CPUT COMMERCE BUILDING HVAC REFURBISHMENT HVAC … · Johann van Zyl Draughtsman ....

Prepared for:

Cape Peninsula University of

Technology

Contact person:

Manelisi Rarani

Tel: (021) 959 6088

Email: [email protected]

CPUT COMMERCE BUILDING HVAC

REFURBISHMENT

HVAC TECHNICAL SPECIFICATION

DRAFT REPORT

REVISION 00

MARCH 2018

Prepared by:

Delta Built Environment Consultants (Pty) Ltd

Contact person:

Pjero Nell

Tel: (012) 368 1850

Fax: (012) 348 4738

Email: [email protected]

P17068_TENDER_REV 01- HVAC REFURBISHMENT (MECHANICAL SPECIFICATION) of 57

DOCUMENT CONTROL

TITLE: HVAC SPECIFICATION

ELECTRONIC FILE LOCATION:

P17068_TENDER_HVAC_TENDER DOC_DOC_GCC_REV 01-HVAC Specification

REPORT STATUS: Draft

REVISION NUMBER: 00

CLIENT: Cape Peninsula University of Technology

Symphony Way, Bellville

Cape Town

7535

CONSULTANT: Delta Built Environment Consultants (Pty) Ltd

P.O. Box 35703

Menlo Park

0102

DATE: March 2018

REFERENCE NUMBER: P15029/R

PREPARED BY: Charl Pienaar Mechanical Engineer

REVIEWED BY: Pjero Nell Mechanical Engineer

APPROVED BY: Walter Ringelmann Director

DISTRIBUTION LIST: COMPANY NAME & SURNAME

CPUT Mr. Manelisi Rarani

RECORD OF REVISIONS

REV. NO. STATUS DESCRIPTION OF REVISION REV. DATE

00 Draft Issued for approval 22/03/2018


APPROVALS

Name Position Date Signature

Mr. Manelisi Rarani Project Manager

DESIGN TEAM (DELTA BEC)

Name Functional Role Date Signature

Pjero Nell Mechanical Engineer

Charl Pienaar Mechanical Engineer

Walter Ringelmann Project Leader

Andre Hayward Mechanical Engineer

Herman Malan Electrical & Electronic Engineering

Johann van Zyl Draughtsman


EXECUTIVE SUMMARY

The works specified in this document are applicable to the upgrade of the heating, ventilation and air-conditioning system of the Cape Peninsula University if Technology’s commerce building.

The commerce building consists of numerous offices for academic staff, lecture auditoriums and retrofitted computer laboratories.

Due to increased student accommodation the ventilation systems have become inadequate and do not comply with the National Building Regulations, therefore the fresh air supply systems require upgrades.

Air-conditioning in offices, classrooms and computer rooms will be done by incorporating Variable Refrigerant Flow (VRF) systems coupled to Fan Coil Units and various other room units. Existing Chilled water Fan Coil Units are to be removed.

Existing chilled water Air-handling Units (AHU’s) servicing the auditoriums are to be replaced with new DX-type AHU’s with separate condensing units situated within existing plant rooms. Supply and return air ducting is to be inspected and replaced to suite the additional airflows required if the sizes are inadequate. Air jet nozzles are to be fitted to provide long throw cooled air.


TABLE OF CONTENTS

APPROVALS ................................................................................................................................. 3 DESIGN TEAM (DELTA BEC)..................................................................................................................................... 3

EXECUTIVE SUMMARY ................................................................................................................. 4

1 GENERAL ..................................................................................................................... 8 1.1 SUPERVISORY STAFF AND IDENTIFICATION ........................................................................................ 8 1.2 QUALITY OF MATERIALS AND WORKMANSHIP .................................................................................. 8 1.3 RATING OF EQUIPMENT ...................................................................................................................... 8 1.4 SPACE REQUIREMENTS AND ACCESS .................................................................................................. 9 1.5 REGULATIONS AND STANDARDS ........................................................................................................ 9 1.6 MAINTENANCE GUARANTEE ............................................................................................................. 10 1.7 PAINTING .......................................................................................................................................... 10 1.8 DAMAGE AND PROTECTION OF WORK ............................................................................................. 11 1.9 WELDING ........................................................................................................................................... 11 1.10 BUILDER’S WORK AND REMOVAL OF EQUIPMENT ........................................................................... 11 1.11 TESTING ............................................................................................................................................. 12 1.12 COMMISSIONING .............................................................................................................................. 12 1.13 STAFF TRAINING ................................................................................................................................ 12 1.14 SCOPE OF WORK ............................................................................................................................... 13

2 AIR CONDITIONING UNITS ......................................................................................... 15 2.1 VRF INSTALLATION ............................................................................................................................ 15 2.2 FAN COIL UNITS................................................................................................................................. 15 2.3 OUTDOOR UNITS ............................................................................................................................... 15 2.4 DESIGN CRITERIA............................................................................................................................... 18 2.5 UNIT REQUIRMENTS ......................................................................................................................... 18 2.5.1 GENERIC UNIT REQUIREMENTS ................................................................................................................. 18 2.5.2 COMPUTER ROOMS’ REQUIREMENTS ......................................................................................................... 19 2.5.3 OFFICE ROOMS’ REQUIREMENTS ............................................................................................................... 20 2.5.4 AUDITORIUM ROOMS’ REQUIREMENTS ....................................................................................................... 21 2.5.4.1 COOLING COILS .................................................................................................................................................. 21 2.6 PERFORMANCE SPECIFICATIONS ...................................................................................................... 24 2.7 PROTECTION AND SAFETY DEVICES .................................................................................................. 24 2.8 ELECTRICAL ....................................................................................................................................... 25 2.9 CONTROLS ......................................................................................................................................... 26 2.10 REFRIGERANT CIRCUITS .................................................................................................................... 29 2.11 INSTALLATION REQUIREMENTS ........................................................................................................ 30 2.11.1 INSTALLATION OF INDOOR AND OUTDOOR UNITS .......................................................................................... 30 2.11.2 INSTALLATION OF CONDENSATE DRAIN PIPES ................................................................................................ 31 2.11.3 INSTALLATION OF REFRIGERANT PIPING ....................................................................................................... 32

3 VENTILATION SYSTEMS .............................................................................................. 35 3.1 SCOPE ................................................................................................................................................ 35 3.2 DESIGN CRITERIA............................................................................................................................... 35 3.3 APPLICABLE STANDARDS .................................................................................................................. 35 3.4 VENTILATION FANS ........................................................................................................................... 36 3.4.1 GENERAL .............................................................................................................................................. 36 3.4.2 IN-LINE AXIAL FLOW FANS ........................................................................................................................ 37 3.5 DUCTING ........................................................................................................................................... 38 3.5.1 GENERAL .............................................................................................................................................. 38


3.6 LONGITUDINAL SEAMS AND TRANSVERSE JOINTS ........................................................................... 42 3.6.1 RECTANGULAR DUCTWORK ...................................................................................................................... 42 3.6.2 CIRCULAR DUCTWORK ............................................................................................................................. 42 3.6.3 THE HANGING AND SUPPORTING OF DUCTWORK ........................................................................................... 42 3.6.4 FLEXIBLE DUCTING .................................................................................................................................. 42 3.6.5 TESTING OF DUCTWORK .......................................................................................................................... 43 3.7 AIR TERMINALS AND DAMPERS ........................................................................................................ 43 3.7.1 GENERAL .............................................................................................................................................. 43 3.7.2 DOOR AND TRANSFER GRILLES .................................................................................................................. 43 3.7.3 WEATHER LOUVRES ................................................................................................................................ 44 3.7.4 FIXING OF WALL-MOUNTED GRILLES AND LOUVRES ....................................................................................... 44 3.7.5 SUPPLY AIR GRILLES AND DIFFUSERS ........................................................................................................... 44 3.7.6 EXHAUST DISC VALVES ............................................................................................................................. 45 3.7.7 VOLUME CONTROL DAMPERS ................................................................................................................... 45 3.7.8 FIRE DAMPERS ....................................................................................................................................... 46 3.7.9 JET NOZZLES .......................................................................................................................................... 48 3.8 AIR FILTERS ........................................................................................................................................ 48 3.8.1 GENERAL .............................................................................................................................................. 48 3.8.2 FILTER MEDIA ........................................................................................................................................ 49 3.8.3 PRIMARY PLEATED FILTER ......................................................................................................................... 49 3.9 SOUND ATTENUATORS ..................................................................................................................... 49 3.10 ELECTRICAL ....................................................................................................................................... 51 3.11 CONTROL ........................................................................................................................................... 51 3.12 OPERATION IN THE EVENT OF A FIRE................................................................................................ 51

4 RETURNABLE SCHEDULES .......................................................................................... 52 4.1 AIR HANDLING UNITS ........................................................................................................................ 52 4.2 FAN COILED UNITS ............................................................................................................................ 52 4.3 OUTDOOR UNITS ............................................................................................................................... 52 4.4 DAMPER ............................................................................................................................................ 53 4.5 FILTER BANKS .................................................................................................................................... 54 4.6 DIFFUSERS ......................................................................................................................................... 54 4.7 DISK VALVES ...................................................................................................................................... 54 4.8 JET NOZZLE ........................................................................................................................................ 54 4.9 RETURN AIR GRILLS ........................................................................................................................... 54 4.10 EXTRACT AIR FANS ............................................................................................................................ 55 4.11 RETURN AIR FANS ............................................................................................................................. 55 4.12 FRESH AIR FANS ................................................................................................................................ 55 4.13 REFRIGERANT CONTROL BOXES ........................................................................................................ 56

APPENDIX A: SUPPORTING DOCUMENTATION ........................................................................ 57

LIST OF TABLES Table 2-1: AHU’s required for the auditoriums .............................................................................................. 15 Table 2-2: FCU’s required for computer rooms .............................................................................................. 15 Table 2-3: Outdoor units required for AHU’s and FCU’s ................................................................................. 15 Table 2-4: Refrigerant Control Boxes ............................................................................................................. 16 Table 2-5: Rooms connected to ODU 04 and ODU 05 ..................................................................................... 16 Table 2-6: Rooms connected to ODU 06 and ODU 07 ..................................................................................... 17 Table 2-7: Design data ................................................................................................................................... 18 Table 2-8: Insulation Wall Thicknesses ........................................................................................................... 33 Table 3-1: Area design data ........................................................................................................................... 35


Table 3-2: Fresh air supply fans ...................................................................................................................... 36 Table 3-3: Extraction air fans ......................................................................................................................... 36 Table 3-4: Return air fans for AHU's ............................................................................................................... 36 Table 3-5: Flange connection data ................................................................................................................. 40 Table 3-6: Recommended minimum angle sizes ............................................................................................ 47 Table 4-1: AHU’s returnable Schedule ............................................................................................................ 52 Table 4-2: FCU’s returnable schedule ............................................................................................................. 52 Table 4-3: Outdoor unit’s returnable schedule .............................................................................................. 52 Table 4-4: Damper’s returnable schedule ...................................................................................................... 53 Table 4-5: Filter bank’s returnable schedule .................................................................................................. 54 Table 4-6: Diffuser’s returnable schedule....................................................................................................... 54 Table 4-7: Disk valve’s returnable schedule ................................................................................................... 54 Table 4-8: Jet nozzle’s returnable schedule .................................................................................................... 54 Table 4-9: Return air grill’s returnable schedule ............................................................................................ 54 Table 4-10: Extract air fan’s returnable schedule ........................................................................................... 55 Table 4-11: Return air fan’s returnable schedule ........................................................................................... 55 Table 4-12: Fresh air fan’s returnable schedule .............................................................................................. 55 Table 4-13: Refrigerant control box’s returnable schedule............................................................................. 56


1 GENERAL

1.1 SUPERVISORY STAFF AND IDENTIFICATION

All artisans and labour members of the mechanical subcontractors and the subcontractors’ staff will wear clothing adequately marked with the relevant subcontractors' name. This shall be applicable at all times while on the premises.

The work shall be done by or under constant personal supervision of a qualified artisan (or qualified technician) that is qualified in the respective trade. Details of this operation and prospective work shall be given at the time of tendering in a cover letter.

1.2 QUALITY OF MATERIALS AND WORKMANSHIP

All materials shall be new, undamaged and free from rust or other defects. Only material of the best quality, which has been approved by the Engineer, shall be used.

The Subcontractor shall, upon the request of the Engineer, produce documentary proof of his satisfaction that the material is of the quality specified. If required, samples of materials for testing shall be supplied by the Subcontractor free of charge.

Where applicable, all material shall be in accordance with the relevant standard specifications of the South African Bureau of Standards (SABS) and the British Standard Specifications.

The installation shall be carried out according to the latest modern engineering practices.

The Engineer reserves the right to reject any work or part thereof that, according to his judgement, does not meet the highest standards of material and workmanship and to enforce replacement of the work at the expense of the Subcontractor.

1.3 RATING OF EQUIPMENT

The Subcontractor shall supply the sizes and rating of all the equipment offered to the Engineer for approval prior to purchasing or ordering such equipment.

All equipment offered shall operate well within the manufacturer’s ratings, and equipment required to be operated beyond these limits will not be considered.


1.4 SPACE REQUIREMENTS AND ACCESS

Tenderers shall ensure that the equipment offered by them can be installed in the available space as shown on the drawings supplied by the Engineer. Should it be found at a later stage that the equipment offered does not fit all costs arising from the rectification of this problem shall be for the Subcontractor’s account.

The equipment shall be installed in such a manner that complete access is provided for operating and maintenance purposes.

Subcontractors shall also ensure that the equipment offered by them will pass through available building openings. Large equipment shall be made up in sections and each section shall be small enough for access through doors and other building openings. All additional costs involved for the modification of equipment or to change the manufacturer of equipment in order to allow access shall be for the account of the Subcontractor.

It must be noted that the outdoor units are located on the roof of the building and as such will require rigging and hoisting. The fan coil units are all easily accessible and should not be a problem to remove or install. Air-handling units will need to be assembled inside the allocated plant rooms.

1.5 REGULATIONS AND STANDARDS

The equipment, installation, commissioning and maintenance shall in all respects comply with the following authorities and regulations:

The Occupational Health and Safety Act, Act No. 85 of 1993

Local municipal regulations, by-laws and ordinances

Local fire department regulations

SANS 10400: The application of the National Building Regulations

SANS 1238: Standard Code for Air-conditioning and Ventilation Ductwork

SANS 10147: Code of Practice for Refrigeration and Air-conditioning Installations

Local electrical supply authority regulations

The wiring of premises Part1: Low-voltage installations, SANS 10142-1 as amended

Regulations of the local water board

Regulations of the local gas board

Montreal Protocol and Copenhagen Agreement.

All losses, costs or expenditures which may arise as a result of negligence to comply with any regulation applicable to this service as specified above, shall be for the account of the Subcontractor.


Where trade names and references to catalogues are found in the specification the intention is to set a particular standard of equipment. Where “other approved” equipment is specified, the Subcontractor shall obtain written approval from the Engineer before he may deviate from the specified equipment. This approval must be obtained at tender stage.

The Subcontractor shall work strictly according to this specification, shall ensure that only the best quality material is used and that the installation is handed over as a complete working system.

1.6 MAINTENANCE GUARANTEE

All equipment supplied and work done as part of this contract shall be maintained and guaranteed for a period of one (1) year from the date of practical completion.

The Subcontractor is responsible for all material and labour during this period.

The Subcontractor shall visit the installation regularly without fail and shall do the scheduled maintenance as prescribed in the operating instructions. These inspections shall be at a minimum conducted monthly. On completion of the visit, a full report shall be prepared and submitted to the Engineer within seven (7) days of the visit. Unsigned reports shall not be accepted.

In case of a breakdown, the Subcontractor shall react within reasonable time, no more than 48 hours since being contacted, and repair the installation to the satisfaction of the Engineer. Should the Subcontractor, with the discretion of the Engineer, not react within reasonable time, the Engineer shall commission another Subcontractor and the cost thereof shall be recovered from the defaulting Subcontractor.

The Subcontractor shall price for a three (3) year extended maintenance period as per the bill of quantities (BoQ) after the one-year period described above has expired and the Contractor shall allow for all expendable materials necessary for servicing, such as lubricating oils, grease, cleaning materials, etc.

1.7 PAINTING

Where applicable, the following painting specifications shall apply:

Iron and steel surfaces shall be properly cleaned by removing all dirt, oil, scale and rust by brushing and sanding until a clean shiny surface is obtained. Thereafter a metal primer shall be applied.

Galvanized surfaces shall be cleaned with a galvanizing cleaning agent and then washed with clean water to remove the factory applied protection against white rust. Hereafter a calcium plumbate primer shall be applied, followed by an undercoat between 24 and 72 hours after application of the primer.


Other surfaces shall be cleaned by removing all dirt, and a primer as specified by the paint supplier for the particular surface shall be applied.

The primer coat shall be followed by a matte undercoat and a final topcoat of high- gloss enamel of an approved colour. Each layer of paint shall be clearly distinguishable from each other by means of different colours and each layer shall be properly sanded before the following coat is applied.

All paint shall at least be of SABS quality for industrial use and shall be approved by the Engineer. Equipment shall be painted according to the National Colour Standards, SANS 1091.

1.8 DAMAGE AND PROTECTION OF WORK

The Subcontractor shall take all precautions necessary for the protection of life, equipment and property in connection with the works during installation.

The Subcontractor shall be held completely responsible for any damage of equipment during transport and installation, as well as any damage to the building and shall repair any such damage at his own expense. Where equipment cannot be repaired to an “as new” condition, it will be completely replaced at the expense of the Subcontractor.

Equipment delivered to site shall be stored in a well-protected area where it cannot be damaged by either the weather or other trades.

Possible damage caused by others must be minimised by installing equipment, if possible, at a time when the work of other trades are practically completed. The contractor shall be held responsible for the repairs of all damaged portions of the installation.

1.9 WELDING

Welding shall be carried out in accordance with the current edition of SANS 10044 Parts 1, 2 and 3, where applicable. All welding shall be performed according to the latest technology and where exposed the surface shall be smoothly finished off.

1.10 BUILDER’S WORK AND REMOVAL OF EQUIPMENT

The following work shall be carried out by the Builder/Main Contractor:

Drilling and cutting of necessary holes in the concrete, brickwork ceilings and wooden doors, including making good to match finish

Concrete plinths for installation of equipment

Waterproofing of roof penetrations and plinths

Provide drain points where required.


1.11 TESTING

The plant shall be tested and operated to meet the performance figures and duties specified. All safety features and interlocks shall be tested.

Pressure tests for water and piping shall be done at a test pressure of 1.5 times the maximum working pressure at the lowest point in the system, but not less than 700 kPa. All instrumentation, which could be damaged during the test, shall be removed from the pipe system.

The relevant system shall be filled with water and all high points shall be vented at least 24 hours before the test. The duration of the pressure test shall be two hours, after which no water leaks shall be visible and no pressure drop shall occur after corrections have been made for changes in ambient temperature during the test period.

Pressure tests shall be completed prior to insulating or covering piping. If leaks are found, welded connections shall be cut out and re-welded. Rectified piping shall be re-tested.

1.12 COMMISSIONING

The installation shall be commissioned in accordance with the relevant codes and recognised commissioning procedure or code approved by the Consulting Engineer.

The Subcontractor shall submit a commissioning programme to the Consulting Engineer at least two (2) weeks prior to the commencement of commissioning and at the same time shall notify the Consulting Engineer of the code or procedure to which the plant will be commissioned.

The results of all checks and measurements shall be recorded in writing during the commissioning period. Commissioning records shall be handed over to the Consulting Engineer prior to the first acceptance of the plant. The commissioning records shall also be included in the operation manuals.

1.13 STAFF TRAINING

The Subcontractor shall be responsible for the training of the Client’s site staff after the commissioning has been completed. The site staff shall receive enough instruction to ensure that they are fully conversant with the equipment concerned. The operating manuals shall be used during training. Upon completion of the training exercise, the Subcontractor is to obtain the Client Representative’s written acceptance of this handover tuition, thus acknowledging his complete understanding of the operational procedures for this installation. Site staff shall be instructed on:


The general operating method of the plant

Starting and stopping instructions

Stopping the plant in an emergency and warning against restarting after an emergency

Positions and normal settings of control equipment

Safety measures

Operational checks on gauges, flow switches, indicator lights, etc.

Name, address and telephone number of a competent person responsible for the maintenance of the plant.

1.14 SCOPE OF WORK

The specification covers the following:

The supply, delivery, installation and commissioning of:

o Variable Refrigerant Flow (VRF) systems o DX-type Air-Handling Units (AHU’s) o DX-type Fan Coil Units (FCU’s) o Various indoor room units o Ablution extraction o Kitchen extraction o Mechanical ventilation using outside (fresh) air.

It will also be expected of the Contractor to remove and dispose of all equipment that is to be replaced during the contract. This project will be completed in two (2) phases and the same Contractor may be considered for both project phases.

Due to the nature of the refurbishments and upgrades, minor building works will be required, e.g. removal of ceilings to expose ducting and replacement of ceilings etc.

Phase 1:

Upgrade complete ventilation systems to meet SANS requirements.

Replace existing chilled water AHU’s servicing the five (5) auditoriums with new DX-type AHU’s with separate condensing units.

Replace the supply and return air ducting in the auditoriums and install air jet nozzles.

Replace existing chilled water FCU’s servicing the computer rooms with new DX-type FCU’s, coupled to new VRF outdoor units.


Phase 2:

Servicing and repairs of existing equipment such as fans, split-units, air terminals, filters etc.

Installation of new VRF systems to service classrooms, offices and server rooms.

Installation of new split-units to spaces as required.

Decommissioning of existing chilled water system and complete removal and subsequent making good of building interior spaces.


2 AIR CONDITIONING UNITS

2.1 VRF INSTALLATION

The DX-type units shall be of the inverter heat pump type.

Table 2-1: AHU’s required for the auditoriums

CODE NUMBERS OF ROW

RTH [W] TOTAL AIRFLOW [L/S]

QTY

AHU 01 4 19 393 832 1

AHU 02 4 20 456 913 1

AHU 03 4 63 396 2 898 1

AHU 04 4 24 268 1 037 1

AHU 05 4 39 822 1 974 1

2.2 FAN COIL UNITS

Table 2-2: FCU’s required for computer rooms

CODE CAPACITY [kW] QTY

FCU 01 14.0 5

FCU 02 18.0 6

FCU 03 22.4 10

FCU 04 28.0 7

2.3 OUTDOOR UNITS

Table 2-3: Outdoor units required for AHU’s and FCU’s

CODE CAPACITY [kW] QTY

ODU 01 64.2 1

ODU 02 103.2 1

ODU 03 135.2 1

ODU 04 140.2 1


ODU 05 145.6 1

ODU 06 156.8 1

ODU 07 163.2 1

Table 2-4: Refrigerant Control Boxes

CODE PORTS QTY

MCU 01 2 Ports 1

MCU 02 4 Ports 3

MCU 03 6 Ports 3

MCU 04 8 Ports 3

MCU 05 13 Ports 1

MCU 06 16 Ports 1

ODU 01 shall be connected to AHU 01, AHU 02, and AHU 04.

ODU 02 shall be connected to AHU 03 and AHU 05.

ODU 04 and ODU 05 shall be combined and connected to various FCU’s and is summarised as follows:

Table 2-5: Rooms connected to ODU 04 and ODU 05

ROOM NO. FCU’s

1.33 FCU 02

FCU 02

1.34 FCU 01

FCU 01

1.37 FCU 03

FCU 02

1.38 FCU 01

FCU 02

2.13 FCU 03

FCU 03


2.35 FCU 03

FCU 04

3.42 FCU 03

FCU 04

ODU 06 and ODU 07 shall be combined and connected to various FCU’s and is summarised as follows:

Table 2-6: Rooms connected to ODU 06 and ODU 07

ROOM NO. FCU’s

2.64 FCU 03

FCU 03

2.65 FCU 03

FCU 03

2.69 FCU 03

FCU 04

2.71 FCU 01

FCU 02

3.65 FCU 04

FCU 04

3.71 FCU 04

FCU 04

3.78 FCU 01

FCU 02

Site-assembled units shall be built to accommodate all components such as filters, coils, heaters, fans, etc. Plenum walls shall be of sheet-metal or masonry construction.

As far as possible the air conditioning units shall be standard factory assembled, piped and wired.

The units shall be delivered factory tested for all operating conditions. Spares shall be freely available in South Africa. On request, the Contractor shall provide the Engineer with performance test certificates.

Each air-handling unit and indoor unit shall be complete with multi-vane centrifugal air-circulation fan, cooling coil, condensate tray, air filters, air discharge and return air grilles and controls. Any discrepancies between this


specification and the supplier’s recommendations that may influence the unit’s performance or guarantee shall be clarified with the Engineer during tender stage.

The electrical power requirements to the condensing units shall be:

Single-phase when the cooling capacity of the unit is less than 10 kW; and

Three-phase when the cooling capacity of the unit is more or equal to 10 kW.

The indoor unit and external condensing unit shall be interconnected with refrigerant piping, electrical wiring and interlocking control cabling. The pipe and cable connections shall be made in accordance with the unit supplier’s recommendations. The refrigerant shall be of the R410a type.

Each condensing unit with connected evaporator unit(s) shall be clearly labelled to identify different split units.

2.4 DESIGN CRITERIA

Table 2-7: Design data

DESIGN DATA

Outdoor summer temperatures 32.2C Db/22.2C Wb

Outdoor winter temperatures 20.0°C Db/15.0°C Wb

Indoor conditions 22.5°C Db/ 50 % RH

Indoor Noise Levels (NC) 35 dB

Altitude above sea level 22 m

Condenser Coil Selection Temperature 38°C Db

Electricity supply 400/250 Volts AC, 50 Hz

2.5 UNIT REQUIRMENTS

2.5.1 GENERIC UNIT REQUIREMENTS

All indoor units shall make use of a DX system with a separate matching remote and an externally located condensing unit that is air-cooled.

The evaporator unit shall be equipped with an easily accessible washable filter, a three speed adjustable cross flow fan driven by an induction motor and evaporator coils manufactured from seamless copper tubing mechanically bonded to aluminium.


Indoor units shall have an integral condensate drain tray with a condensate pump connected to a drain hose connections.

The compressor unit shall be of the hermetic inverter scroll type that is powered by an induction motor and has anti-vibration mounts such as rubber or spring isolators installed. The compressor shall be equipped with crankcase heater, overloads, oil sight glass, manual reset high-pressure switch, low-pressure switch, reversible oil pumps for forced feed lubrication, controls and service valves.

The condenser cooling fan shall be of the direct driven multi-wing, dynamically balanced propeller type axial flow fans. The outdoor unit shall be of the 4-way blow type.

The outdoor unit casing shall be manufactured from mild steel plate and shall be corrosion protected as follows or to a method as approved by the Engineer:

Galvanised

Electro plated.

The outdoor unit shall be colour coated as follows or to a method as approved by the Engineer:

Acrylic resin powder coated

Polyester powder coated.

For reverse cycle units, a proper galvanised steel drip pan with drainage piping or drain piping connected to the integral drain pan shall be provided for the condensing units.

The indoor units shall have an auto swing vane function that allows the vanes to swing up and down automatically. An auto-flap shutter shall close automatically when the unit is turned off.

The control system shall be such that the unit will automatically change from heating to cooling and vice versa. A time delay relay shall prevent the compressor from restarting immediately when changing from heating to cooling and vice versa.

The “auto restart after power failure” option shall be available on all units’ settings. The units shall also be able to operate in a “fan only” mode.

Electrical interlocking shall be provided to ensure that the compressor cannot run without both evaporator and condenser fans running.

2.5.2 COMPUTER ROOMS’ REQUIREMENTS

Computer room type air-conditioning units shall be of the type called for in the Supplementary Specification.


Each unit shall be complete with fans, fan motors and drives, direct expansion coil, electric heaters, air filters, humidifier, control system with alarms and switchboard. The control system shall be externally located. Air-cooled models shall further be complete with compressors and inter-connecting refrigerant tubing.

The unit shall be installed with an appropriate electrode type humidifier of sufficient capacity to maintain the relative humidity in the room at 50% minimum.

The cabinet shall have the same colour and finish as the computer equipment. The air-conditioning Contractor shall determine the exact finish on the computer equipment before an order is placed for the units.

Operating controls shall include on/off switch and delay timers to prevent hunting, push to test for warning lights, manual reset button, loss of power or low voltage indication and red visual displays of the following warning signals:

Change filters

Change humidifier cylinder (where applicable)

Underfloor water alarm

High temperature

Low temperature

High humidity

Low humidity

High-head pressure 1 and 2

Loss of air flow

2.5.3 OFFICE ROOMS’ REQUIREMENTS

Fan-coil units shall be as specified in the Supplementary Specification. Each unit shall be complete with DX coil, control valve, fan, filters, electric heater (if specified) and drainage pan. A control panel with ON/OFF switch, thermostat and fan speed selector switch shall be built in.

Cabinets shall be constructed of not less than 0.8 mm thick steel sheet. Other approved materials are acceptable provided mechanical strength is maintained. Front panels of cabinets shall be removable for access to working parts. The casing shall be lined internally with a glass fibre insulation of the "Sonic Liner" type for sound absorption.

Fans shall be of the centrifugal type directly connected to extend motor shafts. Fans and motors shall be quiet in operation.

Fan motors shall be of the shaded pole or permanent split capacitor type with built-in overload protection. Motors shall have three speed windings and be factory-wired to a junction box.


Drain pans shall be removable for cleaning and shall be properly pitched for positive drainage and shall project under the entire length and width of the coil, including unlagged portions of the flow and return water pipes. Plastic or other approved type drain tubing of not less than 25 mm nominal bore shall be used.

Precautions shall be taken to prevent condensation on the outside of drain pans.

The mean sound pressure levels generated by the units shall not exceed the NC 40 values when measured at a distance of 2 m from the units.

2.5.4 AUDITORIUM ROOMS’ REQUIREMENTS

Air-handling units (AHU) shall be as specified in the Supplementary Specification. Each unit shall be complete with DX coil, control valve, fan, filters, electric heater (if specified) and drainage pan. The filter shall be able to handle the full air quantity. A control panel with ON/OFF switch, thermostat and fan speed selector switch shall be externally located.

Cooling coils shall be provided with face and bypass dampers designed to bypass 100% of the total supply air quantity. Cooling coils shall be of the extended surface type. Coils shall be constructed of copper tubes with aluminium or copper fins mechanically bonded to the tubes and shall be positioned such that a constant face velocity over the coil face area is maintained.

2.5.4.1 COOLING COILS

Each unit shall be provided with a direct expansion cooling coil, The design particulars are as follows:

Altitude: Sea level

Outside design condition 32.2 °C dry bulb

22.2 °C wet bulb

Room condition at a level of 1.5 above floor level: 22.5°C dry bulb

50% relative humidity

DESCRIPTION AHU 1 AHU 2 AHU 3 AHU 4 AHU 5

Outside air quantity l/s 300 300 950 330 550


DESCRIPTION AHU 1 AHU 2 AHU 3 AHU 4 AHU 5

Coil entering conditions:

°C DB

°C WB

27.9

18.4

26.1

17.8

25.7

17.6

26.9

18.0

25.2

17.4

Coil leaving conditions: °C DB

°C WB

12.5

11.3

12.0

10.8

12.0

10.8

12.0

10.8

12.3

11.0

Sensible cooling capacity

W 10 000 11 590 36 790 13 140 24 400

Total cooling capacity W 19 400 20 460 63 400 24 270 39 820

Total heating capacity W 6 930 6 690 21 460 5 980 13 660

Total supply air quantity l/s 830 915 2 900 1 040 1 970

Return air quantity l/s 530 615 1 950 710 1 420

Cooling coils shall be of the extended surface type. Coils shall be constructed of copper tubes with aluminium or copper fins mechanically bonded to the tubes.

All coils exposed to mechanical damage shall be protected during the installation period with galvanised sheet-metal covers, suitably reinforced and stiffened over the entire coil face area. Coil covers shall be removed only when commissioning commences.

Coils shall be positioned to assure an even face velocity over the coil face area. Excessive air-flow resistance due to high coil face velocities shall be avoided.


Coil frames shall be constructed of hot-dip galvanised sheet metal or of a suitable approved corrosion-resistant material. Galvanised frames shall be bolted to the casing/supporting members.

Coil frames shall be so arranged that all moisture condensing on the coil surface will run freely into the drain pan. A positive stop shall be provided to preventing water from running back towards the filters.

Cooling coils in proprietary manufactured units shall be provided with 1,60 mm stainless steel or galvanised sheet-metal drip pans. Drip pans shall be properly pitched for positive drainage and shall project under the entire length and width of the coils. Where eliminators are provided the drip pans shall be provided under the coil section and extended under the eliminators.

A 20 mm galvanised or copper drain pipe shall be provided between the coil drip pan and the drain point. The drain pipe shall be provided with a U-tube water trap to prevent the ingress of unfiltered air.

Water that condenses on headers, U-bends connecting the coil tubes, refrigerant distributers, etc. shall be afforded free and adequate drainage to the drain pan.

In all air-conditioning units the coil face velocity shall be low enough to prevent water carryover into the supply air stream.

Direct expansion coils shall be circuited for the most economical balance between heat transfer, refrigerant pressure drop and oil return. Suction headers shall be so arranged as to ensure complete drainage of any oil that may be deposited in the coil.

Suitable liquid and vapour distributors shall be provided on multi-circuit coils to ensure uniform distribution of refrigerant between circuits.

Coils shall be selected for maximum heat transfer at suction temperatures of not less than 4°C. Suction temperatures less than 4°C will be permitted only in special circumstances and permission shall be obtained from the Engineer before equipment is ordered.

Each AHU shall be complete with multi-vane centrifugal air-circulation fan, cooling coil, condensate tray, air filters, air discharge and return air grilles and controls.

Condensing units shall be equipped with sealed compressor, an air-cooled condenser and a condenser fan, all mounted on a heavy-gauge steel base. Provision shall be made to prevent feedback of liquid refrigerant to the compressor. The unit shall be suitable for the installation out of doors. Condenser coils shall be protected against vandalism and hail damage. The refrigerant that shall be used is the R410a type.


The units shall be of the reverse-cycle heat pump type. Electric heaters, if specified in the Supplementary Specification shall be interlocked with the fan motor to prevent operation unless the fan is running.

AHU shall be supplied in an attractive and durable finish.

Copper tubing and electric cables, between air-handling and condensing units shall be installed in accordance with the manufacturer’s recommendations. The Contractor shall supply suitably sized sleeves for piping and cables to be built in by others if builders work does not form part of the Contract. All visible piping and cables inside or on the outside of buildings shall be installed in adequately sized trunking.

Each air-handling unit shall be provided adequately sized drainage pipes and these pipes shall terminate in the nearest drain or gulley. Visible drain piping shall be neatly surface-mounted using saddles not more than 1 500 mm apart. Drain piping shall be installed with an adequate fall in the flow direction and shall incorporate a properly designed U-trap to prevent the ingress of unconditioned outside air. Copper drain piping shall be soldered. Suitable pipe cement shall be used on all PVC pipe joints.

All refrigerant suction lines shall be adequately insulated as per the Engineer’s specifications and shall be fastened with a quick zip fastener or a similar fastener. Those portions of the lagging exposed to the weather shall be painted with two coats of exterior-quality PVA .The colour shall be of such to suit the surrounding area and shall be approved by the Engineer.

2.6 PERFORMANCE SPECIFICATIONS

Cooling and heating capacities are room conditions and all equipment shall be de-rated to meet these requirements.

De-rating shall be done to compensate for the following:

Altitude above sea level

Refrigerant pipe lengths

Design conditions specified.

All units shall be capable of meeting total and sensible cooling requirements as required by each room. Tenderers shall provide proof of de-rated capacities with their tender. All capacities specified are to be achievable at medium evaporator fan speed.

2.7 PROTECTION AND SAFETY DEVICES

Thermal protection shall be provided for the compressor, and indoor and outdoor fan motors. Overcurrent relay shall be provided for the compressor, indoor and


outdoor fan motors to ensure overcurrent protection. Safety switches shall be provided to prevent the pump from running dry and condenser coils shall be protected against vandalism and hail damage. Electric heaters, if specified in the Supplementary Specification, shall be interlocked with the fan motor to prevent operation unless the fan is running.

Protection fuses shall be provided for all control circuits.

The compressor shall have high and low refrigerant pressure protection.

The indoor and outdoor units shall comply with the safety requirements as set out in SANS 60335-2-40: Household and similar electrical appliances – Safety. Part 2-40: Particular requirements for electrical heat pumps, air-conditioners and dehumidifiers.

All AHU shall be supplied in an attractive and durable finish.

2.8 ELECTRICAL

Generally the power to indoor units shall be provided by the electrical contractor in a weather proof isolator mounted within 1 m from the condensing unit. The Mechanical Contractor shall do the entire electrical installation from the isolator to the condensing unit and the indoor unit.

Where the Electrical Contractor provides a cable only to a distribution board that serves a group of air conditioning units, the Mechanical Contractor shall provide the distribution board, connect the incoming power cable and shall do all the electrical wiring from the distribution board to the condensing units and the indoor units.

In all instances the Mechanical Contractor shall provide isolators as required. All electrical and control cables shall be neatly strapped to the refrigeration piping or shall be mounted in a galvanised cable tray.

The entire electrical installation shall comply with SANS 10142-1-2003: The wiring of premises Part 1: Low-voltage installations.

Conductors from different switchboards may not be installed in the same conduit or cable channel. The number of conductors in a conduit shall comply with the requirements of the Code of Practice for the Wiring of Premises, SANS 10142.

On completion, the Contractor shall issue a certificate of compliance for the entire electrical installation.

Electrical and control cables mounted between indoor and outdoor units shall be installed without joints in the cable and shall be of the UV protected type.


Low voltage cables shall be PVC-insulated cables in accordance with SANS 1507 for all supply voltages up to 1 000 V.

Only armoured cables shall be used for underground cable runs, whether installed in pipes or laid in the ground. Unarmoured cables may be used only when installed in conduits or enclosed metal ducts along the entire cable run.

All cables installed on cable trays, in floor trenches or in vertical riser ducts, and all cable runs that are partially installed in conduits, underground pipes or metal ducts, shall be armoured.

All cables shall comply with the relevant SANS, EDC or NEMA specifications and shall be installed, fixed, protected and terminated in a proper fashion according to approved methods and in accordance with the manufacturer's specifications and the Code of Practice for the Wiring of Premises, SANS 10142. The Contractor shall employ competent staff for the installation of the various cable types.

Cables with conductor sizes of less than 1.5 mm² shall not be used, except for communication or control systems where the supply voltage is less than 50 V. Only cables with copper conductors shall be used unless approved otherwise.

Cable sizes shall be determined strictly in accordance with the relevant tables of the Code of Practice for the Wiring of Premises, SANS 10142. Special attention shall be paid to group de-rating factors and cables sized for equipment requiring low voltage drops (especially in the case of motors starting high inertia loads). Cables spaced apart by a minimum of two cable diameters need not be de-rated.

2.9 CONTROLS

Where and if room controls are required, they shall be of the hard wired, wall-mounted electronic type located externally to the room. Controls shall be of the same manufacture as the air conditioner. Controls shall be mounted over a flush mounted 100 mm x 50 mm electrical box. Control wiring shall be installed in a 20 mm electrical conduit from the controller to the air conditioning unit. The conduit and outlet box shall be chased into the wall by the Electrical Contractor.

Controls shall have the following minimum functionality:

Manual ON/OFF

ON/OFF by 24 hour / 7 day timer

Room temperature display

Room temperature adjustment

Cooling / ventilation selection.

A red and green light to indicate the running status of the unit.

Controllers shall be of the proportional position (modulating or throttling) type having adjustable proportional control (gain or sensitivity).


The room temperature shall be controlled by a master control system with the master controller being externally located.

For heating, the electric heating elements shall be controlled through a 10 step controller. The heating control system shall be in operation only when the bypass dampers are fully open.

Step controllers shall be of the electronic type and shall be complete with the minimum number of electric relays for the number of steps specified. Individual stage switching of electrical heater banks shall be delayed to prevent overloads on the supply after a power failure. The switch condition shall be indicated by pilot lamps located on the front panel of the step controller.

An enthalpy controller shall be provided to switch the control to the exhaust, outside and return-air dampers which shall then be proportionally controlled from the sub-master controller when the enthalpy or temperature of the outside air is lower than that of the return air. When heating is again required, the control shall be switched back to the electric heaters and the dampers shall remain in the minimum closed position for the outside and exhaust air and in the maximum open position for the return air.

Condensing pressures on reciprocating compressors shall be controlled at the minimum value as recommended by the manufacturer.

Condensing pressures on air-cooled condensers shall be controlled by starting and stopping the fans or automatically controlled variable-speed fan motors shall be provided. Automatically controlled dampers are also acceptable.

All switchboards shall be totally enclosed, vermin- and insect-proof, drip-proof and dust-proof to at least Class IP 42 of IEC 144.

Surface-mounted switchboards shall be used only where they are not larger than 1 200 mm wide x 1 200 mm high and the mass is such that the switchboard can safely be supported by four expansion type bolts on the surface of the wall. All other switchboards shall be of the floor-standing type.

The name of the switchboard manufacturer shall appear on each switchboard.

The switchboard shall consist of a 2 mm sheet metal enclosure, suitably braced with the necessary reinforced fixings for wall mounting. All joints shall be welded. A 20 mm front edge, beyond which no equipment must protrude, shall be provided.

All equipment shall be mounted on a strengthened chassis, solidly fixed to the enclosure.

The front shall be covered by a hinged panel(s) with machine-punched slots and holes for the flush mounting of circuit breakers, instruments, indicator lights, push


buttons, etc. Contactors, motor protection units, etc. shall not protrude beyond the panel. Instruments, indicator lights and control pushbuttons can also be mounted on the panel(s). The panel(s) shall have a square key-operated lock, solid hinges and a chromium-plated handle.

Sturdy gland plates to accommodate all power cables shall be provided within 300 mm of the bottom of the switchboard. A hole of the correct size to accommodate cable glands shall be made on site by means of chassis punches.

The board shall be provided with a P4000 support for cables in order to relieve the glands of mechanical stress.

Terminals for all outgoing control, instrumentation, monitoring, alarms and low-voltage supply circuits shall be located at the bottom and/or top of the switchboard and shall be accessible via hinged front panels. These terminals shall be installed away from terminals for power circuits. All outgoing circuits must terminate on numbered terminal strips. The correct terminal size shall be used for each conductor. Only one conductor terminal shall be allowed. Bridging contacts on the terminals shall be used for parallel-connected circuits. All outgoing power cables shall terminate within 300 mm of the gland plate to avoid long leads. Where this is not possible, each lead must be separately braced. Power cable sizes up to and including 70 mm² may terminate on clamp-type terminals where the clamping screws are not in direct contact with the conductor, but bear upon a clamping plate. Connection to the equipment can then be made with cables that are similarly connected to the terminals. All power cable sizes larger than 70 mm2 shall terminate on busbars that are connected to the associated equipment. Conductors shall have lugs that are sweated or crimped. Looping of incoming supply wiring to large circuit-breakers and contactors, etc. is not acceptable. Each device shall be individually connected to the supply busbar.

Each switchboard shall be provided with a means to isolate the incoming supply. This may be achieved by the use of an isolator, circuit-breaker (fixed or draw-out) or fuse switch, rated to make against the full system fault at that point and break the full-load current. The incoming supply section containing the switchgear, protection equipment, controls and instrumentation shall form a clearly labelled, self-contained unit behind one or more hinged panels.

The operating handle of the isolator, circuit-breaker or fuse switch controlling the incoming supply shall protrude through the panel and shall be interlocked to ensure that the panel can be opened only when the supply is off.

Equipment that cannot be flush-mounted on the panel shall be mounted on a suitable metal chassis and shall protrude through a close-fitting cut-out in the panel. All protection relays contained in enclosed units with glass fronts shall be flush-mounted on the hinged panels. Contactors, thermal overload relays, etc. shall be mounted on a chassis behind the panel.


The switchgear, protection and control equipment, instrumentation and monitoring equipment for the supply circuits to motors or other electrically operated mechanical equipment shall be grouped separately in the switchboard.

The mounting of equipment shall comply with SANS 1180 where applicable. Equipment to be mounted on the chassis shall be mounted by means of bolts, washers and nuts, or by bolts screwed into tapped holes in the chassis plate. In the latter case, the minimum thickness of the chassis plate shall be 2.5 mm. The latter method shall not be used where boards will be subject to vibration or mechanical shocks. Self-tapping screws shall not be accepted.

In designing the switchboard, the following requirements shall be strictly adhered to:

There shall be a minimum distance of 50 mm between any piece of equipment and the frame or internal partitioning. This minimum space is required on all sides of the equipment. In the case of a single row of single-pole circuit-breakers, the spacing on one side of the row may be reduced to 25 mm if the incoming side of the circuit-breakers is connected to the busbar

There shall be a minimum of 75 mm between horizontal rows of equipment. The maximum outside dimensions of equipment shall be considered

Circuit-breakers up to a fault rating of 10 kA may be installed adjacent to each other. For higher ratings, a minimum of 40 mm shall be allowed between circuit-breakers or isolators

Sufficient space shall be provided for wiring, allowing for the appropriate bending radius

Space for future equipment shall be allowed as specified

Time switches shall not be located amongst switchgear.

2.10 REFRIGERANT CIRCUITS

Refrigerant piping shall be in accordance with the following standards:

SABS 1453: Copper tubes for medical gas and vacuum services

SABS 0147: Refrigerating systems including plants associated with air conditioning systems.

Fittings shall be copper based capillary solder fittings in accordance with SABS 1067. All soldered joints on proprietary manufactured units shall be carefully checked and remade if found damaged in transit.

Pipe size selections shall be such as to produce moderately low velocities whilst ensuring:


Proper oil return to the compressor and minimizing lubricating oil being trapped in the system

Practical lines without excessive pressure drops and with proper feed to evaporators

Liquid refrigerant does not enter the compressor during operation and at shutdown.

Refrigerant piping shall be sized and fitted with the necessary oil traps strictly in accordance with the unit manufacturer’s requirements.

All refrigerant pipelines shall be insulated with the class-O lightweight, elastomeric nitrile rubber tube insulation. Insulation thickness shall be 13 mm.

Suction and liquid pipelines shall be insulated separately and joints on insulation shall be glued with the insulation manufacturer’s recommended adhesive to create a vapour barrier.

The installation of trunking and trays shall form part of this mechanical contract.

2.11 INSTALLATION REQUIREMENTS

2.11.1 INSTALLATION OF INDOOR AND OUTDOOR UNITS

During installation, care shall be taken to ensure that no vibrations are carried over to structures to which the indoor and outdoor units are fixed.

Outdoor condensing units shall be installed as indicated on the project drawings.

Where installed on wall mounted brackets, the condensing unit shall be securely bolted to the mounting bracket with adequately sized fasteners.

Where installed on a concrete slab, the condensing unit shall be fitted on top of neoprene vibration isolating pads and 450 mm square concrete paving slabs.

The air-cooled condensers shall be able to meet the cooling requirements at an ambient temperature of 35°C at an altitude of 22 m.

The condensing unit shall factory-assembled, air cooled type and shall be delivered to site ready for installation. Condensing units shall be equipped with one or more hermetically sealed compressors in a weather-protected compartment, a condensing coil, casing, fan(s) and motor(s), condensing pressure control equipment and a weatherproof mains isolator.

The condenser unit shall be rigidly constructed of steel or aluminium sheeting with adequate structural supports. The base section shall consist of a robust steel-channel frame galvanised after manufacture. Quickly removable access panels or hinged doors shall be provided for maintenance and repairs. Panels/doors shall be provided with quick-release fasteners. Bolts or screws are


not acceptable. Steel surfaces shall be degreased and coated with dry powder or epoxy resin paint and baked after application. Baked enamel or similar proven methods are also acceptable provided that the paint finish is hard-wearing, durable and capable of withstanding a wide range of weather conditions.

Condensing coils shall be of seamless copper tubes mechanically bonded to aluminium or copper fins. Inlet headers shall be designed for uniform gas distribution through all individual circuits and shall be arranged to prevent trapping of oil. The coil face velocity shall not exceed 3 m/s. The coil assembly shall be factory-tested for leaks and shipped with a holding charge of refrigerant R410a. Coils shall be designed and tested at a pressure of not less than 2400kPa.

Condensing coils exposed to the weather shall be provided with louvres for protection against malicious damage and hail.

Condensing units shall be provided with a weather-protected control panel. Control panels shall be provided with a mains isolator, mini circuit-breakers, fan contactors and overloads, head-pressure controller or fan speed controller (if fitted), compressor starting contactors and overloads, an adjustable timer to limit the number of starts per hour, low and high-pressure switches, an oil protection switch on compressors fitted with a positive feed lubrication system and crankcase heater controls.

2.11.2 INSTALLATION OF CONDENSATE DRAIN PIPES

If an outdoor unit (heat pump type) is mounted against a wall more than 1 m above ground / floor level, the unit shall be fitted with an uPVC drain pipe neatly saddled to the wall. Drain pipe sizes for outdoor condensing units shall be to the supplier’s specification.

Condensate drain pipes shall always run together with refrigerant pipes and shall always be installed in the same trunking and on the same cable trays for as far as the installation permits. Surface mounted drainage piping shall only be allowed where condensate drain pipes run in a different direction to either a service duct, waste water pipe or any other location as indicated on the project drawings. Surface mounted drain piping shall be secured to the wall by means of galvanised steel saddles at no more than 1 m intervals.

The indoor units shall be mounted on the inside of exterior walls and the mechanical contractor shall drill sufficiently sized holes through which refrigerant pipes, drain pipes and cable wires shall penetrate directly behind the indoor unit. Drain pipes running from the indoor unit through the wall shall be adequately sloped to ensure positive drainage.

All condensate pipes running from indoor units to waste water pipes, outlet gullies or open wastewater points shall be fitted with a u-trap or self-sealing waste valve (waterless) at a location as indicated on the project drawings.


uPVC pipes shall be used for drainage piping from indoor units. Drain pipe sizes

for indoor units shall be 32 mm for all unit sizes.

The first 5 m of drain piping shall be insulated with class-O lightweight, elastomeric nitrile rubber tube insulation. Insulation thickness shall be 13 mm.

Horizontal mounted drain pipes shall be installed at a slope of 20 mm per 1 000 mm, ensuring positive drainage.

Where drainage piping or control cabling is required to be installed flush-mounted, positioning and chasing shall be done in good time to meet construction programmes.

2.11.3 INSTALLATION OF REFRIGERANT PIPING

Refrigerant piping shall be arranged so that normal inspection and servicing of the compressor and other equipment is not hindered. Locations where copper tubing will be exposed to mechanical damage shall be avoided. Hangers and supports where piping goes through walls shall be installed to prevent transmission of vibration to the building.

Refrigerant piping in ceiling voids and mounted internally against walls shall be installed in 101 mm wide galvanised steel light duty cable trays (per unit). Pipes shall be strapped over insulation to cable trays at 500 mm intervals with suitably sized cable ties. Cable trays shall be 152 mm wide where drain pipes run together with refrigerant piping.

Externally mounted refrigeration pipes and drain pipes shall be mounted in cable trunking (127 mm x 76.2 mm). Cable trunking shall be complete with clip-on covers. Pipes and cables shall be strapped together every 500 mm with suitably sized cable ties and loosely fitted in the trunking. The trunking shall be manufactured from galvanised steel and epoxy powder coated to a colour as specified by the Engineer.

All joints in pipe lines shall be silver-soldered or approved equivalent. Ordinary soft solder shall not be used. All soldered joints on proprietary manufactured units shall be carefully checked and remade if found to have been damaged in transit. Silver solders shall be in accordance with SANS 23.

Any insulation material not covered by the trunking and which is exposed to the elements shall be neatly strapped with cable ties to minimise the possibility of dirt and water entering between the insulation and refrigeration pipes.

All refrigeration pipes shall be sized to the supplier’s method. The refrigerant charge shall be accurately calculated by the same method. The Contractor shall adhere to the recommended maximum pipe lengths as set out by the manufacturer.


All joints installed horizontally shall be mounted with branch piping in a horizontal plane.

Only synthetic oil compatible with the refrigerant shall be used to lubricate any cutting, reaming and flaring tools.

Only phosphor copper brazing rods shall be used without any flux on the piping joints. The pipework shall be continuously purged with low-pressure nitrogen during all brazing operations.

Simple purging of the refrigerant pipes between the indoor and outdoor units shall not be acceptable. Refrigerant pipes shall be correctly pressure tested with nitrogen and a small amount of refrigerant to 3.8 MPa for R410A and left for 24 hours to ensure that the pressure does not drop. A vacuum pump shall then be used to purge the piping for longer than 2 hours to -100 kPa. The system shall be capable of holding this vacuum for 1 hour or to the satisfaction of the Engineer.

The system shall then be charged in the liquid state with the calculated amount of additional refrigerant by using an accurate charging scale (charging cylinder shall not be used). Only once the system is correctly charged shall the refrigerant valves on the outdoor units be opened.

The Contractor shall make use of colour coding (insulation type straps) to differentiate between refrigerant pipes running from refrigerant risers to different thermal zones.

Refrigerant pipes for multiple outdoor units shall be correctly arranged to meet the manufacturer’s requirements. Where multiple outdoor units are used, an insulated oil equalisation line shall be installed between the units.

The Contractor shall apply the class-O, lightweight, elastomeric nitrile rubber tube insulation in such a manner as not to cause leaking. The wall thickness of the insulation shall be to the following table:

Table 2-8: Insulation Wall Thicknesses

REFRIGERANT PIPE DIAMETER (MM) WALL THICKNESS (MM)

6.34 9

9.53 9

13.7 13

15.88 13

19.05 19


3 VENTILATION SYSTEMS

3.1 SCOPE

The following installations shall be specified under this section of the project specification:

Fresh air supply

Ablution extraction

Kitchen extraction.

3.2 DESIGN CRITERIA

Table 3-1: Area design data

DESIGN DATA

Outdoor summer temperatures 32.2C Db/22.2C Wb

Outdoor winter temperatures 20.0°C Db/15.0°C Wb

Indoor conditions 22.5°C Db/ 50 % RH

Indoor Noise Levels(NC) 35

Altitude above sea level 22 m

Electricity supply 400/250 Volts AC, 50 Hz

3.3 APPLICABLE STANDARDS

The air conditioning units and installation in general shall be in accordance with:

SANS 1424-1987: Filters for use in air-conditioning and general ventilation

SANS 1238:2005: Air-conditioning ductwork

SANS 10173:2003: The installation, testing and balancing of air-conditioning ductwork

SANS 60335-2-80: Household and similar electrical appliances – Safety Part 2-80: Particular requirements for fans

SANS 10108: The classification of hazardous locations and the selection of apparatus for use in such locations.


3.4 VENTILATION FANS

3.4.1 GENERAL

Table 3-2: Fresh air supply fans

CODE DESCRIPTION AIRFLOW [L/S] QTY

FAF 01 Axial flow, variable pitch blade, ø400 1165 1

FAF 02 Centrifugal, backward wheel 3410 3

Table 3-3: Extraction air fans


EAF 01 Axial flow, variable pitch blade, ø315 300 1

Table 3-4: Return air fans for AHU's


RAF 01 Axial flow, variable pitch blade, ø315 532 1





The combination of fans and attenuators shall be such that the specified noise levels are achieved.

Where no pressure requirements are indicated, the Contractor shall estimate the fan static pressure requirements for the system layout and tender accordingly. Where filters are included in the system, the static pressure losses through filters shall be estimated at 180 Pa throughout each stage of filtration. Fans shall be capable of handling at least 5 % more air than required to allow for possible duct leakages.

Ventilation and extraction fan duties as specified on the tender drawings shall be checked against the respective system’s design resistance once all information on


the selected system is available. Where fan duties are found inadequate, the Contractor shall notify the Engineer before ordering the equipment.

Fans shall be selected to operate at or as close to maximum efficiency as possible and for a maximum speed of 1440 rpm (4 pole motors).

Attenuators shall be mounted directly onto the fan casing with flexible connections between the ducts and attenuators.

Fans shall be fitted with the manufacturer's nameplates permanently fixed to the casing in a prominent position, clearly indicating manufacturer, model number, size, speed, maximum operating speed, maximum power absorbed, and serial number. Fan impellers shall be of die-cast aluminium alloy and shall be accurately balanced to ensure vibration free running. Impellers shall be clamped in split steel or aluminium hubs. Impeller blade pitch angles shall be manually adjustable.

Fan air inlets/outlets not connected to ducting or equipment shall be protected with easily removable safety wire mesh screens.

Fans situated outside and exhausting air vertically shall be complete with non-return, weather proof cowls as per the drawings.

Indicating arrows for both direction of rotation and direction of airflow shall be provided on fan casings.

All fans shall be installed in accordance with the manufacturer's requirements and recommendations.

All fans shall be mounted on anti-vibration mountings or supported from anti-vibration hangers.

Bearings shall be of the ball or roller type and shall be quiet in operation. They shall be sized to give a long life (not less than 100 000 hours) at the loads imposed by the application.

Belt guards shall be arranged to permit lubrication and use of speed counters with the guards in position. Belt guards shall have adequate ventilation for belt cooling.

The construction and design of electrical apparatus for ventilation equipment in hazardous environments shall comply with the relevant SANS specification, e.g. SANS 10108. The electrical installation shall comply with SANS 60335-2-80: Household and similar electrical appliances – Safety Part 2-80 Particular requirements for fans.

3.4.2 IN-LINE AXIAL FLOW FANS

Axial flow fans shall be of the non-overloading, aerofoil type with peak power requirements occurring at normal operating pressure range. The fan motor shall


have a rating exceeding this requirement. Axial flow fans shall operate at the highest possible efficiency at the lowest possible blade tip speed.

Impeller blades shall be manufactured from a die-cast aluminium alloy clamped in a split steel or aluminium cast hub. Hubs on larger fans shall be manufactured from hot dip galvanised steel. The blade pitch shall be adjustable at the hub. Cast steel hubs shall be electro-coated.

Axial flow fan casings shall be manufactured from hot dipped galvanised mild steel with predrilled flanges on both ends of the fan. An access panel of ample size shall be provided in the casing. All fasteners shall be zinc plated.

Fan motors shall be totally enclosed and shall be of the squirrel-cage induction type with protection to IP 55 standard. An external weather proof terminal box forming part of the casing shall be included in the design for motor connections. Where belt driven fans are used, belts shall be of the V-belt type with grooved pulleys. Belts shall be oil resistant, non-sparking and non-static. Belt drives shall comply with OHSA requirements.

Fans used for smoke and fume extraction shall comply to the relevant SABS and SANS standards for such fans as well as have a certified fire rating. The smoke extract fans shall be able to keep operating at 300°C for no less than 60 minutes.

Axial flow fans shall be statically and dynamically balanced in accordance with ISO 1940 – 1973 within grade G6.3.

Axial flow fans shall always be resiliently mounted on anti-vibration mountings to prevent carry-over of vibration to the structure to which the unit is fixed.

Fans shall be installed with sound attenuators to comply with noise levels as specified in Section 3.2 except for the fresh air fans.

3.5 DUCTING

3.5.1 GENERAL

Sheet metal ductwork shall be manufactured in accordance with SANS 1238, and installed balanced and tested as set out in SANS 10173. The installation and manufacture of ductwork shall strictly be in accordance with SANS standard specifications with specific attention given to the following:

Changes in size and shape of ducting: refer to SANS 1238, Section 6.3

Access openings, doors and covers: refer to SANS 1238, Section 5.3

Sealant requirements: refer to SANS 1238, Section 5.6

External ducting insulation: refer to SANS 10173, Section 5.4


Material thickness and duct stiffening for low pressure ductwork: refer to SANS 1238, Section 6 for rectangular ductwork and SANS 1238, Section 7 for circular ductwork

Radius and square bends as well as turning vanes: refer to SANS 1238, section 6.4.

Unless the sheet-metal ductwork is inherently corrosion protected, all sheet-metal shall be protected against corrosion as outlined in SANS 1238, Section 8.

It shall be the responsibility of the installing contractor to ensure proper assembly and sealing of sheet-metal ductwork and insulation strictly in accordance with SANS specifications.

The air duct system shall be of the low pressure type and the ductwork shall be manufactured of galvanised mild steel with general material requirements as set in Section 5.1 and 5.2 of SANS 1238. The ductwork shall either be circular or rectangular in cross-section as indicated on the project drawings.

The first dimension given on the drawings for rectangular ductwork shall be read as the width-on plan and the depth- on section, and the second dimension shall be read as the depth-on plan and the width-on section.

The duct dimensions shown on the drawings are sheet metal dimensions. All final dimensions shall be checked on site, or verified by means of architect’s working drawings and structural drawings, before the fabrication of the ducting.

Sealing membranes and adhesives for affixing insulation shall meet the indexes for surface spread of flame, heat contribution and smoke production as set out in Section 4 of SANS 1238.

The inner surfaces of ducting shall be smooth and no internal insulation shall be used. Dampers, sound attenuators, duct splitters and turning vanes shall be installed where indicated on the drawings.

Flexible connections shall be provided between all fans, sound attenuators and ducting. Flexible connections exposed to weather shall be provided with protecting galvanised sheet steel cover strips. The material used for flexible joints shall comply with the requirements as set out in SANS 1238, Section 5.5. Flexible connections shall be provided on both sides of the equipment.

Ducting shall always be installed in such a way, that, especially in plant rooms, maximum height between the floor and the underside of ducting is achieved.

The installation and testing of hangers shall comply with the requirements as set out in SANS 10173. All hangers shall be treated against corrosion and shall be painted.


Reinforcement, duct stiffening and fastening accessories shall be galvanised and installed where required. Only duct accessories manufactured from compatible materials, which comply with SANS 10173, shall be installed with the ductwork. Tie rods shall be manufactured from galvanised steel. Rivets, screws, bolts and other fastening equipment shall be corrosion proof.

As an alternative to the transverse joints specified in SANS 1238 other flanged joints such as MEZ-flanges will also be considered provided that flanges of this type meet the following specification.

Table 3-5: Flange connection data

LONGEST SIDE OF DUCT (mm)

FLANGE HEIGHT (mm)

MATERIAL THICKNESS OF FLANGE (mm)

NO. OF INTERMEDIATE

CLAMPS

100 - 600 20 1 0

601 – 1200 20 1 1

1201 - 1800 30 1.2 2

1801 - 2400 30 1.2 3

OVER 2400 To SANS 1238

MEZ-flanges or equivalent products shall be manufactured from cold rolled steel and hot-dip galvanised after manufacture. The sealant between mating flanges and between the flange and sheet-metal shall comply with SANS 1238 clause 4.7

Ductwork connected to equipment, such as heater batteries, sound attenuators, air handling units, etc. shall be provided with flanges for easy removal of the equipment.


The following figure illustrates class “A” and class “B” duct fittings.


3.6 LONGITUDINAL SEAMS AND TRANSVERSE JOINTS

Pieces of ductwork shall be joined with the necessary sealants, as applicable, as set out in SANS 10173, Section 5.

3.6.1 RECTANGULAR DUCTWORK

Longitudinal seams and transverse joints for rectangular ductwork shall be in accordance with SANS 1238, Section 6.

As an alternative to transverse joints specified in SANS 1238, other flanged joints such as MEZ-flanges will also be considered provided that they meet the SANS requirements. MEZ-flanges or equivalent products shall be manufactured from cold rolled steel and hot-dip galvanised after manufacture.

3.6.2 CIRCULAR DUCTWORK

Longitudinal seams and transverse joints for circular ductwork shall be according to SANS 1238, Section 7.

3.6.3 THE HANGING AND SUPPORTING OF DUCTWORK

Hangers and supports for rectangular and circular ductwork with no insulation shall comply with SANS 10173, Section 5.3 “Ductwork with no vapour barrier”. The hanger and support types used for ducting with insulation may be used.

3.6.4 FLEXIBLE DUCTING

Flexible ducting shall comply with the requirements as set out in SANS 10173, Section 5.7. Flexible ducting shall be proprietary manufactured with a fire rating to SABS 0177 Part 3 Class 1. The flexible ducting shall have an adequate working pressure and temperature range to suit the application of the installation.

Flexible ducting shall at all times be kept to a length not exceeding 1.5 m. Flexible ducting shall not have more than the equivalent of one 90o bend and bends shall be of maximum possible radius. Flexible ducting shall be supported with sufficient and correct brackets that will ensure maintenance of shape.

Flexible ducting shall be provided between air terminals, diffusers and all locations as indicated on the project drawings.

The inner core shall be of aluminium laminate with a heavy duty steel helix core.


3.6.5 TESTING OF DUCTWORK

All ducting shall be leak tested in accordance with SANS 10173, Section 4.3. No ducting shall have leakage rates in excess of 5 % of the required air flow rate in any section of ductwork or in excess of the SANS permissible leakage rates, whichever is the smallest.

3.7 AIR TERMINALS AND DAMPERS

3.7.1 GENERAL

Where selected by the sub-contractor, air diffusion equipment shall be selected in accordance with the manufacturer’s recommendations capable of passing the specified air quantity at the appropriate throw without creating excessive resistance, noise or local draughts. All air diffusing equipment shall be capable of meeting the NC level requirements, as specified in Section 2, for the space environment where the equipment is installed.

In all instances where spigot boxes (plenums) are used for the connection of air diffusion equipment, the inside surfaces shall be painted black to prevent visibility of the internal surface from ground level.

During commissioning of the system, each grille, diffuser, valve etc. shall be set to deliver the specified air quantity. It is the Contractor’s responsibility to check regenerated noise levels of the grilles offered against the overall acoustic performance of the system required. Noisy grilles that exceed the NC level requirements of the given space shall be replaced at the Contractor’s expense with more suitable types.

3.7.2 DOOR AND TRANSFER GRILLES

Transfer air grilles shall be complete with fixed curved blades and outer frame on both sides of the wall or partition. Transfer air grilles shall be of aluminium extruded type, naturally anodised or epoxy powder coated to a colour as specified by the Engineer. Openings in walls where transfer grilles are to be installed shall be provided by the Building Contractor.

Door air grilles shall be installed in wooden doors only. In cases where steel and glass doors are used, transfer grilles or transfer ducting as an alternative shall be installed. Door air grilles shall be of the chevron-blade type. Door air grilles shall be manufactured from extruded type 5OS anodised aluminium, naturally anodised or epoxy powder coated to a colour as specified by the Engineer.

Transfer ducting shall comprise of galvanised sheet metal ducting and aluminium curved blade intake and outlet transfer grilles. Flexible ducting shall not be used as transfer ducting.


3.7.3 WEATHER LOUVRES

Weather louvres shall be manufactured from extruded aluminium sections and finished in a colour as approved by the Engineer.

Weather louvres shall be constructed with drip edges to blades and rigid frames to enable building in of the louvres.

Weather louvres shall be watertight and shall prevent the entrainment of raindrops at a face velocity of up to 2.5 m/s.

Galvanized expanded metal or wire mesh screens with 12 mm opening sizes shall be fitted behind the blades of each weather louvre.

Top and bottom blades shall be fitted flush with the frame and be smooth without grooves, channels or recess where dirt or water can collect.

The free area through the louvre available for airflow shall be a minimum of 65 % of the nominal area of the louvre.

3.7.4 FIXING OF WALL-MOUNTED GRILLES AND LOUVRES

All wall-mounted grilles and louvres shall be fixed to a hard wood frame. The timber frames shall be supplied with the grilles as part of this installation.

The timber frames shall be manufactured in such a way that the grilles fit into them and such that the flanges of the grilles extend past the outer edge of the frames by approximately 5 mm. The timber frames shall be provided with the necessary cleats with which to mount them in brick or concrete walls. The depth of the timber frames shall be similar to the walls in which they are fitted.

The frames shall be supplied to the builder in good time so that they can be built into the walls. Should the mechanical contractor fail to do this, the frames shall be let into the walls afterwards and all builder's work, making good and painting shall be for the account of the mechanical contractor.

3.7.5 SUPPLY AIR GRILLES AND DIFFUSERS

Where type SD or DD grilles are specified in the BoQ, the supply air grilles shall be manufactured of extruded type 5OS anodising grade aluminium and shall be provided with opposed blade volume control dampers, unless specified otherwise on the project drawings. Volume control dampers fitted with supply air grilles shall conform to SANS 1238, section 6.5 requirements. The blades shall be adjustable from the front of the grille.

Where type CD ceiling diffusers are specified on the project drawings diffusers shall be manufactured from extruded type 5OS aluminium that is either naturally anodised or epoxy powder coated to a colour as specified by the engineer. CD


ceiling diffusers shall be complete with an opposed blade damper, plenum box with spigot and ceiling plate. CD type diffusers shall have a standard flat frame with blade spacing and distribution pattern as indicated on the standard drawings.

Where FGR diffusers are specified on the project drawings, diffusers shall be manufactured from fibre glass matt and approved SABS fire retardant resin painted to a colour as approved by the Engineer. The face plate shall be adjustable for air balancing

Where CVD and CCVD diffusers are specified on the project drawings, diffusers shall be manufactured from steel and powder coated to a colour as specified by the Engineer. Diffusers shall be equipped with a locking bracket to lock the adjustable radial disc once the system has been balanced.

Diffusers shall be installed at the locations where indicated on the project drawings. The Contractor shall install insulated flexible ducting of length not exceeding 1.5 m and of the same diameter as the diffuser, extending from the supply duct to the diffuser. Spigots shall be attached to the ducting and sealed with silicon sealer around the outer perimeter of the joint. Flexible ducting shall be strapped to the diffuser and spigots with steel straps to form an airtight connection.

Alternatively, where indicated on the project drawings, diffusers shall be “hard” connected to ducting with rivets or taper screws and sealed with silicone sealer to form an airtight connection. All diffusers shall be capable of meeting the discharge pattern and throw requirement as set out on the project drawings.

3.7.6 EXHAUST DISC VALVES

Disc valves shall be supplied and installed in the ceilings of the ablution areas and connected to the extract ducts by means of sheet metal spigots and flexible ducting.

The disc valves shall consist of a ring and central disc, which when rotated shall adjust the volume through the outlet. During commissioning of the system, each disc valve shall be set to exhaust the specified air quantity.

Disc valves in ceilings shall be of the polypropylene type, in a finish to match the ceiling colour.

3.7.7 VOLUME CONTROL DAMPERS

Volume control balancing dampers shall be installed in branch ducting to ensure a balanced air flow to all duct sections.

Damper blades, links and damper frames shall be of rigid construction and manufactured from galvanised steel. Dampers shall comply with SANS 1238.


Dampers for positive volume control purposes shall be manual or electric actuator driven as specified. Dampers shall be of the link or gear type.

A manually adjustable damper shall be fitted with an external adjusting lever in an accessible position. The lever shall be mounted on a square shaft and fitted with a locking mechanism that clearly indicates the current position of the blade. "OPEN", "CLOSED" and "OPERATING POSITION" shall also be clearly marked on each damper.

The inside cross-sectional area of the damper shall be equal to that of the connecting ductwork, and shall conform to the same standards of air-tightness as the rest of the ductwork system. The damper shall be fitted to the ducting in which it is installed by means of a flanged connection.

Dampers creating unacceptable vibrations and noise levels will be rejected and will need to be replaced at the Contractor's expense.

Single blade dampers shall have a width and length not exceeding 200 mm and 1 000 mm respectively. The overall dimensions of the blade of a rectangular damper shall be such that, when assembled in a duct, the clearance between the damper and the duct is suitable for the purpose for which it was designed, and the clearance shall be not more than 10% of the duct dimensions. Additionally, each damper shall have an acceptable stop that is integral with or is securely fixed to the casing and that prevents the damper blade from being moved past the fully closed position.

Multi-vane control dampers shall be of the opposed blade type. The length of individual damper blades shall not exceed 1 200 mm. Spans greater than 1 200 mm shall be covered using multiple frame units. The height of individual damper blades shall not exceed 225 mm and, to reduce penetrations through the casing to a minimum, the blades shall be connected internally by means of a linkage system and have only one external operating shaft.

3.7.8 FIRE DAMPERS

Fire dampers shall be installed where indicated on the drawings.

Fire/smoke control dampers shall comply with SABS 193 as amended, and shall be SABS marked and shall be proven to be low leakage when in the closed position.

Fire dampers shall be flanged on both sides and an access panel shall be provided in ducting at each fire damper with the location of these preferably on the upstream side of the damper.

Fire damper markings shall be as follows:

Manufacturer's name or trade name or trade mark

Fire resistance rating, in hours


Vital instructions regarding installation, direction of airflow, mounting position.

The open or closed status of the damper shall be clearly indicated outside the casing for inspection purposes.

Fire dampers shall have at least a two-hour resistance rating when tested in accordance with SABS 193.

Only solenoid-actuated fire dampers shall be used. Fusible linked dampers are not acceptable.

Labels shall be installed on the ceiling grid below all fire dampers indicated their positions, and reading: "Fire damper above". Each fire damper shall be wired to the switchboard with a LED to signal if the damper has been closed.

Dampers shall be sized so that when in the open position the nominal free air area is not less that the connected duct free air area.

Fire dampers shall be installed according to the manufacturer's and SABS requirements and recommendations.

Fire dampers shall be installed so as to form part of a continuous barrier to the passage of fire when in a closed position. Where a fire damper cannot be fitted immediately adjacent to the fire wall, the section of ducting between the damper and the wall shall be of at least the same metal thickness and fire rating as the damper casing.

Dampers shall be self-supporting in case of duct destruction due to heat. Care shall be exercised when installing the dampers’ support frame to ensure that the closing device is accessible.

Sheet metal sleeves shall be provided for the housing of the fire dampers where fire dampers are mounted in walls. These sleeves shall be built into the walls by the building contractor. Retaining angles shall be installed on the four sides of the fire damper sleeve on both sides of the wall. The angles shall be fastened to the sleeves only and not to the wall. The retaining angles shall lap the masonry by a minimum of 25 mm around the entire opening. Recommended minimum angle sizes are:

Table 3-6: Recommended minimum angle sizes

LARGEST DIMENSION OF FIRE DAMPER

ANGLES

Up to 1 200 mm 38 x 38 x 3,2 mm

1 200 mm to 1 800 mm 44 x 44 x 2 mm

Over 1 800 mm 51 x 51 x 4,8 mm


Clearance shall be provided between the sleeve and the masonry opening on the top and at the sides of the fire damper to allow for expansion. Allow a gap of 1 mm for each 100 mm of sleeve width or depth but the gap shall not exceed 15 mm.

All fixing and installation materials, i.e. bolts and nuts, rawl-bolts and mortar works shall be as per fire damper manufacturer's specification and shall not affect the fire rating of the fire damper installation. Combustible materials such as plastic or similar rawl-bolts and plugs are not permitted.

3.7.9 JET NOZZLES

In areas such as the auditoriums where air is required to travel long distances jet nozzles shall be employed. These nozzles shall be located at the rear of the room and shall be able to deliver fresh conditioned air the required distance of 10 m and have a flow rate of 280 L/s. The air velocity shall be 1.0 m/s.

The noise level of these jet nozzles shall be at a level that is lower than 20 dB.

“Trox® Technik” size 450 shall be used or similarly approved jet nozzles, with extended spigots. The minimum duct diameter that will accommodate this nozzle is 600 mm. The jet nozzles should be adjustable up and down as well as from left to right.

3.8 AIR FILTERS

3.8.1 GENERAL

Air filters of the make, type and size as specified on the drawings shall be installed.

Filters installed close to exposed air inlets, shall be protected by means of weather louvres and wire mesh screens.

Filter holding frames shall be of approved manufacturer with standardized dimensions to enable replacement with equivalent filters of all recognized manufacturers.

Construction and manufacture of all components shall be such that under no circumstances any un-filtered air can by-pass filters or filter banks.

Sufficient space shall be allowed in front or behind filters, to enable inspection and servicing.


3.8.2 FILTER MEDIA

Washable filter media shall be fitted behind hinged return air grilles where

indicated on the project drawings. The filter media shall be 100 grams / m² density and 5 mm thick. The filter media shall be of the synthetic type and shall be capable of arresting lint found in the return air. The filter media shall fit and extend past the outer perimeter of the wire mesh in the return air grille such that the bypass of unfiltered air is avoided. The filter media shall be fire proof. Glass fibre filter media type shall not be acceptable.

3.8.3 PRIMARY PLEATED FILTER

Primary filters shall be of the 50 mm pleated washable panel type. The media shall be synthetic and shall be of the self-supporting type. The media shall fit into and extend to seal all round in the panel frame to ensure that no air bypasses the media. The filter outer panel frame shall be of galvanised steel.

All filter accessories, including the channel filter holding frames and clips shall be standard products of the filter manufacturer. Filter holding frames shall be manufactured from galvanised steel. Filter holding frames shall be bolted or riveted together and where necessary shall be suitably reinforced in larger arrangements to withstand all possible operating conditions. An airtight seal shall be provided where filter holding frames are joined together. All metal parts shall be sufficiently protected against corrosion.

Primary filter panels shall fit into channel holding frames with sealing gaskets located between filter panel and channel holding frame. Where the channel holding frames are located on the downstream side of the filter, at least two spring loaded clips shall be used to ensure a positive seal against the edge gaskets and to keep filter panel in place. Where the channel holding frames are located at the upstream side of the filter, at least four spring loaded clips shall be used. All clips shall be from stainless steel.

The primary filter shall be of filtration class G3 and have an average ASHRAE arrestance of 90 % tested by SABS. The dust holding capacity shall not be less than 150 g per square meter. The initial (clean) and final (dirty) resistance of the filter shall be 65 Pa and 250 Pa respectively. The above-mentioned features shall be based on a rated face velocity of 2.5 m/s.

3.9 SOUND ATTENUATORS

Sound attenuators shall be provided and installed in positions as indicated on the relevant drawings and in such places where the system attenuation alone is inadequate. Special attention shall be given to noise regeneration due to heater banks, dampers etc. inside ductwork.


Where attenuators are selected by the Subcontractor, the attenuator shall be selected such that the pressure drop on both suction, and discharge attenuators are minimized whilst meeting the noise level attenuation performance levels as required. The absorption material shall be moisture-repellent, non-flammable and shall be abrasion-proof up to air-speeds of 20 m/s. Except where otherwise stated in the Supplementary Specification, sound attenuators in ductwork after supply air fans shall be designed for an insertion loss large enough to limit the total sound-pressure level of the noise at a distance of 1.5 m directly in front of the first air outlet in the duct system to the NC level specified.

Background noise levels shall be measured separately with the plant switched off and shall be deducted from the total measured sound-pressure levels.

Sound attenuators shall be of the proprietary manufactured type. Field fabricated sound attenuators shall be used only when specified in the Supplementary Specification or where written approval is obtained from the Engineer.

Field-fabricated sound attenuators shall be double-walled with the inner wall consisting of galvanised perforated plate. The perforations shall be 10 mm holes at 25 mm centres or the manufacturer's nearest standard. Expanded metal will not be acceptable. The inner and outer walls shall be held together with stiffening webs at approximately 300 mm centres. The lining thickness shall be at least 75 mm.

The internal free area of field-fabricated sound attenuators shall be not less than the cross-sectional area of the connecting ductwork as indicated on the drawing. The statistical pressure loss through proprietary manufactured sound absorbers shall not exceed the maximum permissible pressure loss at the design NC level as recommended by the manufacturer. Where the sound attenuators are larger than the ducts, the joining duct sections shall be enlarged to the size of the attenuator. All sound attenuators shall be provided with flanged connections.

Sound attenuators in plant rooms shall be installed in or as close as possible to the plant room wall to prevent the break-in of plant room noise into the duct after the sound attenuator. Where this is not feasible due to space limitations, the duct section between the sound attenuator and plant room wall shall be externally insulated and plastered with a suitable hard-setting plaster at least 10 mm thick on all four sides. Where ducting passes through an external noisy area it shall be treated to prevent any noise transmission into the duct.

The Contractor shall submit noise-estimating sheets for all systems as well as the insertion loss ratings of sound attenuators for approval before ordering. Failure to do so may result in additional costs to the Contractor if noise levels in any area should exceed the specified values.


3.10 ELECTRICAL

The Electrical Contractor shall provide an isolator within 1 m from the ventilation fans. The Mechanical Contractor shall do the entire electrical installation from the isolator to the fans.

Where ventilation fans are required to be interlocked with air conditioning units, the Mechanical Contractor shall provide a control DB-board as indicated on the project drawings. The Electrical Contractor shall do all wiring to the control DB-board. The Mechanical Contractor shall do the entire electrical installation from control DB–board to the corresponding AC units and ventilation fans.

3.11 CONTROL

Generally, ventilation fans shall be supplied with a 24-hour, 7-day timer or shall be switched on/off with the light switch, whichever the case; the mechanical contractor shall be responsible for the supply and wiring of the necessary equipment.

Where fans are required to be interlocked with air conditioning units, the mechanical contractor shall provide the control DB with the necessary relays and control equipment. The ventilation fan shall switch on and off with the corresponding air conditioning unit. The control panel shall be labelled as indicated on the project drawing.

Smoke extraction fans shall be interconnected with the smoke detection system, (by others) allowing start-up when smoke is detected.

3.12 OPERATION IN THE EVENT OF A FIRE

All ventilation fans shall, upon receiving a signal from the fire detection system, switch-off.

The Mechanical Contractor shall allow for this function in the interlocking control DB boards.


4 RETURNABLE SCHEDULES

Schedules below shall be completed and returned to the engineer for approval. No equipment that is not technically approved shall be approved for payment when claims are submitted.

4.1 AIR HANDLING UNITS

Table 4-1: AHU’s returnable Schedule

CODE MAKE MODEL RTH [kW] TOTAL AIRFLOW [L/S]

AHU 01

AHU 02

AHU 03

AHU 04

AHU 05

4.2 FAN COILED UNITS

Table 4-2: FCU’s returnable schedule

CODE MAKE MODEL CAPACITY [kW COOLING]

FCU 01

FCU 02

FCU 03

FCU 04

4.3 OUTDOOR UNITS

Table 4-3: Outdoor unit’s returnable schedule

CODE MAKE MODEL CAPACITY [kW COOLING]

ODU 01


ODU 02

ODU 03

ODU 04

ODU 05

ODU 06

ODU 07

4.4 DAMPER

Table 4-4: Damper’s returnable schedule

CODE MAKE MODEL SIZE(mm)

BD 01

BD 02

BD 03

BD 04

BD 05

BD 06

BD 07

BD 08

BD 09

BD 10

BD 11

BD 12

BD 13

BD 14

BD 15


4.5 FILTER BANKS

Table 4-5: Filter bank’s returnable schedule

CODE MAKE MODEL SIZE [mm] TYPE

FB 01

FB 02

4.6 DIFFUSERS

Table 4-6: Diffuser’s returnable schedule


CVD 01

4.7 DISK VALVES

Table 4-7: Disk valve’s returnable schedule


DV 01

DV 02

4.8 JET NOZZLE

Table 4-8: Jet nozzle’s returnable schedule

CODE MAKE MODEL SIZE SOUND POWER LEVEL[dB]

THROW [m]

JN 01

4.9 RETURN AIR GRILLS

Table 4-9: Return air grill’s returnable schedule


EAG 01


EAG 02

EAG 03

EAG 04

4.10 EXTRACT AIR FANS

Table 4-10: Extract air fan’s returnable schedule

CODE MAKE MODEL CAPACITY [L/S @ ESP]

EAF 01

4.11 RETURN AIR FANS

Table 4-11: Return air fan’s returnable schedule


RAF 01

RAF 02

RAF 03

RAF 04

4.12 FRESH AIR FANS

Table 4-12: Fresh air fan’s returnable schedule


FAF 01

FAF 02

FAF 03

FAF 04


4.13 REFRIGERANT CONTROL BOXES

Table 4-13: Refrigerant control box’s returnable schedule

CODE MAKE MODEL PORTS

MCU 01

MCU 02

MCU 03

MCU 04

MCU 05

MCU 06


APPENDIX A: SUPPORTING DOCUMENTATION

CPUT COMMERCE BUILDING HVAC REFURBISHMENT HVAC … · Johann van Zyl Draughtsman ....

Documents

Transcript of CPUT COMMERCE BUILDING HVAC REFURBISHMENT HVAC … · Johann van Zyl Draughtsman ....