Revised Approved Document M recommends all nosings made apparent by means of a permanently contrasting material 55mm wide on both tread and riser. Revised ADK recommends the same for buildings other than dwellings but then recommends different size nosings for common access areas in buildings that contain flats?
Can anybody explain why the difference?
ADM states: Contrast visually: "Where illuminance on surfaces is greater than 200 lux, a difference in light reflectance value should be a minimum of 20 points"
Is anybody aware of any research that backs this up?
Gradus as a leading manufacturer of stair nosings has always erred on the side of caution and insisted on a light reflectance value difference of 30 points for nosings on stairs.
I would welcome opinions please.
Thank you
Regards
Keith Oakes
Technical Director
Tel 01625 428922
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