What is the most cost-effective way of reducing criminal damage to property? We consider the whole-life costs of Secured by Design standards for housing refurbishment
A burglary will often result in physical damage to a property, which can be costly to repair. Secured by Design is a police initiative to help reduce crime during the design process, and housing developments win an award if the estate design and building components have met the strict standards.
Here we consider the whole-life cost issues associated with housing to meet the Secured by Design criteria – particularly the potential payback associated with reduced incidences of burglary. Then we look in detail at the enhanced component specifications, which influence durability, as well as improving security.
Crime statistics for estates that have undergone refurbishment to meet Secured by Design standards show a decrease in the total crime rate. A comparison between estates in West Yorkshire with Secured by Design status and without it, showed that the rate of burglary was twice as high in the non-Secured by Design estates.
<B><font size="+2">Performance variables</font></b>
A basic whole-life performance assessment can be considered taking a hypothetical estate of 100 dwellings based on the West Yorkshire data. The key whole-life performance variables are:
- Number of dwellings
- Cost of refurbishment to Secured by Design standard
- Burglary rates before and after refurbishment
- Cost of burglary.
The approximate cost to refurbish a dwelling to Secure by Design standards is £650. The total cost for our 100 dwelling estate is £65,000. Therefore the payback period, through reduced burglary costs, is less than two years.
This analysis does not consider the costs of other crimes, which also reduce following Secured by Design improvements. Nor are the 'soft' benefits of improved component durability performance incorporated. In reality, the payback period would be shorter.
<B><font size="+2">Secured by Design </font></b>
<B>Design and component issues</b>
The range of design and component issues covered by Secured by Design include:
- Natural surveillance (routes and public spaces are overlooked by property)
- Minimisation of access and through routes to reduce escape options
- Clearly defined private spaces as a buffer between public spaces and dwellings
- Management of maintenance to ensure cleanliness to convey the message that anti-social behaviour is not tolerated
- Physical security to make committing a crime more difficult.
There are further whole-life performance benefits in specifying components to meet the Secured by Design standard. Components are more robust, they can withstand greater use and misuse, and they are tested to higher performance standards than average components. The result is that components have longer service lives as well as reduced repair and replacement demands.
Secured by Design component standards are currently set at a minimum level. It may be necessary to introduce more stringent standards for particular locations. Manufacturers can submit components for performance and security testing at an accredited testing house. Successful components can be licensed as Secured by Design components. Only those components with exactly the same specification as the tested component should be used on schemes.
Doors and windows are key Secured by Design components, as typically, points of burglary entry are:
- Windows — 29% of cases by rear window
- Doors — 25% of cases by rear or front door.
<B><font size="+2">Door assemblies</font></b>
The minimum standard is that door assemblies meet: Product Assessment Specification PAS 23–1:1999 General Performance Requirements for Door Assemblies. Part 1, Single Leaf External Door Assemblies (excluding annexes). The durability aspects of the standard include:
- Tests for operating forces, which ensures that excessive force is not required to operate hardware (eg to open and shut a door)
- Tests for different weather exposure categories
- Tests to ensure the door can withstand loads in use, such as slamming resistance, abusive forces on handles and a cyclical test of 50,000 full locking, opening and closing operations.
- Door sets are tested manually, mechanically and by impact loads.
- The PAS 24 soft body impact test (part of PAS 24) is based on a 30kg bag hitting the door three times in three locations. In contrast the PAS 23 soft body impact test alone requires three strikes to the centre of the door in both the direction of opening and against the direction of opening.
- Although PAS 24 tests are aimed at providing enhanced security by simulating burglary attack, the standard can also be used to specify doors which improve resistance and tolerance of accidental misuse common in social housing. Secured by Design requires compliance with both PAS 23 and PAS 24.
- <B>External door lock standard</b>
- The minimum standard for locks on external doors under BS 3621:1998 Specification for Thief Resistant Locks, requires testing in the following areas: Operational - includes key insertion, key rotation, throw and withdrawal of the cylinder lock for 60,000 cycles in each case. This equates to about 30 years of simulated use assuming six opening and closing cycles a day.
- Corrosion resistance, defined with reference to BS EN 1670, whereby Class 3 environments are those which are often wet or subject to slight pollution — that is most external environments, particularly damp interiors — hardware should pass the 96-hour neutral salt spray test. Class 4 for polluted environments, such as combinations of industrial and coastal pollution — hardware should pass the 240-hour neutral salt spray test.
- Various strength tests mean that the lock case, bolt, fixings and striker plate are all better able to withstand occasional misuse as well as being thief resistant.
<B><font size="+2">Window assemblies</font></b>
Window standards for the differing framing materials are quoted to define fitness for purpose standards. Service lives of between 25 and 40 years should be attainable depending on the materials and details of the frame construction, as well as the environmental conditions. All window standards refer to:
- BS 6375–2, which defines operation and strength characteristics. Minimum standards of usage, such as resistance to excessive operating forces and release of jammed sashes are tested. Variable geometry hinges are classified by the "release of jammed hinge test" — Class A strength is suitable for all situations and Class B is only suitable for light duty domestic applications.
- Insulating glass units to BS 5173, which can give a service life of 20 years if correctly installed.
Aluminium windows to BS 4873:1986. Minimum durability standards relate to:
- Framing material thickness, alloy composition and jointing methods
- Coatings (anodised to BS 3987, liquid organic to BS 4842 and powdered coatings to BS 6496)
- Corrosion resistance standards for hardware.
PVCu windows to BS 7412:1991. Note this standard has been superseded by BS 7412:2002. Defines minimum durability standards for:
- PVCu material, weld, jointing and reinforcement requirements
- Glazing gaskets and weather stripping
- Window hardware, except window fastenings — corrosion resistance to Class 4 of BS EN 1670.
Timber windows to BS 646 or BWF Timber accreditation scheme. Defines minimum durability standards for:
- Timber species, timber quality, preservative treatments and adhesives
- Profiling of surfaces to encourage shedding of water and improved adhesion of protective paint or stain coatings
- End grain sealing to limit moisture penetration and prevent development of decay.
Steel windows to BS 6510:1984. Defines minimum durability standards for:
- Corrosion protection to the steel; galvanised to a minimum of 490g/m2 coating mass.
- BS 7950:1997 Specification for enhanced security performance of casement and tilt/turn windows for domestic applications:
- A series of manual and mechanical loads are applied to the window, which are indicative of improved performance in daily use from accidental loading or improper use.
Further informationFurther information about Secured by Design is available from the Association of Chief Police Officers at www.securedbydesign.com. Statistics relating to Secured by Design schemes and crime figures are sourced from a paper written by Rachel Armitage: An Evaluation of Secured by Design Housing within West Yorkshire, Home Office Briefing Note 7/00, September 2000. Building Performance Group has an established whole-life cost appraisal and assessment process with an expert software tool to enable analysis of component options and maintenance strategies. BPG has written three component life manuals, which define components in terms of durability: HAPM Component Life Manual covers over 500, largely domestic, building components; and BPG Building Fabric Component Life Manual, both published by E&FN Spon, contact 01264-332424; BLP Building Services Component Life Manual, published by Blackwell Science. A research paper on Window Ironmongery 2002, produced by insurance and risk management specialists Building LifePlans (a sister company of Building Performance Group) gives further information on durability aspects. Contact BLP for a free copy on 020-7204 2434. For more information email p.mayer@bpg–uk.com at Building Performance Group or telephone Peter Mayer on 020-7240 8070.
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By Peter Mayer of Building Performance Group