DMRC ELECTRICAL STANDARDS & DESIGN WING...

DMRC Electrical Standards & Design Wing DMES-E/0001

SPECIFICATIONS FOR AIR HANDLING UNITS (AHUs) Draft-1

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DELHI METRO RAIL CORPORATION LIMITED

DMRC ELECTRICAL STANDARDS & DESIGN WING (DESDW)

SPECIFICATION NO.

DMES- /E/0005/DMRC-E-E&M-AHUs-01

SPECIFICATIONS FOR AIR HANDLING UNITS (AHUs)

Issued on:

Date Stage

10 December 2014 Draft-1

DELHI METRO RAIL CORPORATION LTD. 7th Floor, B-Wing, Metro Bhawan, Fire Brigade Lane,

Barakhamba Road, New Delhi –110 001



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Previous Record of specification

Stage Date Draft -1 10-Sep-14



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TABLE OF CONTENTS

1. DETAILED DESCRIPTION OF THE EQUIPMENT AND ITS APPLICATION IN DMRC -AIR HANDLING UNITS (AHUS) ........................................................................................................................................................... 4

2. GOVERNING SPECIFICATIONS ............................................................................................................... 4

3. TECHNICAL AND INSTALLATION REQUIREMENT ................................................................................ 10

4. SPECIAL CONDITION ............................................................................................................................ 20

5. SYSTEM EFFICIENCY ............................................................................................................................ 20

6. SAFETY AND PRECAUTIONS ................................................................................................................ 20

7. RELIABILITY, MAINTENANCE, SPARES AND LIFE ................................................................................. 20

8. MATERIAL AND MANUFACTURING ..................................................................................................... 21

9. TRAINING ............................................................................................................................................ 21

ANNEXURE-A ............................................................................................................................................... 22

AHUs’ AIR FILTER ......................................................................................................................................... 22

10. SCOPE .............................................................................................................................................. 22

11. CODES AND STANDARDS ................................................................................................................ 22

12. GENERAL ......................................................................................................................................... 23

13. FILTER IDENTIFICATION ................................................................................................................... 23

14. WASHING FACILITIES FOR WASHABLE FILTERS ............................................................................... 24

ANNXURE-B ................................................................................................................................................. 25

FACTORY ACCEPTANCE TEST OF AIR HANDLING UNITs .............................................................................. 25

ANNEXURE-C ............................................................................................................................................... 29

PRE- COMMISSIONING CHECK LIST OF AIR HANDLING UNITS.................................................................... 29

ANNEXURE-D ............................................................................................................................................... 34

PERFORMANCE ACCEPTACNCE TEST OF AIR HANDLING UNITS ................................................................. 34



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1. DETAILED DESCRIPTION OF THE EQUIPMENT AND ITS APPLICATION IN DMRC -AIR HANDLING UNITS (AHUS)

This specification is applicable to the air handling unit system which is used as a sub-assembly to Environmental Control System to maintain temperature, humidity and airflow at the Underground Metro Station of DMRC.

Air handling unit shall be double skin type (AHRI or EURO vent certified) complete with twin blower housing with duct, fan with motor and pulley and associated electrical protection, twin cooling coil, UVC emitter, filters along with different accessories as specified in different sections of this specification.

The AHUs is supplied with chilled water through insulating piping and air to be conditioned through an air plenum. The AHU unit supplies conditioned air to the concourse, platform, office, selected equipment rooms, etc. as per the design documents. The specification covers design, manufacturing, installation and commissioning of the AHU.

Metro Station air conditioning systems shall be designed to maintain specific design parameters as follows: 1. Minimum 0.005 m3/s fresh air per person. 2. Station air conditioning system design conditions shall be:

Platform - 27 degree Celsius at 55% RH Concourse - 28 degree Celsius at 55% RH

2. GOVERNING SPECIFICATIONS

Air handling units shall conform to different standard for different part of it. It consists fan, motor, belt, coil section, filter section, UVC emitter. The air handling unit shall be AHRI or EUROVENT certified. Motor shall conform to IS/ IEC 60034 and IS 325, filter media shall conform UL 900, and painting shall conform ASTM B117 etc.



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2.1 Standards

The air handling units shall satisfy the following requirements and shall also comply with standards in force when AHUs units are manufactured, particularly which are in the following table (Unless otherwise stipulated in the specification, the latest version of following standards shall be applicable)

Standard Description ECS SYSTEM STANDADRS AHRI STANDARD Eurovent Standard EN-1886-2007 certified

Unit performance , coil performance and mechanical strenghth

ANSI/AHRI 430-89 Central station using air handling units ANSI/AHRI 410 Coils AFBMA STANDARD 9 Load ratings and fatigue life for ball bearings 11 Load ratings and fatigue life for Roller ball bearings AMCA STANDARD 210 Laboratory method of testing fans for rating 300 Test code for sound rating of air moving device ANSI STANDARD S12.34 Survey methods for Determination of sound power levels of Noise

Sources ANSI/ASQC Z1.4 Sampling procedure and tables for inspection by attributes ASTM STANDARD A 123 Standard requirements for hot-dip galvanized zinc coatings on iron and

steel products made from rolled pressed and forged shapes, castings, plates, bars, and strips

A 239 Standard Practice for Locating the Thinnest Spot in a Zinc (Galvanized) Coating on Iron or Steel Articles by Preece test (copper sulphate dip)

A 525 Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process

A 588 Standard Specification for High-Strength Low-Alloy Structural Steel, up to 50 ksi [345 mpa] Minimum Yield Point to 100mm thick, with Atmospheric Corrosion resistance

B 247 Standard Specification for Aluminum and Aluminum-Alloy Die Forgings, Hand Forgings, and Rolled Ring forgings

B 686 Standard Specification for Aluminum Alloy Castings, High-strength



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E 94 Standard Guide for Radiographic TEST E 155 Reference Radiographs for Inspection of Aluminum and Magnesium

Castings

BS STANDARD BS 848 Fans for general purpose BS 6540 Air filters used in air conditioning and general ventilation. Methods of

test for atmospheric dust spot efficiency and synthetic dust weight arrestance

BSEN 779 Particulate air filters for general ventilation. Determination of the filtration performance

Military Specifications (MIL. Spec.) MIL-P-24441/A General specification for (ships), Paint, Epoxy-Polyamide MIL-P-24441/1A Paint, Epoxy-Polyamide, Green Primer, Formula 150 Type 1 MIL-P-24441/2A Paint, Epoxy-Polyamide, Green Primer, Formula 151 Type 2 SP-10 Near White Blast Cleaning PA-1 Shop, Field and Maintenance and Painting MIL 105E Sampling procedures and tables for inspection by attributes ISO STANDARD ISO 5801 Industrial fans- performance testing using standardized airways UL UL 900 Standard for test performance of air filters unit IEC IS/IEC 34-1 Rotating electrical machines - Part 1: Rating and performance IS/IEC 34-5 Rotating electrical machines - Part 5: Degrees of protection provided by

the integral design of rotating electrical machines IS/IEC 34-6 Rotating electrical machines - Part 6: Methods of cooling (except

traction engine) IS/IEC 34-7 Rotating electrical machines - Part 7: Classification of types of

construction, mounting arrangements and terminal box position (except traction engine)

IS/IEC 34-8 Rotating electrical machines - Part 8: Terminal markings and direction of rotation

IS/IEC 34-9 Rotating electrical machines - Part 9: Noise limits IS/IEC 34-14 Rotating electrical machines - Part 14: Mechanical vibration of certain

machines with shaft heights 56 mm and higher - Measurement, evaluation and limits of vibration severity

IEC 85 Thermal evaluation and classification of Electrical insulation IS STANDARD IS 325 Three-phase induction motors -Specification IS 14261 Transmission Devices - V-belts - Endless Narrow V-belts for Industrial

Use IS 2494 V belts- Endless V belt for industrial purposes



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Standard Description ECS SYSTEM STANDADRS ARI STANDARD ANSI/AHRI 430-89 Central station using air handling units ANSI/AHRI 410 Coils AFBMA STANDARD 9 Load ratings and fatigue life for ball bearings 11 Load ratings and fatigue life for Roller ball bearings AMCA STANDARD 210 Laboratory method of testing fans for rating 300 Test code for sound rating of air moving device ANSI STANDARD S12.34 Survey methods for Determination of sound power levels of Noise

Sources ANSI/ASQC Z1.4 Sampling procedure and tables for inspection by attributes ASTM STANDARD A 123 Standard requirements for hot-dip galvanized zinc coatings on iron and

steel products made from rolled pressed and forged shapes, castings, plates, bars, and strips

A 239 Standard Practice for Locating the Thinnest Spot in a Zinc (Galvanized) Coating on Iron or Steel Articles by Preece test (copper sulphate dip)

A 525 Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process

A 588 Standard Specification for High-Strength Low-Alloy Structural Steel, up to 50 ksi [345 mpa] Minimum Yield Point to 100mm thick, with Atmospheric Corrosion resistance

B 247 Standard Specification for Aluminum and Aluminum-Alloy Die Forgings, Hand Forgings, and Rolled Ring forgings

B 686 Standard Specification for Aluminum Alloy Castings, High-strength

E 94 Standard Guide for Radiographic TEST E 155 Reference Radiographs for Inspection of Aluminum and Magnesium

Castings

BS STANDARD BS 848 Fans for general purpose BS 6540 Air filters used in air conditioning and general ventilation. Methods of

test for atmospheric dust spot efficiency and synthetic dust weight arrestance

BSEN 779 Particulate air filters for general ventilation. Determination of the



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filtration performance

Military Specifications (MIL. Spec.) MIL-P-24441/A General specification for (ships), Paint, Epoxy-Polyamide MIL-P-24441/1A Paint, Epoxy-Polyamide, Green Primer, Formula 150 Type 1 MIL-P-24441/2A Paint, Epoxy-Polyamide, Green Primer, Formula 151 Type 2 SP-10 Near White Blast Cleaning PA-1 Shop, Field and Maintenance and Painting MIL 105E Sampling procedures and tables for inspection by attributes ISO STANDARD ISO 5801 Industrial fans- performance testing using standardized airways UL UL 900 Standard for test performance of air filters unit IEC IS/IEC 34-1 Rotating electrical machines - Part 1: Rating and performance IS/IEC 34-5 Rotating electrical machines - Part 5: Degrees of protection provided by

the integral design of rotating electrical machines IS/IEC 34-6 Rotating electrical machines - Part 6: Methods of cooling (except

traction engine) IS/IEC 34-7 Rotating electrical machines - Part 7: Classification of types of

construction, mounting arrangements and terminal box position (except traction engine)

IS/IEC 34-8 Rotating electrical machines - Part 8: Terminal markings and direction of rotation

IS/IEC 34-9 Rotating electrical machines - Part 9: Noise limits IS/IEC 34-14 Rotating electrical machines - Part 14: Mechanical vibration of certain

machines with shaft heights 56 mm and higher - Measurement, evaluation and limits of vibration severity

IEC 85 Thermal evaluation and classification of Electrical insulation IS STANDARD IS 325 Three-phase induction motors -Specification IS 14261 Transmission Devices - V-belts - Endless Narrow V-belts for Industrial

Use IS 2494 V belts- Endless V belt for industrial purposes

2.2 Abbreviations

AHU- Air Handling Unit

ASHRAE- American Society of Heating, Refrigerating and Air-Conditioning Engineers



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ASTM- American Society for Testing and Materials

BMS- Building Management system

BS- British Standard

DMRC- Delhi Metro Rail Corporation

ECS- Environmental Control System

EN- Euronorm standard

FRLSOH – Fire Retardant Low Smoke Zero Halogen

IEC- International Electro technical Council

IES- Illumination Engineering Society, UK

IS/BIS- Bureau of Indian Standards

ISO- International Standard Organization

TVS- Tunnel Ventilation System

ANSI- American National Standards Institute

AFBMA- Anti-Friction Bearings Manufacturers Association

AMCA- Air Moving and Control Association

AWS- American Welding Society

IEEE- Institute of Electrical and Electronic Employer's Representatives

UL- Underwriters Laboratories, Inc.

SAT- System Acceptance Test

IEC- International Electro technical Committee

IS- Indian Standard

DIN- Deutsche Industrie Normen

PICV- pressure independent control valve

EPDM- Ethylene propylene diene monomer



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3. TECHNICAL AND INSTALLATION REQUIREMENT

Air handling units shall be double skin type filled by insulating material consisting of several part such as AHU housing, Fan and accessories, Fan Motor and starter, Coil Unit, Filter, Illumination, PICV, UVC emitter etc. These parts various parts with technical requirements are as follows:

3.1 AHU Housing

3.1.1 The unit shall be panel construction with extruded aluminium forming the structural frame to house all internal components. Double skin construction shall be provided by sandwich type 50 mm thick injected with polyurethane foam (CFC free) of minimum 40 kg/m3 density.

3.1.2 Outer skin shall be minimum 1.0 mm galvanized steel sheet while inner skin shall be minimum 1.2 mm galvanized steel sheet. The sheet should have a minimum galvanization of 275 GSM with powder coating on the exposed side or 120 GSM and precoated on exposed side. The inner skin is required to be epoxy painted on the exposed side.

3.1.3 The noise level as measured at 1 m from any surface of AHU shall not be more than 85 dB with both the fan working.

3.1.4 The units shall be provided with the access doors and door guard. Access door size as follows:

Filter Unit: Two access door of minimum dimension of 800 mm × 1500 mm (width × height) to service filter unit with lookout glass.

Fan and Coil Unit: Two access door of minimum dimension of 800 mm × 1500 mm (W×H) to service coil and fan unit with lookout glass.

3.1.5 The door handles, hinges and other accessories of the doors shall be of SS or nylon with robust and proven design in all respects. The door and frame shall be provided with neoprene rubber double ripped/T-gasket fixed in the extruded sections to prevent any air loss.

3.1.6 The complete unit shall be provided with four point lift to transport as a complete unit using standard rigging devices. Otherwise, it should be transported in dismantled condition with assembly at site under supervision of the manufacturer.



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3.1.7 The door to access the fan section shall be provided with micro-switch to prevent its accidental opening with fan working. The micro-switch shall be fitted on a sturdy base and shall be placed in such way that it shall not hurt anyone during entrance to the fan section.

3.1.8 The sandwich panels shall be bolted from outside with a cover cap on the bolt head and the framework with soft rubber gaskets in between, to make the joints airtight. All fasteners used should be of stainless steel otherwise boltless construction shall be followed.

3.1.9 Pipe and conduit entry through the sandwich housing panel shall be designed and formed using suitably sized and designed rubber gasket for elastic cushion and prevention of loss of air.

3.1.10 The entire housing shall be mounted on anti-vibration rubber pads designed to support the entire weight of the AHU ensuring no transfer of the vibration to the floor. The housing shall be earthed following necessary standards.

3.2 Fan and Accessories

3.2.1 The fan shall be centrifugal with backward inclined type, airfoil blades, double inlet double width type having a fan of total efficiency not less than 80%. Fans shall be of non-overloading characteristic. Fans shall be AMCA certified for air and sound rating performance.

3.2.2 Fan casing shall be of sheet steel construction adequately stiffened and braced and shall be entirely free from vibration or drumming during normal operation. The steel sheet required to be hot dip galvanized.

3.2.3 All fans with an inlet eye diameter exceeding 300mm shall have a bolted access door on the scroll for access purposes. The size of access panels shall be such as to facilitate cleaning and maintenance of the impeller.

3.2.4 Drain sockets or holes with copper drain pipe brought out to an accessible point, valved and plugged, shall be provided.

3.2.5 Fan casings shall be fitted with flanges on the outlet connection suitable for connection of discharge ductwork and flexible connections. The fan outlet shall be connected to a duct casing with fire retardant double canvass. The duct casing shall be secured with fan outlet with EPDM tube gasket to prevent any air leak.



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3.2.6 Where the inlet side of the fan is connected to ductwork, matching flanges for connection of flexible connections shall be provided for inspection doors or sight ports for establishing the direction of rotation shall be provided

3.2.7 The wheel & housing shall be fabricated from heavy gauge galvanized steel or for other proven designs; the manufacturer shall submit related documents in support of the provenness.

3.2.8 Fan impellers shall be backward sloping blades as specified on the Equipment Schedule and/or Drawings. Impellers shall be rigidly fixed to solid bright steel shafts adequately sized and proportioned to ensure that the maximum operating speed is not more than 60% of the first critical speed. The shaft shall be protected by reliable anti-rust coating.

3.2.9 The fan impeller shall be mounted on a solid shaft supported on angle iron frame using heavy duty ball bearing. The fan shall be selected for a speed not exceeding 1800 rpm.

3.2.10 The shaft shall be extended beyond the drive side bearing for mounting of overhung pulley.

3.2.11 The shaft shall be supported on ring lubricated self-aligned sleeve bearings for shaft of 150mm diameter and larger. Each bearing shall have large oil storage capacity to insure efficient lubrication. On shaft of sizes smaller than 150 mm diameter, grease lubricated self-aligned ball bearings or sealed maintenance free bearings shall be used. The entire assembly shall be mounted on suitably designed anti vibrating pads to reduce noise transmission with bearings of minimum average life of 200,000 hours. The manufactuers shall submit OEM’s certificate for the correct selection of bearing.

3.2.12 For centrifugal fans used in air handling units (AHUs) one coat of corrosion proof coating shall be applied to all non-working surfaces of shafts at the factory.

3.2.13 The impeller & fan shaft shall be statically and dynamically balanced.

3.2.14 The fan outlet velocity shall not exceed 12.7 m/s.

3.2.15 Fan housing with motor shall be mounted on a common extruded GI (galvanized iron) or extruded aluminium alloy base mounted inside the fan section on anti-vibration springs mounts.

3.2.16 Vibration isolators shall be provided in accordance with “Acoustic Treatment and Vibration control” section of this M&W specification.



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3.2.17 The fan is coupled with motor with a complete multi High Performance Composite 'V' belt drive. The driven V belt shall be rated at 150% of the operating power input. The V belt shall be selected in consultation with DMRC engineer with submittal of best options available with the leading manufactuers of V belt.

3.2.18 Belt guards shall be of galvanised steel framing with expended mesh screen. All belt guards shall have access opening at the shaft ends to enable tachometer reading to be taken.

3.3 Fan motor & starter

3.3.1 The fan motor of continuous duty at an ambient temperature of 400 C shall be totally enclosed, class F insulation to BSEN 60085 or IEC-60085, self cooled squirrel cage induction motor, which shall have a minimum rating as given under "Schedule of Equipment". The starter rating shall match the motor rating and will conform to specifications under "motor and switch gears”. The motor shall be of reputed manufacturing unit confirming to IEC 60034/IS 325 (latest version). The motor shall be of high efficiency class as per EFF-1 or IE-2.

3.3.2 Motors shall be mounted inside the housing on a slide base to permit adjustment of drive belt tension.

3.3.3 Motor starter shall be delta star or soft starter as per BOQ and mounted outside the housing.

3.4 Coil Unit

3.4.1 Coils shall be manufactured by the supplier of the AHU. Coil Unit shall be removable by unbolting it from the panels in the coil section.

3.4.2 The cooling coil shall be of seamless copper tubes not less than 0.5 mm thick and minimum 12 mm O.D. conforming to this specification.

3.4.3 The bends shall be ready made with solder rings on both ends. Seamless bend at one end and solder ring at another is also acceptable.

3.4.4 The coil shall have continuous aluminium dual sine wave fins having a minimum thickness of 0.15 mm with hydrophilic coating. The fins shall be spaced by collars forming integral part of the fins. The tubes shall be staggered in the direction of airflow. The number of cooling coil and fin spacing shall be designed depending on the AHU capacity and shall be submitted along with design document for approval of DMRC. The fins shall be uniformly bonded to the tubes by mechanical or hydraulic expansion of the tubes.



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3.4.5 The coils shall be designed to operate at 17.5 kg/cm2 working pressure and 150 °C temperature. It shall be tested against leaks at a pressure not less than 23 kg/cm² compressed air underwater. This pressure shall be maintained for a period of 2 hours. No pressure drop should be observed, indicating any leaks.

3.4.6 The water headers shall be of copper pipes, to connect all the tubes. The headers shall be complete with water In and out connections, vent plug on top and drain at the bottom.

3.4.7 The condensate at the coil unit shall be collected in the drain pan of size as per cooling coil requirement and of 18 gauge thick of SS-316 steel. The top and bottom drain trays shall be connected with SS 316 pipe of minimum 25 mm dia for continuous transfer of condensate from the top tray to bottom with a suitably designed slope for free flow of condensate to the drain pipe. The bottom drain pan shall be a sandwich type in such way that during sandwich two plates of SS do not touch each other, with 12 mm thick closed cell polyurethane puff or polyethylene foam to prevent any condensation at the bottom. Drain pipe connecting to the bottom drain pipe shall be of SS-304.

3.4.8 Coil tube water velocity shall not exceed 2.5 m/s. When water velocities of less than 0.60 m/s are encountered, a method of turbulation shall be provided.

3.4.9 The coil frames should be of SS-304.

3.4.10 The air velocity across the cooling coil shall not exceed 2.8 m/sec.

3.5 Filtration

3.5.1 Each AHU shall have one or maximum two sized filters conforming to the specifications at annexure A.

3.6 Illumination

3.6.1 Four marine CFL of suitable wattage (two for coil section and two for filter section) shall be provided to illuminate the fan and filter area for maintenance and attention to equipment. The wiring shall be through a flexible conduit using FRLS cable and branching of cable by using rigid T joint ensuring no exposure of the wire.

3.6.2 The lamps shall be without any switch and to operate by the micro-switch only with protection MCB for any fault.

3.7 Accessories

3.7.1 Each air-handling unit shall be complete with the following accessories:

1. Stem type thermometers at coil inlet and outlet, with tubing and gauge cocks.



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2. Pressure gauge with cock at inlet of the coil, with tubing and gauge cocks.

3. Butterfly valves at the inlet of the coil and PICV at the outlet of coil.

4. Drain line from the unit up to floor trap.

5. Automatic air Vent Valves on pipes.

6. Fire retardant Flexible connection between the fan outlet and duct.

7. Vibration isolators of 90% efficiency between AHU and foundation.

3.8 Pressure Independent Control valve (AHU)

3.8.1 Valve shall be electronic, dynamic, modulating, 2 ways, control device. Maximum flow setting shall be adjustable to 51 different setting within the range of the valve size. It shall be BMS compatible.

3.8.2 Valve actuator housing shall be rated to IP44. Actuator shall be driven by 24 VDC motor and shall accept 2-10 VDC, 4-20mA, 3-point floating or pulse width modulation electric signal and shall include resistor to facilitate any of these signals. Actuator shall be capable of providing 4-20mA or 2-10 VDC feedback signal to control system. Optional fail safe system to power valve to either open of closed position from any position in case of power failure shall be available Extended LED read - out of current valve position and maximum valve position setting shall be standard.

3.8.3 Air handling units PICV shall be installed with 3 Nos. ball valve (for flow, return and by-pass), Y-strainer, drain hoze connection with pressure temperature meters.

3.8.4 It shall comply with following specification:

• The PICV valves shall meet the following high performance generic specific criterion: Valves should be pressure independent and should have integral differential pressure control over built in control valve and flow control.

• The valves should have a bon net for temperature control and diaphragm operated differential pressure controller all built in one valve body.

• Valves should be protected against overload with a safety spring Valves should be inline body type and should be suitable for modulating control at temperatures between -10 and +120 Centigrade

• Valves shall be suitable for Pressure class PN25 Valves body to me made only from Ductile Iron and surface should be Dual solid painted.



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• The diaphragm and gaskets shall be made from EPDM or HNBR (hydrogenated acryolonitrile-butadiene rubber).

• The valve sear shall be made from stainless steel.

• The valve should be designed for readjustment of flow rate at site without removal of actuator.

• The pressure drop on the flow control spring / throttle should not exceed 45kPa.

The PICV for AHUs air terminal units with shall have the following criterion with respect to the above mentioned:

• The valve should have integral spring and diaphragm arrangement for differential pressure control.

• Valve should be capable of operating under maximum differential pressure of 400kPa.

• The pressure drop on the now control spring/ throttle should not exceed 60kPa.

• The minimum lift on the control valve shall be 10 mm and 3 mm resp. Generally PICV valves shall be a single assembly, however, for larger valves to the district cooling plant shall be a differential pressure valve (DPC) and low loss control valve (CV).

• Installation and construct ion shall comply with below mentioned specification

S.NO. SIize construction Ends

1 80 mm and above DZR brass

2 Stem/ spindle Non rising of stainless steel

3 Sealing on seat Stainless steel disk of ASTM A296 Gr. CA-15 with EPDM sealing

4 Sealing on spindle Double seal by SPDM back flow & graphite asbestos packing

5 Hand wheel C 1 (260) or cast Bronze



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6 Double a) Indicator scale from “0” to fully open

b) Interpolation scale for fine setting at 1/10 of hand wheel turn

c) Temper proof setting with lock shield

7 Direction of flow Flow arrow on valve body

8 End connection Threaded to BS -21 or Flange type ISO (228) and ANSI



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3.9 UVC Emitters

3.9.1 General requirements

3.9.1.1 Supply, Installation, Testing and Commissioning of Emitters System suitable for mounting in AHUs to reduce mold , mildew and fungus growth on the coil and keep the coil surface clean eliminating need for coil cleaning program.

3.9.1.2 The tube shall be - Double Ended Type

3.9.1.3 Each component and product is to be inbound and outbound tested before shipment under Mil Standard 105E and ANSI/ASQCZ 1.4.

3.9.1.4 Tested in accordance with the general provisions of IES Lighting Handbook, 1981 Applications Volume, total output per inch of length shall not be less than 1OµW/cm2 at one meter, in a 400 fpm air stream of 45 Deg. F. After installation, the output per inch of lenth shall not be less than 30 µW/cm2 on coil surface at any location.

3.9.1.5 Sufficient no. of UVC emitter tube shall be used to cover the spread of coil surface for the requirement as given in above para or BOQ.

3.9.1.6 The wiring for UVC emitter shall be from the panel provided outside the AHU through conduit. The UVC emitter shall be switched off if the door of the AHU is opened accidently or intentionally.

3.9.1.7 Emitters and fixtures shall be installed downstream of the cooling coil at right angles to the coil fins, such that UVC energy bathes all surfaces of the coil and drain pan. The wiring kit for emitters shall be supplied by manufacturer / strategic business partner / authorized dealers of manufacturer / business partners only.

3.9.1.8 Proper Caution Labels shall be installed on all accesses to the UVC Emitters when installed.

3.9.2 Equipment

3.9.2.1 Units shall be high output, HVAC type, and germicidal UVC light sources, factory assembled and tested. Components shall include a housing , reflector, high efficiency electronic power source, Emitter sockets and Emitter tube, all constructed to withstand HVAC environments

3.9.2.2 Double ended Unit housings shall be made of 304 stainless steel with Units having electrical connectors on both ends to simplify gang wiring and wiring to power. They shall include mounting holes to assist in securing the fixtures.



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3.9.2.3 DE reflectors shall be constructed of high spectral finished aluminium alloy with a minimum 85% reflectance of 254 mm UVC energy.

3.9.2.4 The Emitters shall be designed to operate at 230 V, 50 Hz with a high p.f. and shall be UL listed to comply with UL Standard 1995 and capable of igniting each Emitter at temperatures from 35 - 170 Deg. F in airflow velocities to 1000 fpm. They shall be equipped with RF and line noise suppression.

3.9.2.5 Emitter tube shall be of the high output, hot cathode, T5 (15mm) diameter and medium bi-pin type. They shall produce 95% of their energy at 254 mm and be capable of producing the specified output at airflow velocities to 1000 fpm at temperatures of 35 - 170 Deg. F. UVC Emitters shall not produce ozone or other secondary contamination.

3.10 Painting

3.10.1 Units supplied with casing exterior factory painted shall able to withstand a slat water. Spray test in accordance with ASTM B117 for a minimum of 500 consecutive hours. Unit casing exterior shall be provided with standard colour as approved by the Engineer.

3.11 AHUs TESTING

The air-handling unit shall be typed tested with design and manufacturing process certified by AHRI or Eurovent. The sub-assemblies shall be tested based on the respective standards as mentioned in Para 2 above. AHUs shall be tested for performance rating by measuring air quantity and coil performance by measuring temperature difference, water pressure drop across coil and then calculating the capacity. AHU testing shall be done according Annexure-B.



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4. SPECIAL CONDITION

After installation and initial testing of AHU unit, the performance test shall be repeated after 3 months of period for sustainability of design. In case, there is any defect identified during the test as per annexure-B, the manufacturer shall arrange modification or repairs on all the installed units as required.

5. SYSTEM EFFICIENCY

5.1 The pressure drop across the filter unit, motor and air loss shall be as per the standards appearing in the specification.

6. SAFETY AND PRECAUTIONS

6.1 The material used in the manufacturing shall be fire retardant and low smoke except the rubber gasket used at different locations and specified in this specification.

6.2 Entry into the AHU is prohibited when in working condition and shall switch off automatically if there is intentional or accidental opening of the fan and filter unit doors.

6.3 Electrical protection towards any defect in the motor and wiring for illumination or UVC emitter shall be provided.

6.4 Wiring shall of FRLSZH class as per the norms fixed for wiring in underground stations.

7. RELIABILITY, MAINTENANCE, SPARES AND LIFE

7.1 The AHU shall be designed for continuous and reliable operation. The Condition monitoring system shall be provided for measuring the pressure drop across filters for excess pressure drop, air flow, etc. to assess the condition of the equipment and timely maintenance. The firm shall submit a maintenance schedule at the time of design approval for simultaneous approval of the maintenance schedule.

7.2 The manufacturers shall advise the list of spares required for replacement during schedule maintenance. The purchase specification for each of these items, particularly bought out items shall be furnished at the time of design approval.

7.3 Each bought out items shall have a logo/trade mark of the manufacturer along with a contact address.



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8. MATERIAL AND MANUFACTURING

8.1 The manufacturer shall use and employ manufacturing practices as stated in his ISO manuals and should be able to demonstrate the quality practice to the engineer in charge of the DMRC engineer on demand.

8.2 The manufacturer methods employed shall conform to the various standards and shall be best in the fields.

8.3 All fasteners like bolt, screw, nut, washer, spring washer etc shall be of stainless steel for non-corrosive function.

9. TRAINING The contractor shall provide the following details

Bound booklet consisting of the details of the equipment, assembly drawings and summary of test results.

Operating manual Warranty/DLP Purchase specification of maintenance spares List of staff trained



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ANNEXURE-A

AHUs’ AIR FILTER

10. SCOPE

This specification covers air filters to be employed in environmental control systems.

11. CODES AND STANDARDS

11.1 This specification covers air filters to be employed in environmental control systems. Filter shall conform, where applicable to the following standard:-

1) UL 900- Standard for test performance of air filters units.

2) BSEN779- particulate air filter for general ventilation, requirement, testing, making

3) ASHRAE standard 52-76- Method of testing air cleaning devices use in general ventilation for removing particulate matter.

4) Other standard as specified

11.2 Fire Properties

11.2.1 Air filters and their enclosure shall be constructed from materials which conform to the fire property requirements of one of the following standards:-

11.2.2 BS476 : Pt. 4 - Non-combustibility Test for Materials;

11.2.3 BS476 : Pt. 6 - Method of Test for Fire Propagation for products with indices "I" £12 and "i" £6;

11.2.4 Underwriters Laboratories Inc. UL900 - Test Performance of Filter Units, Class I or Class 2;

11.2.5 DIN53438: Pt. 3 - Response to Ignition by a Small Flame, Surface Ignition, Class F1.



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12. GENERAL

12.1 The filter frame shall be made of SS-304 material of minimum 50 mm thick panel type and with V filter media. The filter media shall be secured into the frame with vertical or horizontal rod of suitable thickness at each node of ‘V’ and riveted on the housing frame at both ends. The filter media surface shall be protected by suitable sized expanded metal material.

12.2 The filter element shall be of minimum 90% efficiency down to 10 micron particle size

12.3 Filter media shall be UL-900 approved and shall be water washable.

12.4 The periphery of the filter pack shall be continuously bonded to the inside of the enclosing frame thus eliminating the possibility of air bypass.

12.5 Filter’s frame holding structure shall be factory fabricated with aluminium material and shall be equipped with a minimum of four heavy duty positive sealing fasteners. The gaskets shall be able to prevent air bypass between the filter and frame, between the adjacent frames and between the frames and housing. The fasteners shall be capable of being attached or removed without the use of tools. All gaskets shall have the same fire property requirements as the air filter, as detailed in Clause above.

12.6 The filter’s frame holding structure shall be factory fabricated and assembled. They shall incorporate access doors, extruded aluminium tracks and individual holding frames designed to accommodate standard size filters in efficiency and construction rating specified for the installation.

12.7 Type test certificates for each type of filter media intended for use on the installation shall be submitted.

13. FILTER IDENTIFICATION

13.1 When filter assembly is bought out item of AHU manufacturer shall have following information clearly marked or stamped in a readily accessible location:-

• Manufacturer's Name and address; • Month/Year of manufacturing; • Filter type and model number; • The standard to which the filter has been type-tested.



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14. WASHING FACILITIES FOR WASHABLE FILTERS

14.1 Where washable filters are to be provided the Contractor shall provide one set of duplicate cleaning tanks (one to wash, one to rinse). These tanks shall be such as to accommodate all sizes in the Contract.

14.2 The filter cleaning tanks shall be constructed of at least 1 mm thick stain less steel and suitably stiffened around the top edges by continuous external turned over inverted 'u' sections. The tanks shall be 0.4 m deep. They shall be supplied with 18 mm drain down cock for emptying but shall also have external handles to facilitate turning over to clear sludge.

14.3 10 litres of cleaning detergent of concentrated soap, suitable for washing the filters shall be provided by the Contractor for each 10 m3/s of or part thereof the total air handling capacity of equipment for ongoing maintenance.

14.4 At the end of the defects liability period i.e. when maintenance certificate is about to be issued the Contractor shall provide to the employer 10 litres of similar detergent for each 10 m3/s of or part thereof the total air handling capacity of equipment for ongoing maintenance.



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ANNXURE-B

FACTORY ACCEPTANCE TEST OF AIR HANDLING UNITs

AIR PERFORMANCE TEST

1. PURPOSE

To Demonstrate run test of one no. AHU at full load condition (Designed Air Capacity

& Static pressure).

2. SCOPE

The AHU operation shall be shown on reduced speed.

3. RESPONSIBILITIES

Quality Control Department

4. PROCESS

a. Check the unit thoroughly, there should not be any loose component or part inside the unit.

b. Check the belt alignment & free movement of blower.

c. Check the motor rating, fan model, drive set size, filter size, coil size etc.

d. Connect the motor with electrical supply.

e. Check the direction of blower.

f. After getting satisfied with all the checks close the door of AHU.

g. Switch on the electrical supply to motor.

h. Observe the run test of the AHU.

Note: - This test shall be offered on 1 no. AHU of each configuration.



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UNIT LEAKAGE TESTING

5. PURPOSE

To evaluate the leakage of AHU as per DW 143 standard.

6. SCOPE

Testing of AHU at works in order to check its leakage .The test will be done at 1000 Pa positive pressure.

7. RESPONSIBILITIES Quality Control Department

8. INSTRUMENTS REQUIRED

Air duct leakage test rig, Magnehelic gauge & inclined tube manometer

9. PROCESS

a. Fix the GSS sheet on all outlets. b. Connect the flexible pipe of testing rig to the unit. c. Start the fan of testing rig. d. Supply the air inside the AHU till the desired pressure of 1000 Pa is achieved (as per DW 143

STANDARD). e. Note down the reading of Magnehelic gauge (pressure mm) & inclined tube

(Leakage mm).

f. Convert the inclined tube reading in to lit/sec with the help of conversion chart. g. Calculate the leakage in CMH/CFM.



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10. All reading shall be noted down in the format.

OUTER DIMENSION OF UNIT :- L= W= H=

SURFACE AREA :-

S.NO, DESCRIPTION UNITS READING READING FROM

1 UNIT SURFACE AREA (A) Sq M DRAWING

2 MAGNEHELIC PRESSURE (P) Pa MAGNEHELIC PRESSURE GAUGE

3 LEAK FACTOR (F) Ltr/Sec/Sq.

M FROM TABLE

4 MAX. PERMITTED LEAKAGE (Lp) Ltr/Sec Lp=F X A

5 MANOMETER / M. G. READING MMWC INCLINED TUBE MANOMETER / M.

G.

6 MANOMETER / M. G. READING Pa INCLINED TUBE MANOMETER / M.

G. X 10

7 ACTUAL LEAKAGE (La) Ltr/Sec FROM GRAPH

MAX. PERMITTED LEAKAGE (Lp) :- ACTUAL LEAKAGE (La) :-

RESULT :-

CHECKED BY :-

APPROVED BY :-



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COIL LEAKAGE TESTING

11. PURPOSE To evaluate the leakage of Coil.

12. SCOPE Testing of coil at works in order to check its leakage .The test will be done at 21 Kg/cm2 for 2 hours air pressure under water.

13. RESPONSIBILITIES Quality Control Department

14. PROCESS

1. Check all the coil components such as tubes, fins, coil casing are in good physical shape. 2. Check that air vent and drain plugs are provided to eliminate the entrapped air and condensate if

any. 3. Each coil is leak-tested just before packing & crating. Our standard method of testing is charging

the coil with compressed air at a minimum of 21Kg/cm2 and placing the coil under water. 4. Any fault discovered during such tests shall be at once remedied and the test reapplied until the

section under test is considered sound. 5. Upon completion of the test, the air shall be released away as possible. 6. After that the coil will be filled by nitrogen gas minimum of 40-50 PSI pressure.

VIBRATION TEST

Visual inspection of the free running unit is done for any undue vibrations. If noticed, the cause of the vibration is identified & suitably rectified. However, the actual vibrations observed at factory may also take in to account the impact of other running machines of the shop floor, adjoining load carrying moving equipment etc. so the exact vibration level can’t be measured in the factory.



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ANNEXURE-C

PRE- COMMISSIONING CHECK LIST OF AIR HANDLING UNITS

Make Location AHU Model No. & Designation

AHU Drawing Reference

Date of Test

MECHANICAL CHECKS

Sl.No. Description of Item Yes No Remarks

1 External and Internal Cleanliness of AHU

2 All Components, bolts fixing are secured and covered with screw caps where required.

3

All bots, washers are made of stainless steel. Check purchase documents to confirm the specification and make to which it has been procured.

4 Impellers are secured and freely rotated by hand

5

Vibration Isolators are provided and Anti Vibration Mounting is properly fitted. Check manufacturer’s logo on the item clearly visible and date of manufacturing.



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6

Belt Tension and alignment of pulleys are corrected. Record belt tension and check for its adjustment. Record the make and the specification to which the belt is procured.

7 Belt/Drive Guards are fitted.

8

Flexible Connection is Secured and Air Tight. Check for any visible sign or indication of air leakage by simple paper test.

9

Drain Pan has been provided and check with spirit level about the slope and record it. Check also free flow of water on the drain pan towards the outlet pipe.

10 Bottom Drain pan and pipe Insulation is provided to prevent condensation

11 Check for any damage to Cooling Coils and Fins and are in good condition.

12 Panel Type Filters has been provided

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No Leakage of Air surrounding the filters. Check by simple paper test. Check quality of gasket used and bedding on it.

14 Door Guard is provided with hinges and latch.

15 Drain Line is connected to the nearest drain

16

Temperature and Pressure gauges are provided at location easily visible. Make of temperature and pressure gauges are of proven makes.

17 Butterfly valves and its operation

18 Two-way valve

19 PICV

20 Flexible Connections

21 Y-Strainer



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22 Bypass line for Cooling Coils

23 Chilled water pipe insulation for its durability and workmanship

24 Motorized Damper on AHU outlet

25 Manual Damper in Air Plenum

26 Surrounding opening of Manual Damper has been sealed.

27 Motor and fans are fitted at same level

ELECTRICAL CHECKS

Sl.No. Description Yes No Remarks

1 Power and Control Wiring correctly installed, secured and aligned.

2 Cable Termination to motor is properly glanded

3 Door Limit Switches has been provided. Check for its sturdiness and mounting.

4 Lighting is provided in FAN Section and Filter Section

5 Motor Earthing has been provided correctly

6 MOD cabling completed.

PRILIMINARY & INITIAL OPERATION OF AHU

Motor Motor Rating (kW)

Rated Rated RPM Rated Voltage



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Make Amps

Sl.No. Description of Item Measured Value Remarks

1 AHU's fan rotation is correct.

2 AHU free from abnormal vibration & undue noise.

3 MOD is interlocked with AHU motor

4 Door Limit Switch interlocked with fan motor

5 No abnormal overheat or over current of motor.

6 No seepage of lubricant from bearing housing.

7 Motor RPM

8 Check running current is balance on all phases.

9 Megger test - M ohm/Motor insulation



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Other Comments:-

Tested By:- Witnessed By:-

For For DMRC/Project For DMRC/O&M

Signature:- ______________ ________________ _______________

Name:- ______________ ________________ _______________

Date:- ______________ ________________ _______________



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ANNEXURE-D

PERFORMANCE ACCEPTACNCE TEST OF AIR HANDLING UNITS

Make Location AHU Model No. & Designation

AHU Drawing Reference

Date of Test

AHU DATA (Performance data as claimed by the Manufacture)

TYPE Size/Row Cooling Capacity

Air Flow Total Pressure

MOTOR DATA (Name Plate Data)

Make

Model No.

Rated RPM

FRAME NO. kW/HP Full Load Current



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DRIVE DATA

GROOVE TYPE NO. OF GROOVES BELT SIZE

FAN PULLEY MAKE Motor PULLEY MAKE BELT MAKE with manufacturer’s data

FAN PULLEY DIA Motor Pulley Dia. MOTOR RPM

STARTERS

TYPE

O/L RANGE O/L SETTING

TIMER SETTING

PERFORMANCE DATA

PARAMETERS DESIGN MEASURED



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SUPPLY AIR VOLUME l/s

RETURN AIR VOLUME l/s

TOTAL STATIC PRESSURE (Pa)

AIR TEMPRATURE ON COIL oC/F

AIR TEMPRATURE OFF COIL oC/F

ENTERING WATER TEPRATURE oC/F

LEAVING WATER TEMPRATURE oC/F

WATER FLOW RATE l/s

RELATIVE HUMIDTY

(a) FRESH AIR (b) SUPPLY AIR (c) RETURN AIR

FAN RPM

MOTOR RPM

Noise at one meter distance dBA

ELECTRICAL

PARAMETERS

(a) VOLTAGE

R-Y

Y-B

B-R

(b) CURRENT

R

Y



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B

COOLING CAPACITY OF AHU

(The formula based on which the cooling capacity is calculated shall be given here to avoid any dispute)

Other Comments:-

Tested By:- Witnessed By:-

For………….. For DMRC/Project For DMRC/O&M

Signature:- ______________ ________________ _______________

Name:- ______________ ________________ _______________

Date:- ______________ ________________ ________________

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