Air Conditioning System Specification

8/12/2019 Air Conditioning System Specification

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SECTION 6 - SPECIFICATIONS

96

AIR CONDITIONING AND MECHANICAL VENTILATION SYSTEM

General

a. This Scope of Work and Technical Specification and associated clause by clause compliance

statements and Tender Drawings , which are part of this Contract, describe the specificScope of Work that the Contractoris required to carry out.

b. All equipment, components and accessories required for the completion and successful

operation of the Workcovered under the Scope of Work either specified in detail or not, shallbe supplied and installed by the Contractor as necessary to enable it to be calibrated,

commissioned and put into operation in accordance with the Design Parameters.

c. The engineering design and the specifications of equipment and material supplied shall be in

accordance with this Scope of Work and Technical Specifications and applicable IndustryStandards specified. If the equipment either does not conform to specifications or is not

acceptable to Employer based on past operating experience, the Contractor shall propose

alternative equipment for review and acceptance by theEngineer.

d. In case of a conflict in the requirements specified, the Contractor shall bring this to theattention of the Engineer and shall obtain such applicable requirements for this Project in

writing from theEngineer.

e. The Contractorshall have no right to decide on his own the requirements in case of such a

conflict, and in case of such an eventuality, he will be doing so at his own risk and cost as theEmployerreserves the right to reject any or the complete part of such Workarising out of the

Contractor's own decision.

f. The drawings listed in Appendix I are for specifying the scope of work in enough detail and

to explain the design intent. Contractor shall develop detailed design drawings for theconstruction based on these drawings and the specific equipment and material proposed forthe works.

g. The specification of equipment and material specified herein are to be considered as the

minimum requirement, and the Contractorshall carry out his own basic and detailed design

necessary for the specifications of the proposed equipment.

h. All documents, drawings data and instruction books to be submitted by the Contractor shallbe written in English language.

Applicable Standard Specifications

Contractor shall ensure that the proposed Air Conditioning and Mechanical Ventilation system

comply with following Standard Specifications,

i. ASHRAE Standard 15-1994 - Safety Code for mechanical refrigeration

ii. ASHRAE Stand. 62-1999 - Ventilation for acceptable indoor air quality

iii. ASHRAE Stand. 70-1991 - Method of testing for rating the performance of air

outlets and inlets.

iv. ASHRAE Stand. 70-1991 - Method of testing for rating the performance of air

outlets and inlets.


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v. ASHRAE Guideline 4-1993

- Preparation of operation & maintenance

documentation for building systems

vi. ASHRAE Guideline 1-1996 - The HVAC commissioning processvii. SMACNA (1985) - HVAC Duct construction standards

viii. SMACNA (1981) - HVAC Duct system design

ix DW/142 (1982) - Specification for sheet metal ductwork

x. CIBSE Guide A (1999) - Environmental design

xi. CIBSE Guide B - Installation & equipment data

xii. CIBSE Guide C (1986) - Reference data

xiii. CIBSE Guide E (1997) - Fire engineering

xiv. CIBSE Guide F (1998) - Energy efficiency in buildings

xv. ASHRAE handbooks - HVAC applications, Systems and Equipments

xvi. B.S. 5643 (1984) - Glossary of air conditioning terms buildings

xvii. B.S. 5720 (1979) - Code of practice for air conditioning in buildings

xviii. B.S.EN 779(1993) - Air filters

xix. B.S.5588 - part 9 (1989) - Code of practice - Duct works (fire precaution)

xx. B.S. 6821 - Method of testing of dampers and valves

xxi. B.S. 4434 (1989) - Specifications for safety aspects in the design,

construction and installation of refrigerating

appliances and systems.

Scope of Work

Scope of Work shall cover supply, installation, testing, balancing and commisioning of Air

Conditioning and Mechanical Ventilation System for the proposed office building. This Contractincludes supply and installation of equipment and erection of necessary plumbing, ducting, andinstallation of other electrical and mechanical equipment as specified in detail hereunder:

i. 2 nos. - 10Tons Air cooled Ducted Packaged type Precession Air Conditioner

ii. 2 nos. - 10Tons Air cooled Ducted Split type Air Conditioner

iii. 1 no. - 15Tons Air cooled Ducted Split type Air Conditioner

iv. 2 nos. - 20Tons Air cooled Ducted Split type Air Conditioner

v. 1 lot

- Externally insulated duct work consisting of plenum boxes, bends, take offs,

reducers, sound attenuators, junction boxes, volume dampers etc.,

vi. 1 lot - Ceiling diffusers, dampers, etc.,

vii. 1 lot - Exhaust fans and related duct work, air grills, etc.,

viii. Provide comprehensive warranty and service for one complete year after commissioning thesystem and equipment.

ix. Provide operational spare parts for two years of operation after the one year warranty period.


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x. Provide As-Built Drawings, Spare Parts catalogue, Operation & Maintenance Manuals.

Design Criteria

Contractorshall adopt the following design criteria as a minimum for thisProject:

4.1 General

Equipment Operation in server

room

: 24 Hours

4.2 Outdoor Condition

All equipment, material and devices and their specified ratings furnished under this Work

shall be suitable for operation in the following outdoor conditions:

Annual Average Dry Bulb Temperature : 31 C

Annual Average Wet Bulb Temperature : 27 C

Maximum Dry Bulb Temperature : 33 C

Maximum Relative Humidity : 90%

4.3 Indoor Design Condition for server room

Dry Bulb Temperature : 18 C to 22 C

Relative humidity : 50% to 60%

4.4 Electrical System Parameters

Low Voltage system is 400V, ac 3 phase 4 wire system and the neutral is effectively

grounded. The ratings of circuit breakers, control gear and other relevant equipment shall be

selected considering the system fault level at the location.

Nominal voltage : 400, ac 5%

System frequency : 50 Hz

System fault level : 25kA

4.5 Allowable noise Level

In room : 50 dB(A)

In open air at a distance of 2 meters : 60 dB(A) for overall area


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Working Drawings

Contractor shall prepare and provide scaled working drawings taking into consideration the design

intent of the tender drawings, specifications, architectural schemes, structural layouts and any otherfactor as relevant to the works. The working drawings shall be in enough detail indicating equipment size,pipe connection details, equipment make, model, ratings and duty. In case of air registers and diffusers and

similar items, airflow rates, neck size, type, etc. for each type shall be indicated.

The working drawing shall provide details necessary for coordinating works with other trades such as civil

works, electrical, plumbing, etc.

The drawings shall be of scale 1:50. Detailed equipment and piping layout drawings of Scale 1:20 shallbe provided for Pump Room and Machine Room (one set for each rating).

The Contractor shall submit two sets of working drawings to the Engineerfor approval at least one month

prior to commencement of work at site.

Contractor shall incorporate any modifications required by the Engineerand shall obtain approval thereon.

Two set of approved working drawing stamped Issued for Constructionshall be kept in the Contractors

Site Office and one set shall be updated promptly showing all relevant details marked up as necessary to be

taken for preparing final As-Built drawings.

Balancing, Testing and Commissioning

Contractor shall carry out system balancing, testing and commissioning as per ASHRAE & CIBSE

Standard Commissioning code, or as directed by theEngineer. The duct work shall be tested as specified inDW142 and DW143. Contractorshall demonstrate to the Engineerthat the system operates satisfactorilyand the design parameters are met.

Test protocols as per the standard specifications shall be prepared and submitted to the Engineer onemonth before the schedule date of testing.

Operation and Maintenance Training

Contractorshall provide operation and maintenance training to the Employersstaff on operation and

maintenance of the system. The Contractormay propose his own recommendations or other trainingprograms that the Contractor considers beneficial for the Employer in their efforts towards

independence and self reliance in the operation, maintenance of the installed Air Conditioning and

Mechanical Ventilation System.

Warranty and remedy of defects

Contractor shall warrants that the Work is engineered and designed in accordance with the highestquality, efficiency and state of the art design and with best engineering practices; shall meet the design

criteria and the design intent; and be fit for the purposes intended.

At any time prior to or within one (1) year after the commissioning, if the Engineerdiscovers that the

Workdoes not conform to the warranty set forth above, Contractorshall, after receipt of notice from theEmployer, promptly perform or arrange for the performance of any corrective action required to make theWork conform to the warranties set forth above, including all Work of removal, engineering, design

replacement or re-fabrication of material and reinstallation as may be necessary.


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g. Compressors shall be provided with the following protection and display features:

Phase failure Phase reversal/phase sequence Phase imbalance 3-phase ground fault Over-current thermal overload Microprocessor based overload trip protection 3-phase power monitor RefrigerantHigh Pressure RefrigerantLow Pressure

h. Voltage/Current rating of the power conductor to the unit shall meet or exceed

minimum unit nameplate voltage and rated full load current.

i. Appropriate surge protection shall be incorporated in the motor controller to protect or

avoid malfunction from surges resulting from sudden load reductions.

j. Flexible and/or rigid conduits shall be used as necessary for the cable run from Main

MCCB to the power input socket of the unit.

k. Following documents shall be available from the manufacturer, at the work site during

installation, start up and training/instruction:

i. Start up, operation and maintenance instructions

ii. Installation instructions

iii. Field wiring diagrams

vi. One complete set of certified drawings.

10.2.1 Air Cooled Packaged UnitPrecision Air Conditioner

a. Packaged Type Precision Air Conditioner shall be of microprocessor-controlledmodular in construction, air cooled using hermetically sealed compressor, with

refrigerant R-407A or equivalent.

b. Unit shall be of floor standing type subject to approval of theEngineer.

c. Refrigerant pipes shall be provided with supports and anchoring as appropriate to

prevent amplifications resulting from compressor discharge gas pulsations and

mechanical vibrations. Allowance shall be provided for thermal expansions andcontractions of pipes, by providing appropriate elbows and 3 dimensional pipeconfigurations.

d. Refrigerant charging ports/connections shall be provided for field charging of

refrigerants. Suction and discharge gauge connectors shall also be provided for fixingpressure gauges for maintenance.


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e. Internal cabinet insulation shall be as per ASHRAE 62.1 for Mold Growth, Humidity

& Erosion, and shall be tested as per UL 181 & ASTM 1338.

f. Package units shall be manufactured in a facility which has been registered by

Underwriters' Laboratories, Inc. (UL) and by the International Organization for

Standardization ISO 9000 Series Standards for quality.

g. Exposed metal surfaces of the packaged Units shall be galvanized and/or powder

coated with manufacturers standard colour shade, direct-to-metal. Mounting brackets

shall be of adequate strength and factory fixed to the cabinet.

h. Neoprene rubber isolation pads shall be provided under all support points of the unit.

i. Unit shall be provided with the following Set Point Parameters:

Temperature Set Point 18 C - 29 C

Humidity 20% - 80%

j. Unit shall be provided with the following Alarm / Protection Features:

High Temperature

Low Temperature

High Humidity

Low Humidity

High Water Alarm - Lockout Unit Operation

High Head Pressure

Loss of Power

Compressor Short Cycle

10.3 Duct Work

10.3.1. General

a. Duct work shall be of galvanized, cold rolled, close annealed, patent

flattened steel sheets, in accordance with HVCA DW/142, suitable for thesystem pressure involved.

b. Access doors to ductwork shall be of the hinged insulated type, exceptspecified otherwise. Access doors and door openings in the ductwork

shall be adequately stiffened.

c. Transformation pieces shall be constructed such that the angle on any side

does not exceed 20 to the axis of the duct. Where this is not possible, theEngineer's approval shall be obtained.

d. Where branch ducts occur at taper or transformation pieces, the length ofsuch pieces in the main ducts shall be symmetrical about the axis of the

branch duct.

e. Sharp edges or corners on ductwork, on associated equipment, supports,

angles, etc., will not be permitted.


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f. Duct connections to equipment shall be fabricated in sections with mild

steel angle frames to permit easy removal of the complete plant or anyone component.

g. All riveted joints shall be sealed with 75mm wide adhesive tape, applied

externally and all connections to plant made with felt or asbestos jointingto minimize transmission of vibration.

h. All bolts shall be bright steel with nuts and washers serialized. Rivets and

self-tapping screws shall be Galvanized, serialized or similarly treated toavoid corrosion.

i. Where steel ducts connect to constructional work, the end of the steel ductshall project into the wall of the constructional duct and a galvanized mild

steel angle flange shall be provided for grouting into the brickwork orreinforced concrete and felt or rubber insertion shall be provided to seal

the joint. A thermal barrier shall be provided where necessary.

j. Each section of the duct work shall be tested at works before folding and

the quality of the sheet shall permit folding without cracking. All ductsshall have a smooth internal finish, free from projecting angles, nuts or

rivets, etc.

k. Ductwork shall be manufactured from sheets of the thickness given in

relevant detail drawing. Where ductwork is external to the building, inlet

cowls, extract gratings, etc, the thickness of the ducts shall be at least twogauges thicker than that given in the table. External duct work shall bespecially fabricated and painted with two coats of black bitumastic paintsuch as 'Evode No. 5Q5H - Appexior', or equivalent subject to Engineers

approval.

l. Joints for rectangular ductwork of a side wider than 600mm shall be

flanged by means of 40mm x 40mm x 3.2mm galvanized mild steelangles. Angles used as flanges or stiffeners shall be riveted to the

ductwork with 8 SWG rivets at 50mm pitch. The joint faces of all flangesshall be drilled for 10mm bolts at 75mm pitch.

m. Slip joints shall be not less than 150mm long with the spigot carefully

swaged circumferentially to act as a stiffener and a register for the socketend.

10.3.2. Duct Supports

Ductwork shall be adequately supported on supports and brackets,adjustable in height, fixed to the building structure with specially

designed brackets and cantilevers and spaced to ensure adequate support.Where practicable a support shall be fitted at each joint in the ductwork.

All ductwork supports shall conform to HVCA DW/144. All supports

shall be of Hot dipped galvanized mild steel. All cuts and drill holes shallbe treated with cold galvanizing paint.

Felt pads shall be fitted between the ducts and the supports to reducetransmission of noise and vibration. Supports shall be spaced to prevent

distortion and drumming of the ductwork.


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Where ductwork is insulated a non-compressible insulation spacer equal

in thickness to the insulation shall be placed between the duct and itssupport.

Sleeves shall be fitted to ducts at points where they pass through walls,

floors and ceilings. Sleeves shall be made of Galvanized mild steel.Timber may be used if approved by the Engineer. The gap between theduct and the sleeve shall be filled with fiberglass insulation of density 45

kg/m3.

10.3.3. Dampers

a. Volume dampers shall be provided at positions where branches or sub-

branches leave the main distribution ducts as indicated in the drawings.

Dampers shall be of adjustable stainless steel aerofoil manufactured inaccordance with HVAC DW/144.

b. Multi-leaf dampers shall be of the opposed blade type with blades rigidlyfixed to the operating spindle, the end of which shall be housed insynthetic bearings. The respective leaves of multi-leaf dampers shall belinked by toothed gears housed in a protective casing with a manual gear

controller and indicator. The set air volumes shall be indicated on a labellocated adjacent to each damper.

c. Fire dampers shall be supplied and fixed in ducts, where indicated indrawings, or detailed elsewhere in the specification and shall comply withthe relevant British Standards. An access panel shall be provided in the

ductwork adjacent to each fire damper.

d. The air leakage past through a damper in the fully closed position shallnot exceed 5%. Dampers shall be as manufactured by TROX or equal and

approved.

10.3.4. Splitters and Turning Vanes

Where changes of direction occur in duct runs and space does not permit

large radius bends to be installed, square or short radius bends may be

used provided with internal splitters or turning vanes of true aerofoilsection as detailed in HVAC DW/144.

Turning vanes shall be rigidly fixed to prevent vibration and the edgesshall be smooth and free from burrs, etc. to prevent air noise. Contractor

shall submit general arrangement drawings of splitters and turning vanesto theEngineerbefore the fabrication.

10.3.5. Diffusers and Grilles

a. The Contractorshall provide and install grilles and diffusers as indicatedin the drawings. In addition to complying with these specifications thesegrilles and diffusers shall comply with any specific requirements specified

under Interior Designs.

b. Supply and return air diffusers and grilles shall be manufactured from

extruded Aluminium.


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c. Return and extract air diffusers and grilles shall be of similar construction

as those for supply air, but without dampers, unless indicated otherwiseon the Drawings.

d. Fresh air inlet grilles or any grille subject to atmospheric corrosion shall

be manufactured from robust aluminium alloy extrusions, designed toallow a minimum ingress of rain water. Supply and return air diffusersand grilles shall be of stove enameled paint finish, in accordance with the

Engineersapproved colour shade.

e. Grilles fixed on external walls shall be fitted with insect / bird screens.

f. Grille and diffuser dampers shall be made of Aluminium or Galvanizedsteel and be provided with a removable key so that adjustment can be

made from the face on the grille or diffuser. All grilles and diffusers shallbe fitted with a rubber sponge gasket or flexible PVC sheet for airtight

joint.

10.3.6. Plenum Boxes

Plenum boxes shall be of Galvanized sheet steel, acoustically lined internally

and thermally insulated externally. The connecting spigot shall be fitted with avolume control damper. For applications requiring NR 25 or below the

maximum length shall be 1.5m. Approved proprietary boxes may be used

subject to the required sound levels being achieved. Where locally fabricatedboxes are offered, the height of the box shall be 2 x diameter of neck or 500mmwhichever is the greater.

10.3.7. Connections

a. Flexible connections shall be supplied and fitted on all package units and

shall also be fitted to other components where indicated on the Drawings.

b. Flexible connections shall be manufactured from heavy quality, PVCimpregnated, canvas and shall not be less than 200 mm length. The

canvas shall be securely fixed to air handling units and ducting with

Galvanised mild steel angle frames to provide perfect airtight joints. Theflexible connections shall be pre-insulated to minimize condensation.

c. Circular flexible ducting shall be installed as shown in detail drawing to

the diameter indicated. Flexible ducts shall be pre-insulated with thermalinsulation having thermal conductance of 1.305 W/mK.

d. Flexible connections shall be capable of withstanding full operatingpressure of the system and shall have tested to a test pressure of at least

50% higher than the system operating pressure.

e. Duct connections to equipment fitted with anti vibration mountings shallhave flexible connections to isolate the vibration from the piping or

ducting system. All flexible connections shall be installed with the axisparallel to the connecting duct and shall not be used to form a duct offset.


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10.4 Thermal Insulation of Duct Work

10.4.1. General

Thermal insulation shall be applied on the duct surfaces operating on a surfacetemperature below the surrounding temperature and the surface temperature belowthe dew point of the surrounding air.

10.4.2. Material

Insulation material shall be flexible duct insulation formed from uniformlytextured, Glass wool fiber bonded with a thermosetting resin to form lightweight, flexible blankets which is laminated with single sided two way re-

inforced aluminium foil vapour barrier. Thermal conductivity of Glass wool

blanket shall not exceed 0.035 W/mK at mean temperature of 20 C. The

insulation shall have fire performance such that it passes CLASS 0 as per BS

476 Part 5, 6 & 7 under building regulations section E 15.

10.4.3. Thickness

Ceiling plenums - 5 mm, 0.035 W/mK, 24 Kg/m3

Ducts facing outdoor atmospheric conditions - 50 mm, 0.034 W/mK, 32 Kg/m3

10.5 External Noise

No piece of plant located externally or in a plant room shall have a noise level which is

sufficient to impinge on rooms to the extent of producing an NR value greater than thatspecified above for the office rooms. Any noise produced by equipment outside a room

shall be additional to any noise produced by equipment inside or serving that room in terms

of NR criteria.

Main supply duct up to the first branch-off and main return duct up to 3000mm length fromthe unit shall be acoustically lined internally with an acoustic layer as indicated in the

drawings in addition to the external thermal insulation.

10.6 Electrical Works

10.6.1 General

a. The incoming supply will be at 400V, 3 phase, 3/4 wire, 50 Hz and the

panels shall be suitable for a fault rating of 25 kA at 400 volts. Phasesequence colouring shall be Red, Yellow and Blue. All sections of thepanel shall be suitably labeled.

b. Motor starting panels shall have the following sub-sections:

Supply incoming section Motor starting section separate for each motor Automatic control circuits and Indicators Small power distribution section Protection devices/ equipment


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10.6.2 Electric Panel Enclosures

a. The interior of enclosure shall be powder coated with gloss white paint.

The exterior of the enclosure shall be powder coated with cream colour

paint. All cut-outs and holes to be drilled in the panel enclosure shall

be carried out in the factory before rust proofing and powder coating.

b. All cubicles shall be adequately earthed independent of the earth

connection via the cable glands, and panel doors and other cubicle

sections shall be electrically bonded to each other for proper earthing.

c. Enclosures shall be of wall mounted type and shall have protection classIP 54 as per IEC 529.

d. Enclosure dimensions shall be carefully selected so that adequate workingspace

is available for easy replacement of components. Access to the cubicles

or cubicle compartments for all normal routine maintenance shall befrom the front.

e. Enclosure doors shall be suitably brazed and hinged to ensure uniform

pressure right along the rubber beading. The rubber beading shall be flat

type that provides protection against dust and drops of water. Doorsshall be lockable with special type key (triangular) operated locks.

Hinges shall be made of suitable non-corrosive material.

f. Arrangement of components shall be logically designed and shall beapproved by theEngineer. Cable entry shall be as existing where knock

out flanges shall be fixed. All cables shall terminate at connectionsinstalled at the bottom part of the enclosure.

Bus bars shall occupy the top portion of the enclosure. Contactors andprotective devices shall be in the middle portion of the enclosure. All

meters shall be conveniently located for easy reading and MCCB'slocated at convenient heights. Maximum mounting height of theenclosure/instruments shall be decided considering the operational

convenience during the design stage.

g. Wiring within the enclosure shall be done in neatly arranged PVC cable

trays with detachable lid and shall be properly tied. All wires shall benumbered. The control wiring diagram suitably laminated shall be fixed

on to an interior wall of the enclosure.

10.6.3 Supply Incoming Section

Incoming section of the Panel shall consist of the following basic elements:

One 4 pole moulded case circuit breaker with thermal magnetic over load andearth fault trip.

One voltmeter with selector switch for monitoring phase to neutral and phase-to-phase voltages.


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One supply voltage monitor with following features and interlocked with both

of themotor starters.

Supply voltage imbalance, (single phasing, adjustable). Under and over voltage. Lamp indicator to indicate operating condition of supply voltage.Set of lightening voltage surge-arrestor/diverter.

10.6.4 Bus Bars

All bus bars (TP or TP&N running over the entire length of panel) shall be of

copper and of adequate thermal and short circuit capacity to withstand extremefault or short circuit conditions without permanent damage. Current density inthe bus bars shall not exceed 3A per mm

2under all operating conditions.

An earth bus bar shall be provided at the bottom portion of the enclosure.

10.6.5 Automatic Control and Interlocks

Necessary control relays, transducers, cables and accessories shall be providedfor automatic operation of the units according to the control strategy.

10.6.6 Earthing Terminals and Connections

Earthing bar shall be provided mounted in the lower part of the enclosure (earth

bus) and shall be marked Main earth terminal and shall be complete withscrew-connections, for earthing conductors.

Earth conductors shall be sized in accordance with relevant IEE regulations or

equivalent. PVC cable insulation shall be green/yellow.

10.6.7 Field Wiring

a. Power and control wiring, switchgear, protection gear and otheraccessories shall be provided for complete installation of equipment as

necessary.

b. Field-supplied conductors, devices and wiring, material used fortermination, splice and tap conductors and devices shall be UL listed

and in compliance with applicable codes and specifications. Installation

shall be done using manufacturer recommended tools.

c. The routing of field installed conduit and conductors and the location of

field-installed devices shall not interfere with equipment access or the

reading, adjusting, or servicing of any component.

d. Equipment installation and all starting and control devices, must complywith details in equipment submittal drawings and literature.

e. Wire and cables with aluminum conductors shall not be used.


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10.6.8 Control Wiring

a. Control wiring of the packaged units, indoor and outdoor shall be wired

as necessary to the plant control circuits to make the system fully

functional as an integrated system.

b. Control scheme shall be as such the individual packaged units can beoperated independently through their respective unit controllers

(manual/auto) or through the system management controller.

c. Field supplied control conductors shall be at least 18 AWG or larger.

d. Terminating device contacts and spare safety device contacts shall have24 V ac rating. Minimum current rating shall be 60 mA, and nominal

current shall be 10mA. Switches shall be with gold plated bifurcatedcontacts.

e. Low Voltage power wiring and control wiring (30V or less) shall be inseparate conduits.

f. For all field wiring the cables and the connected equipment shall be

provided with permanent plastic tags and labels which will easily

identify the cable or equipment, and shall be correctly referenced in"As-Built" drawings.

g. For all cable installations, both ends of the cable shall be colour codedand labeled for easy identification.

10.6.9 Moulded Case Circuit Breaker (MCCB)

MCCB's shall be manually operated type manufactured as per ICE 157-1 orequivalent.

Each pole of the MCCB shall be shielded by insulated phase barriers, and circuit

breaker contacts shall have adequate suppression.

MCCB's shall be fitted with thermal and Magnetic overload trips and thermal

trip shall be adjustable for all capacities. For capacities exceeding 100 A, the

magnetic trip too shall be adjustable.

Breaking capacity according to ICE 157 at 416 V shall be above 25 kA for allMCCB's used.

Each incoming circuit breaker shall in addition be provided with instantaneousearth faults protection.

10.6.10 Contactors

Contactors shall conform to relevant industry standard and/or UL listed formotor starting contactors. Contactors incorporated in motor starters shallconform to BS 775 and/or BS 5424 or equivalent.

Capacities of the contactors shall be carefully selected leaving sufficient extra

capacity.


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10.6.11 Controls, Indicators and Alarms

Indication lamps and push buttons shall be provided and be coloured as follows:

Lamp Marking Colour

On

FaultOff

Green

AmberRed

Switch Button Marking Colour

Start

Stop

Green

Red

10.7 Spare Parts

List of spare parts shall include Manufacturers' recommended spare parts for all items of

plant of the mechanical and electrical services installations to provide maintenance for a

period of two years after the one year of warranty period.


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Documents

Air Conditioning System Specification