THE ARUP JOURNAL SEPTEMBER 1972 Vol.7 No. 3 September 1972 Contents Appendix 1 - Application checklist (ii) The location, i.e. whether at ground level, materials (study mixtures of metals due to Published by Ove Arup Partnership 1 Select as first choice the best possible on or within a building. other equipment). THEARUP 13 Fitzroy Street. London. W1 P 6BQ position, checking for: (iii) A guide to surrounding environment, When the tower is to be installed in the open, (a) Effect on tower e.g. built-up areas, woodland, harbour, etc., the enquiry should state whether ancillary items such as immersion heaters, ball valves, Editor: Peter Hoggett Free access for entering air, ample perforation which may affect performance or selection of Art Editor: Desmond Wyeth FSIA Recirculation danger (L< 10H), need fordecks materials. Adjacent railways, process effluxes, strainers, fan guards, cover, thermostats and JOURNAL Editorial Assistant: David Brown Prevailing wind, orientation of tower batteries and industrial chimneys should be mentioned. motor starters are to be- included in the quotation. The Berry Lane Viaduct, 2 Air contamination ; other plant items, effluxes, 3 Limitations by J. Nissen filters Are there any restrictions in height, plan area, 5 Services Uplift in air wet bulb or access for erection which may affect the The enquiry should state the volts, phase, The Evry 1 Competition, 6 Spoiling of fan performance due to position type of tower offered ? Is there a preference cycles of the electricity supply, and should, if possible, give the source of the make-up by M. Barclay of tower in its surroundings for a particular type, e.g. induced draught (low plan area), forced draught (limited air access), water if this is other than town mains supply, The need for fire precautions e.g. artesian well. lake, river. Mass housing - 8 cross draught (height limitation) should be flexibility with standardization, (b) Effect of tower stated. Bibliography by B. Seymour Condensation of moist air discharge; cones Specify also: and bonnets (1) GURNEY, J. D.andCOTTER, I.A. Cooling Limitations due to noise (adjacent residential towers. McLaren & Sons Ltd., 1966. Now A study of a large landslide 12 Downwind vapour nuisance areas at each side or below) available from Applied Science Publishers Ltd. at Heme Bay, Kent, Windage and carryover nuisance Limitations on carryover due. for instance, to by E. Bromhead Noise from fans and water; silencers, part- (2) INSTITUTION OF HEATING AND windows adjacent to discharge VENTILATING ENGINEERS. IHVE Guide speed motors, anti-splash decks, anti-vibration Tubular steel microwave 15 Limitations in working weight due to structural 1965. Section J 5c. IHVE Guide Book, insulation towers for Nigeria, considerations for a roof-mounted tower Volume B. 1970. by M. Shears Weight of tower and water Restricted access for air inlets, and dangers (3) GOLDBERG. N. Control of noise of Dangers from accidental leakage of recirculation. cooling towers. Air Conditioning, Heating and Planning to avoid cooling 19 Appearance and visual suitability. Ventilating. 60 (6), pp. 58-61. 1 963. tower misapplication problems 4 Construction (4) JONES. R. S. Misapplication and incor• by D. Gurney 2 Evaluate any problems and compare alter• The enquiry should state: native locations. rect location of cooling towers. A paper read Whether the casing is to be of before the Cooling Tower Institute. 16-18 3 Examine alternative types, arrangements (a) manufacturer's supply June. 1969. and finishes of tower. (b) builder's work supply Front cover: The Berry Lane Viaduct. (Photo: David Faggetter) (5) KUNESCH, A. M. Relative merits of 4 Provide maximum useful information to Whether the basin is to be of combining natural and mechanical draft Back Cover: Computer drawing of Nigerian radio tower potential suppliers - see checklist for (a) manufacturer's supply cooling towers. A paper read before the specification to suppliers. (b) builder's work supply Cooling Water Association in London on 25 February, 1972 tunnel would have had to be artificially lit attractive than others. Berry Lane passes Appendix 2 — Checklist for specification If (a) in either case, a statement of materials (6) EVALUATED weather data for cooling The Berry Lane 24 hours a day. through narrow tunnels on both sides of the to suppliers should be requested, or specified, in the equipment design. Head Wrightson Processes Our main task was easy to formulate: we site so that only light traffic could pass this 1 Performance - specify: enquiry, as should a description of ancillary fittings such as drains, purge connection, Ltd., London, 1963. Viaduct should design a structure which would not way. The main access should therefore be (i) The water flow rate from the north along the cutting for the future make-up valve, etc. act as a barrier and which would preserve the (ii) The inlet and outlet water temperatures Acknowledgements character of the woods as much as possible. road where it is wide to provide for sliproads. If (b), the enquiry should specify cover for Jorgen Nissen (iii) As a check, the heat to be removed The author is grateful for very real help and It was more difficult to see how this could be This cutting will, of course, not be available supply of all necessary drawings to enable the encouragement from friends and colleagues The Berry Lane Viaduct will carry the London done. A 35 m wide slab suspended some 1 8 m at the beginning of the contract and the (iv) The design ambient wet bulb temperature contractor to construct the casing and/or who have offered advice and guidance, North Orbital Trunk Road over a deep valley above ground is an imposing feature which foundations will, therefore, most likely have (v) Altitude of site basin, including the necessary baffles, filters quoted examples and made pictorial material to be constructed from Berry Lane. Fortunately, in Chorleywood. A small country road called cannot be hidden away, but in this case the 2 Location - give: and drains to trap and remove sludge. available: among these are A. M. Kunesch, they can be made as simple footings as we Berry Lane runs along the bottom of the valley woods seemed to help us. Inside the woods (i) The area or town in which the site is Preference for any material, e.g. type of E. LeMay, J. R. Neller, D. P. Rayfield, K. Rogers found firm chalk below a very thin layer of and the Metropolitan railway runs on the there are no long views along the valley; the located packing, should be stated. Restrictions in and G. Slaughter. south slope. The valley is full of trees and trees stand in the way, and the ground is alluvium over most of the area. very pleasant and much used by walkers. It is mostly in the shade of the trees. The trees are The structure should also be suited for a residential area and private houses lie in the same height as the viaduct and we felt construction over Berry Lane and. more the woods. that we might soften the impact of the important, the railway. This is very busy as it carries the Metropolitan underground trains The North Orbital Road is being designed by structure if we could design a light and as well as trains for British Rail. Work over the the Department of the Environment, but in unobtrusive support structure of the same April 1 971 we were asked to prepare a design scale as the tree trunks. We would, so to for the viaduct. It was only natural that our speak, try to keep the feel of the wood under clients should stress the importance of the the bridge. To succeed in this, it would be environmental aspects in their brief as these very important that the woods should be were the raison d'etre for the structure. An disturbed as little as possible during construc• Fig 1 below tion and that their natural character could embankment had earlier been considered ; it In designing this bridge, we were determined easily be restored in the areas that were would have been some 18m high and around to preserve the woods through which it disturbed, so that a scar would not be left for 100 m wide at the bottom and would com• passes, as much as possible. From this long. This limited the construction methods pletely have destroyed the woods. It would consideration followed ideas for a construc• that we could consider. also have severed the valley into two separate tion method and appearance and these Access to the site is restricted and some parts which would have been connected only principles resulted in the proposed tabletop construction methods are therefore more by a 100m long tunnel for Berry Lane. This structure. (Photo: McMasters-Christie). Printed in England by Thompson & Tompkins Ltd. Droplets of moisture can be tossed from the rails can only be carried out at night and then Huntonbr d g* tops of high discharge velocity towers even only for three hours at a time and there are Ml when eliminators are fitted. The combination restrictions on the methods of construction that the railway authorities will allow. of concentrated impurities in the water and Strati sunshine will mark the paint finishes on Having identified these main considerations Latimw motorcars and plant. Unless the air discharge we were soon able to establish some general velocity is low, and very effective eliminators principles. It seemed right that a simple are fitted, towers should not be located close repetitive structure should be used ; we could see no reason to single out either Berry Lane to car parks and roadways used by the LaTimar Sta WATFORD general public. or the railway and make larger spans over them and we found in our cost estimates that : (d) Fan and water noise the economic range of spans in any case is ClKr lay weed o0(S This subject and its problems and solutions, larger than both these spans.