Staircase: Design, Safety and Guidelines

Staircase Guidelines, governed by Part M and Part K of the UK building standards, provide essential direction for safe and compliant staircase construction. Adhering to these standards is crucial for accessibility and safety, particularly in public and commercial spaces. CAT, a leading manufacturer of stair nosings, offers a diverse range of options in brass, aluminium, stainless steel, and PVC to meet these regulations. While not legally mandated, CAT emphasizes best practices as a vital measure to enhance safety on all steps and staircases, ensuring adherence to industry guidelines and reducing risks for users.

6 Steps to a Staircase Guidelines

Channel Material, Gauge & Shape

Choosing the Front Shape

There are three main step profile shapes. The names describe the shape of the front edge, which is matched to the profile of the steps:

Choosing the Back Edge (gauge)

Depending on the type of floor finish, the back edge of the stair nosing may be 5mm gauge for carpet or carpet tiles, 2.5mm gauge for LVT and vinyl or a ramped back for resilient flooring or where no floor covering exists.

Choosing the Material

*Please note that although matched to control samples, finishes will vary from batch to batch. Antique finishes are hand applied to special order.

Light Reflective Value (LRV’s)

CAT offer a range of stair nosings with a choice of aluminium, brass, coloured PVC or Olympic Grip and Carborundum inserts. Building regulations require that the stair nosing contrasts with the flooring material by a minimum of 30 points on the Light Reflectance Scale or LRV.

LRV is a measurement that expresses the percentage of light that is reflected from a surface with lighter finishes at the upper end of the scale and darker finishes at the lower. Architects need to comply with the building regulations applicable to the structure under consideration. Since 2004 guidance has existed on access to and use of buildings. The guidance is particularly concerned with provisions to assist the disabled, including those who are visually impaired.

The Light Reflectance Scale is calibrated from 0 to 100 and measures how much light is reflected from the colour and shade of material where Black = LRV 4.25 and White = LRV 84.22. The guidance highlights the need for certain surfaces and features to “contrast visually” with their surroundings. This is relevant to a wide range of non-residential buildings including,hospitals, schools, hotels, theatres, etc.

Current Guidance

The current guidance in the regulations BS8300:2009 is that adequate visual contrast is provided if the Light Reflectance Value (LRV) of the contrasting areas exceeds 30 points, “i.e., the contrast between the stair edging and the floor covering”. The testing equipment used to assess the LRV of CAT product finishes is an integrated sphere spectrophotometer.

Click here to find out more about our LRV’s.

Slip Resistance Values (SRV’s)

Research by BRE, referenced in BS 8300-2:201,8 demonstrates that when a stair tread depth is below 300mm the risk of overstepping is increased. Installing a suitable stair nosing will increase the slip resistance at the step edge.

CAT manufacture a unique castellated PVC infill that maximises the overall slip resistance and provides an excellent SRV and PTV.

CAT stair nosing infills and treads have been independently tested for slip resistance values (SRV). For use in dry conditions, all our stair nosings and infill test results show a low risk of slip, contributing to the overall safety aspect of interior staircase installations. We also manufacture a range of purpose-designed stair nosings for use in external or wet areas, which also provide a low risk of slip in wet conditions.

The values published are for the normal direction of travel when installed on stairs, i.e., ascending and descending. It must be noted that many factors will contribute to the safety of stairs, not solely the floor covering or the stair nosing fitted.

Click here to find out more about our stair nosing SRV’s.

Nosing Channel Infill Options

As standard, CAT provides a unique range of castellated aluminium, brass and PVC inserts which offer a higher slip resistant value (SRV) compared to smooth textured PVC inserts.

With a choice of 21 colours in PVC and a variety of finishes available on our aluminium or brass inserts – CAT have a wide choice of options to highlight a step edge, meet design intent and fulfil LRV regulations.

Additionally, CAT also manufacture high slip resistant stair nosing inserts, olympic grip and carborundum for wet/outdoor situations.

Legislation & Standards

The following legislation and standards relate to the specification and use of stair nosings:

• Building Regulations 2010 – Approved Documents K and M.
• BS 8300-2:2018 – Design of an accessible and inclusive built environment.
• BS 5395-1:2010 – Code of practice for the design of stairs with straight flights and winders.
• BS 9266:2013 – Design of accessible and adaptable general needs housing.
• BS 8493:2008+A1:2010 – Light reflectance value (LRV) of a surface.

Fixing & Technique

CAT recommends that all nosing profiles are fixed with screws and adhesive. We offer a choice of fixing methods.

Retrofit Option

When installing stair nosings with PVC, aluminium, or brass infills retrofit offers a neat concealed fixing. Retrofit nosings are supplied cut to size with a pre-drilled channel for countersunk screw fixings and a pre-taped infill.

Drilled Option

When choosing mechanical fixing option, CAT also recommend using adhesive to prevent ‘rattle’ and achieve the most secure installation. CAT recommend the use of Stycco Flex, a rapid curing flexible adhesive from F.Ball & Co. Please contact the sales office for details. When adhesive only is used, ensure adequate cure time is allowed before allowing pedestrian access to the step(s).

Full installation guides are available to assist customers with their stair nosing and infill installations, here.