A discrepancy in the stated dimensions for clear opening widths (COWs) in current regulatory guidance and standards for residential developments could be resolved by the draft Approved Document M. Responses to the consultation draft to be made by November 7th, 2014 and all the information is available on the Department for Communities and Local Government site here.
The images below are extracted from my recent talk at the National Register of Access Consultants Autumn Conference and explain my delight at reading part of the draft: at last the oddity about clear opening widths is resolved!
The first slide shows the required minimum clear opening widths for doors plotted against the width of an indirect approach in Table 4 of the current Approved Document, . At the top of the slide is a blue cow.
Slide 2: The Wheelchair Housing Design Guide states a minimum clear opening width of 775mm for an internal door, and a minimum approach width of 1200mm when any door approached from it is not entered head-on. (The text and diagram for this requirement contradict each other in the document). The graph shows the Part M, table 4 line and a single cross for the Wheelchair Housing Design Guide requirement. A blue and pink cow are at the top of the page.
This graph shows why I've always suspected that the dimensions stated in the Lifetime Homes standards are an error. The blue and pink cows at the top of the page are present again, joined by an orange cow, which is upside-down. The orange line added to the graph shows that the relationship between clear opening width and approach is consistent with Approved Document M for wider approaches, but when the approach is less than 1050mm wide the required clear opening width is 900mm, arguably showing that this width is excessive.
The blue cow now has a green friend representing the dimensions for clear opening widths in Category 2 of the draft Approved Document, which is largely based on the Lifetime Homes standards. The clause in the draft states two dimensions: a minimum clear opening width of 800mm for indirect approaches of between 800mm and 1050mm wide, and 775mm minimum for an approach wider than 1050mm.
The pink cow returns with a cross on the graph to represent the proposed clear opening width and approach specified in Category 3 of the Draft Approved Document, which is based on the requirements of the Wheelchair Housing Design Guide. A minimum clear opening width of 850mm with a minimum approach width of 1200mm, regardless of the direction of approach.
Unfortunately the method of measuring the clear opening widths for doors in the draft Approved Document is the same as it is in the current document, and therefore different to the method stated in The Approved Document for buildings other than dwellings, Lifetime Homes standards and the Wheelchair Housing Design Guide. I'm hoping that this will be changed before publication.
This post is about just one aspect of the changes proposed to the regulations for dwellings. There is a lot of material to read through and comment on. Follow this link to see the documents and scroll down for a link to the consultation survey.