TECHNICAL TOPICS - STAIRCASES

Welcome to Technical Topics. The aim of this column is to explore some of the areas that influence the design and effectiveness of a storage system. Technical Topics is a regular feature of Rack It, so, if you have a subject you would like included, let us know.

Providing suitable access to elevated areas within a warehouse, such as a mezzanine floor, is integral to the service that our Redifloor department provides. There are a number of alternatives for you to consider including staircases, access ‘cat’ ladders and lifts. But by far the most common requirement is for staircases, and it is these that we will be considering in more detail in this Technical Topics.

Staircase design is covered by (amongst others) BS5395: Part 1, BS5395: Part 3 and BS5950: Part 5. General guidance on staircase design is also contained within Approved Document K of the Building Regulations. Additionally, all staircase designs are required to conform to Approved Document M (AD M) of the Building Regulations.

The Part M recommendations take precedence over those of Part K. For consideration of means of escape in the event of fire, reference should be made to Approved Document B, but we will not be exploring issues raised by Part B in this article.

A Part M ‘ambulant disabled staircase’ will have the following characteristics, unless an Access Statement is submitted by the end user (more about access statements later). Unfortunately, there is insufficient space here to list all the requirements of the regulation but here are a selection that you may or may not have come across before:

• The rise of each step is between 150mm and 170mm, and the going at least 250mm.
• Materials for treads should not present a slip hazard, particularly when wet.
• Tread nosings should be highlighted with a permanently contrasting material 55mm wide on both the tread and the riser.
• The stair should avoid open rises.
• No doors should swing across landings.
• Clear tread width should be not less than 1200mm and the landings at least 1200mm long.
• The overlap of treads should be no more than 25mm and avoided if possible.

Part M Handrail

• There is continuous handrail on each side of a flight and landings.
• Handrail should extend safely at least 300mm horizontally beyond the top and bottom of a flight of steps.
• The vertical height to the top of the upper handrail from the pitch line of the fl ight of stairs is between 900mm and 1000mm, and from the surface of a landing is between 900mm and 1100mm.
• Its surface is slip resistant and not cold to the touch.
• Its profile is either circular with a diameter of between 40mm and 45mm, or oval preferably with a width of 50mm.
• The clearance between the handrail and any adjacent wall surface is between 60 and 75mm.

Access Statements

Storage and office mezzanine floors will normally require at least 1 no. Part M ‘ambulant disabled’ staircase, fulfilling the requirements outlined above.

However, where an access statement is provided for building control purposes, then a lesser standard of access may be acceptable. This may involve the supply of a Part K staircase, or the implementation of only some of the recommendations of AD M.

It is extremely rare in the authors experience for a full Part M staircase to be required in a warehouse environment, particularly "in parts of buildings where it would be either reasonable for access to be restricted or unreasonable for certain groups of people to require access."

However, consultation with the approval body at an early stage is always recommended to avoid any costly surprises.

For more information about Redirack's handrails, visit our dedicated mezzanine floor website at www.redifloor.co.uk