MODEL ENGINEERING SPECIFICATION

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1 MODEL ENGINEERING SPECIFICATION C04 Mechanical ventilation and air conditioning systems 1997 STATUS IN WALES ARCHIVED For queries on the status of this document contact or telephone Status Note amended March 2013

2 National Health Service Model engineering specifications C04 Mechanical ventilation and air conditioning systems Issue date April 1993 Revision 1: March 1995 Crown copyright Revision 2: April 1996 Revision 3: November 1997 Latest amendments shown in bold

3 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.

4 DESIGN NOTES FOR C04 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 Unless the designer states otherwise the general layout of input air plants should be as indicated in HTM 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 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 Clause 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. 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.

5 DESIGN NOTES FOR C04 PAGE 3 Clause Clause 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. 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 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 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 Clause Clause 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. 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. 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.

6 DESIGN NOTES FOR C04 PAGE 4 Clause Clause Clause Clause Clause Clause Clause Show positions and sizes of instrument/control connections on the scheme drawings. The designer shall mark on the drawings the positions of all isolation, balancing and control dampers using a suitable code to differentiate each type. 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. 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. 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. 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. 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 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.

7 DESIGN NOTES FOR C04 PAGE 5 Clause Clause Clause 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. 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. 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 The drip trays shall be easily accessible and shall be connected to a water and 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 The designer shall ensure the drain or gulley provided leads into a foul drain system. Clause and 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 and Clauses and Clause 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. 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. Alternative forms of humidification shall be specified in Part D, however steam humidification is, at the moment, the preferred option.

8 DESIGN NOTES FOR C04 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 BUT EXCLUDING VOLATILES are considered suitable. Clause 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 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 Safety interlocks shall be provided by means of an air pressure switch located after the supply fan to achieve the following:- (i) (ii) stop the supply fan motor if still running following belt failure; shut down the humidifier. Clause 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

9 DESIGN NOTES FOR C04 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 Clause 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. 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 Dynamic balancing of fans is covered by clause 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

10 DESIGN NOTES FOR C04 PAGE 8 desirable however that the need for ear muffs is avoided and the noise level is kept below 85 dba. Clause Attenuator construction is referred to in clause 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 The designer shall ensure that the whole of the ventilation and air Disease conditioning system designs comply with HTM 2025; see also HTM See Page 1 of these notes. In particular:- 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 (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 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 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.

11 DESIGN NOTES FOR C04 PAGE 9 Electrical There is no provision in this Specification for equipotential bonding that Requirements may be required in accordance with the IEE Wiring Regulations - BS 7671: 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 Design and Build Contracts Controls Summary 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. 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. 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. A summary of Designer Requirements to produce Part D, scheme specific, is given at the end of the Design Standards.

12 DESIGN NOTES FOR C04 PAGE 10 DESIGN STANDARDS HEATING AND VENTILATING CONTRACTORS' ASSOCIATION DW/142 : 1982 DW/143 : 1983 DW/151 : DW/TM1 : 1987 DW/TM2 : 1991 Specification for sheet metal ductwork - Low, Medium and High pressure/velocity air systems and DW/142 Addendum A This standard is in the process of being revised. A practical guide to Ductwork Leakage Testing. Specification for Plastic Ductwork. Ductwork - Acceptance scheme for New Products Rectangular Cross Joint Classification. 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 - Design Notes for Ductwork Commissioning Codes A - Air Distribution C - Automatic Controls R - Refrigeration W - 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 The control of Legionellae in Healthcare premises - a code of practice. Health Technical Memorandum Ventilation in healthcare premises. Health Technical Memorandum Acoustics.

13 DESIGN NOTES FOR C04 PAGE 11 INSTITUTION OF ELECTRICAL ENGINEERS IEE Wiring Regulations - BS 7671: 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 WATER BYELAWS The Byelaws, current edition, of the local Water Undertaking.

14 DESIGN NOTES FOR C04 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

15 C04 INDEX PAGE 16 GENERAL 01 Scope 01 Installations Generally 02 Standard References 03 AIR DISTRIBUTION DUCTWORK 02 Requirements 01 Ductwork General 02 Ductwork Supports 03 Ductwork Dimensions and Materials 04 Ductwork Construction 05 Fittings 06 Access Openings, Panels and Covers 07 Test Holes 08 Instrument Connections 09 Control Dampers 10 Fire Dampers 11 Sound Attenuation 12 Flexible Joints 13 Flexible Ductwork 14 Grilles, Registers, Diffusers, Louvres, Relief Flaps 15 Single and Dual Duct Air Control Units 16 Extract Hoods 17 Service Identification 18 Leakage Testing of Ductwork Sections 19 Leakage Checks on Completed Systems 20 FANS 03 General Requirements 01 Bearings 02 Centrifugal Fans 03 Axial Flow, Mixed Flow and In-Line Centrifugal Fans 04 Roof Mounted Units 05 AIR HEATER COILS 04 General Requirements 01 Steam or Hot Water Coils 02 AIR COOLER COILS 05 General Requirements 01 AIR HUMIDIFIERS 06 General Requirements 01

16 C04 INDEX PAGE 17 AIR FILTERS 07 General Requirements 01 Installation of Filters 02 Primary/Pre-Filters 03 Secondary/Main Filters 04 High Efficiency Particulate Air (HEPA) Filters 05 Extract Filters 06 AIR HANDLING UNITS 08 General Requirements 01 Drainage 02 Site Requirements 03 NOISE CONTROL 09 Vibration Control 01 Plant Noise 02 Attenuation 03 Grille, Register and Louvre Noise 04 Overall Noise Level 05 PROTECTIVE FINISHES 10 Ductwork and Supports 01 Plant 02 Final Paint Finish 03 DISINFECTION 11 General Requirements 01 COMMISSIONING AND TESTING 12 General Requirements 01 Installation 02 End of Index

17 C04 ELEMENT 01 PAGE 1 GENERAL 01 Scope 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 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.

18 C04 ELEMENT 01 PAGE 2 BRITISH STANDARDS General BS 21: 1985 BS 4504: Part 3 Section 3.1: 1989 Section 3.3: 1989 BS 5720: 1979 BS 8313: 1997 Ductwork BS 1449 Part 2: 1983 BS EN 10051: 1992 BS EN 10131: 1991 Specification for pipe threads for tubes and fittings where pressure-tight joints are made on the threads (metric dimensions). Circular flanges for pipes, valves and fittings (PN designated). Steel, cast iron and copper alloy flanges. Specification for steel flanges. Specification for copper alloy and composite flanges. Code of Practice for mechanical ventilation and air conditioning in buildings. Code of Practice for Accommodation of Building Services in ducts. Steel plate, sheet and strip. Specification for stainless and heat resisting steel plate, sheet and strip. Specification for continuously hot-rolled uncoated plate, sheet and strip of non-alloy and alloy steels. Tolerances on dimensions and shape. Cold-rolled uncoated low carbon and high yield strength steel flat products for cold forming. Tolerances on dimensions and shape. BS EN 485 Aluminium and aluminium alloys - Sheet, strip and plate : 1994 Technical conditions for inspection and delivery 485-2: 1995 Mechanical properties 485-3: 1994 Tolerances on shape and dimensions for hot-rolled products 485-4: 1994 Tolerances on shape and dimensions for cold-rolled products. BS EN 515: 1993 Aluminium and aluminium alloys. Wrought products. Temper designations. BS EN 573 Aluminium and aluminium alloys. Chemical composition and form of wrought products : 1995 Numerical designation system 573-3: 1995 Chemical composition 573-4: 1995 Forms of products.

19 C04 ELEMENT 01 PAGE 3 BS 1470 : 1987 BS 1474: 1987 BS EN 10143: 1993 BS 4848 Part 4: 1972 (1986) Specification for wrought aluminium and aluminium alloys for general engineering purposes: plate, sheet and strip. Specification for wrought aluminium and aluminium alloys for general engineering purposes - bars, extruded round tubes and sections. Continuously hot-dip metal coated steel sheet and strip. Tolerances on dimension and shape. Hot-rolled structural steel sections. Equal and unequal angles. Fans BS 848 Part 1: 1997 Part 2: 1985 BS 4675 Part 1: 1976 (1986) BS 5060: 1987 (1993) BS 3456 Part 102 Section BS 5285: 1975 (1988) BS 6861 Part 1: 1987 Fans for general purposes. Performance testing using standardized airways. Methods of noise testing. Mechanical vibration in rotating machinery. 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 : Mechanical vibration - evaluation of machine vibration by measurements on non-rotating parts - general guidelines. Specification for performance and construction of electric circulating fans and their regulators. Specification for safety of household and similar electrical appliances. Particular requirements. Electric fans and regulators. Specification for performance of a.c. electric ventilating fans and regulators for non- industrial use. Balance quality requirements of rigid rotors. Method for determination of permissable residual unbalance.

20 C04 ELEMENT 01 PAGE 4 Air Heating BS 4857 Part 1: 1972 (1983) Part 2: 1978 (1983) BS 4954 Part 1: 1973 (1987) Part 2: 1978 (1987) BS 5141 Part 2: 1977 (1983) Methods for testing and rating terminal reheat units for air distribution systems. Thermal and aerodynamic performance. Acoustic testing and rating. Methods for testing and rating induction units for air distribution systems. Thermal and aerodynamic performance. Acoustic testing and rating. Specification for air heating and cooling coils. Method of testing for rating of heating coils. Air Cooling BS 4434: 1995 BS 5141 Part 1: 1975 (1983) Specification for safety and environmental aspects in the design construction and installation of refrigerating appliances and systems. 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 BS 4718: 1971 BS 3958 Sound power levels of noise sources (Parts 0 to 7 as appropriate). Methods of test for silencers for air distribution systems. Thermal insulating materials.

21 C04 ELEMENT 01 PAGE 5 Part 5: 1986 Specification for bonded man-made mineral fibre slabs Filters BS 3928: 1969 BS EN 779: 1993 Method for sodium flame test for air filters. (Other than for air supply to I C combustion engines and compressors.) 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 BS 6496: 1984 (1991) 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. 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.

22 C04 ELEMENT 01 PAGE 6 BS EN 1057 Replaces Part 1 of BS BS 3510: 1968 Specification for a basic symbol to denote the actual or potential presence of ionising radiation. BS 2598 Glass plant, pipeline and fittings. Part 1: 1991 Specification for properties of borosilicate glass 3.3. Part 3: 1980 (1989) Specification for pipeline and fittings of nominal bore 15 to 150mm: compatibility and interchangeability. Part 4: 1980 (1989) Specification for glass plant components. BS 3790: 1995 BS 5304: 1988 Specification for endless wedge belt drives and endless V-belt drives. Code of practice for safety of machinery. BS 5378 Safety signs and colours. Part 1: 1980 (1995) Specification for colour and design. Part 3: 1982 (1995) Specification for additional signs to those given in BS 5378 Part 1. BS 6281 Part 1: 1992 BS 8233: 1987 Devices without moving parts for the prevention of contamination of water by backflow. Specification for type A air gaps. Code of practice for sound insulation and noise reduction for buildings. INSTITUTION OF ELECTRICAL ENGINEERS IEE Wiring Regulations - BS 7671 : 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

23 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 HTM HTM HTM Ventilation in Healthcare Premises Hot and Cold Water Supply, Storage and Mains Services The Control of Legionellae in Healthcare Premises - a code of practice Acoustics HEATING AND VENTILATING CONTRACTORS ASSOCIATION: DW/142** DW/143 DW/151 DW/TM1 DW/TM2 Specification for Sheet Metal Ductwork and DW/142 Addendum A Ductwork Leakage Testing Specification for Plastic Ductwork Ductwork - Acceptance Scheme for New Products Rectangular Cross Joint Classification 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: A - Air Distribution C - Automatic Controls R - Refrigeration W - Water Distribution BUILDING SERVICES RESEARCH AND INFORMATION ASSOCIATION BSRIA Application Guide 1/75 Manual for Regulating Air Conditioning Installations

24 C04 ELEMENT 01 PAGE 8 BSRIA BSRIA Application Guide 1/77 Document for Air System Regulation Application Guide 3/89 Commissioning of Air Systems in Buildings HEVAC ASSOCIATION Fan Application Guide. Second Edition 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

25 C04 ELEMENT 02 PAGE 1 AIR DISTRIBUTION DUCTWORK 02 Requirements 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.

26 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 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.

27 C04 ELEMENT 02 PAGE 3 Ductwork Dimensions and Materials 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 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.

28 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.

29 C04 ELEMENT 02 PAGE 5 Instrument Connections 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.

30 C04 ELEMENT 02 PAGE 6 Fire Dampers 11 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:- 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.

31 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.

32 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.