MES Mechanical C04 Mechanical ventilation and ... - Health in Wales

MODEL ENGINEERING SPECIFICATION C04 Mechanical ventilation and air conditioning systems 1997

STATUS IN WALES ARCHIVED

For queries on the status of this document contact [email protected] or telephone 029 2031 5512 Status Note amended March 2013

National Health Service Model engineering specifications

C04 Mechanical ventilation and air conditioning systems © Crown copyright

Issue date April 1993 Revision 1: March 1995 Revision 2: April 1996 Revision 3: November 1997 Latest amendments shown in bold

DESIGN NOTES FOR C04

PAGE 1

MECHANICAL VENTILATION AND AIR CONDITIONING SYSTEMS

FOR USE OF DESIGNER ONLY THIS SECTION MUST BE DETACHED FROM THE SPECIFICATION BEFORE PROCEEDING TO ASSEMBLE TENDER DOCUMENTS

1.

If you have not already read the general information on Model Specification for Building Services in Health Care Buildings, please do so! This system approach to contract documentation has been prepared by many experienced design engineers throughout the country, to enable you to utilise your own expertise on Health Care Premises projects to the full extent and to reduce the repetitive work to a minimum.

2.

This is only a section of the specification suitable for tender documentation.

3.

The content of this section is set out at the front of the document.

4.

To make a full specification for contract documentation it will have attached:PART A - Standard General Conditions and Preliminary Clauses PART B - General Clauses Common to Buildings Services, Plant and Equipment PART D - Detailed description of Extent and Nature of the Works It is the designer's prerogative to add to or delete from any Element (or part thereof) of this Specification in Part D only. It is NOT the designer's prerogative to alter any part of Specification C04; comments should be forwarded to NHS Estates. Designers should ensure that all relevant standards (BS, BS EN, IEC, ISO etc) are the latest issues , including all amendments.

5.

The requirements of the relevant sections of the NHS Estates - Health Technical Memorandum 2040, The Control of Legionellae in Healthcare Premises - A Code of Practice, together with HTM 2025 Ventilation in Healthcare Premises should be noted.

Issue date: April 1993

Revision 3: November 1997


PAGE 2

Compliance with HTM 2040 should satisfy the statutory requirements of complying with the Health & Safety Commission's Approved Code of Practice - "The prevention or control of legionellosis (including legionnaires disease)", effective January 1992. Unless the designer states otherwise the general layout of input air plants should be as indicated in HTM 2025. This is particularly important as regards the position (and spacing) of the cooler battery or humidifier and the final filter. Proposed/draft tables on schedules of equipment/plant forming the ventilation system are given at the end of these notes. The designer should add (or modify) these as required for the specific scheme. 6.

The following notes explain the basis on which the clauses have been written.

This specification is generally based on standards/requirements of the HVCA DW/142 specifications for Sheet Metal Ductwork and DW/142 Addendum A; hence these should be complied with unless stated otherwise in this Specification or Part D. The designer should read thoroughly and understand the requirements of DW/142 and related documents. The design of the plant and selection of equipment should aim to minimise the unwanted distribution of excess moisture within the ductwork. Clause 01.01

The "FOREWORD" in DW/142 explains the pressure classifications and option to air leakage test. For health buildings projects all classes shall be tested unless stated in Part D. The pressure classification to Table 1 of DW/142 Part Two should be specified as appropriate in Part D, along with leakage classification providing this is suitable. See Appendix A in DW/142 Part Eight for possible uprating in some instances (A.2.4 special cases) and for general guidance on air leakage. See also DW/143 - A Practical Guide to Ductwork Leakage Testing.

Clause 01.02

Suitable alternatives to those listed in WRc Directory may be included in Part D. ALL materials used must be such that they will not support the growth of bacteria; this is particularly applicable to sealants, gaskets etc.

Clause 01.03

The latest dates of standard references are given at the time of issue of this specification. If subsequent standards are to be complied with the designer should include these in Part D. Any related EC/Statutory requirement must be complied with by the Contractor. The level of cleanliness of ductwork, see HVCA DW/TM2 shall be given in Part D.




PAGE 3

Clause 02.01

This clause accepts that ductwork to DW/142 is suitable for health care premises, subject to a few exceptions as noted in other clauses or, if the designer requires for the specific scheme, in Part D.

Clause 02.02

Disinfecting of ductwork may be the exception rather than the rule. Standard of ductwork cleanliness shall be given in Part D. Ductwork should be designed to prevent "ponding"/excess moisture forming anywhere within the system. Refer to Clause 01.03 above as regards the need to disinfect ductwork. The designer must ensure that fire stopping requirements are included for by others unless he specifically requires the ductwork contractor to carry out this work. Fire stopping around the ductwork is normally a builder's item; the designer must liaise with the Architect. Insulation of ductwork will be carried out by the insulation contractor.

Clause 02.03

Spring supports to DW/142 or flat straps bolted through the duct are not considered suitable. The designer will need to determine and indicate on drawings where fixings can safely be attached to the building so that the contractor can work accordingly and fix his costs with reasonable accuracy. Any flanges/fixings should be designed to take the weight of a man cleaning inside a duct that is sized for this purpose.

Clause 02.05

The intention is to leave the choice of construction to the contractor, unless the designer states a particular method in Part D. The ductwork manufacturer must ensure that the method of construction will guarantee that the air leakage limits specified will not be exceeded.

Clause 02.06

If the designer feels that standard medium radius fittings to DW/142 are not suitable he may specify his requirements in more detail with consideration being given to available or restricted space. Square bends with turning aerofoil vanes may be unavoidable in some instances and should be shown on the drawings. Ductwork joints should use fixings that do not intrude into air space.

Clause 02.07

Access openings are outlined in DW/142 Part Seven Section 21 and generally one opening per position, but the designer may decide on two openings in some instances (e.g. small ducts might require access openings every 3 metres). All access positions should be marked on the scheme drawings.




PAGE 4

Clause 02.09

Show positions and sizes of instrument/control connections on the scheme drawings.

Clause 02.10

The designer shall mark on the drawings the positions of all isolation, balancing and control dampers using a suitable code to differentiate each type.

Clause 02.11

Fire dampers shall coincide with fire compartment walls or floors and sub-compartment walls or enclosures which the architect should identify on the drawings and state the fire ratings. All dampers shall be of metal construction and operated in accordance with the guidance in HTM 81. All fire dampers shall be shown on the tender drawings. ALL dampers shall be tested in situ.

Clause 02.12

Ensure the damper operation and closed and open indication is included in the electrical specification. Refer to Standard Specification C46. Additional information for the ductwork contractor may be required in Part D.

Clause 02.13

The insulation and surface protection (trade name "EUROLAN") is based on DHSS letter ED75/8 (1975). The silencer position prior to the final filter is as recommended in HTM 2025, so that any loose materials would be held.

Clause 02.15

Flexible ductwork branches shall be kept to a minimum and used as final connections only if shown on the drawings, or permitted in Part D.

Clause 02.19

DHSS Data sheets NE1.1 to 1.10 outline the requirements for hazard markings. See also C82 - Colour coding for identification of building services. The designer shall ensure that the Mechanical Contractor carries out the colour coding in conjunction with the ductwork contractor. All ductwork must be colour coded.

Clause 02.20

Refer to DW/142 Part Eight Appendix A and B and DW/143 for air leakage testing calculations and procedures. The designer should specify the extent of testing he requires; whether a certain number of selected sections, or the whole of the ductwork. The cost of testing should be asked for as a separate sum in the tender. The testing does not include plant items, dampers etc. As a guide to the lengths of ductwork that can be tested a typical currently available test fan has the following range:Variable flow of 25 to 350 litres/second at 500 Pa. Variable flow of 25 to 190 litres/second at 1000 Pa.




PAGE 5

Clause 02.21

This is a leakage check on the complete system to be carried out after the fan has been initially run and with all items of plant fitted. Any unacceptable leakage points should be rectified before insulation is applied and the system commissioned.

Clause 03.01

DHSS Data Sheets DV 1.1/33 give a range of speeds for fans of different types with efficiencies and noise. The most suitable fan position (for A/C plant) will need to be determined (see HTM 2025 and 2040). Fan motors in the air stream should be totally enclosed, forced air cooled, thermistor protected. See Item 5 Page 1 of the Design Notes.

Clause 03.03

Backward blade types are specified, but the designer may specify otherwise in Part D. Fans of more than 7.5kW at the shaft should in any case be backward blade type.

Clauses 02.01 05.01 and 06.02

The drip trays shall be easily accessible and shall be connected to a water sealed trap of depth not less than twice fan static head with drain lines suitably sized and laid to fall (1:20) on all sides and arranged to terminate with a Type A air gap above an open tundish or drain which shall itself be trapped; see HTM 2025 and HTM 2040. The designer shall ensure the drain or gulley provided leads into a foul drain system.

Clause 05.01 and 06.01

The designer should ensure that the electrical specification includes for a re-chargeable and portable (hand held) luminaire, complete with charging unit, for each plantroom. Alternatively, waterproof bulkhead lighting can be considered. Eliminator plates must be included for downstream of the coil.

Clauses 05.01 and 06.01

Separate drains for cooling coils and humidifiers shall be provided. During the design consideration shall be given to the methods which will be used to regularly cleanse the system components. This usually is either chlorination or "steam" cleaning. The procedures shall be detailed in the operating and maintenance manuals produced for the scheme.

Clauses 05.01 and 08.02

The designer should be aware of condensation occurring on the underside of drip trays and adjacent plant/duct areas. The design should be such that any condensation cannot be entrained in the air flow and can discharge, from the base of the ducting/plant, to a safe position.

Clause 06.01

Alternative forms of humidification shall be specified in Part D, however steam humidification is, at the moment, the preferred option.




PAGE 6

The designer should liaise with the humidification manufacturer(s) as regards his design requirements for the scheme(s). Humidifiers shall be arranged to have up to a 30 minutes delay after start-up of main ventilation plant and a 10 minutes delay on the main ventilation plant shutdown after humidifiers cease operating. The designer shall allow sufficient space for removal of humidifier plant etc. The designer shall ensure that dry steam only enters the humidifier. The designer shall inform the humidifier manufacturer of the quality of steam available. Clean dry steam is preferred from the hospital boiler plant provided the boiler water treatment does not render this steam unsuitable for direct humidification. When boiler steam is used a warning notice must be prominently displayed in the boiler house. Boiler water treatment that complies to the Federal Drug Administration (FDA) Regulation 21: Part 173310 BUT EXCLUDING VOLATILES are considered suitable. Clause 07.02

The designer shall specify the actual rating required for the scheme in Part D, if different to that included in the Specification. Bag filters may not be acceptable. All filter arrangements must have air tight sealing around the filter media and filter unit framework and must also have adequate access available for replacing dirty filters. Automatic roll filters are not generally acceptable.

Clause 08.01

The sequence of plant items listed should be generally as recommended in HTM 2025 but may differ (ie position of fan) depending on the type of plant to suit the proposed services and hence must be specified in Part D (see proposed schedules) and shown on the drawings. Most air conditioning plants would be expected to follow HTM 2025. Safety interlocks shall be provided by means of an air pressure switch located after the supply fan to achieve the following:-

Clause 08.02


(i)

stop the supply fan motor if still running following belt failure;

(ii)

shut down the humidifier.

The designer shall ascertain the policy of the particular water undertaking for the area concerned and arrange for A/C plant drainage to be routed, normally to the foul stack, accordingly. The design must include for the glass trap and Revision 3: November 1997


PAGE 7

type A air gap (BS 6281) from each cooling coil/humidifier to the floor gulley/channel/trap provided by others. The designer shall include for trace heating of glass traps if required. Each drainage/drip tray should have a slope of approximately 1:20 in all directions to the drain outlet position. Side outlet connections are not permitted. All the above applies equally to Element 05 and 06. Clause 08.03

The location of A/C plant and/or prevailing site conditions may dictate the necessity for air handling units to be delivered in sections and assembled on site. The designer to specify such requirements in Part D.

Clause 09.01

The designer must closely liaise with the plant/attenuator manufacturers to control noise, vibration to acceptable limits. Noise and vibration should be controlled as far as is practicable at source and reference to manufacturers noise data and careful selection of plant and anti-vibration devices and provision of adequate plant bases as required by Part B will help to achieve this. For fans mounted on floors the deflection and natural frequency of the floor must be considered when selecting anti-vibration devices so as to avoid unacceptable floor movement. HTM 2045 and the CIBSE guide give useful guidance on noise and vibration control.

Clause 09.02

Dynamic balancing of fans is covered by clause 03.01. Vibration will also occur on starting up of plant and this requires to be allowed for. The combined noise created by the air handling plant working at its noisiest condition will need to be established taking into account the effect of and need for sound absorbing insulation of the plant. The designer should assess the total sound level from air handling and any other plant and discuss with the architect the need for acoustic treatment of the plant room itself for both internal noise control and noise transmission prevention to rooms above, below, or adjacent, both through the building structure and the ductwork. If the noise within the plant room cannot be kept below 85 dBA when starting up or running, then personnel must wear protective ear muffs when in the room, this must be brought to the attention of the users of the plant. It is




PAGE 8

desirable however that the need for ear muffs is avoided and the noise level is kept below 85 dBA. Clause 09.03

Attenuator construction is referred to in clause 02.13 and the need for these may be established from manufacturers noise spectrum data and the CIBSE guide and working through the system to the various rooms. If the resultant sound pressure levels in the rooms are too high attenuation will be required on the system. The noise climate in any room is determined by the acoustic sum of the inputs, ie external noise, hospital noise, plant noise, terminal noise and occupancy noise. In the absence of precise information it is usual to ascribe equal values to those sources.

Legionnaires Disease

The designer shall ensure that the whole of the ventilation and air conditioning system designs comply with HTM 2025; see also HTM 2040. See Page 1 of these notes. The reliance on cooling in air conditioning systems shall be subject to scrutiny, overcome possibly by using increased air change rates. Deep core planning shall if possible be avoided. See HTM 2025.

In particular:1.

1(a)

Wet cooling tower systems shall not be used.

(b)

Only direct steam injection humidifiers shall be used unless specified in Part D.

2. The distance to the floor drain, open channel or tundish from the air handling unit must be given or shown on the drawing to allow the drainage pipework from the unit to be provided. The design of this pipework determines the height of the unit above the plant room floor. The drainage system must conform to the requirements of HTM 2040 and HTM 2025. 3. All refrigeration for air conditioning should comply with Section C10 - Refrigeration of the Model Specification and the latest DoH Recommendations. Refer to the C10 Designer Notes. 4. The requirement to provide drip trays (See Clause 05.01 and 06.02) shall apply to all inherent wet areas to ensure that water cannot accumulate. Purpose made stainless steel drain trays are available to meet these requirements and the designer should include his requirements in Section D. See also Designer Notes in C81 for general details of drainage.




Electrical Requirements

PAGE 9

There is no provision in this Specification for equipotential bonding that may be required in accordance with the IEE Wiring Regulations - BS 7671: 1992. To ensure that the Regulations are not overlooked the designer should consult the electrical designer for a decision on the need for bonding and agree how this should be specified. Apart from flexible ductwork connections there is usually continuity throughout a sheet metal ductwork system. Any requirement must be included in Part D of the Electrical Specification. The electrical wiring systems and equipment shall be suitable for use in the atmospheric conditions likely to exist in Plant Rooms.

Commissioning and Testing

The designer must include, in Part D, his requirements for thorough commissioning and testing of all mechanical ventilation systems. Records of satisfactory tests together with operation and maintenance requirements must be included for and be of an acceptable standard. Minimum requirements are given in Element 12 of this Specification.

Design and Build Contracts

It is essential, with "Design and Build" type contracts, under which the client retains no clerk of works on-site and there is no "commissioning" period, that immediately before occupation the measures outlined in HTM 2025, 2040 and 2027 Hot and cold water supply, storage and mains services have been taken for disinfection etc.

Controls

This Specification does not include requirements for control systems for ventilation plants. However, the designer should initially consult HTM 2025 and Specification C54 Building Management Systems - as the basis for the control arrangement(s). The detailed requirements for the various ventilation plants should then be subject to discussion with control manufacturers.

Summary

A summary of Designer Requirements to produce Part D, scheme specific, is given at the end of the Design Standards.




PAGE 10

DESIGN STANDARDS HEATING AND VENTILATING CONTRACTORS' ASSOCIATION DW/142 : 1982

Specification for sheet metal ductwork - Low, Medium and High pressure/velocity air systems and DW/142 Addendum A 1988. This standard is in the process of being revised.

DW/143 : 1983

A practical guide to Ductwork Leakage Testing.

DW/151 :

Specification for Plastic Ductwork.

DW/TM1 : 1987

Ductwork - Acceptance scheme for New Products Rectangular Cross Joint Classification.

DW/TM2 : 1991

Guide to Good Practice - Internal Cleanliness of New Ductwork Installation.

CHARTERED INSTITUTION OF BUILDING SERVICES ENGINEERS CIBSE CIBSE Guides A, B & C Technical Memoranda TM8 Commissioning Codes A C R W -

Design Notes for Ductwork Air Distribution Automatic Controls Refrigeration Water Distribution

DEPARTMENT OF HEALTH

ED75/8

Hazard Notice - Ventilation Plant Air Silencers particularly those in operating theatre air conditioning plant.

NHS ESTATES Health Technical Memorandum 2040 - The control of Legionellae in Healthcare premises - a code of practice. Health Technical Memorandum 2025 - Ventilation in healthcare premises. Health Technical Memorandum 2045 - Acoustics. Issue date: April 1993



PAGE 11

INSTITUTION OF ELECTRICAL ENGINEERS IEE Wiring Regulations - BS 7671: 1992.

HEALTH AND SAFETY Health & Safety at Work Act 1974 Health & Safety Executive Guidance Note PM5 Health & Safety Executive Guidance Note HS(G)70 Health & Safety Commission Approved Code of Practice The Prevention or Control of Legionellosis (including Legionnaires Disease) Control of Substances Hazardous to Health Regulations COSHH Code of Practice Reducing the Exposure of Employed Persons to Noise

BUILDING REGULATIONS The Building Act 1994 and the Building Regulations 1991 and subsequent amendments, including all Approved Documents. Approved Documents

-

'B' Fire Spread 'E' Airborne and Impact Sound

BUILDING SERVICES RESEARCH AND INFORMATION ASSOCIATION BSRIA Application Guide 1/75 Manual for Regulating Air Conditioning Installations. BSRIA Application Guide 1/77 Document for Air System Regulation. BSRIA Application Guide 3/89 Commissioning of Air Systems in Buildings. BSRIA Air Filters - A Selection Guide SG 7/91.

HEVAC ASSOCIATION Fan Application Guide. Second Edition 1982. WATER BYELAWS The Byelaws, current edition, of the local Water Undertaking. Issue date: April 1993



PAGE 12

WATER RESEARCH CENTRE (WRc) Water Fittings and Materials Directory - current edition. BRITISH STANDARDS Relevant British Standards or BS Codes of Practice or their EC equivalent. NHS ESTATES ENGINEERING SPECIFICATIONS RELATED TO C04 C01 C02 C07 C10 C41 C51 C54 C81 C82

Common Services Mechanical Thermal Insulation Heating, Hot and Cold Water Systems Equipment Refrigeration Common Services Electrical (low and extra low voltage) Electrical Requirements for Specific Equipment Building Management Systems Above Ground Sanitation System Colour Coding for Identification of Building Services

End of Design Notes



C04

GENERAL

INDEX

PAGE 16 01

Scope Installations Generally Standard References AIR DISTRIBUTION DUCTWORK

01 02 03 02

Requirements Ductwork General Ductwork Supports Ductwork Dimensions and Materials Ductwork Construction Fittings Access Openings, Panels and Covers Test Holes Instrument Connections Control Dampers Fire Dampers Sound Attenuation Flexible Joints Flexible Ductwork Grilles, Registers, Diffusers, Louvres, Relief Flaps Single and Dual Duct Air Control Units Extract Hoods Service Identification Leakage Testing of Ductwork Sections Leakage Checks on Completed Systems FANS

01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 03

General Requirements Bearings Centrifugal Fans Axial Flow, Mixed Flow and In-Line Centrifugal Fans Roof Mounted Units AIR HEATER COILS

01 02 03 04 05 04

General Requirements Steam or Hot Water Coils AIR COOLER COILS

01 02 05

General Requirements AIR HUMIDIFIERS General Requirements


01 06 01


C04

INDEX

AIR FILTERS

PAGE 17

07

General Requirements Installation of Filters Primary/Pre-Filters Secondary/Main Filters High Efficiency Particulate Air (HEPA) Filters Extract Filters

01 02 03 04 05 06

AIR HANDLING UNITS

08

General Requirements Drainage Site Requirements

01 02 03

NOISE CONTROL

09

Vibration Control Plant Noise Attenuation Grille, Register and Louvre Noise Overall Noise Level

01 02 03 04 05

PROTECTIVE FINISHES

10

Ductwork and Supports Plant Final Paint Finish

01 02 03

DISINFECTION

11

General Requirements

01

COMMISSIONING AND TESTING

12

General Requirements Installation

01 02

End of Index



C04

ELEMENT 01

GENERAL Scope

PAGE 1

01 01

The work covered in this Section of the Specification includes the supply, delivery, installation, commissioning, testing, setting to work and the subsequent 12 months defects liability period, all to the Engineer's satisfaction the Air Conditioning and Ventilation installations. Section C04 sets down the general requirements for mechanical air handling extract and input systems and covers ductwork, fans, cooling coils, heating coils, humidifiers, air terminal devices, filters, attenuation and ductwork leakage testing. It does not cover controls, instruments, or ancillary services to the plant which will be specified in other Sections or in Part D. Detailed requirements for the plant, ductwork and commissioning will be specified in Part D. Ductwork is generally to HVCA-DW/142 together with Addendum A. The Mechanical Contractor shall provide all the necessary information to the Engineer, at the earliest time and to meet the overall programme prepared by the Main Contractor. Installations Generally

02

Materials incorporated into the works shall not support microbiological growth, this applies particularly to mastics, gaskets, etc. Suitable materials may be found in Part 5 of the WRc Directory. Where available environmentally friendly products should be given preference. All materials used in the construction of cooling coils/chillers batteries and humidifiers should withstand bio-degradation. Preference should be given to ductwork installers who are members of HVCA and/or certified to BS 5750. The Ductwork Contractor shall be chosen from the list given in Part D. Standard References

03

The materials components and completed installations shall conform as applicable with the following Standards, including all amendments, current at the time of tendering. Construction products should comply with European Standards and Technical Specifications (ESTS). Wherever reference is made to a British Standard a corresponding ESTS (generally ISO series) shall be equally acceptable. Where available all materials, equipment etc forming part, or whole, of the services specified in the Contract, should be obtained from BS EN ISO 9000 "Quality Assurance" certified manufacturers and preferably "kite marked" or EC equivalent. The latest dates of standard references are given at the time of issue of this Section.



C04

ELEMENT 01

PAGE 2

BRITISH STANDARDS General BS 21: 1985

Specification for pipe threads for tubes and fittings where pressure-tight joints are made on the threads (metric dimensions).

BS 4504: Part 3

Circular flanges for pipes, valves and fittings (PN designated). Steel, cast iron and copper alloy flanges.

Section 3.1: 1989 Section 3.3: 1989

Specification for steel flanges. Specification for copper alloy and composite flanges.

BS 5720: 1979

Code of Practice for mechanical ventilation and air conditioning in buildings.

BS 8313: 1997

Code of Practice for Accommodation of Building Services in ducts.

Ductwork BS 1449 Part 2: 1983

Steel plate, sheet and strip. Specification for stainless and heat resisting steel plate, sheet and strip.

BS EN 10051: 1992

Specification for continuously hot-rolled uncoated plate, sheet and strip of non-alloy and alloy steels. Tolerances on dimensions and shape.

BS EN 10131: 1991

Cold-rolled uncoated low carbon and high yield strength steel flat products for cold forming. Tolerances on dimensions and shape.

BS EN 485 485-1: 1994 485-2: 1995 485-3: 1994 485-4: 1994 BS EN 515: 1993

Aluminium and aluminium alloys - Sheet, strip and plate. Technical conditions for inspection and delivery Mechanical properties Tolerances on shape and dimensions for hot-rolled products Tolerances on shape and dimensions for cold-rolled products. Aluminium and aluminium alloys. Wrought products. Temper designations. Aluminium and aluminium alloys. Chemical composition and form of wrought products. Numerical designation system Chemical composition Forms of products.

BS EN 573 573-1: 1995 573-3: 1995 573-4: 1995



C04

ELEMENT 01

BS 1470 : 1987

Specification for wrought aluminium and aluminium alloys for general engineering purposes: plate, sheet and strip.

BS 1474: 1987

Specification for wrought aluminium and aluminium alloys for general engineering purposes - bars, extruded round tubes and sections.

BS EN 10143: 1993

Continuously hot-dip metal coated steel sheet and strip. Tolerances on dimension and shape.

BS 4848 Part 4: 1972 (1986)

Hot-rolled structural steel sections. Equal and unequal angles.

PAGE 3

Fans BS 848 Part 1: 1997 Part 2: 1985

Fans for general purposes. Performance testing using standardized airways. Methods of noise testing.

BS 4675

Mechanical vibration in rotating machinery.

Part 1: 1976 (1986)

Basis for specifying evaluation standards for rotating machines with operating speeds from 10 to 200 revolutions per second. Withdrawn and replaced by BS 7854 : Part 1 : 1996 Mechanical vibration - evaluation of machine vibration by measurements on non-rotating parts - general guidelines.

BS 5060: 1987 (1993) Specification for performance and construction of electric circulating fans and their regulators. BS 3456 Part 102

Specification for safety of household and similar electrical appliances. Particular requirements.

Section 102.342 1988 Electric fans and regulators. BS 5285: 1975 (1988) Specification for performance of a.c. electric ventilating fans and regulators for non- industrial use. BS 6861 Part 1: 1987


Balance quality requirements of rigid rotors. Method for determination of permissable residual unbalance.


C04

ELEMENT 01

PAGE 4

Air Heating BS 4857

Methods for testing and rating terminal reheat units for air distribution systems.

Part 1: 1972 (1983)

Thermal and aerodynamic performance.

Part 2: 1978 (1983)

Acoustic testing and rating.

BS 4954 Part 1: 1973 (1987) Part 2: 1978 (1987)

Methods for testing and rating induction units for air distribution systems. Thermal and aerodynamic performance. Acoustic testing and rating.

BS 5141 Part 2: 1977 (1983)

Specification for air heating and cooling coils. Method of testing for rating of heating coils.

Air Cooling BS 4434: 1995

Specification for safety and environmental aspects in the design construction and installation of refrigerating appliances and systems.

BS 5141 Part 1: 1975 (1983)

Specification for air heating and cooling coils. Method of testing for rating of cooling coils.

Air Terminal Devices BS 4773 Part 1 Section 1.1: 1991 Part 2: 1989

Methods for testing and rating air terminal devices for air distribution systems. Aerodynamic testing. Testing under laboratory conditions. Acoustic testing.

Air Control Devices BS 4979: 1986 Methods of aerodynamic testing of constant and variable dual or single duct boxes, single duct units and induction boxes for air distribution systems. Attenuation BS 4196

Sound power levels of noise sources (Parts 0 to 7 as appropriate).

BS 4718: 1971

Methods of test for silencers for air distribution systems.

BS 3958

Thermal insulating materials.



C04

Part 5: 1986

ELEMENT 01

PAGE 5

Specification for bonded man-made mineral fibre slabs

Filters BS 3928: 1969

Method for sodium flame test for air filters. (Other than for air supply to I C combustion engines and compressors.)

BS EN 779: 1993

Particular air filters for general ventilation. Requirements, testing, marking.

Fire Tests BS 476 Part 4: 1970 (1984) Part 6: 1989 Part 7: 1987 (1993) Part 20: 1987 Part 21: 1987 Part 22: 1987 Part 23: 1987 Part 24: 1987

BS 5588 Part 9: 1989

Fire tests on building materials and structures. Non-combustibility test for materials. Method of test for fire propagation for products. Method for classification of the surface spread of flame of products. Method for determinationof the fire resistance of elements of construction (general principles). Methods for determination of the fire resistance of loadbearing elements of construction. Methods for determination of the fire resistance of elements of construction. Methods for determination of the contribution of components of the fire resistance of a structure. Method for determination of the fire resistance of ventilation ducts. Fire precautions in the design and construction and use of buildings. Code of practice for ventilation and air conditioning ductwork.

BS 6496: 1984 (1991) Specification for powder organic coatings for application and stoving to aluminium alloy extrusions, sheet and preformed sections for external architectural purposes, and for the finish on aluminium alloy extrusions, sheet and preformed sections coated with powder organic coatings. Miscellaneous BS 2871 Part 2: 1972 Part 3: 1972


Specification for copper and copper alloys. Tubes. Tubes for general purposes. Tubes for heat exchangers.


C04

ELEMENT 01

BS EN 1057

Replaces Part 1 of BS 2871.

BS 3510: 1968

Specification for a basic symbol to denote the actual or potential presence of ionising radiation.

BS 2598 Part 1: 1991 Part 3: 1980 (1989)

Glass plant, pipeline and fittings. Specification for properties of borosilicate glass 3.3. Specification for pipeline and fittings of nominal bore 15 to 150mm: compatibility and interchangeability. Specification for glass plant components.

Part 4: 1980 (1989) BS 3790: 1995

Specification for endless wedge belt drives and endless V-belt drives.

BS 5304: 1988

Code of practice for safety of machinery.

BS 5378 Part 1: 1980 (1995) Part 3: 1982 (1995)

Safety signs and colours. Specification for colour and design. Specification for additional signs to those given in BS 5378 Part 1.

BS 6281

Devices without moving parts for the prevention of contamination of water by backflow. Specification for type A air gaps.

Part 1: 1992 BS 8233: 1987

PAGE 6

Code of practice for sound insulation and noise reduction for buildings.

INSTITUTION OF ELECTRICAL ENGINEERS IEE Wiring Regulations - BS 7671 : 1992. HEALTH AND SAFETY AT WORK ETC ACT 1974 and including:Health and Safety Executive Guidance Note PM5 Health and Safety Executive Guidance Note HS(G) 70 Control of Substances Hazardous to Health (COSHH) 1994



C04

ELEMENT 01

PAGE 7

CODE OF PRACTICE REDUCING THE EXPOSURE OF EMPLOYED PERSONS TO NOISE HMSO 1982 BUILDING ACT 1984 AND BUILDING REGULATIONS 1991 NHS ESTATES HTM 2025 -

Ventilation in Healthcare Premises

HTM 2027 -

Hot and Cold Water Supply, Storage and Mains Services

HTM 2040 -

The Control of Legionellae in Healthcare Premises - a code of practice

HTM 2045 -

Acoustics

HEATING AND VENTILATING CONTRACTORS ASSOCIATION: DW/142**

Specification for Sheet Metal Ductwork and DW/142 Addendum A

DW/143

Ductwork Leakage Testing

DW/151

Specification for Plastic Ductwork

DW/TM1

Ductwork - Acceptance Scheme for New Products Rectangular Cross Joint Classification

DW/TM2

Guide to Good Practice - Internal Cleanliness of New Ductwork Installation

CHARTERED INSTITUTION OF BUILDING SERVICES ENGINEERS CIBSE Technical Memoranda TM8

-

Design Notes for Ductwork

Commissioning Codes:

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Air Distribution Automatic Controls Refrigeration Water Distribution

A C R W

BUILDING SERVICES RESEARCH AND INFORMATION ASSOCIATION BSRIA


Application Guide 1/75 Manual for Regulating Air Conditioning Installations


C04

ELEMENT 01

BSRIA

Application Guide 1/77 Document for Air System Regulation

BSRIA

Application Guide 3/89 Commissioning of Air Systems in Buildings

PAGE 8

HEVAC ASSOCIATION Fan Application Guide. Second Edition 1982.

WATER BYELAWS The Byelaws, current edition, of the local water undertaking Water Research Centre (WRc) - Water Fittings and Materials Directory, in particular Section 5000 onwards. **

THE REQUIREMENTS OF DW/142 MUST BE READ IN CONJUNCTION WITH DW/142 ADDENDUM A. HENCE WHERE DW/142 IS REFERRED TO IN THE TEXT IT SHALL ALSO REQUIRE DW/142 - ADDENDUM A TO BE TAKEN INTO ACCOUNT AND COMPLIED WITH.

End of Element



C04

ELEMENT 02

AIR DISTRIBUTION DUCTWORK Requirements

PAGE 1 02 01

Shall:liaise with the Main and all other Sub-contractors as necessary. include for sub-letting the ductwork installation(s) to a specialist contractor and include for all materials, labour and other incidentals necessary to satisfactorily complete works. state in the Appendices to the tender documents (Part D) naming the sub-contractor who will carry out the works. prior to the manufacture of any ductwork, include for the preparation of detailed drawings of the ductwork installations, including supports, for submission to the Engineer for acceptance in principle. provide a complete schedule of rates to the Mechanical Contractor within 14 days. Ductwork General

02

Shall be:generally manufactured and installed in compliance with HVCA Specification DW/142 and DW/142 Addendum A with exceptions as specified in subsequent clauses with the standard of design and quality of workmanship such that the service conditions and leakage limitations specified in Part D are met. constructed such that all internal surfaces are generally smooth and will not normally retain dust/moisture. run generally parallel with walls and ceilings in order to circumvent building projections or pass through structures where permitted as shown on the drawings. installed where practicable with not less than 100mm space between wall, ceiling or floor and finished face of duct or insulation for cleaning purposes. kept clean during fabrication and as installation proceeds in compliance with the standards defined in the HVCA Guide to Good Practice - Internal Cleanliness of New Ductwork Installations, DW/TM2 and to the level specified in Part D. cleaned down outside on completion of each section by brushing, vacuum cleaning, use of grease and oil remover, to remove ALL foreign matter including labels before commissioning of the system. disinfected inside if specified in Part D.



C04

ELEMENT 02

PAGE 2

constructed using WRc approved sealants, gaskets, joints, adhesives, etc, which will not support bacterial growth and which produce minimal fire or smoke hazards if involved in a fire, this to include attachments such as grilles, etc. fire stopped around the perimeter of ductwork penetrating fire compartments by others unless specifically stated in Part D. provided with weatherproof collars where roofs or external walls are penetrated. installed to avoid any formation of water; should this be a possibility the Design Engineer to be informed. The layout of any drains to be as specified for cooling coils and humidifiers (Clause 05.01 and 06.01). Drainage pipework will be by others, ie not in the ductwork contract.

Ductwork Supports

03

Detailed drawings of the ductwork supports not shown in DW/142 Addendum A to be submitted and assessed by the Engineer at the same time as the ductwork drawings are submitted for acceptance in principle. Shall comprise:supports and hangers generally to DW/142 Addendum A which totally supersedes DW/142. insulated ductwork supports for warmed/cold/heat recovery ducting, details are given in Section C02 Thermal Insulation and/or Part D. the insulation of ductwork shall be carried out by the Insulation Contractor after satisfactory completion of ductwork/plant leakage testing. hot dipped galvanised after manufacture where exposed to outside weather conditions. Pre-galvanised and painted sections may be considered. See also Element 10 of this Specification. fixings for attaching supports or hangers to the building structure or fabric as detailed in DW/142 Addendum A. spanning supports on to the floor slab for vertical ductwork passing through floors, with additional intermediate supports as necessary. lightweight supports for flexible metal ductwork arranged to avoid crushing the corrugations or causing electrolytic action.



C04

ELEMENT 02

Ductwork Dimensions and Materials

PAGE 3

04

Shall be:to the nominal cross section sizes shown on the drawings and based on DW/142 standard sizes and thicknesses. Non-standard sizes may be used where appropriate. Minimum nominal sheet thickness to be not less than 0.6mm; see Table 4 of DW/142. This is acceptable as regards ductwork passing through fire barriers to Building Regulations. flanged throughout in plantrooms. installed with a minimum of slip joints. of mild steel fabricated from hot dipped galvanised sheet to BS EN 10143. Grade Z.2. G-275 coating. of stainless sheet to DW/142 Appendix G if stainless steel construction and grade is specified in Part D, using thickness as for mild steel. of aluminium sheet to DW/142 Appendix J if aluminium construction is specified in Part D, using thicknesses to DW/142; material grade to be specified in Part D. Ductwork Construction

05

Ductwork shall be:constructed with sealed seams and cross joints selected from DW/142 and DW/142 Addendum A and meet the air leakage requirements specified in Part D. stiffened and braced externally only using galvanised sections/profiles listed in DW/142. sealed with an approved sealing compound including longitudinal joints; the sealant used shall permanently retain adhesion and elasticity through a temperature range of 0° to 70°C; Sections 9, 13 and 27 of DW/142 refer. Fittings

06

Shall be:standard arrangement to DW/142 and Addendum A wherever possible. arranged with vanes in the bends of rectangular sub branches connecting directly to grilles and diffusers. for square bends fitted with aerofoil section turning vanes mounted in runners and rigidly fixed to the inside of the duct as specified in Part D, for bends below 300mm and to DW/142 Addendum A for bends 300mm and above. Issue date: April 1993


C04

ELEMENT 02

PAGE 4

as detailed on the drawings or in Part D for special change shapes e.g. connecting fans to ductwork. where branch connections are not formed as part of the main duct have the branch either welded or rivetted to the main duct. The branch connection to be accordingly formed for either welding direct or rivetting with a flange to the outside of the main duct. Access Openings, Panels and Covers

07

The number and location of all access doors, panels and covers other than those regarded as standard practice (see DW/142 and DW/142 Addendum A) will be marked on the contract drawings or listed in Part D, including type to be used. Shall be:fitted in readily accessible locations and suitable for the purpose. provided to the sizes, requirements and positions recommended in DW/142, utilising suitable proprietary products which meet the relevant pressure classifications. provided adjacent to filters, cooling coils, fans, heating coils, humidifiers, and all dampers to facilitate easy cleaning and maintenance. sealed, to ensure an airtight seal with a soft neoprene full face gasket secured to the ductwork with adhesive. constructed from 1.6mm hot dipped galvanised mild steel sheet secured to the ductwork and 6mm flash welded threaded studs welded to the ductwork at 100mm max equal centres and complete with brass wing nuts and washers. Note: Access covers to be constructed as above with folded edge and diamond stiffened when fitted on flat ductwork surfaces and be complete with lifting handles. Hinged access doors to be as access covers and be complete with heavy gauge brass hinges, secured with heavy gauge mild steel Fitch fasteners up to 600mm high and forged or cast steel wedge tightening refrigerator type door handles over 600mm high. Curved surfaces to be with cadmium plated heavy gauge steel toggle catch and hook fasteners. Test Holes

08

Shall be:13mm diameter and provided before and after each plant component, at all main branches and before all balancing dampers. Each test hole to be sealed (with 'top hat' external type grommet) and in accordance with CIBSE Commissioning Code Series A, positioned as agreed with the Engineer on the ductwork layout drawings and (if necessary) after the installation of the ductwork.



C04

ELEMENT 02

Instrument Connections

PAGE 5

09

Shall be:provided at all positions shown on the contract drawings, suitably drilled or bossed and screwed to sizes given. Control Dampers

10

Shall be:of a proprietary make where specified in Part D. all flanged and generally to the requirements of DW/142 and DW/142 Addendum A. constructed from corrosion resistant materials. installed where shown on the drawings and/or as detailed in Part D. of the "aerofoil" blade construction (double skin section) of the same material as the associated ductwork and securely fixed to each side of a central (in-blade) operating spindle supported in sintered bronze lined cast aluminium bearings. single blade up to 200mm ducting height. elsewhere multi-blade, opposed blade type with each blade not exceeding 175mm in width nor longer than 1200mm. arranged so the blade tips overlap each other by 10mm and be covered with soft neoprene edge strip, fixed with adhesive, to form a good seal between the blades. arranged to have the blades linked so they operate from a single lever comprising a cast aluminium operating lever and quadrant (with locking screw) incorporating a selflubricating bronze bearing and the words "OPEN" and "SHUT" cast on the quadrant. After final balancing the quadrant shall have a small 'V' shaped notch, filed in the quadrant, indicating the centre line of the level when in the operating position. Each damper shall have an adjacent access or inspection door so that the operation of the blades may be observed. Motorised dampers suitable for 24V on-off reversible motor with, manual override facility, shall generally be to the above requirements and installed where shown on the drawings and as scheduled in Part D.



C04

ELEMENT 02

Fire Dampers

PAGE 6

11

Shall be:installed to meet the requirement of HTM 81 and be installed where shown on the drawings; types to be as specified in Part D. complete with HEVAC/HVCA installation frames except where indicated in Part D. of the multi-blade curtain type with stainless steel blades completely out of the airstream and certified that they comply with BS 476: Part 20. fitted in all vertical and horizontal ductwork as required by HTM 81. fitted with an access opening on either side; incorporating the largest opening which can be obtained with one dimension 300mm minimum. Consideration should be given to the use of removable duct sections where the efficient use of access openings cannot be achieved. tested in situ with testing and automatic re-set facilities if smoke or heat detector operated types and indication that damper is closed. This shall be in liaison with the Controls Sub-contractor. See also requirements in Part D. retained by a thermally actuated device set at 74°C and designed to ensure rapid closure on release. BS 5588: Part 9 refers. Note: Intumescent fire dampers are NOT permitted. The Ductwork Contractor shall demonstrate to the Engineer or his representative, the mechanical operation of each fire damper. Replaceable thermally actuated devices shall be included for. Fire stopping, between the damper frame and the structure to which it is fitted, shall be carried out by others or be included for in Part D. Power operated fire dampers shall be generally as shown on the drawings and specified (including power supply failure requirements e.g. close on supply failure and automatically re-open when supply is re-established) in Part D. Sound Attenuation

12

Shall:be by means of purpose built attenuators type tested to BS 4718 at the manufacturers works or an approved testing laboratory with certificates provided, as specified in Part D.



C04

ELEMENT 02

PAGE 7

incorporate the attenuator infill of mineral fibre mat to BS 3958 Part 5 faced one side with a bonded white glass cloth, the whole being capable of resistance to mould, vermin, moisture and odours and non-combustible to BS 476 Part 4 with fire propagation index of not more than I = 12 and i = 6 to BS 476 Part 6. The mat being bonded to the inner surface with all joints sealed and further secured under a perforated non-corrodible metal cover over the glass cloth facing. be located so that sound attenuating material is not nearer to a fire damper than one metre and is not fitted anywhere after the final filter unless shown on the drawings and/or specified in Part D. Flexible Joints

13

Shall be:provided at fan inlet and outlet connections and any other positions shown on the drawings to details specified in Part D. equal in cross section to the points of connection and not longer than 250mm or less than 50mm.

of "Neoprene" Coated Glass Fibre or other materials excluding asbestos and have fire resistance properties of 30 minutes integrity, Class 1 Surface spread of flame to BS 476: Part 7 and not produce smoke or toxic fume hazards if involved in a fire. complete with galvanised mild steel backing flats drilled to suit flanges or fitted with proprietary flanges. installed without undue deflection or slackness between correctly aligned ductwork and fan flanges or spigoted connections. Flexible Ductwork

14

Shall be:used for final connections to grilles and diffusers ONLY if shown on the drawings and/or specified in Part D. to a standard of air tightness equal to that of the ductwork. constructed to meet the fire precautions recommended in BS 5588 which comprise:Length of flexible ductwork branches not to be longer than 1.0 metre, or pass through fire compartment walls, floors or enclosures of sub-compartment walls or enclosures, or cavity barriers.



C04

ELEMENT 02

PAGE 8

Fire resistance to meet BS 476: Part 6 with indices of performance not more than I = 12 and i = 6. Materials which will not produce smoke or toxic fume hazards if involved in a fire and as specified in Part D. Grilles, Registers, Diffusers, Louvres, Relief Flaps

15

Shall be:of the sizes, materials, types, noise ratings as specified in Part D and/or shown on the drawings. designed/installed for easy removal, in-situ adjustment from within the room. complete with sealing gaskets and free from burrs with all ledges or crevices designed so that dust build up can be kept to a minimum. fitted with two sets of individually adjustable blades and opposed or rhomboidal dampers, lockable in any position, on supply grilles. fitted with one set of adjustable blades and opposed blade dampers, lockable in any position, on extract grilles. Fitted with corrosion resistant weatherproof louvres and mesh screens at all external intake or exhaust positions, mesh to be not less than 6mm and not more than 12mm. of the non-vision type for transfer grilles. of the balanced blade type for pressure relief flaps, with fine adjustment of relief pressure settings and give a seal as airtight as practicable when closed. constructed from stainless steel or cast aluminium alloy complete with in-built lugs. fitted with iris and volume control damper and have concealed type fastening for circular ceiling diffusers. constructed to provide distortion free corrosion resistant units free of drumming, having minimal air leakage with regard to the working pressure and giving uniform distribution of air, with equalisation incorporated if necessary.Plenum boxes will be as specified in Part D. type tested at the manufacturer's works or an approved testing laboratory for flow and noise to BS 4773 Parts 1 and 2 and certificates provided. Weather louvres (acoustic/non-acoustic shall be specified in Part D. The Mechanical Contractor shall be responsible for ensuring correct hole sizes, fixing details and weathering requirements.



C04

ELEMENT 02

Single and Dual Duct Air Control Units

PAGE 9

16

Shall be:constructed to provide a distortion free corrosion resistant unit having minimal air leakage with regard to the working pressure and incorporating acoustic treatment if necessary to the requirements described for attenuators. fitted with easy access for cleaning. See Element 02/07. complete with control damper(s) reset manually or by automatic control. with or without heat exchanger, as specified in Part D. type tested at the manufacturers works or an approved testing laboratory for damper leakage, casing leakage and flow rate control to BS 4979 and certificates provided. Extract Hoods

17

Shall be:of the sizes and materials specified in Part D and as detailed on the drawings. adequately braced and supported independently of ductwork with all surfaces smooth and free of sharp edges and crevices. provided with perimeter drain channel and drain point on kitchen hoods and incorporate corrosion proof grease eliminators of corrugated plate or crimped wire mesh, complete with quick release clips and grease drip tray. fitted with piping, drain taps and keys to tray and gulley by others. Service Identification

18

Ductwork should comply with C82 Colour coding for identification of building services, and DW/142 Appendix C, shall be carried out by the Mechanical Contractor in conjunction with the Ductwork Contractor. Additional hazard symbols to BS 3510 and BS 5378 on extract systems carrying radio-active, infectious, toxic, chemical or explosive substances shall be as specified in Part D. Service identification of insulated ductwork will be carried out by the Mechanical Contractor. All fire, control, regulation dampers shall be identified on their respective ductwork and at a visible position on the building fabric if the ductwork is concealed.



C04

ELEMENT 02

PAGE 10

Each grille, diffuser and relief flap (and their settings) to be uniquely identified together with their locations. This work will require liaison with the Ductwork and Commissioning Contractors. The Mechanical Contractor shall supply and fix colour coded identification buttons to ceiling tiles where any damper on a duct run is above a suspended ceiling. Leakage Testing of Ductwork Sections

19

Shall be:applied to erected sections of the ductwork complete with access doors, at the test pressure and flow rates, as specified in Part D, before insulation is applied to ductwork. carried out generally in accordance with DW/142 and DW/143 using portable fan and test equipment. recorded on test sheets based on DW/142 and DW/143 examples and compared to acceptable leakage rate specified in Part D. interpreted as requiring that sections which need unacceptable levels of remedial work on seams or joints are to be replaced by new sections; this requirement to be identified during the preliminary test to DW/143 paragraphs 4.9 and 4.10. all "in duct" plant to be tested to the same leakage classification by the manufacturer and as installed on site.

Leakage Checks on Completed Systems

20

Shall be:carried out when the fan has been first set to work and before thermal insulation is fitted and a visual inspection made of all connections from plant to ductwork including any untested joints between tested sections and all joints and seams not previously subjected to leakage pressure tests, including plant casings, grille joints, dampers, etc.

End of Element



C04

ELEMENT 03

FANS

PAGE 1

03

General Requirements

01

Shall:before items of ventilation plant are ordered, include for a detailed set of calculations to be submitted, for comment, containing the following:(i)

Each fan operating point and system characteristics.

(ii)

Each fan in duct sound power level.

(iii)

Each attenuator insertion loss.

(iv)

Resultant room NC levels with all plant running.

Fans shall be:of the types, duties and manufacture, as specified in Part D. provided with protective finishes as necessary for the service conditions specified and free of damage to the protection when installed. capable of aerodynamic and acoustic performance specified when related to the required application and the relationship of air inlet, air outlet, ducted or free configuration, as standardised under Types A, B, C and D to BS 848: Part 1 Clause 17.2 and BS 848: Part 2. provided with performance and noise data based on type testing at the Manufacturer's Works or an approved testing laboratory. where fitted with impeller and shaft assemblies and pulleys, dynamically balanced at the Manufacturer's Works at the normal maximum speeds using guidelines for balance quality and standard to BS EN 6861: Part 1 and BS 4675: Part 1 and as appropriate to the size and safety operation of the fan at its intended maximum operating speed. operated at not greater than the maximum design speed and power rating. driven by electric motors complying with Part C51, Electrical requirements for specified equipment, mounted outside the air stream unless otherwise specified in Part D. Fan motors in the air stream to be totally enclosed, forced air cooled, thermistor protected. identified by non-ferrous metal plates (or other recognised permanent means) on casings stating:Manufacturer's name Fan Model and Serial Number Impeller size Impeller clearance mm for centrifugal fans Issue date: April 1993


C04

ELEMENT 03

PAGE 2

Speed of impeller Maximum rps Direction of Rotation Electrical details (on motor) provided with lifting attachments for safe handling of the complete unit, and actual weight painted on the unit if over 25 kilogrammes. Bearings

02

Shall be:ring-oiling sleeve, ball, or roller, to fan makers recommendations to suit the installed attitude of the fan, the duty and noise criteria. arranged for ease of lubrication and maintenance without the need to re-align replacement bearings and provided with protection against over-lubrication, loss of lubrication, ingress of dust, etc. independent of involute casings on centrifugal fans. Centrifugal Fans

03

Shall:be 2 speed motors capable of full volume at full speed and half volume operation to the requirements given in Part D. comprise a centrifugal fan complete with its motor, rigid welded steel base frame, Vee-belt drive and wire mesh protection guard. The base frame is to be fitted with anti-vibration mountings. have base frames of a rigid welded construction designed to carry the fan, motor and slide rails as compact as possible. Each frame is to have compression spring anti-vibration mountings selected by the fan manufacturer, to provide an isolation efficiency of 95% or greater at all points of operation. include for provision and installation of any necessary inertia bases to increase the mass of the isolation system to achieve this requirement. Impellers shall be:of the backward blade type generally to give fan total efficiency of not less than 78%, or alternatively of the forward blade type if specified in Part D. constructed of mild steel, aluminium alloy, or other materials, suitable for the speed and application Volute casings shall be:of galvanised mild steel sheet suitably stiffened against vibration and drumming. Issue date: April 1993


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ELEMENT 03

PAGE 3

constructed with integrally sealed or welded joints to withstand maximum static pressure of the system without air leakage. designed so that the impeller can be easily withdrawn from the casing and re-assembled after installation. provided with bolted flanged connections at inlet and outlet. provided with drain point and brass plug at a position to suit the installed attitude of the fan. provided with bolted access cover and seal in lower half of casing for inspection of impeller. Drive shall be:Multi-Vee belt matched set to BS 3790 through overhung pulley keyed or taper locked on fan shaft for ratings to 30 kW, or keyed on only above this figure, with provision for key removal. guarded to BS 5304 as required by Part B01: General clauses common to building services, plant and equipment. Motors shall be:supplied in duplicate and of the same duty, as specified in Part D. The standby motor may be stored (wall-mounted) adjacent to the fan unit if specified in Part D. suitable for 415V, 3ph, 50 Hz supply, 960 or 1440 rpm. capable of speed control if specified in Part D. Axial Flow, Mixed Flow and In-Line Centrifugal Fans

04

Impellers shall be:capable of giving fan total efficiency of not less than 75% for either guided vane types, mixed flow types, or in-line centrifugal types. constructed of mild steel, aluminium alloy, or other materials, suitable for the speed and application. Stators shall be:constructed with galvanised steel or aluminium alloy vanes. Casings shall be:of galvanised mild steel, aluminium alloy, or other materials suitable for the application, and stiffened against vibration and drumming, with supports attached for bolting to frame or structure. Issue date: April 1993


C04

ELEMENT 03

PAGE 4

designed with bolted flanged ends and of sufficient length to allow complete withdrawal of unit from ductwork. constructed to withstand maximum static pressure of the system without air leakage and provided with airtight cover and seal for inspection of fan. provided with electrical terminal box on outside of casing pre-wired to motors when internally mounted. Drive shall be:direct motor drive mounted axially with fan in air stream, or matched set multi-vee belt drive from external motor, or direct drive from motor mounted externally between a bifurcated casing, as specified in Part D. assembled so that direct driven fans have the motor positioned correctly relative to upstream or downstream flow in accordance with fan makers recommendations. Anti-Vibration Mounts shall be:provided between fan and casing or housing and for external motor drives. 05

Roof Mounted Units Shall be:generally to the previous Clauses 03/03 and 03/04. complete with weatherproof cowls, bases and casings assembled to provide a water tight seal to the building structure. provided with corrosion proof bird screen not greater than 12mm or less than 6mm mesh.

End of Element



C04

ELEMENT 04

AIR HEATER COILS General Requirements

PAGE 1 04 01

Batteries shall be:of the types, duties, materials and manufacture, suitable for the heating medium to be used, and the external environmental conditions as specified in Part D. supported adjacent so that ductwork does not take the weight. arranged for easy removal without disturbing ductwork or services. provided with the necessary mechanical and electrical service connection points. Steam or Hot Water Coils

02

Shall be:constructed from solid drawn copper made from tube to BS EN 1057 and BS 2871: Parts 2 or 3 according to duty. complete with tubes, plain on frost coils and copper or aluminum finned on heating coils, with fins securely bonded in contact with tubes; the tubes to be arranged for maximum air contact. provided with copper or gunmetal headers arranged to give uniform flow through tubes, the coil being held in a compatible metal frame. complete with coil end cover boxes to minimise air leakage. arranged for total free draining of the coil circuit complete with drain points and plugs as necessary and air vent connection points. complete with galvanised mild steel casing not less than 1.2mm thick, flanged with removable cover plates for withdrawal of coil. assembled to allow for contraction and expansion of coil. arranged for all service connections to be flanged to BS 4504, and screwed to BS 21 for connections 50mm and below. type tested at the Manufacturer's Works or an approved testing laboratory and rated for thermal performance to BS 5141: Part 2 with airflow resistance not more than 65 Pa at 2.5 m/s face velocity and certificates provided. tested at the Manufacturer's Works for pressure soundness to 1.5 x working pressure or 20 bar.g. whichever is greater and certificates provided.



C04

ELEMENT 04

PAGE 2

if steam, fitted with condensate collection arrangement that will not allow a vacuum to form within the coil or cause a back pressure so as to prevent the release of condensate from the coil

End of Element



C04

ELEMENT 05

AIR COOLER COILS General Requirements

PAGE 1 05 01

Batteries shall be:of the types, duties and manufacture, suitable for the cooling medium to be used, as specified in Part D. designed for a maximum face velocity of 2.5m/s and also to prevent condensate carryover. installed to meet the safety requirements of BS 4434 if refrigerant cooled type. tested at the Manufacturer's Works for pressure soundness to 1.5 x working pressure or 20 bar.g. whichever is greater and certificates provided. complete with casing and drip tray to withstand bio-degradation; stainless steel to BS 1449: Part Grade 316 is advised. supported adjacent so that ductwork does not take the weight. arranged for easy removal without disturbing ductwork or services for inspection and cleaning. provided with the necessary flanged mechanical services connection points. provided with an easily removable drip tray (large enough to capture all water condensed) designed to a fall of 1 in 20 in all directions to the drain outlet to self drain under all working conditions to avoid formation of pools of water. The drain outlet must be suitable for connection to a glass trap and a drainage system to conform to the requirements of HTM 2040 and HTM 2025, see also Element 08/02 of this Specification. A bypass baffle to be fitted under the coil in the tray to prevent air bypassing the coil. provided with access doors upstream and downstream incorporating glazed and sealed viewing windows and designed to afford easy access for inspection and cleaning. manufactured from materials that will not support microbiological growth; this includes surface finish mastics, gaskets, insulation, sealants etc. This applies to both batteries and drip trays. The Water Fittings Directory lists suitable materials. NOTE: External cleansing may be with a water solution containing 5 ppm chlorine or as specified in Part D. Alternatively steam may be used. not greater than 1.00 metres in height, where this is exceeded each battery shall have its own drip tray. made from tube to BS EN 1057 and BS 2871, Parts 1, 2 or 3 according to duty with refrigerant tube degreased and dehydrated internally. Coils for DX systems to be made from refrigerant grade copper. Issue date: April 1993


C04

ELEMENT 05

PAGE 2

fitted with copper fins securely bonded on in contact with tubes and copper or gunmetal headers arranged to give uniform flow through tubes, the coil being held in a comparable metal frame and the complete block assembly electro-tinned. alternatively with aluminium fins and not tinned, if specified in Part D. fitted with fins extended to form an eliminator on the downstream side. It is essential that downstream eliminator plates are fitted. provided with the coils arranged for total free draining of the coil circuit complete with drain point and plug and air vent connection point and refrigerant coils with suction and liquid connections. In "Packaged" air handling systems, the return bends/header pipework on each battery should be within the air stream and suitably baffled. In "made-up" air handling systems they should be uninsulated but enclosed in insulated (removable) covers. flanged with removable cover plates for withdrawal of coil, for inspection or disinfection. arranged for all service connections to be flanged to BS 4504, and screwed connections to BS 21 for pipes 50mm and below. type tested at the Manufacturer's Works or an approved testing laboratory and rated for thermal performance to BS 5141: Part 1 with airflow resistance not more than 125 Pa at 2.5 m/s face velocity and certificates provided. Note: Condensation can occur on the underside of drip trays and adjacent areas. To overcome this potential the plant/ducting arrangement should be designed and installed such that any condensation can discharge from the base of the plant/ducting to a safe position. End of Element



C04

ELEMENT 06

AIR HUMIDIFIERS General Requirements

PAGE 1 06 01

Humidifiers shall be:of the types, duties, manufacture and installation specified in Part D. steam injection manifold type with internal noise attenuation, complete with steam heated jacket, inlet strainer, high efficiency separating chamber, a final separating chamber located between the control valve and manifold(s), all supported on corrosion proof chassis, with all internal components of stainless steel or non-ferrous metal. fitted with a condensate collection arrangement that does not cause a back pressure so as to prevent the release of condensate. arranged to completely mix steam with air without carry-over of moisture and must have at least 1 metre without obstructions downstream. An eliminator to be provided if required. provided with an easily removable drip tray designed to a fall of 1 in 20 in all directions to the drain outlet and self drain under working conditions to avoid formation of pools of water. The drain outlet must be suitable for connection to a glass trap and a drainage system and conform to the requirements of HTM 2040 and HTM 2025; see also Element 08/02 of this Specification. in a package form which will discharge clean, dry steam and designed such that all condensate is removed from the steam before it leaves the outlet nozzles and without objectionable steam noise; the humidification lance should be sited to prevent steam impinging onto the sides of the duct, condensing and generating excess moisture. supported adjacent so that ductwork does not take the weight. arranged for easy removal of manifold and associated pipework without disturbing ductwork or other services. tested at the Manufacturer's Works for pressure soundness to 1.5 x working pressure minimum and certificates provided. provided with outer casing constructed to withstand maximum static pressure of the system without air leakage. constructed from materials which will withstand bio-degradation; this applies particularly to mastics, gaskets, insulation etc. Stainless steel to BS 1449: Part 2 Grade 316 is advised. provided with airtight access door, complete with glazed viewing window, designed to afford easy access for inspection and cleaning. The door to be fitted with a large PVC label (red lettering on white background) stating:-



C04

ELEMENT 06

PAGE 2

'WARNING' INTERMITTENT LIVE STEAM FROM MANIFOLD WITHIN DO NOT ATTEMPT TO SERVICE WITHOUT CLOSING AND ISOLATING STEAM AND ELECTRICAL SUPPLIES arranged for all service connections to be flanged to BS 4504. provided with a stable steam supply pressure of not greater than 1.5 bar (a low noise level being the criteria) via a pressure reducing valve assembly; the PRV shall be suitable for the maximum and minimum humidifier load. A spare PRV shall be included. provided with a high limit humidistat installed to ensure that the saturation in the duct does not exceed 70%, particularly during plant start up. provided with a delay in the humidifier control system in order to prevent excessive condensation when starting up from a total plant shut-down, so that the humidifier is not brought into use until 30 minutes after the start-up of the ventilation plant. Steam connections to humidifiers to be arranged with a dirt pocket and trap set as close to the humidifier as possible such that the steam condition at entry to the humidifier is as dry as possible. provided with certification that motor compatibility and response rate of the steam control valve motor have been checked and confirmed with both the humidifier and control manufacturers. The control circuit shall incorporate time delays to avoid continuous cycling of the valve between fully closed and fully open, the steam control valve being arranged to "fail safe" in the event of power failure and be interlocked so that steam cannot be injected into the system unless the fan(s) is running. The requirements for the control system are detailed in Part D. installed with particular care being taken in positioning the humidifier section of the ventilation plant, in order that the required drainage system can be readily installed and easily maintained. The drainage system (drain tray, drain outlet etc) shall be capable of removing all the moisture produced. The steam quality shall be given in Part D. End of Element



C04

ELEMENT 07

AIR FILTERS General Requirements

PAGE 1 07 01

Filters shall be:generally to the basic requirements in Elements 03 to 06. The specific type of filter(s) and rating may differ from that in Clause 03, 04, 05 and 06; reference to be made to Part D. of the types, duties, efficiencies, resistances, manufacture, as scheduled and specified in Part D. where required on extract ductwork etc, to the requirements specified in Part D. provided with galvanised mild steel casings flanged to match ductwork. made from filter media for which the Manufacturer is to supply satisfactory type test certificates. fitted with non-combustible frames to BS 476 Part 4. free of asbestos, metal wool, plastic foam type materials, or any materials which may introduce hazards from smoke or toxic fumes if involved in a fire. proof against shedding of fine particles into the air stream. tested at the Manufacturer's Works or an approved testing laboratory for performance efficiency to the appropriate British Standard and certificates provided guaranteeing general application filters based on type testing but with HEPA filters individually tested. supplied in duplicate initially to provide one spare set for each filter position, with the spares being carefully packed for storage. complete with inclined manometer and connecting PVC tubing to clearly indicate initial and final filter resistance in Pascals. with the plant running, carefully examined for ingress/egress of unwanted air around seals.

Installation of Filters

02

Shall be:in corrosion proof holding frames free of distortion, located against durable renewable seals to ensure a positive air tight seal and installed to Manufacturer's recommendations ensuring filter correct way round relative to air flow. Issue date: April 1993


C04

ELEMENT 07

PAGE 2

arranged to provide easy access to filter media for cleaning, removal or replacement with side or front withdrawal as required. if located in the main duct, provided with viewing ports and low voltage lighting switched from outside the duct and accessible for maintenance. Primary/Pre-Filters

03

Shall:have an ARRESTANCE of at least 80% to BS EN 779 - Eurovent Grade EU3. be suitable for a face velocity of up to 2.5m/s. Secondary/Main Filters

04

Shall:be of the multipocket bag type, if specified in Part D, which will also specify the number of pockets and bag length. or, be of the pleated paper type if specified in Part D. have an EFFICIENCY of at least 60% to BS EN 779 - Eurovent Grade EU6 if specified in Part D. alternatively, have EFFICIENCY to BS EN 779 and equivalent Eurovent Grade as required and as specified in Part D. be suitable for a face velocity of up to 2.5m/s. High Efficiency Particulate Air Filters (HEPA)

05

Shall:be of the replaceable panel type. have a penetration to BS 3928 and equivalent Eurovent Grade as specified in Part D. be extremely well fitted and absolutely air tight at the seals and pass a stringent in-situ test using DOP Dispersed Oil Particle and electronic measuring instrument. be provided with a housing such that the DIN 1946 leakage test can be performed if specified in Part D. suit a face velocity of up to 2.5m/s maximum.



C04

ELEMENT 07

PAGE 3

06

Extract Filters Shall:be of the types, grades and manufacture as specified in Part D. be contained within a "safe change" housing and provided with a plastic service bag and heat sealing if specified in Part D. be constructed with a particle board or other frame suitable for incineration if specified in Part D.

End of Element



C04

ELEMENT 08

PAGE 1 08

AIR HANDLING UNITS

01

General Requirements Units shall comprise:a rigid airtight assembly made from component parts equal in construction, accessibility and performance to parts individually described in previous clauses with component type selected to suit the working medium as specified in Part D. casing construction based on the double metal skin insulation panel method with acoustic and thermal insulation materials having fire resistance and other properties as previously described and not harbour dust etc. access doors/panels and viewing windows as stated in Element 02.07 but of basic construction as stated in this Element. inside surfaces to be free from structural projections and have smooth and easily cleaned finishes. internal sloping surfaces, for humidifier and cooling coil sections drainage to ensure moisture can easily discharge via the drain outlet. gradual change shapes between sections to minimise pressure drop, with not less than minimum spacing of components to Manufacturer's recommendations to ensure satisfactory operation at each stage and allow easy/reasonable access for inspection and cleaning. fan belts, fan motor and filter motors, generally located outside the air stream or as specified in Part D. component parts for an Operating Department should generally be supplied in the following order unless otherwise specified in Part D:Fresh air inlet Back-draught damper Frost coil Pre-filter Silencer Fan Cooler Coil Heater Coil Humidifier Alternative position of fan Silencer Control damper Final filter


) ) ) ) ) ) } ) ) ) ) ) )

Note: This alternative will not apply to a Twin Theatre Unit served by one fan


C04

ELEMENT 08

PAGE 2

Allowance in the installation height of air handling units for sufficient ground clearance (minimum 600mm) to enable the glass traps to be observed and dismantled and the drainage pipework to be installed as described in 08.02. All sections which may require removal for maintenance to be easily removed and all coils to have slide tracks for side withdrawal. NOTE: IF ALTERNATIVE FAN POSITIONS ARE CONSIDERED THE COOLING COIL DRAIN MUST ALWAYS BE LOCATED ON THE POSITIVE PRESSURE SIDE OF THE FAN. Drainage

02

Drainage shall:be applied to ALL cooling coils/steam humidifiers/heat recovery/eliminators as required. See Note below. be provided from each drip tray below cooling coils, humidifiers or other nominated positions. be fabricated using pipework installed with a gradient of at least 1 in 60 from the trap to discharge, with a class A air break above a floor gully, channel or open tundish provided by others to BS 6281. See also Specification C81 Above Ground Sanitation Systems. Individual drainage systems shall not be connected together until after discharge over a tundish ie each individual drain system shall have an air-break, type A to BS 6281 current edition. be complete with a trap which need not be directly under the drainage tray provided that the pipework connecting the two has a continuous fall. incorporate traps to BS 2598 of clear (borosilicate) glass to show (visibly) the integrity of the water seal, and provided with a means for filling. Permanent markers on each trap should be provided to indicate the water seal levels, when the system fan is running at its design duty. Incorporate quick release couplings to facilitate removal of the traps. The depth of any trap shall be at least twice the static pressure head generated by the fan irrespective of fan position. be supported such that no load can be transmitted through the drainage system to the borosilicate glass trap and under NO circumstances can the dimensions of the air break be reduced to less than that specified in BS 6281. have traps fitted to plant located outside or in unheated plant rooms trace heated as required in Part D. be connected to a foul drain only.



C04

ELEMENT 08

PAGE 3

03

Site Requirements Shall:include for each unit to have lifting lugs or marked lifting positions and be off-loaded and installed using correct tackle and spreader bars if necessary in accordance with the Manufacturer's recommendations, so that distortion and buckling does not occur. where specified in Part D provide for each unit delivered in sections and assembled on site. Note: Condensation can occur on the underside of drip trays and adjacent plant/duct areas. To overcome this potential the plant/ducting arrangement should be designed and installed such that any condensation cannot be entrained in the air flow and can be discharged from the base of the plant/ducting to a safe position.

End of Element



C04

ELEMENT 09

NOISE CONTROL Vibration Control

PAGE 1 09 01

Shall be:provided by means of carefully selected anti-vibration mountings, to suit the mass and speed, supported on adequate plant bases as required by Part B, capable of resisting torque reaction on start-up and damping out vibration to within the just perceptible band at maximum operating speeds or conditions. kept to minimum requirements by selecting plant with low vibration generation and with rotating or reciprocating parts suitably dynamically balanced. incorporated in ductwork runs by means of anti-vibration couplings, hangers and supports if specified in Part D. incorporated in service pipework runs to the vibrating plant by means of anti-vibration supports close to the plant and in three planes, or by flexible pipework connection, as specified in Part D. Plant Noise

02

Shall be:not greater than 85 dBA within the plant room from the fans, coolers, heaters, humidifiers, etc, when starting up or running. reduced to the noise levels specified in Part D where the plant is near to departments sensitive to noise. checked using method to BS 4196 during commissioning, with single speed plant running at full speed and variable speed plant running at the noisiest intermediate speed. Attenuation

03

Shall:be by the use of an acoustic infill that is inorganic, inert, vermin-proof, non-hygroscopic and non-flammable and complies with BS 476 Parts 4 and 24. be fitted in the airway surfaces with a covering/sheeting of a fire-proof inert material to prevent particles of acoustic infill becoming airborne. be incorporated into the ductwork system or plant arrangement as necessary to reduce noise from fans and plant items in order to achieve the acceptable limits within the rooms at the design air volume flows, as specified in Part D.



C04

ELEMENT 09

PAGE 2

include confirmation of the fan sound power levels and attenuator insertion losses for all systems requiring attenuators with the attenuation manufacturer. This information to be forwarded to the Design Engineer before the items are ordered. ensure each attenuator is mounted in accordance with the Manufacturer's instructions and installed prior to the final filter unless otherwise shown on the drawings or specified in Part D. 04

Grille, Register and Louvre Noise Shall be:kept to the minimum by selecting types having low noise producing characteristics without high tonal noise and with acoustically treated external inlet and outlet louvres. checked in-situ during commissioning when the system is fully working.

05

Overall Noise Level Shall be:specified in Part D based on levels set down in HTM 2025. checked and recorded during commissioning activities for both internal and external noise levels.

End of Element



C04

ELEMENT 10

PAGE 1 10

PROTECTIVE FINISHES

01

Ductwork and Supports Shall be:painted in accordance with DW/142 Part Seven Table 29 and 30, or as specified in Part D. galvanising or other metallic zinc finish damaged by welding shall be suitably cleaned and painted with one coat of zinc-rich or aluminium paint.

02

Plant Shall be:painted by the Manufacturer as necessary to protect all parts from corrosion or other reactions under working conditions and include the Manufacturer's standard final finish.

03

Final Paint Finish Shall be:applied by others as specified in Part D.

End of Element



C04

ELEMENT 11

DISINFECTION

PAGE 1

11 01

General Requirements Prior to Practical Completion all humidifiers and cooling coils/chiller batteries, eliminators etc shall be disinfected, by the Contractor, to the procedures listed below, who shall certify that the work has been carried out (to this requirement) and the date when it was undertaken. Disinfection Procedure (i)

All procedures shall comply with the Health and Safety at Work Act and COSHH Regulations.

(ii)

Notify all persons working in those areas served by the plant to be disinfected.

(iii)

Switch off all ventilation plants served by the devices to be disinfected.

(iv)

Close the plant isolation dampers or blades.

(v)

Open and remove the inspection covers on both sides of the devices.

(vi)

Spray all internal surfaces of the humidifier section or cooling coil/chiller battery with a 5 ppm chlorine solution until all surfaces are thoroughly wetted; also flood drip trays and drainage system with the same solution and allow to stand for a minimum of 2 hours.

(vii)

Spray all internal surfaces of the humidifier coil/battery with sufficient clean water to remove all traces of the chlorine solution from the battery and drip tray.

(viii)

Restore plant to normal operation.

(ix)

Immediately before practical completion the Mechanical Contractor shall arrange for swab tests from all drain trays and cooling coil/chiller battery tubes/fins. Satisfactory results (ie no presence of Legionellae) must be obtained prior to practical completion.

(x)

As an alternative to steps (vi) and (vii) above, the surfaces may be steam cleaned. If steam cleaning is to be carried out (using portable equipment) then the procedures and plant specification shall be included in Part D. Again, all procedures (which must be in writing) shall comply with The Health & Safety at Work Act.

IT IS ESSENTIAL THAT THESE PROCEDURES ARE DETAILED IN THE OPERATING AND MAINTENANCE MANUALS PRODUCED FOR THE SCHEME. ANY VARIATION WILL BE SPECIFIED IN PART D. End of Element



C04

ELEMENT 12

COMMISSIONING AND TESTING General Requirements

PAGE 1 12 01

The work in this Section is a minimum requirement and includes the testing, setting to work, commissioning and handover, all to the Engineer's satisfaction, the whole of the installed Ventilation Services and Associated Equipment. More detailed requirements for commissioning and testing will be given in Part D. The Mechanical Contractor should note the need for close co-operation between the Main Contractor and the Engineering Sub-Contractors in producing the Master Programme for the scheme. To assist the Contractors to appreciate the extent of the works and the necessary sequence of events, a drawing should be prepared, detailing the various stages of the testing and commissioning procedures. The Mechanical Contractor shall ensure that adequate time allowance is made for all the testing and commissioning, Witness Testing, production of commissioning data, instructions to Estates Staff and Handover of Operating and Maintenance Manuals. 02

Installations The requirements for the commissioning and testing of the ventilation installations shall be carried out in conjunction with Element 02, Clauses 20 and 21. The whole of the supply, extract and all other ventilation and air-conditioning installations shall be commissioned and tested by the Mechanical Contractor in conjunction with the Ductwork Contractor and in accordance with following:(i)

CIBSE

Commissioning Code, Series A - "Air Distribution Systems"

(ii)

CIBSE

Commissioning Code, R - "Refrigeration"

(iii)

CIBSE

Technical Memoranda TM8

(iv)

HVCA

DW/142 "Specification for Sheet Metal Ductwork" DW/143 "Ductwork Leakage Testing"

All checks etc shall be undertaken in the correct chronological order, as specified in the Codes and other related documents. The Mechanical/Ductwork Contractor shall, prior to testing the system(s):(a)

ensure that all specialist equipment, fans, filters, washers, heater, coolers etc are (or have been) tested in accordance with the relevant British Standard;

(b)

ensure that all dust etc is removed from inside the ductwork with all grilles and specialist equipment removed from the ducting;



C04

(c)

ELEMENT 12

PAGE 2

ensure that all equipment ie air heaters, coolers, grilles, humidifiers etc, be thoroughly cleaned/disinfected.

Where because of prevailing weather conditions the performance of the plant(s) cannot be fully tested prior to handover, the Mechanical Contractor shall carry out the required testing after handover, at the time agreed with the Contract Administrator or his representative. All air leakage tests shall be carried out before the application of thermal insulation. Sections of air ductwork in shafts etc or any other inaccessible position shall be individually tested before being concealed. Leakage testing of ductwork services shall be:applied to erected sections of the ductwork complete with access doors but no insulation, at the test pressure and flow rates, as specified. carried out generally in accordance with DW/142 and DW/143 using portable fan and test equipment. recorded on test sheets based on DW/142 and DW/143 examples and compared to acceptable leakage rates specified. interpreted as requiring that sections which need excessive remedial work on seams or joints are to be replaced by new sections, this requirement to be identified during the preliminary test to DW/143 paragraphs 4.9 and 4.10. The Mechanical Contractor shall test the operation to ensure tightness of all joints, correct rotation of motors, that oiling and greasing has been carried out, secureness of supports, eliminating of vibration and noise and their transfer to structure and room, correct damper operation, correct pulley alignment and belt tightness, operation of controls, operation of grille blades etc. The tests shall establish that every item is in working order ready to be started up and this shall be demonstrated to the Contract Administrator, or his representative, before start up. The testing and regulation shall ensure that the design air volumes are achieved in all ducts and at all grilles and diffusers with the whole plant in operation. Measurements and records shall be made indicating that specified temperatures are obtainable. Suitable instruments, test gauges etc, as agreed with the Contract Administrator, or his representative, shall be provided and used for this purpose by the Mechanical Contractor. The Mechanical/Ductwork Contractor shall record in triplicate the following tests on all plants as applicable. (i)


All fan and fan motor speeds and duties.


C04

ELEMENT 12

(ii)

All air volumes through grilles, registers etc and all air changes in air conditioned spaces.

(iii)

All dampers and valves shall be adjusted to obtain the design air flow rates.

(iv)

All water valves shall be adjusted to give proper water circulation.

(v)

All pump speeds and duties.

(vi)

Temperature and humidity readings shall be taken in individual rooms as specified.

(vii)

Temperature of air inlet and outlet of each air-heater or cooler battery.

(viii)

Water flow rate/pressure drop through each heater/cooler battery.

(ix)

Sound levels in selected areas.

PAGE 3

"Space Test Positions" shall be 1.0 to 1.65 metres above floor level at the centre of rooms, less than 40m² floor area. For rooms greater than 40m2, then at the centre of each 40 sq m of floor area. The Mechanical Contractor shall be responsible for ensuring the minimum possible amount of noise interference from other sources during the carrying out of noise tests. The Mechanical Contractor shall forward, in triplicate, a schedule of air quantity and air velocity readings taken for all ventilation plant ductwork and each grille and/or diffuser. This schedule shall also include all test data obtained during the period of this test. The Mechanical Contractor shall ensure that all plant/equipment comprising the Works (in particular fans, condensers and plant installed external of the main building structure) complies with the requirements of BS 4142: Method of Rating Industrial Noise Affecting Residential and Industrial Areas. Further requirements will, if necessary, be given in Part D.

End of Element End of C04



MECHANICAL VENTILATION AND AIR CONDITIONING SYSTEMS

Summary of Designer Requirements to Complete Part D - Detailed Description of the Works

GENERAL 1.

Initial page(s) of Part D shall give detailed description of input/extract ventilation systems and areas served. The designer shall also include simple mimic diagrams of air handling units (package or one-off) and mimic diagrams to located the areas they serve.

2.

The schedule below lists the requirements the designer must take into account in producing the specific scheme details needed in Part D for tendering purposes. The schedule is, by its very nature, flexible and thus accommodates small schemes and schemes up to a large Trust Hospital. Some of the tables may not apply to all schemes.

SCHEDULE OF REQUIREMENTS CLAUSE NO

DESIGNER NOTE

PART D EQUIPMENT SCHEME SPECIFIC REQUIREMENTS

01.01

Scope: Ducting to DW/142

Refer to other related Sections: B01, C01, C02, C10 etc. State any alternative/ additional standard.

01.01

Controls etc

Insert requirements or refer to other related sections. Manufacturers names may be included.

01.03

Standard References

Add in any additional references/updates as applicable.

02.01

Specialist Contractor

Include list of Specialist Ductwork Contractors (usually 6) who may tender for the works. Alternatively refer to this (and include) elsewhere in the specification.

02.02

General

Include/confirm ductwork leakage limitations.

02.02

General

Include which standard of cleanliness of ductwork as given in DW/TM2.

CLAUSE

DESIGNER

PART D EQUIPMENT

1

NO

NOTE

SCHEME SPECIFIC REQUIREMENTS

02.02

General

Include disinfection requirements as required.

02.02

General

State who will carry out fire stopping. This is usually the Main Contractor.

02.03

Ductwork Supports

Include any additional requirements above that in DW/142 and/or C01, C02. See also attached sketches.

02.04

Ductwork Materials

Materials and their grade should be stated.

02.05

Ductwork Construction

Air leakage requirements. See also 02.02.

02.06

Ductwork Fittings

Provide/arrange details of special shapes.

02.07

Access

Detail additional requirements etc.

02.10

Control Dampers

Schedule type/size etc; see proposed sheet. Include any special installation requirements.

02.11

Fire Dampers

Specify make(s). List power operated dampers. Include who will carry out fire stopping: see 02.02. Include other forms of testing.

02.12

Smoke Dampers

Confirm method of operation. Specify arrangement and make.

02.13

Sound Attenuation

Schedule type/size etc; see proposed sheet. Confirm location.

02.14

Flexible Joints

Specify alternative jointing.

02.15

Ductwork (flexible)

Specify standard/make of flexible ducting and limitations of use.

02.16

Grilles

Schedule input/extract grilles etc, together with type/size etc; see proposed sheet.

02.17

Air Control Units

Schedule of ACHs including volumes etc; see proposed sheet.

02.18

Extract Hoods

Specify requirements if different to C04 standards.

02.19

Identification

State who will include for colour coding and hazard symbols etc.

02.20

Leakage Testing

Refer to Element 12 - Commissioning/ Testing. Include requirements as applicable.

2

CLAUSE NO

DESIGNER NOTE

PART D EQUIPMENT SCHEME SPECIFIC REQUIREMENTS

03.01

Fans

Schedule types and duties etc; see proposed sheet. State if motors are out of air stream, ½ volume etc. Refer also to C51.

04.01

Heater Coils

Schedule duties/rating, steam or water etc; see proposed sheet.

05.01

Cooling Coils

Schedule duties/rating etc; see proposed sheet. The method of cleaning the coils must be determined ie "steam" from a portable generator or chlorous solution. Note: The use of chlorine may not be acceptable to maintenance staff due to potential skin disorders etc.

06.01

Humidifiers

Schedule performance requirements etc and refer also to Element 08.02. State the quality of steam required and pressure available if from existing service.

07.01

Filtration

Schedule performance requirements including type, location, housing, performance etc for both input and extract/recirculation air; see proposed sheet.

08.01

Noise

Schedule noise attenuation requirements; see proposed sheet. Plant noise levels to be included.

10.01

Finishes

Paint finishes other than in DW/142 to be stated including final finish.

11.01

Disinfection

The method to be adopted to disinfect coils etc (ie chlorine or "steam" cleaning) must be resolved and stated.

12.01

Commissioning and Testing

Additional criteria to be incorporated together with performance parameters.

3

AIR HANDLING PLANT SCHEDULE SCHEME TITLE Location/ Ref No

NOTES:

Fresh Air Vol m³/h

Sheet No .... Room Air Vol m³/h

Mixer/ Discharge Box

Filters Type

Fan Vol m³/h

Heating Coil Air on °C db

Cooling Coil Air on °C db

Resistance Pa

Air off °C Htg LPHW 87° - 70°C

Air off °C Chilled Water 12° - 6°C

Humidifier Air on °C db db wb

Air off °C

db wb Steam kg/h @ 1 bar

Remarks

VENTILATION FAN SCHEDULE SCHEME TITLE Fan Reference

NOTES:

Sheet No .... Location/ Room No

Volume m³/s High Speed Low Speed

Pressure Pa

Duct Resistance Fan Excluding Fan VP

Fan Model of Equal

Remarks

AIR HEATING COILS SCHEDULE Plant Rooms & Zones SCHEME TITLE Zone Heater Coil Ref

NOTES:

Sheet No .... Location/ Room

Air Vol m³/s

Air On Air Off °C

Water Flow l/s

Approx Size WxH

AIR FILTER SCHEDULE Plant Rooms & Zones SCHEME TITLE System Ref No

NOTES:

Sheet No ....

Type

EU Rating

Volume Vol m³/s

Approx Size WxH

Remarks

FROST COIL SCHEDULE

SCHEME TITLE Frost Coil Ref

NOTES:

Associated Plant or Air Handling Unit

Sheet No .... Air Vol m³/s

Air On Air Off °C

Water Flow l/s

Approx Size WxH

ATTENUATOR SCHEDULE

SCHEME TITLE

Ref No

NOTES:

Sheet No .... System Ref/ Location

Criteria NC

Nominal Size HxWxL

Volume Flow m³/s

AIR COOLING COILS SCHEDULE Plant Rooms & Zones SCHEME TITLE Zone Cooler Coil Ref

NOTES:

Sheet No .... Location/ Room

Air Vol m³/s

Air On Air Off °C

Water Flow l/s

Approx Size WxH

LOUVRE SCHEDULE

SCHEME TITLE Ref No

NOTES:

Fan

Sheet No ....

System

Nominal Size WxHxD

Type

Volume Flow m³/s

MOTORISED DAMPER SCHEDULE

SCHEME TITLE Damper Ref

NOTES:

Sheet No ....

System

Location

Mounting

Nominal Size WxH

DOOR TRANSFER GRILLE SCHEDULE

SCHEME TITLE Grille No

NOTES:

Sheet No .... Location

Volume m³/s

Size

Finish

SUPPLY/EXTRACT DIFFUSER SCHEDULE

SCHEME TITLE

Ref

NOTES:

Location

Sheet No .... Supply S Extract E

Volume m³/s

Face Pattern

Throw m

Neck Size mm

Spigot Dia mm

AIR PRESSURE CONTROL VALVE SCHEDULE

SCHEME TITLE Valve Ref

NOTES:

Sheet No ....

Location

Volume m³/s

Pressure Pa

No of Valves

Nominal Size WxH