New design guidance for car parks

Institution of Structural Engineers revamps advice to designers as cars grown in size and electric powertrains become the future

New guidance on the design of multi-storey and underground car parks will address the impacts of growing care sizes, the rise of the electric vehicle and concerns over fire safety.

Design recommendations for multi-storey and underground car parks was first published by the Institute of Structural Engineers (IStructE). in 1976 and has since gone through four editions.

The institution says the new guidance is not a fifth edition, but instead represents a completely revised and updated set of information for anyone involved in car park design, construction, maintenance and reuse.

The new guidance has been edited by a structural and parking consultant Chris Whapples working with a team of contributors.

Whapples notes that when the first edition was published the average family saloon was almost 200mm narrower and 500kg lighter than today’s models.? Whapples said: “The updated publication reflects the significant changes to vehicular size, weight and manoeuvrability in recent years, to offer modern guidance on parking bay sizes and deck loadings. These trends are necessitating a new approach the internal layouts of car parks.

“Despite significant increases to vehicular size, weight and manoeuvrability, guidance on parking bay sizes and deck loadings has not, until now, truly reflected these evolutions.”

The guidance recommends the new length of a parking bay to increase from 4.8 metres (16 feet) to 5.0 metres (16.4 feet), and the width of a standard parking bay is likely to increase from 2.4m (8 feet) to 2.6 metres (8.5 feet).

The revised guide also takes account of the rise of hybrid and electric vehicle use.

Whapples said: “Even in the 11 years since the fourth edition was published, the huge rise in hybrid and electric vehicle (EV) use, together with the need for inclusive design and a far greater emphasis on sustainable solutions, have necessitated a substantial revision to internal layouts and requirements for structural design.”

The guide also looks at changing requirements for structural design, with particular attention the minimisation of fire spread. The fire at the Kings Dock car park on 31 December 2017, a blaze that destroyed 1,360 cars, raised questions about the whether or not current fire regulations are adequate and how best to configure structural materials to minimise fire spread.

The IStructE guidance has been produced in parallel to work being undertaken to update Approved Document B for fire safety and a British Parking Association (BPA) Fire and EV Charging Infrastructure Advisory Panel.

The guidance is based on UK design methodologies and practice, and where possible or appropriate, has considered any likely updates to the Eurocodes and Building Regulations. However, IStructE said the principles set out in the guide have global applicability.

The guide, which will be published on 23 December, can be pre-ordered now.

How the guide works

The new edition of Design recommendations for multi-storey and underground car parks has two parts. The first part looks at the conceptual design of car parks and is primarily intended for clients, architects and project managers. The second section looks at detailed design elements, and is aimed at structural engineers and those involved in construction and maintenance.
The guide features the latest thinking on:

• internal layouts
• requirements for the structural design
• the impact of significant changes to vehicular size, weight and manoeuvrability
• making the required major changes sustainable,
• minimising fire spread.

The guide features 3D models that illustrate the positives and negatives of different parking layouts. There are chapters on sustainability and achieving zero carbon design. It also looks at personal safety, including ways of preventing suicide.

The publication sets out technologies used in car parks, such as payment and access control systems, as well as electric vehicle chargepoints.

The future-proofing designs is discussed, such ensuring new car parks meet the needs of autonomous vehicles.

The modification and upgrading of existing structures is also covered, as is discussion of special structures such as mechanical car parks.

There is also a section on asset management that is consistent with the Institution of Civil Engineers’ Recommendations for inspection, maintenance and management of car parks.

Comments

• Russell Simmons, managing director of Ballast Nedam, said: “I am very pleased to have had the chance to be involved in this publication as a contributing author, and also to represent the BPA’s interests in terms of driving up standards. I certainly see this publication as the go-to set of recommendations to follow when designing a car park. It really has brought the recommendations up to date, and is a much needed, relevant, reference point.”
  
• Dave Smith, BPA head of marketing and communications, said: “Larger parking bays will make it easier for everyone to navigate into and out of spaces, and reduce the risk of damage to other vehicles when opening doors. It will also hopefully mean that drivers are not spending lots of time circling around looking for spaces that they can easily access. The irony is that the future may see a trend for self-parking cars, which will mean the width of a parking bay will be less of an issue.”
  
• Fiona Petch, director at Fatkin, said: “It was great to be invited to contribute to this! My first output as an author, other than some academic papers, and hopefully not my last.”