If a peak space temperature to about 28ºC is acceptable to the occupants then a naturally ventilated solution is a viable option.

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1 Air handling units Aesthetic Not to add significantly to the existing ambient noise levels. Functional requirements If a peak space temperature to about 28ºC is acceptable to the occupants then a naturally ventilated solution is a viable option. Any AHU/FCU/VAV/VRV units must be controlled via the local TBC BeMS control system to FULLY control AND monitor the systems. All FCU s and AHUs shall be fully controlled and monitored by the University BeMS without the use of any communication protocol conversion adaptors (e.g. gateways, conversions, etc). Each unit (or pair of units) shall be fitted with a TBC series controller for control and monitoring functions. OEM fixed programme controllers will NOT be permitted. TBC compatible interfaces or TCP protocol controllers will NOT be permitted. AHU s will incorporate 2 No (run and stand-by) standard squirrel cage induction motors to BSEN IE3 ratings (with TBC Variable speed drives as standard) with double bearings to fans. Consideration of use of permanent magnet motors must be made if energy savings, reliability and readily available spares/replacements can be demonstrated. Direct drive fans will be preferred but if belt drives to be used, at least triple-set belts and pulleys will be used. All ductwork will be fully pressure tested in accordance with HVAC DW144 with the exception that the maximum permitted leakage rates will be half of those specified in DW144. Aluminium ducts are to be used and not fabric ducts ('socks'). Bends and changes in direction and sizes of ducts should be swept to reduce the fan power. All ductwork outlet and intake grilles must be supported independently from suspended ceiling(s) by means of 4 No (minimum) independent supports either drop-rod or wire type supports. All supports must be vertical or within +/- 5 0 from the vertical plane. Where congestion of services above fittings is experienced, due allowance for additional stud drop rod and channel support under the congestion must be allowed for.

2 To ensure that all supply and extraction systems are as efficient as possible, suspended, accessible or non-accessible ceiling voids will not be used as plenums. All supply and extract to be fully ducted to outlet/extract grilles. All AHU s, condenser units, compressors, motors, fans and any other items of mechanical plant must be fitted with anti-vibration acoustically isolating mountings. All AHU s will incorporate Low Pressure Hot water primary pre-heat and secondary main heat coils for heating medium. Direct gas fired units will not be used. All heating and cooling coils will be controlled by the use of three port mixing/diverting valves with the third port fully utilised and not blanked off. Two port valves will not be used. Occupancy / Demand control of ventilation systems such as PIR detection and CO2 levels shall be considered as an energy saving measure within offices, seminar room and lecture theatres for example, and shall operate in conjunction with CO2 control. Flow rates should be automatically matched to demand, and availability controlled to operating times. The system shall be designed to external temperature conditions of -5 o C to +35 o C for critical areas including ASUs, Critical Computer Suites and Server Rooms, or any critical laboratory area. Specific, critical AHU spaces at the TBC should be designed to external temperature conditions of -10 o C to +35 o C. Ensure air handling unit is sealed to prevent air leakage at design pressure. Air leakage testing shall be undertaken on site by the manufacturer, when an air handling unit is site assembled, otherwise all units shall be factory pressure tested. Air handling unit access Air handling units shall not be installed within sealed voids that provide awkward or no maintenance access. Provide access openings and covers complete with opening devices, and sealed to prevent air leakage. Ensure seals are designed for normal maintenance operations for a minimum of 10 years. Facility to be provided to allow full and easy access to each item of equipment. Provide a suitably IP rated bulkhead light (compact fluorescent type) in each of the access and fan sections. Lights to be switched by a switch mounted on the side of the unit. Walk-in air handling units Ensure floor is double skin with internal framework to support weight of two men, tools and equipment. Provide weatherproof bulkhead luminaries and switches. Provide non-slip floor surface

3 Ensure access doors can be operated from inside and outside. Provide walkways in units over 2m high. External air handling units Construct air handling units for external use. Ensure casing is sealed with a permanently elastic sealing compound. Provide weatherproof isolators. Provide connection for lightning protection. Provide sealed, pitched roof, extended beyond outer edges of unit case. Arrange unit to shed water from roof in a controlled manner. Fan section Provide frame for motor and fan and comply with fire regulations. Ensure frame is isolated from casing. Supply fan guards. Provide flexible connection between fan discharge and casing spigot. Ensure flexible connections comply with fire regulations. Provide manometer connections to measure static pressure at fan inlet eye. Provide manometer connections to measure static pressure at fan discharge, and additionally as agreed. Fans shall be specified as direct drive. Filter section All AHU s to be complete with class G3 pre-filters on intake air to protect source coils. All bag filters to be G7 minimum and will be fitted with G4 panel pre-filters or roller pre-filters Provide frames to allow withdrawal of filters. Filters are all to be fully accessible for complete withdrawal. Filter panels shall be replaced with new after commissioning is complete and before handover. Differential pressure indication across each filter bank is required for larger systems. Filters shall be constructed such that no harmful fibres are carried out into the air stream.

4 Heater batteries Electric heater batteries shall not be specified as the coil heating method of air handling units, unless there is no other viable alternative. Unit heat recovery, other more efficient and carbon reductive methods shall be explored, e.g. VRV load expansion, LPHW coils etc. Provide slide rails to allow each coil section to be removed independently for access. Fit baffle plates to prevent air bypass of coil. The maximum air velocity through coils shall not exceed 4m/s. All fan coil unit heating valves to water batteries will be of the three port mixing/diverting types only with the third port fully used and not blanked off. Two port valves will not be permitted. Cooling coil sections Provide slide rails to allow each coil section to be removed independently for access. Water shall not be carried over from the cooler into the air stream. All fan coil unit cooling valves to water batteries will be of the three port mixing/diverting types only with the third port fully used and not blanked off. Two port valves will not be permitted. Incorporate drip trays with drains to both coil and headers in the bottom of the tray with sufficient unrestricted fall to a drain outlet. Side outlet connections will not be permitted. The maximum air velocity through coils shall not exceed 2.0m/s, if eliminator not provided. The velocity shall not exceed 2.5m/s with an eliminator fitted. Drainage from air handling unit components Provide drainage pipework from cooling coils, humidifiers and components where water may collect. Comply with recommendations in CIBSE Technical Memorandum TM13 in connection with Legionnaires' disease. As a minimum provide the following; Drain pans shall be fitted under cooling coils and humidifier, laid with a minimum fall of 1 in 20 in all directions towards a bottom drain connection. Traps shall be clear. A space of not less than 600mm shall be provided on either side of cooling coils and humidifiers to facilitate inspection, cleaning and maintenance.

5 No materials, which support bacterial growth, shall be used in any of these assemblies. Provide an air break between trap outlet and drainage system. Pipe to drain. Arrangement: Ensure traps under suction have outlet lower than inlet by depth equivalent to at least one and a half times working pressure. Ensure traps under positive pressure have inlet and outlet at same level. Humidifier section Ensure casing is specially treated for moisture. Humidifiers are only to be of the electrode boiler type. Control dampers All dampers are to be provided with position indicator and locking device. Ensure damper motors are selected to match torque rating of dampers. Access Provide access sections, not less than 600mm wide, upstream and downstream of each component for inspection, cleaning and maintenance. Lifecycle To be designed to a minimum of 30-years. Product selection should be made taking into account the full lifecycle costs. All factors that influence total system cost should be identified and quantified. Subjective factors such as fuel cost, component reliability, and maintenance costs are included. Approved manufacturers Air handling unit TBC Spares Three belts for belt driven fans. One complete set for each bank of filters.