The May 2009 issue of the NBS Journal included an article that reviewed the competing TRL pendulum, German ramp and BCRA Tortus test methods for determining the slip resistance of floor coverings. It reported on the SlipSTD European research project that potentially could provide a simple classification system to replace them. The SlipSTD Consortium has now published a publicly available specification (SlipSTD PAS) which includes details of the classification system.
There is also an update to the CIRIA publication C652 Safer surfaces to walk on – reducing the risk of slipping. Published in 2006, the original report quickly became the authoritative reference for everything dealing with the slip resistance of pedestrian surfaces.
NBS Building work section updates are responding to these important developments.
The SlipSTD project
This project was co-financed by the European Commission* and had a project objective: "To define common 'European' minimum slip resistance requirements for ceramic tiles based on defined and measurable surface properties in preference to traditional slip resistance testing." The project reached completion in August 2009 and has succeeded in proposing a simple three value classification system that takes into account the anticipated type of contaminant, the existence of any slip reducing control measures and the cleaning regime. The table below indicates the three classes and their defined use areas.
SlipSTD classes for hard floor coverings used in internal pedestrian areas
|Suitable use areas|
|Class 1||Areas that are foreseeably clean and dry and are routinely maintained as such.|
|Class 2A||Areas foreseeably contaminated with water and/ or dry contaminants.|
|Class 2B||Areas foreseeably contaminated with other liquid contaminants with a viscosity higher than water, such as oil or grease.|
The underlying research that supports the classification system was based on a different approach to assessing the slip potential of floor coverings. Surface properties were measured to establish those surface characteristics that best correlate with slip resistance as determined by the established test methods. Primary surface parameters Pk and Pp were measured using optical topography techniques and value ranges established for Class 2A and Class 2B performance requirements.
The outcome is a document titled SlipSTD Publicly Available Specification (SlipSTD PAS) – Classification of hard floor coverings according to their contribution to reduce the risk of pedestrian slipping. The SlipSTD PAS explains the scientific background to this new approach and includes a test method to determine the classification of products. The simple laboratory test is carried out on a floor covering sample or a moulded duplicate surface of an installed product. The SlipSTD Consortium believes the classification system can be extended to other than hard floor coverings.
The SlipSTD PAS also includes guidance on contaminants, floor maintenance programmes, cleaning agents and techniques for cleaning ceramic and natural stone floor coverings. Cleaning methods are defined and the efficacy of manual and machine methods discussed.
The document recognizes the responsibilities of the designer/ specifier, floor covering manufacturer and those responsible for the post installation care in achieving and maintaining the safety and appropriate slip resistance of the floor covering. It determines that the designer/ specifier should:
- Select a floor covering with properties that satisfy any national legislative requirements
- Refine the selection taking into account project specific conditions and the need to use a SlipSTD PAS assessed Class 1, Class 2A or Class 2B product
- For projects using large areas of Class 2 floor coverings, consider installation and approval of a control sample prior to commencing full installation.
The SlipSTD classification system is innovative and unlikely to quickly replace the pendulum and ramp classification methods. However, the representation of major European tile manufacturing countries on the SlipSTD Consortium may produce sufficient momentum to encourage manufacturers to declare SlipSTD classes for their products. The SlipSTD classification system has also been referred to the appropriate CEN committee for consideration as a new work item and inclusion as a European Standard.
The SlipSTD project was coordinated by CERAM Research Ltd, and included as UK members: The Tile Association, the HSE and the RIBA (represented by NBS). The SlipSTD PAS is available as a free download from the SlipSTD website (www.slipstd.com ).
CIRIA C652 Safer surfaces to walk on – reducing the risk of slipping
The update to this report is being authored by the same team from Arup that produced the original 2006 publication, guided by a steering group that includes additional representatives from the insurance industry and floor covering manufacturers. It provides an opportunity to include new research work, feedback based on the use of guidance contained in the original publication and topics not previously covered.
The new research covers investigatory work into the slip characteristics of some generic floor types including galvanized surfaces, terrazzo tiles, natural and artificial stone products, in situ cementitious surface toppings and resin floor coatings. The SlipSTD PAS document and classification systems are reported.
The update lists key issues including:
- The difficulty specifiers have in understanding the various standards and slip resistance data used by overseas manufacturers
- The use and accuracy of slip resistance data for flooring products and footwear, with a need for consistency to help the specifier understand the performance of products
- The lack of data on the performance of walking surfaces, including the change between factory and installed performance.
It notes the effectiveness of appropriate floor surface specification can be negated by incompetent installation, which would seem to support the SlipSTD recommendation for the use of pre installation control sample areas.
The update, which is planned as a web-based supplement to the original publication, will be available early in 2010.
NBS work section updates
NBS Building general guidance on slip resistance is principally focused on work section M40 - Stone/ concrete/ quarry/ ceramic tiling/ mosaic. To help identify the differences between the various slip resistance test methods, new guidance will be included on the German ramp and TRL pendulum methods. Guidance on the SlipSTD classification system and SlipSTD PAS document will be included which will support revised clause items for specification of slip potential to a SlipSTD class.
All of the 'M' floor covering/ surface work sections include a clause for control samples which generally requires the completion and approval of a designated area prior to proceeding with the full installation. An item allowing the slip resistance testing of control sample areas will be added in section M40. Similar updates to control sample clauses in other sections are likely to follow.
M10 – Cement based levelling/ wearing screeds and M41 – Terrazzo tiling/ in situ terrazzo already include a clause for post installation slip resistance testing. To complement and support the revised control sample clause in M40, new clauses for post installation slip resistance testing are to be added. The version of M50 (Rubber/plastics/cork/lino/carpet tiling) released in Update 2009-3 already includes a post installation slip resistance test clause.
The use of the revised control sample and the post installation testing clauses should help ensure the designed slip resistance of M40 floor coverings are realized. The SlipSTD PAS, the original and new CIRIA documents look beyond handover at the continuing need to retain slip performance. So when you next specify a slip resistant floor covering, remember to consider the cleaning and maintenance regimes required to ensure the continued safety of those walking on the surface.