What is the most cost-effective way to deal with disabled access for new or existing buildings? Peter Mayer of Building Performance Group considers the whole-life costs of implementing the proposed Part M
In 2002 the Office of the Deputy Prime Minister carried out a broad consultation to amend Part M of the Building Regulations, dealing with disabled access in buildings. Depending on the government's legislative timetable, the revised Part M should come into force in autumn 2003 for England and Wales. Alternative recommendations are proposed for Scotland and Northern Ireland to bring all regulations in line.
The proposed changes include:
- Updating of requirements to take account of the new British Standard on approaches to buildings for disabled people; BS 8300:2001
- Extending the scope of Part M so that the provisions in the document are applicable when existing buildings are altered and when there are material changes of use for existing non–domestic building
- The concept of access and use for all.
<B>Whole-life costs — the big picture</b>
The anticipated cost of implementing the proposed changes to Part M is about £200m per annum. However, in whole-life cost terms, these figures need to be balanced with future revenues or costs.
Statistics indicate that fewer than 12 million people are covered by the provisions of the Disability Discrimination Act. This does not include people aged 65 years or above, or families with children below the age of five – although both these groups are expected to benefit greatly from accessible, step-free buildings.
Studies following improvements in accessibility – as well as general improvements at places of entertainment, museums and galleries – show that visitor numbers and revenue streams have both increased, in one instance by as much as 15% and 40% respectively. So tying in accessibility improvements with general refurbishment can pay dividends.
Not carrying out the required work may result in lower rental income or profit when selling a property. Furthermore, as more premises become accessible, buildings with difficult access will eventually become less appealing, as people will simply not bother entering them.
All in all, it makes sense economically and legislatively to make the built environment as accessible as possible.
<B>Whole-life costs — component assessments</b>
When modelling component comparisons over their whole life, there are broadly speaking two types of cost results (see graphs left):
- 'Parallel' whole-life costs, whereby component A has a low capital cost and low whole-life cost, and component B has a higher capital cost and higher whole-life cost. A typical example would be a ramp constructed from in-situ concrete (A) compared with a ramp built from Yorkstone (B).
- 'Crossing' whole-life costs, whereby component C has a low capital cost but high whole-life cost and component D has a higher capital cost but a lower whole-life cost. Specifying external mild steel railings with an organic liquid coating as a finish would be a common example of a type C component. The three- or five-year repainting cycle to maintain the railings makes for the high whole-life cost. Alternatively, an austenitic stainless-steel railing specification would describe a type D component, which has a higher capital cost and no lifetime costs apart from periodic cleaning.
- A whole-life costing appraisal comes into its own when a decision has to be made between two or more components, which satisfy the design and functional requirements in all other respects.
- The model becomes even more interesting when costs of disruption and downtime to a business are considered in detail. Bringing these additional costs into the whole-life model, and the parallel whole-life cost picture often reverts to the crossing type.
- <B>Whole-life costs — component options</b>
- There is a wide range of choices in achieving an accessible building for people who may have visual, auditory, learning or physical disabilities. The options and the key whole-life cost considerations of a selection of components are evaluated on the following page:
- Ramps are designed for internal and external locations, permanent, semi–permanent or temporary use and can be constructed from in-situ solid materials, proprietary prefabricated or lightweight systems.
- External ramps can attract high whole-life costs where components are used, which require regular decoration.
- Adequate provision for drainage or shelter from the elements should be considered as part of any ramp solution. There is nothing worse than a puddle of water at the foot of a ramp after rainfall or having to de-ice a slippery surface in cold weather.
- Where portable ramps are proposed, do not underestimate the cost of staff time in finding and setting up the ramps.
- Consider using slip-resistant coatings to the sloping parts of the ramp, where external ramps are not protected from the weather or slip-resistant surfaces.
- Rails may come in the form of handrails, guardrails or balustrading. Handrails may be wall mounted. All types may be freestanding, anchored within the structure or surface mounted.
- Handrails provide support and guidance at hand level. Oval-shaped handrails with a broad horizontal face provide better hand and forearm support. Where young children are concerned, installation of a second handrail at a lower level would be good practice.
- Guardrails provide protection and stop lateral movement. Guardrails should be more substantial with appropriate mechanical fixings.
- Balustrading combines the functions of handrails and guardrails.
- Timbers and metals are the basic material choices with a variety of finishes.
- Intricacy of design aside, capital costs have an inverse relationship to whole-life costs, meaning that the whole-life cost models are of the 'crossing' pattern.
- Examples of whole-life cost comparison for external handrailings would be:
- Softwood handrails with a low capital cost but high whole-life cost due to short component replacement interval and regular repainting cycle, compared with:
- Western Red Cedar timber handrails, which have a higher capital cost and lower whole-life costs due to its durability and no need for decoration.
- The main whole-life performance issues for external rails are the intrinsic resistance of the base material to the elements and the durability of any finish. Austenitic stainless steel offers a low-maintenance option in metal.
- There is a huge range of options. Signs may be wall, door, column, ceiling or floor mounted; flush or projecting; fixed with screws or adhesive, unfixed; permanent or temporary. Surfaces of signs may be illuminated, reflective, double-sided, tactile, coloured, incorporate audible cues or connected with other communication equipment.
- From the whole-life cost point of view, external signage may need to:Be vandal-proof
- Include properties that limit colour-fading under ultraviolet radiation
- Have a water-shedding cover.
The whole-life cost of illuminated signs would benefit from use of low-energy, long-life lamps.
<B>Special floor coverings</b>
The requirement for bathroom floors is that they should be "slip-resistant when dry or wet". Further guidance is given in the British Standard for design, construction and maintenance of stairs; BS 5395–1. The assessment of slip resistance is complex. Table 4 of BS 5395 lists the slip potential of various floor finishes in qualitative terms; low, moderate and high.
In practice, flooring materials are manufactured with enhanced slip-resistant properties. For example, linoleum or polyvinyl chloride floor coverings can have abrasive particles, such as carborundum or aluminium oxide, incorporated in the matrix of the wearing layer to provide slip resistance.
- Ceramic tiles are also an option. Typically tiles offer enhanced slip resistance where they are profiled and have a matt or rough surface.
- Manufacturers often use the German Standards to provide a quantitative assessment of slip resistance.
- DIN 51097 for barefoot areas, defines three classes in order of increasing slip resistance: A, B and C.
- For showers, class B is recommended.
- For public and commercial areas, DIN 51130 defines five slip-resistant classes – from R9, the lowest, to R13, the highest slip resistance. For instance, for entrance areas, R11 is recommended. For sloping ramps which are used for wheelchair access, R12 is recommended.
- The whole-life cost issues associated with linoleum and polyvinyl chloride floor coverings were detailed in Specifier lifetime costs article November 2002.
- To minimise the cleaning costs and potentially reduce the costs of ceramic tiles, consider using tiles with a protective surface, which repels dirt and contaminates.
- Passenger lifts are the main means of assisted vertical movement in a building. Most commercial buildings will be built with a lift to BS EN 81, whether the lift is powered by hydraulic or traction, or a combination of both. Hydraulic lifts may offer lower capital costs but higher running costs. For medium or high-rise buildings hydraulic lifts are not an option. Hydraulic lifts in a building with intensive use are not recommended.
- From a whole-life cost perspective, lifts can attract a disproportionate maintenance and repair burden, as well as inconvenience while being out of use. BE EN 81 disguises a range of lift component specifications as it is largely concerned about safety; a lift can be safe but unreliable.
- To ensure effective lift reliability and minimise the whole-life costs of maintenance and repairs, specifiers should define the passenger and lift performance requirements for a building including:
- Anticipated loads, passenger calls per hour and passenger actions.
- Speed of operation, number of cars, door opening and closing requirements.
- This will enable the most economical arrangement of lift numbers, size of lifts and equipment to be determined to meet the reliability standards expected from the lift installation and make the whole-life cost a predictable quantity. And one of the most effective ways of reducing in-service costs of lifts, as well as lift downtime, is to ensure the operation of lifts or lift entrances are supervised.