings shall be moulded with non-skid ribbed construction on the top plate and base plate to eliminate the need for bolting. All mountings, however, shall be equipped with bolt holes in the base plate and tapped holes in the top plate so that they may be bolted to the floor and equipment where required.

(d) Plate Bases

Anti-Vibration Rails - An A.V. rail shall comprise a steel beam with height-saving brackets at each end. The steel sections must be sufficiently rigid to prevent undue strain in the equipment.

Steel Plant Bases - Steel plant bases shall comprise an all- welded steel framework of sufficient

rigidity to provide adequate support for the equipment. The frame depth shall be approximately 1/10 of the longest dimension of the equipment with a minimum of 150 mm. This form of base may be used as a composite A.V. rail system.

Concrete Inertia Base - These shall consist of an all-welded steel framework with height-saving

brackets, and a frame depth of approximately 1/12 of the longest dimension of the equipment, with a minimum depth of 150 mm.

The bottom of the frame shall be blanked off, and concrete (2,300 kg/m3) poured in over steel

reinforcing rods positioned 35 mm above the bottom. The total weight of the base shall be at least 1.5 times the equipment total weight.

Pouring forms for split case pumps shall be extended in width to allow for provision of supports for suction and discharge elbows.

11.5 Acoustic Louvers

All acoustic louvers shall be designed to reduce the airborne plant noise down to minimum ambient levels with an air velocity not exceeding 3 M/s.

The louver aero foils shall be constructed of galvanised mild steel (perforated) and packed with a fibre acoustic medium as specified for silencers.

The complete unit shall be supplied complete with a galvanised mesh bird screen and necessary fixing holes and lugs for location within a builders work frame.

12 TESTING AND COMMISSIONING







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The Contractor will balance, regulate and set-to-work the air conditioning system strictly in accordance with ASHRAE, AABC OR NEBB Standards.

Pro-forma test sheets and data log sheets will be submitted to FEWA for approval before the

commencement of commissioning. The Contractor will complete records of all commissioning data for including in the Operating and

Maintenance Manuals. The Contractor will thoroughly clean out all ductwork and items of equipment before starting any fan

or commencing any commissioning of the system. The Contractor will position dampers, calibrate thermostats, tension vee-belts and fit alternative

pulleys as required, to ensure the correct functioning of the air conditioning systems in accordance with the design criteria as specified and air volumes. The Contractor will, when the air conditioning systems and equipment have been put in working

order, demonstrate that each item of plant is functioning correctly in accordance with the Specification and will make any adjustments to FEWA/ENGINEER approval.

The Contractor shall provide performance test certificates in triplicate for specialist equipment

together with a complete set of records indicating all plant settings air volumes for each fan, grille, hood, etc., temperatures, water flow rates, pump and fan heads and noise level readings together with the respective design values.

The Contractor shall carry out the performance test of the complete HVAC system in peak summer

condition for minimum five consecutive days without failure of the plant. All necessary pressures, temperatures and humidity shall be recorded.

All hydraulic testing of pipe work shall be to a pressure equivalent to twice the working pressure.

After the pressure is obtained, the test rig shall be disconnected and the pressure shall not fall more than 2 ½% of the test pressure in two hours.

The Contractor shall allow for testing the installations in whole or in part as necessary to facilitate

the progress of the Works by other trades or to enable the Works to be commissioned in sections and no extra cost will be allowed for testing in part.

Any fault discovered during such tests shall be at once remedied by the Contractor at his own

expense and the test re-applied until the Consultant or his representative is satisfied that the section under test is sound.

13 TEST INSTRUMENTS

The Contractor shall provide all the test instruments required for the commissioning as specified and will demonstrate the accuracy of such instruments before the commissioning is carried out.

The test instruments provided will include the types as specified below: (a) Electronic Direct Reading Anemometers (b) Inclined Gauge Manometers with Pressure Ranges to suit Fan Duties. (c) Pitot Static Tubes to suit Duct Sizes (d) Sling Hygrometers (e) Mercury in Steel Thermometers (f) Dry Bulb Temperature Recorders (g) Combined Temperature and Humidity Recorders (h) Ammeters







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(j) Tachometers

14 DESIGN, SHOP AND AS-BUILT DRAWINGS

The Contractor will furnish Design, Shop and As-Built drawings in accordance with the requirements of Specification for design, shop and as-built drawings.

The Contractor shall prepare 'As-Built' drawings for the whole of the installations and shall

incorporate them in the Operational and Maintenance manuals. The 'As-Built' drawings shall show the complete installation, with full information on each plant item,

position of access, and location of electrical local isolators and shall include a diagram of the complete system, each item of plant with its name, and each valve with its number.The diagram shall also indicate the approximate location of each valve and plant item.

15 OPERATION AND MAINTENANCE MANUALS

The Contractor will provide Operation and Maintenance manuals in accordance with the requirements of Operational and Maintenance Manuals.The Contractor will provide seven sets of operation and maintenance manuals and user guide manuals.

In addition to the manuals as specified the Contractor will provide two sets of operating and

maintenance instructions and manufacturer's leaflets for each item of plant and equipment prior to the site testing of that item of plant or equipment. Such information will be used by the Contractor to assist in the site testing and commissioning of the plant and equipment and for the training of the Employer's maintenance personnel.

16 SPARES

The Contractor will supply Spare Parts in accordance with the requirements of the Spare Parts List. The Contractor will fit replacement filter rolls and panels as required during commissioning. At the

time of ordering each item of plant equipment, valves and fittings required for the works, the Contractor will provide a manufacturer's recommended list of spares for the items so ordered

The spare parts will be delivered at the site together with the items of plant and equipment

appertaining thereto. The Contractor may use the spare parts as required during commissioning procedure. Any spare parts used in such a manner will be re-ordered by the Contractor and air-freighted to the site.

The Contractor shall guarantee a local supply of spare parts of every item during the time of

construction and for a period of two years from the date of hand-over of each building. The parts shall be supplied and installed at no cost to the Client during the two year period.

17 WARRANTY

All Air-conditioning and Ventilation Equipments shall be warranted for a period of minimum 2 year from the date of commissioning.

The compressors for Air Conditioning units shall have a special guarantee of five years from the

contractual completion date and complete compressor shall be replaced if found defective during guarantee period.

18 QUALITY CONTROL







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18.1 Quality Control

Vendor shall comply with the requirements stated in the Specification for Vendor's quality control management.

18.2 Inspection and Testing In general factory tests for the various HVAC system components (condensing unit, evaporator unit, fan, etc.) shall not be repeated but certificates and factory test data shall be made

available. After field installation of mechanical equipment, piping, ducting and control system, the vendor shall perform all tests as specified here in and shall demonstrate the satisfactory operation and performance of all systems components. The following tests shall be performed:

Visual check of all components/equipment according to specification and final drawings.

Electrical tests to verify the continuity and operation for all installed electrical systems.

Duct system pressure testing.

Control system test to verify satisfactory operation of any automatic or manually operated sequence.

Performance testing for pressurization and indoor temperature.

Final test for balancing by recording temperature and relative humidity within the controlled space. All systems shall be kept in operation for a period of five days during which time the final test shall be carried out.

19. Training

a) During the construction and erection of the Works, CONTRACTOR shall be responsible for the satisfactory instruction and training of operation and maintenance personnel appointed by FEWA for this Work.

b) The CONTRACTOR shall provide all necessary instruction materials for this purpose such as

manuals, booklets, pamphlets, drawings, sketches, models, cut-away modules, pictures, photos, colour slides, films etc., before the training This instruction material shall become the property of FEWA.

20. VENDOR'S DOCUMENTATION

The vendor shall submit the following documentation, in English language, along with the supplied equipment and materials as applicable.

(a) General Description of Materials, Equipment, etc. (b) Engineering Flow Schemes (c) Assembly Drawings for Erection with Overall Dimensions (Weights, Anchor,

Details, etc.) (d) Electrical Power Supply and Distribution drawings. (e) Control Panel Drawings. (f) Technical Data, Characteristics Performances (g) List of Spare Parts for two year operation (h) Inspection Testing Plan (i) Calculations, Sizing (J) Test Certificate/Documentation (k) Reference for Similar Supply (l) Installation Manual/Installation instructions (m) Operating Manual/Operating Instructions (n) Maintenance Manual/Maintenance Instructions.

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