Design recommendations for multi storey and underground car parks Despite their seeming simplicity, the design of a car park on multiple levels – whether above ground or below – involves the consideration of a number of significant requirements. These range from efficient circulation to structural matters, crime prevention and health & safety aspects. The various subject areas are discussed in more detail below.
Planning and layout The first consideration for the layout of a car park is the number of vehicles to be accommodated, compared with the space available. Cost constraints for excavation in the case of underground car parks, for example, need to be factored in. Vehicle flow rates will need to be factored in to calculations for the number of spaces to be provided to meet demand at peak times in, for example, a shopping Centre or hospital. Multi storey car parks generally fall in to one of a number of basic layout types: •
lat deck
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!plit level
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!loping deck "or #ramped floor
%$Vehicle Vehic le access to parking areas can be via: •
&xternal ramps
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'nternal ramps
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&nd or centre ramps, or a combination
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vehicle lifts
!imilarly,, vehicle circulation can be organi(ed by: !imilarly •
Combined or separate entry)exit
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*ne+way or two+way traffic
aving established these basic parameters, the primary generator of the layout of a car park is the si(e and constraints of the vehicles that will use it. - hilst in the main this will typically be cars "and to some extent motor cycles%, larger vehicles such as fire appliances or ambulances will also need to be considered. eometrical re/uirements include turning circles, swept paths and ramp gradients. 0otable re/uirements under the 1uilding 2egulations include fire resistance and means of escape "3art 1%, accessibility "3art 4 and 3art M% and guardings "3art 4%. Common vehicle space standards and dimensions can be found in the 0e w Metric andbook, in addition to 5ocal 6uthority highway design guides and the 'nstitution of !tructural &ngineers publication, Design recommendations for multistorey and underground car parks. parks . 7sage matters that affect the design include payment methods "pay machines on parking decks or in stair lobbies, or pay+by+phone% and grace periods allowed after payment, prior to vehicle exit "if pay+on+exit is selected%.
Safety and security Crime+related issues are well covered by the !afer 3arking !cheme publication, !ark "ark #afer !arking #cheme – $ew %uild ar !ark 'uidelines for car park designers, operators and owners: owners: Design principles
*wners and operators obligations under the ealth 8 !afety at -ork 6ct, as amended by ! ' 0 o.
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9;<)9==9 concerning the #stability and solidity$ of employment premises. *ccupiers 5iability 6ct >?; covers the safety of persons entering the premises @ lawfully of otherwise.
Boundaries and Perimeters Aefensible boundaries @ multi storey car parks can use perimeter walls and structure. 1ut barriers need
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consideration. •
6nti+climb measures may also be needed for high suicide risk locations such as hospitals.
Lighting •
5ighting should be even, to eliminate shadows.
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-hite "or light+coloured% walls, floors and ceilings can reduce the /uantity of luminaires needed.
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5ighting to 1! ?+:9= and 1! &0 9
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6nti+vandal cabling. !iting of lighting columns to avoid being used as climbing aids.
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Management Practice •
6ccessibility of attendants via phones, kiosks, 6V links, panic alarms.
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6nti+vandalism measures including anti+graffiti coatings, easy clean surfaces.
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Climbing plants can reduce vandalism.
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!ubscribe to the !afer 3arking !cheme.
Parking Areas or Decks •
6n access control system is. 'mportant, especially for underground "e.g. private residential% car parks. !pecify inward+opening automatic gates or roller grilles)shutters "certified to 53! ;? !29 or -C5 9 129%,
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to avoid creating a recess%, but check against means of escape re/uirements. 2ough surfaces to ramps can deter skateboarding.
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*ne+way circulatory traffic, clear direction arrows, speed restrictors.
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Clearly define pedestrian routes.
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6nchor points for motorcycles and bicycles. !ite any payment machines in the busiest areas.
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Vehicular Access •
'deally the entry and exit should be close together, but separate to one another.
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Consider height restrictors "but capable of over+ride for emergency or maintenance vehicles%.
Pedestrian Access !pecify vandal+resistant lifts, and gla(ed lobby doors.
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6void long passageways.
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3erforated or transparent balustrades aid visibility.
Signage •
Clear, visible, pictorial, colour coded, logical and informative.
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7se internationally+recognised pictograms.
Surveillance and CCTV
Aesign+in passive surveillance features "refer to !ecured by Aesign for principles and ideas%. Minimise
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obstructions e.g. columns, for natural surveillance Comply with the CCTV Code of 3ractice, and register with the 'nformation Commissioner, if filming)recording
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public areas. Comply with the Aata 3rotection 6ct >>B.
Landscaping •
!pecify plants with low natural growth rates "m maximum pruned si(e%.
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3lan a maintenance regime
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!piky bushes are useful deterrents on boundaries.
perator !e"uirements •
!afety for operators if on site, for example in public+facing kiosks.
#ngineering $ Structure Multi storey car parks are essentially elementary building structures, albeit with certain specific performance criteria that must be met. The overall structural form will be heavily influenced by the design geometry adopted. 7nderground car parks will, to a large extent, be determined by the structure above "for example a multi storey building or a public garden%. The structural frame can be either reinforced concrete "precast units or cast in+situ%, steel or a composite structure "steel beams and columns, supporting concrete floor slabs%. 2ibbed or coffered slabs are often used. 5ightweight+ aggregate concrete can reduce overall loadings significantly, and has better fire performance @ but smaller span:depth ratios and additional shear reinforcement are needed. Concrete must be designed to be durable against chemical corrosion attack. 0on+slip finishes in particular to ramps are also prudent, to prevent skidding. eated structures are also possible, although their effectiveness can be /uestionable. Vehicular loading of buildings is covered in !ection D of 1! &0 >>++. 3arapet loading "impact resistance% for car parks is covered in 6nnex 1 of the same &urocode. -ind loads and vibration also need to be taken into account. !tructural resistance to explosions "over and above fire resistance% should also be considered. 7nderground car parks will need extensive retaining wall design, incorporating tanking and land drainage.
#ngineering $ Mechanical and #lectrical Car parks utili(e impulse ventilation to expel carbon monoxide and other pollutants from deep+plan parking decks. This employs a number of small, high velocity fans in lieu of traditional ductwork, operating on the tunnel ventilation principle to direct airflow towards the main extract fan intake points. 0oise control needs to be considered for air handling plant in noise+sensitive areas, or to comply with 5ocal 6uthority bylaws or planning regulations. 6ll surface water in car parks has to be passed through a petrol interceptor before discharging to the main drainage system. 6 full emergency lighting system will be needed, with backup supplies. This is in addition to a fire detection and alarm system, possibly with sprinklers where a fire+engineered design is needed, although consideration should be given to the choice and location of flame suppressant used, where vehicle fuel or electrical fires are a high risk.
Consideration should be given to the provision of electrical charging points for h ybrid or electric cars. 7nderfloor heating is sometimes used, in particular on vehicle ramps to prevent skidding, although its effectiveness can be /uestionable.
Links%references •
Design recommendations for multistorey and underground car parks
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!ark "ark #afer !arking #cheme – $ew %uild ar !ark 'uidelines for car park designers, operators and owners
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*ccupiers 5iability 6ct >?;
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Aata 3rotection 6ct
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!old !ecure
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Thatcham
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Aeister
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1ritish 3arking 6ssociation
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!afer 3arking !cheme: 3ark Mark website
